Safe boost pressure....

[666damned]

hi guys............quick question ,just fitted some nice new gauges and ordered a manual boost controller,engine is stock and boost is giving a peak of 8psi.....what can i safely take it to?.....not looking for huge power gains ,but maybe just a tad more than stock.........


dave

[Nutter_John]

wow a question that has never been asked before !!!

[Stevo]

well from what iv read and please dont hold me to it,........

ya can have 12 psi but if it spikes higher you get the boost cut rareing its ugly head, i dont have any turbos on mi legnum tho so what i say aint gospel by any means.

hopefully that helps

stephen

[Wodjno]

wow a question that has never been asked before !!!

Yes it has ! You EVO driving Muppet

Don't you know how to use the search button ?

And on topic !
Until fuel cut intervenes


Chers

Wodj

[666damned]

wow a question that has never been asked before !!!

wow....... thanx for that john................. ..........

[AlanDITD]

Woodj - i thought this but have discovered otherwise of late. My car doesnt seem to supply enough fuel at like 14psi. The wideband readings were a touch lean than i would have liked. Plus on the 1/4 the car was running rediculously hot and running slower times.


i.e @11psi i was running 13.6 though great was the boost up and quicker times i was very wrong after 1 run i couldnt get the car back in 13's turned it down a touch and it was 13.6-13.8 all day again.

Not sure how much was heat soak or how much was det and the ECU backing off the timing but there was a deinate performance loss.

possibly a big wapping intercooler may help in my case but i know wont be running anything over 11psi.

[Nutter_John]

what AFR's are you reading on full chat ?

Sorry Dave but the question has been asked so many times ( but at least you see the funny side )

[AlanDITD]

what AFR's are you reading on full chat ?

Sorry Dave but the question has been asked so many times ( but at least you see the funny side )

into the mid 13's its not a perm one i have in my car its a dyno one thats been apadated to use on the road.

Even the heat coming out the tailpipe is rediculous on around 14psi. With it turned down its pretty normal.

I need to do some proper logging off the wideband, might pop down tonight and ask to borrow it again.

[Nutter_John]

I'd be very worried if you are running that lean on standards , i assume you have it stuck in the tail pipe and not in the de-cat area

yes is the car runs lean the it will be running hotter , have you checked you ecu to see if it has been updated ( mines etc ) , and have you tried evoscan to see if your hitting knock at those levels

[Wodjno]

Alan. i wasz running upto 1.2 bar on standard fuel pump, but never ran lean. Possibly your FPR is weak and not supplying the correct pressure or your pump is failing at those boost pressures..

Cheers

Wodj

[AlanDITD]

I'd be very worried if you are running that lean on standards , i assume you have it stuck in the tail pipe and not in the de-cat area

yes is the car runs lean the it will be running hotter , have you checked you ecu to see if it has been updated ( mines etc ) , and have you tried evoscan to see if your hitting knock at those levels

I have evo scan mate but i dont have the cable yet. The probe is in the tail pipe so granted the mixture will show slightly leaner anyway as the mixture will be slightly more diluted.

Ill check the ECU tonight although it does look pretty normall compared to the factory one, and ill try do some pulls and logs tonight with the wideband with boost pressure low and high see what AFR's are exactly. Maybe its ok but it did feel slugish as such just didnt really want to rev like it does now. Alot coulod be heat soak. water temp is fine but EGT's although i cant measure them are friggin boiling at 14psi.

[AlanDITD]

Alan. i wasz running upto 1.2 bar on standard fuel pump, but never ran lean. Possibly your FPR is weak and not supplying the correct pressure or your pump is failing at those boost pressures..

Cheers

Wodj

How hot did the car get? i.e if you cover the tail pipe and feel the heat.

the other thing is the carbon on the tail pipe at 14psi i get next to none another thing i though could be an indication of it running lean.

[Subaru ETA]

every car is different. my car can run at 16 - 17psi all day with no fuel cut

[Wodjno]

every car is different. my car can run at 16 - 17psi all day with no fuel cut

Your 1 lucky Dude ! Duuuuude

[miller]

every car is different. my car can run at 16 - 17psi all day with no fuel cut

obviously its here that shows there is a difference between the density of the air in the UK versus NZ. i get fuel cut all day every day at 14psi

as always stated Stock VR4's hit mid 14sec 1/4 mile and always dyno 20bhp higher than our stock!

Got to be!

[AlanDITD]

obviously its here that shows there is a difference between the density of the air in the UK versus NZ. i get fuel cut all day every day at 14psi

as always stated Stock VR4's hit mid 14sec 1/4 mile and always dyno 20bhp higher than our stock!

Got to be!

But denser air = less boost so for that theory to be right they should fuel cut before us.

[vr4-fan]

alan , if you want put your car rich and dont cut 15 psi , get out the thermostat . and done ,

[AlanDITD]

alan , if you want put your car rich and dont cut 15 psi , get out the thermostat . and done ,

Thanks vr4-fan. I think id rather run lower pressures until it could be done safely though

[666damned]

thanx for all the comments guys..................i think....lol.......

[Turbo_Steve]

alan , if you want put your car rich and dont cut 15 psi , get out the thermostat . and done ,

Whilst this WILL make it run richer, the car will also run massively reduced timing when very cold: removing the thermostat causes the engine to run improperly. Also, as the engine heats up, (i.e. using lots of boost) then the ECU will make it leaner, which will then lea B A N G !!! OH No! My engine blew up.