ZeroBanger

ok, I have searched and so far I found that some of you think 14.7 is 1 bar, some think 14.2 and some think 14.5. My calculations and research came up with 14.22 psi=1 bar, but most searches I do seem to say 14.5, so first I need confirmation is 14.5 1 bar?

Next I researched that the power FC can only read 1.2 bar, which is 17.4 psi, am I correct?

Ok I have been having nasty fuel cut issues for ever and I have tried alot and nothing works, I do know I spike (but dont creep).

I know the reason its spikes is because if you .25 over your target boost. Since the PFC cant read over 17.4, if I set my boost to 1 BAR, I cannot get a fuel cut since the sensor cant read it, am I right?

93BlackFD

no, bar is not the same as what the powerFC reads....

powerfc reads in kg/cm2

ZeroBanger

can you translate for me then?

skotx

1.0 kg/cm^2 = 14.22 psi
1 bar = 14.5 psi
1 atmosphere = 14.7 psi (this is atmospheric pressure)

From the PFC manual: When using the factory pressure sensor, boost levels over 1.2 kg/cm^2 (17.06 psi) cannot be accurately measured.

If you set your boost to 1.0 kg/cm^2 (14.22 psi) you would have to spike to 1.25 kg/cm^2 (17.78 psi) to incur a fuel cut.

I've seen your previous posts on fuel cut, and I recall you saying that your spike isn't registered on the PFC max display. My spikes never register either, but my Apexi boost gauge picks them up. My theory is that the PFC isn't sampling fast enough to see the spike, but that's just a guess. To my knowledge, I've never experienced a fuel cut, but I don't tend to push my car extremely hard.

-Scott

ZeroBanger

yea scott, thats right, when driving normal it does not cut, it only cuts from 2nd to 3rd gear when 2nd gear is at or near redline and I shift fast into 3rd.

Hoping setting it to 1 bar will fix it.

twokrx7

iTrader: (1)

With the stock map sensor 1.15 is all the PFC will read. If you set your boost setting to higher than this it will not fuel cut. Assuming you are not using the PFC to control boost of course.

ZeroBanger

Im using the power FC to control boost, why should that make a difference?

es

Have you tried lowering the boost solenoid duty cycles to try & reduce the spikes?

ZeroBanger

Yes, but lets put it this way..

say I have .90 set as my target boost and I have .68 set as my selenoid, I have a likely hood that I will spike, if I dont spike I will hit a good .90 or .91 on my boost at the end of my run.

If I set my boost to .90 and selenoid duty to .50 or .54, I may not spike but I will hit like .78 or .80 on my boost. It doesnt quite work for me.

I thought I could set 1 BAR as my boost and then set my duty cycle back, maybe to .50 or .54, and I may hit .90 or .95 as my boost. I have injectors, FP, power FC, so I'm not worried about the spikes, its just the fuel cut.

ZeroBanger

I ran it at the track tonite and aside from almost wrecking, it did solve the boost cut problem, which is exciting. It did spike like crazy and caused me to spin through 3rd and almost lose control, but hey..no fuel cut.

LOL

Silver93T

You can get a gm 3 bar map sensor

ZeroBanger

Why do I want a 3 bar map sensor? The whole point of raising my boost was so the power FC cannot register teh spike, and it worked. If I get the map sensor I'll hit my fuel cut again, No thanks.

If I ever go parallel, I'll probably get one, but I dont plan on running more than 14-15 lbs anyway.

Later.