Outer Limits 4x4 Board

just wonderin on safe boost pressure and exhaust gas temp on 94 gq with 300,000kms and unknown history. turbo been on for atleast 4 years. dts kit. would like to find happy medium between good power and good engine life

anyone with a good idea?? deisel mechanic or personal experience perhaps??

Welcome to the forum.

First up: learn how to use the search function.

Secondly: Read through the "GQ/GU Bible" sticky at the top of the Nissan section.

The questions you have asked have already been covered many times.

Now, without getting compression tests etc done, there's no way of telling you exactly how you should set it up.

Boost can probably be upped to 10psi with no worries. The recommended maximum temp for EGT's pre-turbo is about 700 ish.

My advice would be to take it to a diesel tuning guru and get them to set it up properly for you.

Enjoy your stay on OL.

Boost is not a big problem as it can help lower egt by leaning out the air/fuel mix. Egt should not go over 550 to 600. Any thing over 600 for any time and you run the risk of cracking/smashing a piston which will total your engine. I run 17 pound boost and rarly get over 450/500 can get hoter if held to the floor up a long steep hill or towing up a hill but since fitting the intercooler I havent had it above 550 and i was flogging it hope I have helped a bit.

BOOSTED GQ wrote:Boost is not a big problem as it can help lower egt by leaning out the air/fuel mix. Egt should not go over 550 to 600. Any thing over 600 for any time and you run the risk of cracking/smashing a piston which will total your engine. I run 17 pound boost and rarly get over 450/500 can get hoter if held to the floor up a long steep hill or towing up a hill but since fitting the intercooler I havent had it above 550 and i was flogging it hope I have helped a bit.

But where are you reading your EGT's from? Post turbo or pre turbo?

with those numbers im guessin post turbo.

have been advised to keep egts at a max of 550 post turbo, by the tuner i've been speekin too.

Yea mate post turbo

Just for everyones future reference, the temperature between pre and post turbo is usually around 100 degrees - give or take a bit.

Should you be looking for similar temperatures post turbo for a petrol engine? Or do the max egt temps vary between diesel and petrol?

Completely different. There have been a few threads containing info on petrol EGT's in the last two months, a search should find them.

Failing that, Joel at PGS is a petrol/gas performance bloke, you could give him a call and hassle him.