Max boost on MY99

[wrx_lou]

Just Wondering if anyone knew how much boost a stock WRX engine will take before if blows apart. Stock it boosts 14psi all day everyday and im wanting to turn it up a little as i just twist mounted a freshly modded VF22. Its got a 38mm Tial gate on it currently running 0.8bar so i was just gonna throw in another spring to take it up to 15.23 PSI.

[Guest]

***just my personnal opinion***

0.8 should be heaps for the average booster from a vf22, i wouldn't go over .8 on a standard wrx (eg, grey injectors, non sti pistons, conrods, fuel pump etc...) but then again i'v heard of wrxs going up in the psi department and handling it........for a lil while that is.

Im only doing .8 bar from my vf22 and that seems to be enough for me and i'v got an sti

[Guest]

do you know if it's one of them "special" wrxs?

[wrx_lou]

well in my opinion its special ;D But clarify what you mean?

It is a NZ new so its got yellow injectors, 260speedo, no speed cut, and STI brakes if thats what you were meaning. And when i say it was running 14 PSI stock I mean thats what the factory computer runs. no taps, no EBC and no remapping.

If it is the model your thinking of, is there anything else 'special' about it? I havent met anyone else with a NZ new 99. All the ones ive seen have been jap imports.

[wrx_lou]

an sorry, its also got a walbro 255lph. (not standard obviously)

[Swindog]

Um? I think its been fiddled. V5 dont do that normally do they? Unless NZ new are totally different?

[funkytown]

yer Matt (loud_as) had a 99 (version 5) nz new had had a real mismatch of parts similar to what was quoted above.

including yellows and 260km speedo... it should also have an orange afm too

It surely should run 1 bar fine.. i mean thats 14.7 psi or what you said is stock, so why run it at 0.8 bar? (unless im missing something here)

A 22 is rated to about 18psi (depending on personal opinion) all day. A stock motor wont like that boost over its entire lifetime however.

EDIT to answer your question 15.23 or 1.1 bar should be ok. Consider doing the split rail mod though.

The more boost you run the less life your block will have. take into account that your ecu will probably have a boost cut somewhere about 1.1 bar.

Also any boost level will creep at night (in the cold).

My V3 would boost cut at 1.2 bar, but did have a Zerosports chipped stock ecu.

[Guest]

yea yea you have one of those "special" wrxs lol, lil bit better then the reg wrx (non sti) not to sure on internals but by the sounds of things you have sti bolt ons ie injectors, afm turbo etc....

boost level you wish to run depends on you but i wouldn't go much more then 16ish psi max if you want it to last a bit longer.

[wrx_lou]

sorry im a bit vague with some details. I droped it down to 0.8 when i installed a T3/T4 with external wastegate. the spring in the gate was rated 0.8 when i bought it. never changed it or ran an EBC. The ECU has just been changed to a haltech E8 and awaiting tuning when i get the new setup running. Just tryna figure out a decent value to run (safely) for a while before i actualy do rebuild, which will no doubt happen eventualy. Would rather do that in my own time though.

[wrx_lou]

the A/F is aftermarket too. story goes, had the car for a week and all of a sudden the engine would just hunt like hell when warm. took it in and they put on a custom A/F and did something to my step motor? apparently it was spiking.

[Guest]

 wrx_lou said:

sorry im a bit vague with some details. I droped it down to 0.8 when i installed a T3/T4 with external wastegate. the spring in the gate was rated 0.8 when i bought it. never changed it or ran an EBC. The ECU has just been changed to a haltech E8 and awaiting tuning when i get the new setup running. Just tryna figure out a decent value to run (safely) for a while before i actualy do rebuild, which will no doubt happen eventualy. Would rather do that in my own time though.

There you go then mate lol, leave it on .8 till you decide when your ready to rebuild then just boost the FK out of it lol......simple ain't it?

[Guest]

........or if you want to go even lower in psi you could open up your waste gate and replace your 12 psi spring for a smaller 7 psi spring, that ill be safer then a brick shit house.

[wrx_lou]

lol. well that is true, however i wasnt looking at rebuilding for another year or so. I dont think id be able to last with it wound down that low.

[Swindog]

I was running 18psi on a vf22 with no probs for ages...only real prob was oil restrcition to the turbo itself which killed it. I even run 20psi at some points with no probs.

[wrx_lou]

christ! on a nonforged non STI?

[Swindog]

O sorry, fully forged non sti...doesnt really make much difference in a V5 weathers sti or not after its rebuilt with aftermarket stuff same with the later models as they made motors changes in the v5 up.

[wrx_lou]

glad we cleared that up before i pumped 20psi through my rex ;D

[driftrex]

i plan to tune my possum link for 17-18psi on a unforged non sti ;D

i have run it on 17-18psi before with the sti-ra ecu and it ran mint (no detonation), altho would hit boost cut at 18psi, ran it like that for a week til i sorted the right wastegate spring. that was ages ago lol

you have a haltech, so just make sure your tuner is onto it. but then i guess theres always that risk it gonna go BOOOOM!!!

[BC5RA]

 driftrex said:

i plan to tune my possum link for 17-18psi on a unforged non sti ;D

i have run it on 17-18psi before with the sti-ra ecu and it ran mint (no detonation), altho would hit boost cut at 18psi, ran it like that for a week til i sorted the right wastegate spring. that was ages ago lol

you have a haltech, so just make sure your tuner is onto it. but then i guess theres always that risk it gonna go BOOOOM!!!

It is however a matter of time.

But you know this.. :

[driftrex]

 BC5RA']

[quote name='driftrex said:

i plan to tune my possum link for 17-18psi on a unforged non sti ;D

i have run it on 17-18psi before with the sti-ra ecu and it ran mint (no detonation), altho would hit boost cut at 18psi, ran it like that for a week til i sorted the right wastegate spring. that was ages ago lol

you have a haltech, so just make sure your tuner is onto it. but then i guess theres always that risk it gonna go BOOOOM!!!

/quote]

It is however a matter of time.

But you know this.. :

haha yea its a risk im willing to take. besides its always a good excuse to upgrade. i'd be happy to get another 20-30,000kms out of it, anything after that is bonus.

[wrx_lou]

i think im just gonna run a conservative increase. as much as id like to rebuild, i dont have the skills nor the cash to do so.

[driftrex]

fair enough, round 15-16psi should be very safe with your setup.

[nt_a_foz]

Talk to Dave lou hel be the best person to recommend as i assume hes tuning your ecu??

[wrx_lou]

yeah he is. this threads actualy a couple of months old its already set up to run 15.5 controlled by the wastegate.

[DPI]