troy2003

i had my car tuned, but only up to 5300, the shop said it was spiking boost at that point, we opened the wastegate and there was a tear in the diaphragm. i have the new diaphragm, and an 8.7 psi spring, but have not thrown it in, if i am tuned to run 10 psi, but if i throw that 8.7 spring in with the new diaphragm will i be running too rich, or should the a/fr still be pretty good? also i am running 550 cc injectors, my tuner said i was maxxing them out at 272 hp!!???, thats not possible is it??, im thinking maybe time for a new fuel pump.

troy2003

p/s this is only happening in like 4th and 5th gear around 3800-4200 rpms full open throttle

I Love (.)(.)

im thinkin you need a new tuner, but I would think the a/fr would still be ok. just get that new diaphram in and then go get it tuned when you have a chance. and get a wideband so you can keep an eye on it. 550cc injectors will support more than that also.

Cyanide Jello

Sounds like he had mike/steve/kyle tune it...

I was thinkin the same thing... Its not the tune, its the tuner...

troy2003

yea, its already planned for the new tune in about a month, with the new diaphragm and spring, but is that what could be causing me losing boost in high gears at full throttle, and also maybe the fuel pump??....when he told me i was maxing them out, i thought 'huh????, wait......what????'

itssteve16

i dont get how you upgrade the injectors but dont do a fuel pump it just makes sense to do both

troy2003

i wasnt sure it would be a necessity, but from what your saying it is advised, so ill definately be ordering that soon, thanks bro

Fabrik8

Have you upgraded your fuel lines, and do you have a fuel pressure regulator? An FPR can hurt fuel pump flow if the pressure is above stock.

troy2003

only fuel upgrade was to the 550 cc injectors, along with the walbro fuel pump, would new fuel lines and the regulator help remedy my issues?

eclispegs2008

you shouldnt be maxing 550's at 2xxhp. A rule of thumb i heard somewhere was for whatever hp your planning to hit have a cc injector 100cc above your hp. Regardless i think 550's would hold 350hp easy. If your tune is on a apexi vafc or something like that then youll be rich if running a lower boost than the tune. If its a chipped ecu tuned on crome, ect youll be fine. I cant really say whats up with your problem though without a little more info. It would be a good idea to have a fuel pressure gauge and regulator to rule the fuel out though.