Turning the wick up on an NPS

[JohnRogers]

Ok so ive been doing a little light googling before i pull the trigger on a ecu reflash on my Dualcab. My tuner contact has tuned about 25 of these trucks fitted with the 4HK1 motor, hover the 30% extra doesnt seem like a enough power out of a 5.2L engine so i got googling.
Turns out the engine comes in 3 tunes specs 155hp, 195hp and 205hp.The difference being the injector size and ecu parameters, i can purchase all 3 options of inector from Baileys Group for $396 a piece, and the tune will be written to suit my choice so it doesnt matter which ecu i start with apparently. The difference in output is staggering if i can achieve the 25-30% benefit over standard tuning.
Standard output is 115KW/420NM, the standard output of the big injector equipped model is 150KW/637NM and a tuned 30% of this is 195KW/830NM which would be unbelievable even the standard big injector figures would transform the truck. Has anyone else gone down this path???

 

[JohnRogers]

If the suction control valve and Rail pressure relief valve need upgrading its another $750

 

[SkiFreak]

Just make sure that it's only the injectors that are changed between the 3 specs, as I expect some of the driveline components may also get upgraded.

 

[JohnRogers]

probably a heavier clutch but even 200 nm would transform the truck if the clutch cant handle the 400nm increase

 

[javajoe79]

The clutches ability to hold is largely dependent on the weight of the truck too.

 

[Amesz00]

I'd have thought the dpf and exhaust would be the limiting part in a nps.
Anyone have a model for the turbo on hand?

 

[steve66]

Someone on here a while back asked Isuzu about upgrading, needed a new ECU (same as reflashing I guess) and a different DPF (unless you are planning on deleting it), and I think there where concerns raised about the gearbox's ability to handle the extra horses.

Like all mods, the further away from standard the more chance of unintended consequences.

Cheers Steve

 

[SkiFreak]

I'd be more concerned about the front prop shaft and diff, as these are only an option for the NPS300 (as far as I know), and may not be speced for a lot more torque being applied to them.

 

[JohnRogers]

DPF will be optional bolt in for inspections the gearbox and diff should be fine as it'll never be loaded as its an NPS 250 so 4500kg max. Im not trying to build a race truck just be nice to have the berries for long climbs on the freeway and on the beach etc. Once in low range its not about power and attacking climbs im sure concussion from being thrown around the cab will occur before i break axles etc

 

[JohnRogers]

The torque applied to the shaft and diff would be no greater than in a V8 cruiser surely and its nearly 2x the size

 

[Cuddy]

DPF will be optional bolt in for inspections the gearbox and diff should be fine as it'll never be loaded as its an NPS 250 so 4500kg max. Im not trying to build a race truck just be nice to have the berries for long climbs on the freeway and on the beach etc. Once in low range its not about power and attacking climbs im sure concussion from being thrown around the cab will occur before i break axles etc

Hey John, any pics of progress on the build? How will you stay under 4.5t...that will be tough

 

[javajoe79]

DPF will be optional bolt in for inspections the gearbox and diff should be fine as it'll never be loaded as its an NPS 250 so 4500kg max. Im not trying to build a race truck just be nice to have the berries for long climbs on the freeway and on the beach etc. Once in low range its not about power and attacking climbs im sure concussion from being thrown around the cab will occur before i break axles etc

Agreed here. If you had a higher power level AND more weight, there could be issues but without the weight, the drivetrain doesn't see the strain. Most diesels get better MPG while cruising when they're turned up too.

 

[Mr Rehab]

[QUOTE="Has anyone else gone down this path???[/QUOTE]

Well yes, mostly. A friend and I had DPF deleted, EGR disabled and 20% power/torque boost in an Austrian workshop in 2015. We have identical 2010 model Isuzu NPS; my camper weighs 5800kg, his about 6100kg. The power boost figure is a bit vague because the tuner had very little English, hadn't worked with these trucks before and there was no dyno testing. I regretted disabling the EGR at the time as it complicated the changes and was probably unnecessary but it hasn't caused any issues to date.

Both trucks have covered around 60,000km since the changes - neither truck has had problems with gearbox, clutch or diffs. There was a small increase in fuel efficiency from 17L/100km to 16L/100km in our truck. The modest power/torque boost was most noticeable in acceleration when the truck was lightly loaded, not so much when full but it does hold the gears much better in the hills.