FMU necessaty question

[fabio420]

I want to know if I can achieve 15 psi of boost with my current setup, or do I need something like a 1:1 FMU? My current setup:Straight T3 turbo.42/.48a/r370 cc sr injectorsz32 MAFSAFC IIFMIC xs turbo mbcI am currently pushing 11psi, but I'd like to go higher, If still safe.

[Craving4Boost]

i never heard of an 1:1 FMU but that doesnt matter because its not nessasary. why not just add bigger injectors and tune it with your SAFCII? thats what its there for...also that turbo is a good turbo but not THAT good..go with a bigger turbo if you want to boost higher. whats your HP goal? and you have a wideband right?

[nissanfanatic]

wideband it and see.

[hannibal]

Are you asking about an adjustable fuel pressure regulator to raise base fuel pressure? Thats one way to make your 370's flow more. They usually max out around 240-250whp, so I think youre pretty close at 11psi.

The safest way would be to upgrade your injectors and tune with your SAFC. S15 480cc injectors should be good for 300whp and I think you'll be close at 15psi.

[fabio420]

Well, I'm gonna tune it with a wideband and see how much I can get out of it. If I'm not satisfied, I'll get bigger injectors. I'm reluctant to get any other thing because I'm rebuilding a KA to house a gt35 turbo(he-he), and then I know I'll be getting bigger injectors, turbo, et.al.

[Checkered-Member]

Straight T3 turbo.42/.48a/r

those usually max out around 5,000rpms and boost drop to 6-7

how did you get it to 11psi? is the turbo ported?

[fabio420]

Yes the turbo drops boost after 5000 rpm, but in third gear I hit 14 psi at 4000 rpm (briefly at the dyno, with some differences in fuel delivery). I know the turbo drops after 5000 rpm, but my car is automatic, and I don't usually drive at higher rpm's for extended periods. I actually researched before I bought this turbo, and for what I currently want to run, it fits my purpose, which is low end spool. This is after all, my first experiment with boost.

[WDRacing]

That turbo will be a heat pump at 15psi, with or without bigger injectors...lol.

The stock FPR on our 240's is already a 1/1 unit. But you don't run any other rising rate FPR regulator with over sized injectors. You won't be able to progran the SAFCII to run them.

If you have a wideband, then you can answer your own questions. Simply add boost while monitoring the AF mix, keep it at 11.8 or richer and you'll be golden.

What are you doing for timing retard? Once you go over 8-10 psi your going to need somthing to retard your timing or you'll pop the motor very quickly.

WD

[C-Kwik]

FMU is generally referring to a Rising Rate Fuel Pressure Regulator(RRFPR). And all an RRFPR is, is an FPR that raises fuel pressure at a higher rate than 1:1. A 1:1 FPR is nothing more than a regular FPR. A RRFPR would be >1:1, otherwise it would not be a RRFPR. Factory motors generally come with 1:1 FPR's built in.

[ghostchild316]

those usually max out around 5,000rpms and boost drop to 6-7

how did you get it to 11psi? is the turbo ported?

I'm running that same exact turbo.I got it from a salvage yard

mine doesnt max out at 5k or run out of breath at higher RPM.My car pulls pretty damn hard till 6500rpm and the turbo holds .7kg/cm2 all the way to redline.

[fabio420]

I just dynoed the car and the turbo hit 14 psi with more to go, but it kept droping off at 5000 rpm. I recahed my horsepower and torque goal though.