Turbo's on Gq

[Grummo]

Hi all

I am after a bit of information on turbo 4.2 diesel Nissan GQ Patrols as i am planning on buying a td4.2 and i want to either buy one that already has a turbo fitted or turbo it myself however i have a few questions.

Was wanting to know what boost pressure is ok to run on them without majorly shortening engine life or damaging anything as i don't know much about diesel engines. A fellow i work with told me his runs at around 30 PSI and i am just wondering if this is right as turbo's that i have seen in smaller petrol cars run max 15 PSI majority of the time.

Also a mate, who has turboed a few cars, not patrols however, mentioned that sometimes the compression ratio of the engine has to be changed with higher boost pressures. I am just wonder if anyone who has turbo a patrol could enlighten me about this as to whether it is something that needs to be done with a td4.2 or if they have any info on this.

Also the other thing i was curious to know is when doing more extreme 4x4 tracks has anyone ever had any trouble with fuel sloshing around the fuel tank and air being sucked up by the fuel pump. Has anyone had to fit surge tank or something or is air being sucked up not a possibility in patrols?

[nissannewby]

With a proper tune and regular servicing 10-15 will see a good long life out of the td42. Wouldnt worry to much about the compression side of this as diesel are made to withstand a lot higher combustion pressures than petrols. In the diesel world it works a little different there are turbo setups around (tractor pulls etc) that are pushing 100psi. There are people out there who have run 50 through a td42. I have never had a problem with the fuel and have been on some pretty steep stuff i know some people to fit a lift pump near the tank to help the standard one with its job.

[Grummo]

Thanks, I had an idea that diesels could handle higher pressures but i have no experience with diesels what so ever so was not sure. And i didn't think the fuel would be an issue as i have never heard of it happening before, only found out today about air being sucked in being possible after talking with a fella who installed a surge tank in his falcon for when he does drifting and other stuff, and was curious to know whether it was a possibility in off roading.

Also another thing, i read somewhere that when fitting a turbo on a patrol the fuel pump could be turned up with a switch on the back to save having to buy a larger fuel pump if you need it or you could use a small transformer to up the power to the pump to make it work harder. Have you heard anything about this and whether it is possible?

[nissannewby]

the 4.2 has a mechanical pump so the only way to adjust fuel is mechanically. You would only need to install a bigger injector pump (which a standard one can be modified to suit) if your chasing big numbers out them

[Grummo]

Ok thanks. My turbo guru has only installed turbos on newer cars which obviosly must have electric pumps.He has been through 5 or 6 diffrent cars and put turbos on them all but they where all new petrol cars and weren't 4 wheel drivees so there is only so much information i can get from him. I'm not sure how much power i will end up wanting, am only getting info at the moment as i am looking to buy a patrol. But i know i definatly want to turbo as i have driven turbo and no turbo desiels and the turbo is so much better.

Thanks for the help
Grummo

[Woof]

Hey mate, up until about a month ago I was running my turbo at 22, when I got the clutch replaced my new mechanic warned me that if I did not back the boost off I could be up for another clutch or worse....I am also running a modified fuel pump.
The first thing that I did when I got it back was to reduce the boost down to 16 and since then all seems good, I am even thinking about replacing my fuel pump with a standard one as the amount black exhaust is not good.

It is always nice to have that extra get up and go, but at what cost.

[johno90]

^^^ sounds like you need a heavier pressure plate to compensate for increased power. Be carful when deciding boost, not all td42's are the same and each type can only take certain amounts, rule of them is silver top 30psi black top 15 and factory turbo 40 psi.

[Ben-e-boy]

^^^ sounds like you need a heavier pressure plate to compensate for increased power. Be carful when deciding boost, not all td42's are the same and each type can only take certain amounts, rule of them is silver top 30psi black top 15 and factory turbo 40 psi.

How did you come across that rule??

[nissannewby]

There is a thought that the silvers were stronger than the blacks but this cannot be comfirmed until you can actually look at the internals. As i own a blacktop (In a 1999GQ) I know it has all the stronger parts that the silver has having had the engine open. The turbo motors will obviously be stronger as they were designed and made from the factory to have a turbo from the get go.

[Ben-e-boy]

There is a thought that the silvers were stronger than the blacks but this cannot be comfirmed until you can actually look at the internals. As i own a blacktop (In a 1999GQ) I know it has all the stronger parts that the silver has having had the engine open. The turbo motors will obviously be stronger as they were designed and made from the factory to have a turbo from the get go.

I thought the same thing, as far as I am aware the differences between the 2 is just splitting hairs,