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mine runs 15psi and has done for about 7 years from what I can gather. No probs.
Nissans 4.2 motors are built to take a turbo and are really strong. I think if it is generally in good nick then figures of 10 -15psi would not be a prob with an intercooler.
Some say that this will affect the life etc but this is an impossible thing to gauge so is not right. I would be a lot more hesitant to put over 10psi thru a 1hz for example.
Trent Leens has 22psi boost and the only thing the motor has done to it is general servicing and injectors replaced all the time. But thats due to trying to force more fuel in there, not cos they are buggered.
I think with an intercooler upto 15psi should not be a problem as long as it has the fuel set right.
turps wrote:Trent Leens has 22psi boost and the only thing the motor has done to it is general servicing and injectors replaced all the time. But thats due to trying to force more fuel in there, not cos they are buggered.
I think with an intercooler upto 15psi should not be a problem as long as it has the fuel set right.
They actually upped it to 24 or so PSI, but the motor is down on compression.
vn15 wrote:How much power and torque is it in Trents GQ
Lots and lots and probably lots more than the average punter would need.
It produces so much grunt, I dont think the fuel economy is very good. Also read somwhere before (might be the alpine challenge thread), that when ever he puts the foot down the world disapears, for his team mates.
Even still I like it. And with discussion here, I think it has been decided that the early (87-93) ones can be wound out to 15psi and the later (93+)ones you probably want to limit it to 12psi.
having my GQ 4.2 diesel tuned at 18psi after the front diff is fixed ...
will let u know how it goes
H( * )( * )NZ loves B( * )( * )BIES
if a fat lady falls in the forest do the trees laugh?
[quote="RUFF"]although i didnt mean to, i squealed like a girl :armsup:[/quote]
so if you can run 15psi with an intercooler, how high can you go without an intercooler? I currently run about 12psi, but wouldn't mind going a little higher.
bundyrum4x4 wrote:so if you can run 15psi with an intercooler, how high can you go without an intercooler? I currently run about 12psi, but wouldn't mind going a little higher.
I've seen 20psi with no intercooler.... but to be safe 14/15 if you want any sort of lasting quality out of your donk
ehehe no ... i know of enough 4.2 patrols running alot more then 18
H( * )( * )NZ loves B( * )( * )BIES
if a fat lady falls in the forest do the trees laugh?
[quote="RUFF"]although i didnt mean to, i squealed like a girl :armsup:[/quote]
so if you can run 15psi with an intercooler, how high can you go without an intercooler? I currently run about 12psi, but wouldn't mind going a little higher
It really depends on the level of reliability you want from your vehicle, and its intended use. Pre August 1993 built engines with the heavier pistons seem to consistantly take 15 or so psi, while the later ones ought to be limited to 10-12psi....and can be driven all day every day with no problems. If you're wanting performance for competitions you can go in excess of 18-20psi, but knowing that its lifespan would be reduced somewhat.
Going to significantly higher boost then requires serious fuel pump mods to get the most from it.
On the wagon we had before which was a diesel we ran about 22 during comps, i would strongly suggest you get a booste guage if you dont already have one and more importantly a pyro so you can monitor the exhaust temperature. When our car finally died due to a head on we stripped the motor down and there was no sign of ware, so 18 psi shouldnt be a problem provided care is taken and everything is tuned properly.
Joe.
To succeed, focus on the solution, not the problem.
yeh i have a boost guage ... pyro ... looking air fuel mix guage
should be able to tune it on the run then
only on 12psi atm ... till we've fixed the front diff ...
then its off to get dyno's .... im looking at a dual boost controler
$$$$ 12 for traveling and 18 for comps
H( * )( * )NZ loves B( * )( * )BIES
if a fat lady falls in the forest do the trees laugh?
[quote="RUFF"]although i didnt mean to, i squealed like a girl :armsup:[/quote]
Air /fuel mixture guage?? never seen a proper one for diesel, still need to run by the EGT gauge any way, just ensure you know what temp to look for either before of after turbo.
remembering to go to 13+psi, Ive been advised you need a fuel aneroid thing.. No idea if thats how its spelt, but they are about $800, thats why Im stuck at 11psi..
I want 14psi!!! Maybe while wife is in USA later this mth...
aneroid plate is just for ur preboost fuel and when ur boost comes on it opens ur fuel right up
H( * )( * )NZ loves B( * )( * )BIES
if a fat lady falls in the forest do the trees laugh?
[quote="RUFF"]although i didnt mean to, i squealed like a girl :armsup:[/quote]
bogged wrote:remembering to go to 13+psi, Ive been advised you need a fuel aneroid thing.. No idea if thats how its spelt, but they are about $800, thats why Im stuck at 11psi.. I want 14psi!!! Maybe while wife is in USA later this mth...
a fuel aneroid is for altitude compensation,
What you are after is a compensator, they work the same way but do the opposite thing and aneroid reduces fuel as air thins while a boost compensator enriches fuel/air mixture as boost increases
stu
[quote="COOP"] By the way Mr engineering Guru maybe you better get another calculator or learn how to use it![/quote]
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Fathillbilly wrote:a fuel aneroid is for altitude compensation,
What you are after is a compensator, they work the same way but do the opposite thing and aneroid reduces fuel as air thins while a boost compensator enriches fuel/air mixture as boost increases
So I guess one of them is the same cost roughly? Still want to try 14psi!