This time for sure: 2012 Wrangler gets Pentastar V6, 5 speed auto

[haven]

A report in the Toledo Blade says the 2012 Wrangler will be powered by the 3.6L Pentastar V6. A 5 speed automatic transmission will be available. The six speed manual will continue to be the base transmission.
http://www.toledoblade.com/Automotive/2011/05/31/Upgrades-set-for-Wrangler-V6-engine-transmission-2.html

Why the excitement? The 3.8L V6 under the hood of the 2011 Wrangler produces 202 horsepower and 237 pound-feet of torque. The Pentastar V6 is rated to produce 290 horsepower and 260 pound feet.

According to Allpar.com, the Wrangler's EPA fuel economy ratings for 2012 are improved by the new V6 and 5 speed. The 2011 Wrangler with automatic was rated to deliver 15 mpg city, 19 highway. For 2012, the EPA says 16 mpg city, 23 highway.

Jeeps in Europe come with a new 2.8L diesel and 5 speed automatic transmission that produce 300 pound feet of torque and get 35 mpg. Just sayin'.

[tommudd]

Have several friends who work at the Jeep Plant and they have been telling me for a while now about the "upgrades" I get several "unofficial" reports from them on what the new things will be etc. They've been building them for a while now already or at least a few have passed through the line getting ready.
The upgrades will be great

[Warn Industries]

I can't wait to see and drive one of the Pentastar Jeeps. Should be a great upgrade.

- Andy

[JPK]

IMO the more important upgrade is to the five speed auto. The previous 42rfe four speed has just too big a leap between the 1:1 third and the .67:1 overdrive fourth, resulting in too much drama on any downshift at highway speeds.

JPK

[DrMoab]

Waiting for my favorite salesman to give me the word. Ordering one from the factory the day they are available.

[Jwood]

Yeah this should be pretty sweet. Looking forward to it!

[Black_ZJ]

Wow, I may actually look at a JK now! Their pathetic excuse of an engine was a major deciding factor for me a few years ago when I was thinking of buying one.

[Mr. D]

What other upgrades are being done?
It will be some time for me I just lifted my 2004 Rubicon and getting ready for new tires.
Also just have over 90K miles and prepared to make it another 90K :).

[outdoors]

Jeeps in Europe come with a new 2.8L diesel and 5 speed automatic transmission that produce 300 pound feet of torque and get 35 mpg. Just sayin'.

Am I wrong..?
I think some where you are being misled about the mpg of this combination, especially if it was offered in the states.
It gets into the upper twenties in a "much" lighter 2005 Liberty. So I can't see it getting 35 in a JK, just ain't gonna happen here stateside anyways.

[UK4X4]

Yes you are wrong !

read and weep- even with a funny sized gallon !

http://www.jeep.co.uk/wrangler/specs/performance

Wouldn't you like 38mpg on an open road ?

200bhp
and max torque of 460nm

But then you also have to pay almost 3 times as much for gas !

[Black_ZJ]

Am I wrong..?
I think some where you are being misled about the mpg of this combination, especially if it was offered in the states.
It gets into the upper twenties in a "much" lighter 2005 Liberty. So I can't see it getting 35 in a JK, just ain't gonna happen here stateside anyways.

In Europe.... And Mitsubishi has a turbo diesel pickup from the 80's or 90's that was sold here that averages in the 30's per gallon, a local guy has one on 35's that averages 32mpg.

[Black_ZJ]

VW has a tdi motor overseas that sees 60mpg AND would meet US emissions standards, but we will never get that one here either!!

[Haf-E]

38 MPG in UK gallons would be 31.7 in US gallons...

Its confusing though because the website actually says:

EC Combined - mph (L/100km) 34.0 (8.3)
EC Extra Urban - mph (L/100km) 38.7 (7.3)
EC Urban - mph (L/100km) 28.3 (10.0)

I suppose the mph is a typo and should be mpg?

Guess I should do the metric conversion of the L/100km and see...

[irishcoffee]

38 MPG in UK gallons would be 31.7 in US gallons...

Its confusing though because the website actually says:

EC Combined - mph (L/100km) 34.0 (8.3)
EC Extra Urban - mph (L/100km) 38.7 (7.3)
EC Urban - mph (L/100km) 28.3 (10.0)

I suppose the mph is a typo and should be mpg?

Guess I should do the metric conversion of the L/100km and see...

Gents

My manual 6 speed diesel crd 2009 jku wheeld 90k km (56k miles) in last 2 yeaes and I can tell you that after i put the arb front bumper + m8000 warn + alu asfir front skid + 32" bfg (3:73 gear ratio) the consumption is not the same any more as with stock configuration and i had to tune up the engine from 177 hp to 210 hp getting now 468 torque (from 410nm) to feel the same initial crd vm engine.
My jku real:
- mixt consumption is 12,5 l/100km (18,81mpg)
- urban consumption is 13,5 l/100km (17,4 mpg)
- highway consumption (80 mph drive not loaded just with above settings) is 11 l/11,5 l/100km (21,38mpg)
The above conversions were made usinghttp://calculator-converter.com/l_100km_mpg_convert_mpg_to_l_per_100_km.php
Diesel 2,8 crd 2009 Vm crd engines are kinda sensible with kit tunings if setting was not tested and proper setting is proper performed. I've experienced twice limp mode because of wrong tuning setting. Tuning helped me stabilizing diesel consumption about 0,2-0,5 l/100km.

Cheers
John

[grecy]

For 2012, the EPA says 16 mpg city, 23 highway.

Wow. Just wow.
If this is accurate, in the year 2012 Jeep are selling a vehicle that gets 16 MPG city. SIXTEEN!

Pick your adjective of chocie: (I pick all three)
Disgrace, Pathetic, Mistifying

-Dan

[DingusKahn]

I test drove one of these things. And you can too. The 2011 Grand Cherokee has that motor in there, and the vehicles weighs about the same. Lame. Why the hell don't thy put the 5.7 V8 in there???? I will never buy another Wrangler without a good sized diesel or v8.

[irishcoffee]

I test drove one of these things. And you can too. The 2011 Grand Cherokee has that motor in there, and the vehicles weighs about the same. Lame. Why the hell don't thy put the 5.7 V8 in there???? I will never buy another Wrangler without a good sized diesel or v8.

Totaly agree here with a v8 and an improved cooling system!

[jomobco]

and probably stick to 80km to get it. Not the 80mph I usually plow down the road :)

[JPK]

I test drove one of these things. And you can too. The 2011 Grand Cherokee has that motor in there, and the vehicles weighs about the same. Lame. Why the hell don't thy put the 5.7 V8 in there???? I will never buy another Wrangler without a good sized diesel or v8.

According to Jeep.com, Jeep's official website, the weight difference between the GC and the Wrangler Unlimited is 500lbs with the GC the heavier. 500lbs is pretty significant and about an 11-12% increase over the JKU weight. Hopefully that missing 500lbs will make the JKU a decnt performer. The five speed 545rfe will be a tremendous improvment over the four speed 42rfe.

I agree with the V8, but it will never happen. I have a 5.7VVT Hemi in my '10 JKU and it is just excellent and the way they ought to come from the factory, but the f'in Gov't won't let Jeep make them that way, eh. 1. Corporate Fleet Avg milage; 2. the Hemi in the current JK is too long and doesn't allow sufficient crumple zone to meet Gov't stds.

JPK

[vtjeepguy97]

well this is good news! I was in the market for a newer vehicle. My 97 wrangler is just not reliable anymore. So i went down too the local dealer and tried out a 2010 4 door wrangler with the old engine. Now let me say I am a jeep fanatic and have owned several. But I hated driving that jeep. Put my foot to the floor and nothing happened. And I am not the type of guy who needs hundreds of extra horse power under the hood. Well because of the crappy engine that is in the wrangler now I will be the proud owner of a 2006 toyota tacoma come next tuesday! (no worries I am keeping my 97 as an expedition/offroad toy) If jeep had put the penstar in a little sooner then I would have purchased one.

[Bigjerm]

I think Jeep is headed in the right direction... Finally there are moving to a new engine after years of complaints. I owned 2 JKs, an auto and a 6 speed and I now have an LJ and wouldn't drive a JK again without a new engine. If they went diesel we would trade the wife's Liberty in on 1 tomorrow!

[Ryanc]

I think Jeep is headed in the right direction... Finally there are moving to a new engine after years of complaints. I owned 2 JKs, an auto and a 6 speed and I now have an LJ and wouldn't drive a JK again without a new engine. If they went diesel we would trade the wife's Liberty in on 1 tomorrow!

I agree. My 3.8 is anemic, however I regeared to 513 and have a manual, so it is tolerable now. Ive driven the pentastar, its ok. Its a nice drive in the new Cherokee, however, we all know that Chrysler is going to tune it for the Wrangler. I honestly dont think that Jeep will ever bring a diesel here, at least not now with the new motor. Chrysler needs to take notes on what Ford is doing. Their new lineup is light years ahead of Chryslers now.

[JPK]

The latest and greatest news from Allpars is that the Wrangler 3.6 will have the same tune as the GC, which iirc is 290hp and 260lbs'.

For guys who hate the slow throttle response the result of the fly by wire system there are tuners and I think the ProCal that will help with the throttle rsponse time.

[bamabrock]

Wow. Just wow.
If this is accurate, in the year 2012 Jeep are selling a vehicle that gets 16 MPG city. SIXTEEN!

Pick your adjective of chocie: (I pick all three)
Disgrace, Pathetic, Mistifying

-Dan

It is quite pathetic considering GM has half ton 4x4 trucks with 400 hp that get better mileage.

[Frank]

I want a diesel Wrangler. Please jeep, please.

[Super mud]

Well my 87 xj is making about 260lb ft torque with the 4.0 tractor motor, .75:1 Od locking Aw4 and 22mpg stock so I still don't see an improvement over 25 years.
That reminds me how we have failed to produce a car after 30 years that is more efficient than the rigs developed in the 80s. Have you seen honda's new crz hybrid that gets 37mpg? They had a civic in the 80s supposobly getting 50mpg and I know at least 40. The s-10 they put the 4cyl diesel in when they started production got 40mpg and I know a cherokee with a 1.9 nissan diesel getting 35 and modified one getting 45.
I think Ford is the only ones who have made an improvement considering their 300hp 30mpg stang.

[flighht2k5]

Well my 87 xj is making about 260lb ft torque with the 4.0 tractor motor, .75:1 Od locking Aw4 and 22mpg stock so I still don't see an improvement over 25 years.
That reminds me how we have failed to produce a car after 30 years that is more efficient than the rigs developed in the 80s. Have you seen honda's new crz hybrid that gets 37mpg? They had a civic in the 80s supposobly getting 50mpg and I know at least 40. The s-10 they put the 4cyl diesel in when they started production got 40mpg and I know a cherokee with a 1.9 nissan diesel getting 35 and modified one getting 45.
I think Ford is the only ones who have made an improvement considering their 300hp 30mpg stang.

What mods have you done?


Sent from my iPhone using Tapatalk

[JIMBO]

:sombrero: Yea, I think the "Jesus" engine will be a "BOON" to the JK/JKU, but

The 5-spd auto will be a real welcome addition, but

They will still be under geared-

Since I've regeared my '08 JKUR, I've got great mileage and an abundance of "Applied Horsepower" with my 42RLE tranny !!I can't see buying a new one untill Chrysler starts offering some of AEVs options !!

:costumed-smiley-007:wings: JIMBO

[Super mud]

What mods have you done?


Sent from my iPhone using Tapatalk

Not much, Catless exaust, Cowl induction cold air intake, (52-60mm) Bored throttle body, Advanced timing Cps.
Jp dynoed a 4.0 to test certain power gains and just exaust and free flowing intake was like 10-15hp each which is alot for what real world conservative numbers are like.

I plan to do headers and injectors soon. Was planning to do a head swap and bump up the compression and found out my bottom end is pretty worn after doing a rear main seal. So eventually I'll completley rebuild and do everything up all around right to run the higher comp and maybe a taller cam. I would have to get my crank re ground anyway so a stroker wouldn't be to much more to ask for. So lookin at a 300lb ft 4.0 or a 350lb ft stroker respectivley lmao.

[Ford Prefect]

People always say that the USA just does not do Diesel. That is rubbish, IMHO. No one uses it because they really do not know about it. All they would have to do it toss that 35mpg engine in there, and do a comparison between it and the gas engine, tell the people how much they will spend per mile vs the gas and they will not be able to keep them in stock, everyone will want the Diesel...Sigh...

Everyone that does a good diesel engine has negligible, if at all, advertising on the fuel economy advantages of the diesel. Therefore they are relegated to the work trucks alone.

[DrMoab]

If that was the case the crd liberty and the diesel grand Cherokee would have sold a ton. Neither one did well at all.

[JDaPP]

Actually the CRD Liberty did sell a ton. Chrysler underestimated demand as both year models sold out

[4Rescue]

Question is... WHERE in the rev range are those power numbers made??? IMO making more power is useless in a truck if it's all top end. Going to a smaller displacement V6 is NOT going to help, you need a torquier motor, not more HP... Hell, the 4.0L onlt made 190hp, but it made LOTS of torque DOWN LOW where a heavy vehicle needs it. This is just further evidence that the Mopar engineers are just following like sheep instead of bucking badly advised trends in auto-making... Either that or they're TRYING to force people to swap the Hemi in to get an adaquately powered Wrangler. Cause this V6 ain't gonna be it. Oh and where's the Diesel??? All this wasted money swapping in another engine that won't fit the bill either when they could just swap in a KNOWN performer like the VM-Motori CRD... Oh wait, we N.Americans Don't WANT a diesel cause we never buy them... cause they don't offer them... Thumbs DOWN (way down) to Mopar on this one. You've failed intentionaly. Save the high win ding car motors for a sports car you don't build and give folks who want a TRUCK a real TRUCK motor cause the 3.6 isn't it...

Cheers

Dave

[pskhaat]

4Rescue, I actually agree with you here. You wanna know why they put a new auto in there, is to simply allow for a quicker shift on a smaller effective (%) power band and to play the torque rise (which is barely anything) to above 5000rpms. When was the last time you approached an obstacle in the road at 5krpms?

http://jeephowto.com/wk2/engine/3.6_liter_pentastar_graph_01.jpg

Compare to playing the rise below 3krpm in the 4.0:

http://home.pacbell.net/jay_w007/torque_chartsm.jpg

[JIMBO]

:sombrero: As (may be) an interesting side note-

I can cruise my '08 JKUR at 4000 rpm (4lo) at 5mph, works GREAT on steep hills--

:costumed-smiley-007:wings: JIMBO

[Hawkz]

I agree for the most part about the V6 issue. I think if Jeep/Fiat could design a V6 like Fords new Ecoboost, I would be ok with that. Until then we need a diesel or Hemi. (The new Ford ecoboost has more HP and torque than my Ram with the Hemi and a nice flat Torque curve, so it can be done...)

[JPK]

I have seen the 3.8l and the 4.0l torque and HP curves overlaid. The 3.8 actually provides as much or more torque as the 4.0 for any rpm. The 3.8 is a hell of a lot better on the highway and doesn't sound like its going to blow at 3,000rpm's like the 4.0.

I own an LJ with the 4.o and I have to tell you that it isn't as good of an engine all around as the 3.8 as far as drivability on or off road. I'd bet that if my LJ had the 3.8 instead of the 4.0 it's be a better driving Jeep on the highway, city streets, on trails and in the rocks too. The 4.0 has been romanticized since its passing as far as its performance.

The 3.6 won't improve off road performance much, imo. But it will significantly improve the highway performance when mated to the 545rfe. The biggest issue with the JKU and the auto isn't the weak engine, it the HUGE jump from the 1:1 3rd gear to the .67:1 O/D 4th. The 545rfe has the same 1:1 3rd gear, almost the same top O/D gear at an even steeper .67:1 for its 5th, but it has its 4th at .75:1 in between.

If you want to improve off road performanc and stick with the factory engine, regear to a lower gear, lower than factory even when taking larger tires into account. Added bonus is better on road performance too, manual or auto. 5.38's are available for the D44 and now also the D30.

I went Hemi and would do it again in a heartbeat, but my wife's Unlimited Rubicon just isn't that bad stock. Re-gearing to 4.88 would fix every complaint I have - but not as well as the Hemi!

As for that, with my JKU I run the VVT Hemi, 4.88's and 37's and guess what - 5.13's would be better...

As far as the lack of a diesel, I think you can blame the US Gov't on that. The ever tightening regulations make it expensive on the automakers and remove much of the attraction of diesels. Think urea injection now on larger diesels. What a f'in joke. If the JK's see a diesel in the US it will be when the EU and US emmissions regs match up, which I think is two years out. Also the US has got to stop penalizing diesel users with higher fuel taxes.

And truthfully, the market for a JK diesel might really be thin. With the oh so common soccer mom and comuter dad use that the JK's see, especially the JKU, how likely is high demand? Not very likely, imo.

Our company runs a fleet of diesel chassis cab trucks and gas vans. The sad truth is that the gas engines are much, much cheaper to run. Less maintenance - not like the days past when gas engines required frequent tuning, carb rebuilding, new points and plugs while diesels kept on going like the Energizer Bunny. Today its the opposite. More maintenance, more expensive repairs, much of any milage advantage lost to higher fuel taxes. Don't forget higher intitial purchase price either. A diesel light truck doesn't pay for itself anymore.

For a Jeep, the only advantages would be staying within CAFE standards and the torque some want at lower rpms. But again, how many really want it with the trade offs - noise, smell, maintenance, cost - and of those how many would actually pay for it.

What the JKU's really need, imo, is a smaller V8 putting out 300lbs' and 300hp as low on the tach as possible. The ~375hp and lbs' that the 5.7 VVT Hemi put out are substantially more than the JKU's need to be about perfectly powered.

JPK

[JIMBO]

:sombrero: I agree with you somewhat-but



I have seen the 3.8l and the 4.0l torque and HP curves overlaid. The 3.8 actually provides as much or more torque as the 4.0 for any rpm. The 3.8 is a hell of a lot better on the highway and doesn't sound like its going to blow at 3,000rpm's like the 4.0.

I own an LJ with the 4.o and I have to tell you that it isn't as good of an engine all around as the 3.8 as far as drivability on or off road. I'd bet that if my LJ had the 3.8 instead of the 4.0 it's be a better driving Jeep on the highway, city streets, on trails and in the rocks too. The 4.0 has been romanticized since its passing as far as its performance.

The 3.6 won't improve off road performance much, imo. But it will significantly improve the highway performance when mated to the 545rfe. The biggest issue with the JKU and the auto isn't the weak engine, it the HUGE jump from the 1:1 3rd gear to the .67:1 O/D 4th. The 545rfe has the same 1:1 3rd gear, almost the same top O/D gear at an even steeper .67:1 for its 5th, but it has its 4th at .75:1 in between.

If you want to improve off road performanc and stick with the factory engine, regear to a lower gear, lower than factory even when taking larger tires into account. Added bonus is better on road performance too, manual or auto. 5.38's are available for the D44 and now also the D30.

I went Hemi and would do it again in a heartbeat, but my wife's Unlimited Rubicon just isn't that bad stock. Re-gearing to 4.88 would fix every complaint I have - but not as well as the Hemi!

As for that, with my JKU I run the VVT Hemi, 4.88's and 37's and guess what - 5.13's would be better...

As far as the lack of a diesel, I think you can blame the US Gov't on that. The ever tightening regulations make it expensive on the automakers and remove much of the attraction of diesels. Think urea injection now on larger diesels. What a f'in joke. If the JK's see a diesel in the US it will be when the EU and US emmissions regs match up, which I think is two years out. Also the US has got to stop penalizing diesel users with higher fuel taxes.

And truthfully, the market for a JK diesel might really be thin. With the oh so common soccer mom and comuter dad use that the JK's see, especially the JKU, how likely is high demand? Not very likely, imo.

Our company runs a fleet of diesel chassis cab trucks and gas vans. The sad truth is that the gas engines are much, much cheaper to run. Less maintenance - not like the days past when gas engines required frequent tuning, carb rebuilding, new points and plugs while diesels kept on going like the Energizer Bunny. Today its the opposite. More maintenance, more expensive repairs, much of any milage advantage lost to higher fuel taxes. Don't forget higher intitial purchase price either. A diesel light truck doesn't pay for itself anymore.

For a Jeep, the only advantages would be staying within CAFE standards and the torque some want at lower rpms. But again, how many really want it with the trade offs - noise, smell, maintenance, cost - and of those how many would actually pay for it.

What the JKU's really need, imo, is a smaller V8 putting out 300lbs' and 300hp as low on the tach as possible. The ~375hp and lbs' that the 5.7 VVT Hemi put out are substantially more than the JKU's need to be about perfectly powered.

JPK

I don't agree with the "hemi" swap, at least not for my type situation-I have an '08 JKU Rubi with 33.6" Hankook Dynapros and an auto tranny (highly modified) I have 5.38 Dana (lockable) diffs and an aux cooling/monitoring system--

Off road, towing a trailer, there's nothing more I need-

On road, towing or not I have full use of Cruise control and O/D, without downshifting-I can drive like Grandma and get 19 mpg ar tow my trailer and get 16 mpg in O/D--

So, I'm sorry, I have no need for a v8 swap-or Diesel, with my NV241OR xfer case , the only limit to what rocks/hills I can climb, off-road, is purely a matter of "GUTS", cause the JKUR will gothere-and tow the trailer right behindit !!

You're right about the fed/CAFE requirements on ones initial test drive of a new jeep--Gears-Gears-Gears and I'm afraid the new "jesus" engine will be in close to the same position !!

:costumed-smiley-007:wings: JIMBO

[pskhaat]

I have seen the 3.8l and the 4.0l torque and HP curves overlaid. The 3.8 actually provides as much or more torque as the 4.0 for any rpm. The 3.8 is a hell of a lot better on the highway and doesn't sound like its going to blow at 3,000rpm's like the 4.0.

The discreet torque value at any given RPM is not nearly as important as effective differential of them and where they fall in the RPM range. It is the shape of the curve that is just as important if not more-so than the absolute numbers.

As to your second comment about 3krpm highway feel, there is simply no doubt that the 3.8 tries to address both highway and off-road manners, it probably does pretty good in each category. Few engines out there have the true qualities of both on- and off-highway, until an engine can change it's bore:stroke, intake charge, cam, fuel mappings dynamically, we ain't gonna have it both ways.

I've driven both the stock V6 and I6 in the Jeeps and (I'm not the only one) have a preference off-highway for the 4.0, it simply performs better in that environment for nearly every situation I would personally put it in. You may or may not agree.

[JPK]

:sombrero: I agree with you somewhat-but




I don't agree with the "hemi" swap, at least not for my type situation-I have an '08 JKU Rubi with 33.6" Hankook Dynapros and an auto tranny (highly modified) I have 5.38 Dana (lockable) diffs and an aux cooling/monitoring system--

Off road, towing a trailer, there's nothing more I need-

On road, towing or not I have full use of Cruise control and O/D, without downshifting-I can drive like Grandma and get 19 mpg ar tow my trailer and get 16 mpg in O/D--

So, I'm sorry, I have no need for a v8 swap-or Diesel, with my NV241OR xfer case , the only limit to what rocks/hills I can climb, off-road, is purely a matter of "GUTS", cause the JKUR will gothere-and tow the trailer right behindit !!

You're right about the fed/CAFE requirements on ones initial test drive of a new jeep--Gears-Gears-Gears and I'm afraid the new "jesus" engine will be in close to the same position !!

:costumed-smiley-007:wings: JIMBO

We are in agreement with most everything.

But I think that if you had the opportunity to drive a Hemi powered JKU on and off road you would be wanting one.

JPK

[JIMBO]

:sombrero: Heh Heh, you're probably right--ON ROAD, but



We are in agreement with most everything.

But I think that if you had the opportunity to drive a Hemi powered JKU on and off road you would be wanting one.

JPK

If you've never driven a JKU Rubicon with 5.38 gears--OFF-ROAD--IN 4LO--I'm afraid you can't understand, my feelings--

Ciao

:costumed-smiley-007:wings: JIMBO

[JPK]

The discreet torque value at any given RPM is not nearly as important as effective differential of them and where they fall in the RPM range. It is the shape of the curve that is just as important if not more-so than the absolute numbers.

As to your second comment about 3krpm highway feel, there is simply no doubt that the 3.8 tries to address both highway and off-road manners, it probably does pretty good in each category. Few engines out there have the true qualities of both on- and off-highway, until an engine can change it's bore:stroke, intake charge, cam, fuel mappings dynamically, we ain't gonna have it both ways.

I've driven both the stock V6 and I6 in the Jeeps and (I'm not the only one) have a preference off-highway for the 4.0, it simply performs better in that environment for nearly every situation I would personally put it in. You may or may not agree.

More torque = more work. You can pretend its otherwise, but it isn't. The 3.8 has more torque than the 4.0 from down low all the way up. Perhaps some of the myth surrounding the 4.0 is the generally lighter, smaller Wranglers its been in, vs the JK. Or maybe its the noise it makes down low, which is missing from the 3.8. Either way, torque is work, and and 3.8 puts out more across the rpm band.

If you want examples of engines that don't suffer on road performance gaps for off road performance, or vice versa, look no further than the good ole American pushrod V8's. Once the enngine makes more than enough torque down low for a street legal Jeep while making more than enough HP up higher for a Jeep on a street you have the near perfect powerplant. A Jeep can only use so much torque off road and be still drivable on the street and can only use so much HP on the street because its a a Jeep and not a roadster...

JPK

[pskhaat]

More torque = more work. You can pretend its otherwise, but it isn't. The 3.8 has more torque than the 4.0 from down low all the way up.

You still have to have a distance multiplier in order to derive work. As torque is a factor in the work equation it would have a relationship, but not exactly work. Add time into the equation and we get power, RPMs luckily give us both.

A flat torque curve has very little torque rise and as such does not increase torque upon load, which in nice and slow, non-racing, bumpy, off-highway situations is a good thing.


Either way, torque is work, and and 3.8 puts out more across the rpm band.

Torque is only work with RPMs and as most drives I do have a natural way of causing me to slow down naturally when approaching a water crossing, or hill, or larger rock. I prefer one that will increase the torque in the same gear as the load is applied. I just like doing that in the lower half of the RPM range vs. having to keep a good rev to accomplish the same and by that time getting real close to the max power, I'm simply not racing these things, just good old regular off-highway driving.

[JPK]

:sombrero: Heh Heh, you're probably right--ON ROAD, but




If you've never driven a JKU Rubicon with 5.38 gears--OFF-ROAD--IN 4LO--I'm afraid you can't understand, my feelings--

Ciao

:costumed-smiley-007:wings: JIMBO

I as low as I have driven is a 5.13 geared six speed JKU. What an improvement over stock! I think I have an inkling of what you feel, but the 5.38's be even better. An auto even better yet.

Compared to the 5.13's, even the 5.38's too, since I've run with 5.38 geared JKU's, you would find the Hemi with 4.88's and 37's or lower gears the one to lust after.

The Hemis all make more torque at 1200rpms than the V6's make at peak. No matter how low you gear the 3.8 or the forthcoming 3.6, you can't make up for that remendous difference. That available torque gives incredible control. Contrary to what one might think, its possible to overcome obstacles with less tire spin, more control, slower speed.

Of course the Hemi has its drawback, and that is cost.

JPK

[JPK]

You still have to have a distance multiplier in order to derive work. As torque is a factor in the work equation it would have a relationship, but not exactly work. Add time into the equation and we get power, RPMs luckily give us both.

A flat torque curve has very little torque rise and as such does not increase torque upon load, which in nice and slow, non-racing, bumpy, off-highway situations is a good thing.



Torque is only work with RPMs and as most drives I do have a natural way of causing me to slow down naturally when approaching a water crossing, or hill, or larger rock. I prefer one that will increase the torque in the same gear as the load is applied. I just like doing that in the lower half of the RPM range vs. having to keep a good rev to accomplish the same and by that time getting real close to the max power, I'm simply not racing these things, just good old regular off-highway driving.

The torque curves of the 4.0 and the 3.8 are nearly identical. Wish I could find that torque and HP curve overlay. There is so little difference its more than remarkable, until 3500rpms or so, then the 3.8 overcomes the 4.0..

If you think there is significant difference between an earlier Wrangler with a 4.0 and a JK Wrangler with the 3.8, its the difference between the Jeeps and not their engines. Weight, gearing, differential set up, who knows, but it isn't the engines.

BTW, whatever the second HP/Torque curve graph you previously posted, the one below the 3.6 graph, it wasn't for the 4.0 engine.

What you write above are concerns largely overcome with lower gears. Sounds like you 4.0 experience was in Jeeps with lower axle ratios.

JPK

[JPK]

I found the overlaid torque and HP curves of the 3.8 and the 4.0.

As I recalled, the differences are all but non-existant until 3000rpms, when the 3.8 climb away on the torque curve and begins to climb away on HP too.

I think I figured out how to post the graph, here goes:
http://i30.photobucket.com/albums/c341/Nilrik/154_0706_03_z2007_jeep_wrangler_rubicondyno_chart. jpg

Here's a graph of the Hemi torque and HP, its SAE corrected and the engine was run with all accessories and exhaust. But its the pre-VVT Hemi, the 2009 and later VVT has more HP and more torque along with a flatter torque curve, the LX/Grand Cherokee version has 375HP max, can't recall the torque, at least 375lbs'; the truck version has ~395HP and 425lbs' torque, iirc. I have the LX/GC vesion.
http://i30.photobucket.com/albums/c341/Nilrik/0403phr_hemi_17_z.jpg

Here it is resized, it get blurry, still readable though.
http://i30.photobucket.com/albums/c341/Nilrik/0403phr_hemi_17_z-1-1.jpg
Write up goes wih he Hemi graph:
Fig 1This power curve showing 345hp and 375 lbs.-ft. of torque is impressive enough as is, but consider this: it is SAE corrected which shows numbers some 2 percent less and this is the output with the accessories and a full exhaust. In our estimate, this compares with a standard corrected motor of about 395 lbs.-ft. and 365hp.

Just to have all of the graphs in one post for comparison, here's the 3.6 graph:
http://i30.photobucket.com/albums/c341/Nilrik/3_6_liter_pentastar_graph_01.jpg

The 3.6 doesn't look to shabby compared to the 4.0 or the 3.8, eh? And talking about a flat torque curve..., wow.

JPK

[pskhaat]

JPK, yes (and quite surprisingly) the 3.8 has very similar curves. My personal opinion on the 4.0 is just that: opinion and worth not much. The bigger point though is the 3.6 with said flat curve, what I'm arguing is inappropriate for the Jeep, but maybe will satisfy the Costco-goers.

[JPK]

Surely it will please the soccer moms and commuter dads, any HP or toque improvement would, but with 40 or 50lbs' more torque - read ~20% more - in a useable range than either the 4.0 or the 3.8, it will please those who drive their Jeeps off road as well. Torque is everything, whether gotten through gears or through a more powerful engine. This engine is more powerful, and it will respond well to lower gears.

A flat torque curve is not a negative, its a huge possitive. The only reason a Hemi is better than any of the 4.0, 3.8 or 3.6 is because it has more torque at every rpm off idle.

JPK

[pskhaat]

A flat torque curve is not a negative, its a huge possitive

Genuinely curious, why do you think that?

[JPK]

Your question makes me wonder if you understand the relationship between torque and HP. Here's an interesting explanation: http://www.houseofthud.com/cartech/torqueversushorsepower.htm Here's one that, if you think "wide and flat torque curve" when reading will probably help even more: http://www.allpar.com/eek/hp-vs-torque.html

A flat torque curve gives more control since similar torque is available over a wider rpm range. No need for more throttle or rpms to produce the torque required for the task at hand.

Off road a flat torque curve - which means more torque at lower rpms, will enhance the Jeeps potential to crawl at low rpm's. It gives the driver greater control when climbing as well.

On road a flat toque curve means an easier drive and, if you wish, a more spirited drive. No gear hunt for autos, no sifting through the gears for manuals trying to keep the engine speed within the top of the torque curve. The engine with the wider flatter torque curve is within its power band longer, more frequently and it is more often ready to provide the work required at the mear depression of the throttle.

An engine with a peaky torque curve can be a pita to drive, on road or off.

Wide, flat torque curves think diesels, think small block V8, think Jaguar 3.8's and 4.2's of the past, their long gone 5.3 V12, their recent 4.0 V8 and their current 4.2 V8. Peaky torque, think Lotus Elite Turbo, Formula 1 cars, two cycle bikes...

More later, gotta go.

[pskhaat]

Your question makes me wonder if you understand the relationship between torque and HP

Ummm, I think we may need to close up the topic in this thread and call it a difference of opinion. Give me a peaky torque engine way down low any day off-highway :)

[grecy]

I think Ford is the only ones who have made an improvement considering their 300hp 30mpg stang.
I find it so interesting to see a comment like this. I agree with you 100% that Ford seem like the only US auto maker doing anything about power and gas mileage - the interesting question is how did they do it?

It's not a secret - Overhead cams, 4 valves a cylinder, sophisticated VVT, variable exhaust timing, lighter materials, finer internal tolerances, better internal balancing etc. etc. **

In short, they are moving away from "Great hunking V8's" and moving towards much lighter, sophisticated engines. (I applaud this)
And yet, as soon as Jeep try to do this (first with the 3.8, soon the more sophisticated 3.6) time and time again we see people raving along the lines of
"The 4.0 wasWAY better. bring it back!"
or
"Jeep need to put a Hemi in there or it's going to be crap"

I can't imagine how a person in the year 2011 actualy wants a gas-guzzling, noisy, high emission engine with technology from the 70's. It's pure madness.

** NOTE: While you guys in the US might think these are "new technologies" and that a 300hp 30mpg engine is revolutionary or in any way cutting edge, I can assure you these are nothing new. German and Japanese autos have had all this and more since the early 80's.

-Dan

[grecy]

Ummm, I think we may need to close up the topic in this thread and call it a difference of opinion. Give me a peaky torque engine way down low any day off-highway :)

Do some googling on "area under torque curve" until you find an article that speaks to you.
I think what you are trying to say is you want an engine that produces lots of torque early-on in the rev range (low down). You absolutely don't want an engine that "peaks" down low, because it will drop off sharply as the revs climb.

Aside from insane applications (Forumla 1 cars, Honda S2000, or a GSX-R 1000) the goal of every auto maker is a flat torque curve, with as much area under it as possible.

-Dan

[pskhaat]

You absolutely don't want an engine that "peaks" down low, because it will drop off sharply as the revs climb.

Incorrect. That's exactly what I want. Called "torque rise (http://goo.gl/e40Jg)."


the goal of every auto maker is a flat torque curve, with as much area under it as possible.

Which brings us back to the beginning of this topic. Not trying to be obtuse here, I just like my engines with old-school truck characteristics.

[JPK]

I read your link and I can tell you that it is out of date wrt automobiles and non-commercial boats. The HP and torque figures given are the max's just as in gas engines. Torque rise doesn't exist in these applications because they do not even meet the "intermittent" definitions, which can vary by manufacturer, and the engines are not intended to run at a constant rpm. If you doubt me, take a look at the Caterpillar or Cummins light truck or recreational marine sites, the VM or Mercedes vehicle sites. Recreational also applies to some relatively light duty commercial applications as well.

But in any event, if you are willing to live with the substantial penalties of a diesel vs. a modern gas engine, especially within the US and soon the EU due to the ridiculously stringent current (US) and forthcoming (EU) emissions requirements, then you can enjoy torque in the relatively low rpm range for a few more model years - all good off road. But you will be giving up on road performance that many others want or require, like acceleration.

And you will live with the modern diesel penalties vs. the modern gas engine benefits. Those penalties include more frequent maintenance requirements at higher costs, the lack of acceleration compared to the typical gas engine alternative offered in the same model vehicle, higher fuel costs offsetting better mpg, and much, much higher acquisition costs.

Modern gas engines do not share the awful maintenance schedule of their ancestors - no points, no rotors, no coils, no plug wire changes, 100k+ miles plug life, avg of 6000 mile recomended oil change intervals or better - some 10k miles, and they beat the heck out of a modern diesel. I oversee a mixed fleet, and truly, the diesels are an expensive pita, only justified when a gas engine isn't up to the task, like frequent heavy loads, frequent heavy towing or massive annual milage. Furthermore, the modern diesels often lack some of the reliability of the old diesels, the "git home" features, like the ability to run w/o the alternator, the ability to run on only the mechanical pump, the ability to run witout the turbo... Now its computers, particulate filters, urea tanks, BlueDot (something like that,) egr sensors, in tank pumps, high pressure fuel rails all eating into the once renowned diesel relability though some also making diesels easier to live with, cutting noise, smoke and grit, flattening early but peaky torque curves, adding higher rpm capability and HP....

No Jeep sees any of the justifications for a modern diesel. But Jeeps still do best with torque down low off and on road. So a flat toque curve is a huge advantage. A flat torque curve plus appropriate lower, non-mpg gears will make up for the diesels' typical abundance of torque on the low end. And a gas engine will give all around driveablity, better acceleration, less frequent and less expensive maintenance.

The other way to get an abundance of torque down low without going diesel and sacrificing is to start with an engine that produces a ton of torque. That's where the Hemi shines. While the later VVT 5.7 Hemi has more torque and a much flatter torque curve than the one shown in the graph I posted, that pre-VVT engine still has a strong peak at about 4500rpms. However, it produces ~300lbs' right off idle. The abundant torque of eother the pre-VVT or the VVT, peaking at 375lbs' at relatively high revs ensures drivability and that is confirmed by the respective 355 and 375HP at ~5200rpm.

If you compare the available-everywhere-but-the-US 2.8l VM diesel in the Wrangler, it makes 295lbs' torque at 2000rpms. 15% more than the forthcoming 3.6l engine with its flat torque curve, a nice improvement off road (but it weighs more too, though not a lot more.) About 15% less torque than the earlier non-VVT a Hemi. Its drawback is that it only puts out 161HP at 3800rpm, so day to day acceleration, drivability compared to the 3.6 will suffer, and it won't compare on the road with the Hemi. Going to the 3.0 Mercedes engine, once available in the GC is a big step up, with ~390lbs' torque, a relatively flat torque curve and ~240HP. But that engine hasn't been in a Wrangler, and almost surely never will be.

BTW, I have ran in Moab with a 2.8 powered JK on 35's. Reported real world milage was 26mpg, on road performance was said to be ok. It handled the trail with the same ease that the Hemi Jeeps did, no better, and both the Hemis and the diesel seemed to struggle less than the 3.8 powered Jeeps, which you would expect with the abundance of torque down low from the Hemis and the diesel. I also ran with a 3.0 Mercedes powered GC. The GC struggled over the same trail my Hemi cruised through, but that might be the difference between an Unlimited Rubicon with the Hemi, 4.5" of lift, 4.88'd and 37's and the more limited suspension modifications of the GC and its smaller tires.

What Grecy wrote is true of gas engine manufacturers, but it is equally if not more true with diesel manufacturers. They are working hard to flatten torque curves and bring peak torque up in the rpm range to improve drivability.

JPK

[grecy]

Awesome info JPK, thanks.


Going to the 3.0 Mercedes engine, once available in the GC is a big step up, with ~390lbs' torque, a relatively flat torque curve and ~240HP. But that engine hasn't been in a Wrangler, and almost surely never will be.

Fingers are crossed for the newer VM 3.0 in the Wrangler that is confirmed to be coming for the GC in a few years.

-Dan

[JPK]

Awesome info JPK, thanks.



Fingers are crossed for the newer VM 3.0 in the Wrangler that is confirmed to be coming for the GC in a few years.

-Dan

I hope so for the diesel lovers!

But the damned funny thing is that the diesels everyone raves about, including the 3.0 Mercedes engine and the larger VM diesels are all engines that the manufacterers have spent a tremendous amount of time and money making more gas engine like!

JPK

[grecy]

I hope so for the diesel lovers!

But the damned funny thing is that the diesels everyone raves about, including the 3.0 Mercedes engine and the larger VM diesels are all engines that the manufacterers have spent a tremendous amount of time and money making more gas engine like!

JPK

Agree 100%. I think so far, VW is the only company to do this well enough for "normal" people to want to buy in for regular passenger cars.
For me, diesel is about gobs of torque, better mileage, and cheaper re-fuel costs (at least in a lot of countries, diesel is subsidised more than gas, and is cheaper)

-Dan

[Plannerman]

How long has the Pentastar been in use in other vehicles? Is it pretty well proven or will 2012 Wrangler owners be cutting their teeth on a new engine?

[haven]

The 3.6L V6 was introduced in late Summer 2010 for the 2011 model year. So they have a year's worth of experience building the engine.

[Super mud]

Screw this I'll just stroke my 4.0 and bump up the compression then be hanging with the Hemi in the 350lb ft range lol.
Actually after looking at those graphs the 3.8 suprisingly makes torque soon. Though some simple mods on the detuned 4.0 would crap on the 3.8s torque curve.
Also I would have to agree the 4.0 at 3k does sound like it's reving to the moon but alot of xj guys feel it revs fine and gear their rigs to the upper rpm ranges. Also I think it may have to do with the perception from the sound deadening and isolation the motor you get in a jk. But v6s will rev easier and higher. My v6 explorer friend freaked when he saw my tach around 1200rpm while cruising up a hill.
This makes me want to go test drive a jk now

[JPK]

Years ago I had a couple of the smaller square Cherokees in succession, which I think are the XJ's, and I have to say that the 4.0 in those Jeeps didn't sound like it was going to blow past 3k rpms like the TJ/LJ's 4.0 does. Different cam and/or intake?

For a complete JK experience, I'd suggest a test drive an '11 with the 3.8 and a '12 with the Pentastar 3.6. The '12 will hit the dealer showrooms in a month or two. The 3.6 looks like it will be a substantial improvement but the five speed is an equally or more important improvement, imo. Also try a manual vs. the auto... I'm looking forward to the test drives myself.

On stroking the 4.0 to 4.6l or 4.7l, I've heard first and second hand reports which are all but opposite regarding the end results. One fellow I know loves his Golen 4.6l and tells me that it transformed his LJ. Others say, "not worth the trouble or expense." I wonder if the differring reports might be the results of one pleased-with-the-results fellow doing all of the suggested modifications, like injectors, etc, and another not-so-pleased fellow only doing the minimal and skipping the exhaust and injector mods.

I have an LJ as well as a JKU. The LJ's ride compared to the JKU doesn't warrant the stroker, imo. But if I replaced my OME suspension with an AEV/Nth Degree long arm, then maybe - but that ain't happinin.

JPK

[Hawkz]

One thought on the 4.0, I recently installed an Airaid cold air intake on my 2003 TJ and it made a huge difference. It feels more powerful, I am getting better mpg and the engine seems smoother at higher rpms. This is seat of the pants, except the mpg, but it is something to consider. The stock air box inlet is very restrictive by design to keep water out, but I'm sure it affects air flow as well. I'm not a fan of deep water, so I'm not worried about using the cold air intake. The intake is still above the fender, so it isn't going to be sucking water from down low. I considered a snorkle but didn't like any until I saw the new River Raider setup...

The stock XJ air box may have better air flow...

[Metcalf]

The new auto is NOT the 545 that is used behind the hemi. The 'new' auto is the W5A580. The gear ratios are...

3.59, 2.19, 1.41, 1.00, 0.83

Note the DEEP 1st gear....
Note the close 5th overdrive....

The axle gearing on most of the Pentastar applications so far has been VERY tall with this new auto. The GC has 3.07 gears stock with a 30.5" tall tire.

The gearing for the wrangler is going to change a LOT with the new auto.

The Rubicon package now lists 4.10's as an OPTION with the automatic. If the math works out, 4.10 gears with the pentastar/5spd auto combo might work out well for 35-37" tires with the new short overdrive. I would be hesitant to run this gearing, but it would be 'free' to try in the Rubicon.

[jomobco]

Incorrect. That's exactly what I want. Called "torque rise (http://goo.gl/e40Jg)."



Which brings us back to the beginning of this topic. Not trying to be obtuse here, I just like my engines with old-school truck characteristics.

You want a diesel. Or at least you're describing one.

[jomobco]

The new auto is NOT the 545 that is used behind the hemi. The 'new' auto is the W5A580. The gear ratios are...

3.59, 2.19, 1.41, 1.00, 0.83

Note the DEEP 1st gear....
Note the close 5th overdrive....

The axle gearing on most of the Pentastar applications so far has been VERY tall with this new auto. The GC has 3.07 gears stock with a 30.5" tall tire.

The gearing for the wrangler is going to change a LOT with the new auto.

The Rubicon package now lists 4.10's as an OPTION with the automatic. If the math works out, 4.10 gears with the pentastar/5spd auto combo might work out well for 35-37" tires with the new short overdrive. I would be hesitant to run this gearing, but it would be 'free' to try in the Rubicon.

Gear Ratios: 545RFE versus A580 for comparison with what the hemi trucks run
1st 3.00:1 / 3.59
2nd 1.67:1 / 2.19
2nd Prime 1.50:1 / 1.41
3rd 1.00:1 / 1.41
4th 0.75:1 / 1.0
5th 0.67:1 / .83

I see your point. What's stock on the rubi auto 3.73? And what is an X or Sahara gearing? Time to do some calculations with 35's/37's and highway RPM's and see where it sits. Also I'd look at where peak torque numbers come in on the 3.6. I'm gonna drive one of these when they come out. I'm dying to know how the extra gear and the new motor effect the 4 door. :roost:

[pskhaat]

You want a diesel. Or at least you're describing one.

:)

http://backtofoulke.files.wordpress.com/2010/01/price-is-right1.jpg

[Metcalf]

Gear Ratios: 545RFE versus A580 for comparison with what the hemi trucks run
1st 3.00:1 / 3.59
2nd 1.67:1 / 2.19
2nd Prime 1.50:1 / 1.41
3rd 1.00:1 / 1.41
4th 0.75:1 / 1.0
5th 0.67:1 / .83

I see your point. What's stock on the rubi auto 3.73? And what is an X or Sahara gearing? Time to do some calculations with 35's/37's and highway RPM's and see where it sits. Also I'd look at where peak torque numbers come in on the 3.6. I'm gonna drive one of these when they come out. I'm dying to know how the extra gear and the new motor effect the 4 door. :roost:

From what I understand the Rubicon auto will come stock with 3.73 or taller gears. The 4.10 gears are a no cost option.

The option sheet shows 3.73 gears as an option for other models, so I think they some with 3.4X or 3.2X gears stock.

Working the math from the stock gearing on the grand cherokee with this engine trans combo, the optional 4.10 gears should be pretty decent for 35s ( or maybe even 37s! ). The final drive gearing places a 4.10/5spd auto combo right between the old 4spd auto with 4.88s/5.13s.

Will this be the diesel or the hemi most people really want....NO. Will this be a pretty dang decent 2door engine/transmission...PROBABLY. I hope they totally didn't mess up the automatic programming. The new automatic has some promise for sure.

Also of interest. The new 5spd auto has such a deep 1st gear that with a 2.72 t-case it is almost as low as the old 4spd auto with 4:1 transfer case. I kinda wish they would offer a 2.72 t-case in the Rubicon with 4.10 gears. I think that would be a GREAT off the shelf factory combo for 35" tires. I think it would be a lot more flexible than the 4:1 in the transfer case. With a 2.72 low you would still have a VERY decent crawl ratio with the new deep 1st gear auto, but be able to do something like 50-60mph in low range depending on tire size. The new 6400rpm redline helps that also!

[Stumpalump]

I got a company van with that motor in it last month. It's stronger than the old V6 but it makes it's power with a variable speed cam. It runs ok untill you hit about 4000 RPM then you feel the cam kick in and it goes. Basically for normal driving it still bogs and downshifts untill you wind it out and get the cams to move. Don't expect a miracle out of it because it's still a V-6. In the light caravan it goes like a bat out of hell but then again the old V-6 pushed those light vans real nice as well. In a 4 door jacked up JK....You still will be wanting a V-8.

[The Swiss]

I spent the last two days with a Dodge Charger with the Pentastar engine as rental car. This engine seams to be a kind of a mixed bag.

Nope, it does not feel very powerful. No spectacular acceleration; no raw power; no chirping tires (obviously with the Nannie disabled). Kinda disappointing
However, the vehicle is quick, you hit 80mph in absolutely no time. The engine accelerates and does it's job very discretely.
Fuel mileage appears to be good. According to the dash display, I ended up with 29.3 mpg, which might be a "real" 26 mpg. Not bad for the way I was driving it.


I think I will go to the Jeep Dealership to take a Grand Cherokee for a spin to see how the Pentastar performs there.

[ExpoMike]

So there must be something definitely coming in the 2011 Wrangers. I just saw a TV ad last night that had Wrangler Unlimited Rubicon down to under $33,000! They even said they had 5 at that price. I was amazed as I hadn't seen one really under $38,000 on any lots in the area. Sounds like they are clearing out inventory for an upcoming change.

Be interesting to see if this new engine change will make a difference in the complaints of no power.

[JPR4LFE]

I am in the market for a used Unlimited, but I am holding out until the new engine comes out. I guess we will know shortly, but how likely is it that the price of an 07 may come down if this new engine is all its cracked up to be? Any predicitons? It also seems that some of the owners of early Jk's could be ready for an upgrade and I would guess a new engine would be a perfect excuse!

[The Swiss]

Placed my order for a 2012 JKU Rubicon this morning :wings:

[Carolyn]

A few dealers around the country have 1. Or 2. Several members of a Jeep Forum have taken possession, and quite a few are taking delivery within the week...

Meanwhile, I'm quite happy driving my '11 :sombrero: