A BAFFLING QUESTION

blackduck

Explorer
truck pipe.jpg

Ive been talking to my exhaust guy about building a tailpipe out the RHS now ive got all that room after lifting and relocating the tanks.
the factory dump pipe tends to cover the inside of the RH rear wheel from time to time
which is fine until it becomes a front wheel

So hes telling me on a turbo vehicle there really isnt any need for the muffler at all
up side - more power and less weight
and he says the noise is not noticeable

kind of makes sense thinking the turbo would maintain a certain level of back-pressure

not sure about the legalities

What say you??
 

Amesz00

Adventurer
Correct. The best exhaust on any turbo motor is none at all. Obviously that's not practical. But the less resistance after the turbine the better.
I ran no muffler on my old 649. The noise is definitely noticeable, but not from the cab. They are louder than similarly exhausted 4.2 cruisers etc.
sounds a bit like a tractor on steroids, with a little lawnmower mixed in.. lol
you may like it, you may hate it. If you run a hotdog or straight thru muffler you'll still get the same flow benefits, but won't be as loud.

I never had any issues with police, in that truck or my 84.
 

blackduck

Explorer
so new exhaust on and i went with a small straight flow muffler to deaden the noise a tad
its a bit louder than standard and throaty on acceleration

now not sure if theres coincidence but after a week of use and our weekend of torrential rain i find the exhaust brake is activating at idle in neutral
it switches off when you touch the throttle or clutch
so from a quick check the shutter valve and relay are working
but it all seems to work regardless of the position of the exh brake on/off switch on the column
so i took that off and cleaned it to no avail
the only time it shuts down is with the fuse removed ( obviously)
so its getting power from somewhere other than the switch
thought neutral switch stuck closed but it should still shut off with the on/off switch

the only other place it could get power i think would be the throttle sensor ??

what am i missing
any ideas



View attachment exh brake wir diag.docx
 

blackduck

Explorer
It is. Looked at the wiring diagram for the ECU to find some numpty put that switch on the exhaust brake indicator lamp circuit. 10 years ive owned that cab. Never used it never paid it attention. And there was me with the dash all over the place looking for dodgy switches and relays
 

blackduck

Explorer
I was thinking the same thing.
knob jockey.jpg

OK so thanks boys
Ill tag myself with this pic (before you guys get the chance (Owen)) for not observing the bleeding obvious

so much for the KISS method of fault finding
I went straight for the possible faulty component
 

blackduck

Explorer
So was it a worthwhile mod? Notice any increase in power? Any significant extra noise in cab with windows up/ down? Cheers
when it stops raining ill get underneath for a pic of the new muffler tail; pipe set up
Short answer YES
increase in power may be perceived cause it sounds faster
but looking at the standard can it was like a maze god knows how the gas got out
the new one is like looking down the grand canyon

Noise wise
throaty on acceleration
i always have the window down and yes its noticeable
but at speed with the road noise, turbo whine, wind noise and engine noise its just another reason to PUMP UP THE VOLUME
 

LTT70

New member
i have put a 3" S/S exhaust with a small though muffler at the rear. and a 3" exhaust brake from a hino, chipped the CPU.... worth every penny, lot more power, slight less fuel consumption, and quiet...
 

unkamonkey

Explorer
I've always thought about cutting the muffler out of mine But as far as increasing the size of the pipe, I don't know. In some exhaust systems the velocity makes them work better. If you look at the place where the turbo bolts to the exhaust manifold, (at least on mine), It is smaller than exhaust pipe so you already have the first restriction.
 

blackduck

Explorer
I've always thought about cutting the muffler out of mine But as far as increasing the size of the pipe, I don't know. In some exhaust systems the velocity makes them work better. If you look at the place where the turbo bolts to the exhaust manifold, (at least on mine), It is smaller than exhaust pipe so you already have the first restriction.
the way my exhaust guy explained it, if you increase the diameter of the pipe after the exhaust brake you create an echo chamber
more noise no gain
i went 2 1/2 " all the way through
 

unkamonkey

Explorer
I don't have real test data but on the V6 Jeeps if you run a 2 into 1 pipe out the back, they run smoother and seem to deliver better performance. I need to tell the neighbor kid about the echo chamber bit on his Power Stroke. He pulled the muffler and welded in larger pipes, bigger turbo, larger injectors, etc. Did the chip so he could roll smoke. At least we talked him out of doing stacks behind the cab.
He put a muffler back in after a few years so he could hear his radio as he was driving.
 
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