boost pressure and fuel pressure

stee

New Member
hi there, im new to this site, i have just bought a gti-r and im not sure about any internal work that may have been done but i know it still has the standar t28 turbo on it and it has got a mechanical boost control valve fitted and an asjustable fuel pressure regulator on it, im just wondering if any1 knows the safe boost pressure that it should be at and also what kind of fuel pressure it shud be set at so i dont cause any major damage?
hopefully some of you boffins on here should be able to point me in the right direction, cheers.
 

wrc

Member
Stock fuel pressure reg runs at 3 bar. Raises 1psi for every 1psi of boost increase.


Stock boost is at approx 7psi. Aslong as the car is fitted with a 255 lph fuel pump i.e. walbro or similar you can quite happily raise that to 14-15psi (1bar) and run it like that all day long as long as there are no other underlying problems.
 

stee

New Member
well the car is mechanically sound now nd i know its already above 7 psi, its got an after market boost guage fitted but never paid much attention to what it was at becaude the transfer box was howling, but its fixed now so i will check wen i get it on the road tomoro, is that a standard fuel pump or uprated and is there any way of checking what it has fitted?
 

wrc

Member
The only true way of finding out about the pump is to get dirty and have a look mate. Easy really though, entrance through inside the car, 10mm bolts about 6-7 of them from memory. Pull the housing away, unscrew the large cap and have a look. Do a search and you will soon find the cosmetic differences between pumps.

As said, make sure everything is in good condition - thats the most important thing. Make sure coolant is not old and weak, oil the same etc, make sure it has a good oil, no other issues etc i could go on but im sure you get the jist.

If i were you my eyes would be all over that boost guage to see whats going on.
 

gtir_pimp

New Member
dont mess about the fuel pressure, take it to someone who knows what theyre doing with that side of things and get fueling checked on a wideband
 

stee

New Member
im going to change all the oils and coolants just to be on the safe side anyway, i have got reciepts for oils that have been bought but just gunna do them to be on the safeside, and im wanting to get it set-up propperly so i know its not going to blow up LOL it runs absolutly perfect but theres that little bit at the back of my brain telling me not to give it full bananas until i know it is safe to do so, i want to take it to someone that will be able to read what kind of remap it has had and the best boost pressures to run. it must have had a few bits nd bobs done to it because it doesnt half go and the previous owner claims that it is around 311bhp, im not gunna lie, i have put my foot down a couple of times and i think his claim of 311bhp is somewhere near. tomoro will be my first proppa day out init since i got it last week so lets just see what happens nd what kind of boost its running. the previous owner also advised me to run it on super unleaded only, thats another reason why i want it looking at because im unsure if i will cause some kind of melt down by using the wrong fuel LOL wish me luck.
 

stee

New Member
i was more than sure to start off with that stock boost is 7psi, ive never heard of it being 10.635psi LOL how sure are you that is correct?
 

stee

New Member
LOL ive just looked further into it nd it seems you have proved me wrong, how come alot of people say it is 7psi? is it because thats what the standard boost guage goes upto?
 

Animaldaz

Active Member
Stock boost is 0.7bar which is 10.6 psi as already said above. And to get 311bhp your gonna need around 1.2ish bar .
 

stee

New Member
oh yeh my mistake lol, im going to take it out tomorow when i can see and ill see what im getting on the boost guage, i think its somewhere near there but not too sure as the lad who had the car before me hasnt wired a light in for the boost guage so its hard to see at night without crashing lol
 
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