some people say don't go over 7 psi on stock internal so if i use a FMU it should be fine right ? if i use a 450cc dsm injector and afc can i go to like 10 psi for racing and still be safe ? some say don't go over 5 psi on fmu so what is the real deal ?

 

Oh jesus.

It depends on soooooo many factors man. It's really hard to say what YOUR particular motor can handle. It all comes down to tuning, turbo size, motor condition, and about 25 other variables.
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The problem with fmu is that it works the injectors to the max and soon enough you will lean out,detonate,and maybe blow something up.Bigger injectors with afc hack is better becouse you can run richer and be safer at higher boost.you can also detonate with to much fuel but that is rare if you tune it right.If your boost spikes with an FMU its by by engine.

 

unless you watch the boost gauge and let off the gas :P

 

NO DOUBT !! Psi is a very poor measurment of air... CFM is MUCH BETTER.. IE: BIG T-3 @ 7psi can make the same power as a TD04 at 12psi.. PSI doesn't mean a whole lot when asking about "how much boost".. Its more like " how much boost with "XXXXXX" turbo and stock D16A6 and "XXXXXX" brand/size IC..

 

FMU is fine for 6-7 psi. Drag kits use FMU's with stock injectors (240) and all guys I know with those kits run 6.5 to 7 psi without any problems.

Any more boost and you probably want better fuel management.

 

I have a friend that runs a FMU at 15psi ( for about a week anyway ), and he cames his block failed b/c the last person to rebuild it, didn't do something right...

He also refused to get his assibly re-balenced after swapping from A6 pistons to Z6 pistons... Bye bye, motor again..

You can only tell people, not make them do it...

 

sure an FMU works, but there isnt much tunability. i mean tuned properly with like zdyne your gonna prolly push like 20 more hp.

 

i say 25 psi with stock management and a prayer.