GQ 4.2 diesels turboed

[DR Frankenstine]

How do they handle it?
How much is to much boost (I want longevity)
do they have head cracking problems like the toyota non turbo motors?
How many kilowats (at the wheels) can be achieved.

Currently have a factory GU turbo on board pumping 11 lb boost. 2 1/2" straight through exhaust. pyro wont go over 500deg when pushing hard with a load of wood on board. It seams to have plenty of power but more would be good. Im about to front mount an intercooler as well.

[bogged]

How do they handle it?

piss it in

How much is to much boost (I want longevity)

How long is a piece of string.. IMHO for longevity 14psi would be pretty standard for great returns. Some are running 20+psi.. but then they dont really want long lasting, but neddies.

do they have head cracking problems like the toyota non turbo motors?

not that Ive read.

How many kilowats (at the wheels) can be achieved.

How hard do you wanna push 200kw+ if you want a grenade.

Currently have a factory GU turbo on board pumping 11 lb boost. 2 1/2" straight through exhaust. pyro wont go over 500deg when pushing hard with a load of wood on board. It seams to have plenty of power but more would be good. Im about to front mount an intercooler as well.

Intercoolers always help..

[DR Frankenstine]

Thanks bogged
more input would be good though. What are others running (boost etc) and what problems have been experienced if any.
Mines a 98 model with 178000kays on the clock.

[ozy1]

i have a DTS kit on my wagon, it was set up running 12psi, that is the way it was set up at the shop,

i am looking into coolers, most likely front mount,

mine is set up for nice power and logevity, my turbo was put on at 310,000k's and have just ticked over to 320,000, i have had no dramas, im running a 2.5" exhaust, with no mufflers, will be looking into building myself a 3" mandrel bent system soon, to get the gasses out a bit quicker,

[not not]

Mines a shwitzer running 10psi with a bit of extra fuel and 3in zaust no muffler Great round town and pulls well with buggy on trailer in tow. EGT gets to around 550degrees on big hills when up it. But settles to around 400 when i get of it and drive it to about 5psi boost. Turbos been on the motor since it had about 10000 ks on it and its never missed a beat apart from pump rebuild and injectors and shes got around 280000on her now. Good interval on oil changes helps as this turbo is not water cooled just air /oil. Had it up to 18psi with buckets of fuel and went well apart from the pump not lifting the fuel quick enough but an inline pump after the tank would have fixed it.
Cheers Jamie

[spannercrab]

TD42 turbo'd is a match made in heaven - it really evens out the mix - black smoke (unburnt fuel) is a thing of the past in mine.

The less boost the better in terms of engine longevity - the standard "safe" recommendation is 6-8psi non-intercooled, 10-12psi intercooled. I run 10psi non intercooled ... only 30,000km on it, so not exactly an example yet ... come back to me in another 100,000 and I'll let you know

Nissans do not have the same head fragility issues as the Tojo's - they are a much stronger unit. I rebuilt a 2H motor a while ago and the biggest problem was finding a head for it. I literally had 13 heads crack tested and they were ALL cracked - I ended up getting a "good condition" cracked head stitched up (cracks on 4/6 cyls). My diesel mechanic reckons "find me a toyota diesel and I'll show you a cracked head".

How many kW at the wheels can be achieved? Depends on what sort of longevity you're after. I know of a fellow who runs 28psi + LPG injection and achieves 220kW+ at the treads, the truck has 200,000 odd on it (all w/ turbo) and it's getting pretty tired now ...

Best thing you can do with the factory turbo setup is chuck it out and put a new free-flow on it - reduces spool up time, EGT, compressor discharge temps. Flow is everything (apart from a properly matched and tuned t/c setup) Alternately there are a few manufacturers ( such as AXT ) who make upgrade kits for the GU which include new housings etc to increase the flow.

If 500degC is max EGT for you currently, this would indicate that you could bump up the fuel a notch - and perhaps the pump advance to get closer to the 550 mark (no higher!).

[DR Frankenstine]

To make it clear its a 1998 GQ flat tray 4.2 diesel it has a turbo off a GU

[tuff dog]

To get more cheap power put a ball bearing turbo on it. It will not only give you more power but it will boost in alot sooner.I would guess if you havn't done any thing to the turbo then it will be at max boost at about 2800 rpm's. Which is good for towing the boat. My turbo is at full boost at 1200 rpm's, after putting this turbo on it was like a rocket. I also have a front mounted inter cooler. And as for life span, the hard you push the engine the quicker it will blow. Just like a BLOKE !

The next way to get more power is to mod. your fuel pump and that is about $3000

Good Luck

[spannercrab]

I realize what you are saying DR.F, the TD42 is roughly the same in GQ + GU - so the same applies for either.

Turbo upgrade is definately going to give you more performance upgrade while putting less stress on your donk than an intercooler.

[GQ TROL]

If its a 1998 factory non-turboed engine that you've added a GU turbo to, I wouldn't try to squeeze much more power out of it than you already have.

These later non-turboed engines are notorious for cracking heads, pistons and precomb chambers if you get too carried away with fuel and boost. Instead of aiming for big HP figures, look to take some of the stress out of the engine by intercooling, free-flowing exhaust etc to ensure decent engine life. Just make sure the turbo setup is right for your application i.e. towing a boat and lugging it up hills versus highway running at 120km/hr +.