s2k_suprchrgd

I went to get my car tuned today but for some reason my fuel pressure drops after 6K rpm. I thought it was a bad fuel pump so I changed it to a new walbro 255 but still having the same problem. I dont know what else to check or look for??


FYI I'm runing:

Fullrace gt35r kit
aem ems
aem FPR
RC 1000cc injectors
relocated battery in the trunk
9:1 comp built motor

Slows2k

What does the pressure drop to?

s2k_suprchrgd

sorry I forgot to ask my tuner but looking at my pressure guage my car it gets up 5.5 kg/cm2 (78 psi) then drops under 4.0 kg/cm2 (57 psi) as the rpm increases past 6k rpm. My car idles at 3.25 kg/cm2 (46 psi)

RAIN H8R

What are thos numbers in PSI?

Also alot of people have been having issues with voltage tapering off at high rpm. You might want to try running a single power wire straight to teh fuel pump with a relay.

s2k_suprchrgd

^^
5.5 kg/cm2 = 78psi

3.25 kg/cm2 = 46psi

RAIN H8R

Yeah that is what my firnd has too. He has a Walbro 255 HD in tank pump with 750cc injectors. His tapers off as well. Try hardwiring the fuel pump. We will be doing the same to his this week I think, Ill post the results.

camuman

why is fuel pressure so hi ? should be around 50-60ish max. 78 makes no sense. the 57 seems right though at wot. u dont raise pressure to tune your car. i think you shold ditch the aem fpr and go back to oem fpr.

RAIN H8R

the car i was making reference to is funning a stock FPR and it reads around 70psi at 8600.

Sideways

I had pressure dropping at top end and it was a bad clamp on the hose in the pump in the tank.

sbrodacz

Your not reving it to 6k to get pressure readings, are you?