boosting

[Kryostaisis]

this may sound stupid.. but how can you boost an rb25 over 14 pounds? ive got a highflow turbo and ive been told that i dont need to get a fcd to run 18psi, ive got stock ecu...

im guessing it has something to do with my fuel reg??

cheers

[Andi]

Isn't the amount of boost you can run relative to the amount of air the turbo is pushing? I mean the amount of air being pushed at 18psi on a stock turbo might only be about 13psi on a much larger turbo correct?

So in terms of your question, I think the safest thing to do is wind it up to 18psi and run it on a dyno to see if your AFR's are up to it. If they aren't, then you are probably in need of a new fuel pump. You should also be checking what duty cycle your injectors are running at as well.

[Kristov]

I probably wouldnt run 18 psi on stock ecu cos from what i understand and correct me if im wrong once you run too much boost it kicks in to R and R (rich and retard i think). Which means it over fuels and retards ignition timing. So it wont make the power you would expect at at 18 psi. Do you have front mount? If not again i wouldnt run 18 psi through stock cooler. What else have you done to your car cos you probably need to replace the injectors and fuel pump if their stock for 18 psi.

To answer your qusestion i dont know either. Do you have a bleed valve or ebc? Im guessing it doesnt have anything to do with your fuel reg.

[Sumo]

I would be scared of trying to run 18 PSI without having or even understanding the supporting systems needed to support this sort of boost. First of all, do some reading and try to understand how others go about making this power rather then "just screwing" up the boost. To be honest I would be scared running the stock ECU and trying to run that boost, all you need is a leaning out and you son may score a hole in your piston.

Cheers

Sumo

[Kryostaisis]

yeah my timing seems to be retarted... but it was retarding before i had the turbo rebuilt.. the car had some stalling problems... ive tried everthing on the forum accept check the o2 sensor, and the crank angle sensor.. the mods i have on my car are

fmic

greddy profec b II

3 inch turbo back exahust

air filter

fuel pumpn( walbro)guy has checked it.. he says its running really nicely.. he checked it when he adjusted my fuel regulator

sard type rj fuel reg

at first i thought it was the sparks that was retarding my timing... but they are new ngk irridium gapped to .8

the guy i saw today about the reg says hes had many r33 come in and ran that amount of boost without any other mods and they all pulled through every gear.... as i said this happened before i had the turbo rebuilt and now its still seems that alot of air and fuel is getting in there... but the engine isnt doing anything about it... i read on the forum that it may be my crank angle sensor but i have no idea..

ive ruled out fuel becaus he tested the flow and sai the fuel pump was good.. the only part of the fuel system i havent checked is the injectors.. but im going to get them cleaned soon...

any ideas?

[jazza08]

Without doubt ur ECU. If you didnt read the above post r33 ECUs retard timing once boost pressure is to high, infact im suprised u can run 14psi without it being retarded!

If its running that well be happy lol

If you want 18 pounds, buy yourself a power fc or something else as ur stock ECU just wont do it.

[Kristov]

^^^^Agree. Get rid of your stock ECU. By it self it will not support 18 PSI. Apexi, Wolf etc straight plug in replacement should do the trick.

[paulr33]

more boost does not mean more power. with stock ecu and stock fuel pump dont bother going anywhere near 18psi. youll just lean it out and make stuff very unsafe. the stock ecu has boost cut (as many others have said at 12psi). get an aftermarket ecu, fuel pump and tune it. make sure you have full upgraded exhaust as well

[Kryostaisis]

ive got aftermarket fuel pump... guy says as long as i keep the fuel pressure up high it should be fine... infact my fuel pressure was too high... i just installed a sard type rj fuel pressure regulator... but yeah i think i might go for the power fc... as im planning to get the gtr so i want this sorted so i can sell it asap... im going to send it to an auto electrician to see.. if not ill take it to a tuner and just pay him to fix it..

thanx for your help guys

much appreciated

[GTRgeoff]

The stocker turb (even highflow) will be working so hard to make the boost it will be overheating the intake charge, causing lots of back pressure and generallly making the engine overwork, when a better matched turbo for you power will do it easily and efficiently.

Don't even think about skimping $1000 for the PFC when the rebuild you are rapidly heading for will cost a lot more. I also hope you have a FMIC, and bigger injectors. A little detonation just trying to find the limit can end the ring lands life.

I was making 220rwkw at 14psi with highflow turbo, 800hp FMIC, GTR pump and Malpassi reg, and the injectors were close to the limit so at 18 you will kill it.

I'm now on my 3rd rebuild due to various problems, but the last one was me trying to go too hard without the support systems. Shortcuts work, but in a limited way. BTW my GTR makes 260rwkw with standard everything except a boost bleed and exhaust. Computer must be just a bit smarter.