Safe boost levels?

[bnsportsr33]

Hey guys, I'm wondering what you would recommend to run for safe boost levels with my mods, I don't have a lot but I will list what I have

also the turbo has a STEEL wheel and not ceramic, I busted apart the ceramic wheel turbo a while back and my friend sold me a steel wheel one

front mount greddy fmic with piping
downpipe with either 2.5" or 3" exhaust straight back no cat
apexi bov
hks evc4 boost controller
hks mushroom style filter

I believe it's a stock fuel pump but I can't be sure

I know running stock on the street i'll just run 7 psi, but when I want to race or take it to the track what is a safe level to run at? stock internals of course

thanks

[h4X6]

10 psi

I would recommend a Air/Fuel gauge aka wide band so you can watch those AFRs

you need to get that pump upgraded, and and maybe get some injectors (which will mean needing a tune and new ECU management)

[bnsportsr33]

really? only 10 psi? I thought it would handle more like closer to 14, but thanks for the info

[h4X6]

well the turbo probably can. they reason i say 10psi is because of fuel... you have NO supporting mods. you think you have a stock fuel pump... well thats 20+ years old, who knows what its putting out... hence why i said get a wide band o2 sensor. then you can monitor your AFRs... if AFRs are good at 10PSI then raise it to 12... tho i would highly recomment doing the supporting mods and getting a new fuel pump, injectors (probably not needed at 12 psi but recommended to not max them out) and a tune....

[bnsportsr33]

Yea maybe i'll grab a fuel pump , what do you recommend? 255 lph walboro? or is that not good enough? Injectors and tune don't think I can afford that right now as I just finished school month ago and looking for work, I can afford the fuel pump though I believe

[Nismo_line]

walbros are 99 bucks at speedfactor. go pick one up!

[bnsportsr33]

Thanks Travis, will do!

[hp44incgtr]

im running 15 pounds with my gt 2860 i have afr its decent in boost sitting at 11 11 6 cruising around 14 to 14 7 but in an week ill be visiting robin it def made an huge difference installing that sard fuel pump its like that dude say the pump in yo car is dinosaur age do u really wanna trust it if you have an afr its not so bad you could at least see it bfore leaning out..

[Dragon Humper]

Carter Turbine pump, 315lph and about $150. You won't need another pump up to 600hp. With a wide band you can just keep cranking up the boost till you start to get scared and back it off a bit....simple. I would use some Tolulene while you are doing that to be safe, about 20% works as well as C12.



Jon.

[Skym]

With stock ECU tune, fuel system, etc, 10-11psi max before stock ECU can start detecting knock, retarding ignition timing, etc. With FMIC there's more air getting to engine, so lower the boost level 1.5psi or so to suit (boost level usually rises 1-1.5psi more with FMIC). On racetrack, keep boost level lower to reduce blowby and run a catchtank to prevent intake piping, intercooler being coated with oil.

I wouldn't go above 1bar / 14.5psi with stock headgasket (if thrashing car, ECU is tuned, etc). Stock pistons are good to 20psi (from what I understand this is due to amount of heat, expansion of cast piston and this can be reduced with E85 that makes engine run cooler and piston not expand as much at 20psi) when car is thrashed, but up until 20psi the headgasket is the weak point (applies to RB20, RB25, RB26). Above 20psi, minimum, upgrade to forged pistons, ARP conrod bolts with stock forged I beam conrods, etc for reliability.

[Frankyy]

The rb25 with a stock turbo can only run approx 12 psi max since the fuel map was not made past that psi, so the car actually went slower the more psi you put to it even with a good fuel pump, so get injectors, a fuel pump and a tune if you realy wanna make a difference.

The rb25 was way under tuned so it wouldn't compete with the rb26 but a good tuner can easily get 40-50whp more on a complete stock setup