Shawns 95 Escort GT

[bomdoutscort]

On a different topic. I'm only running 11 degrees timing and will be bumping it up to 13 or 14 to get that extra power that i am missing. I was also just told that the gtx ecu pulls 2 degrees of timing when you don't have a knock sensor.

[neuspeedescort]

i ran my car at 15 psi and 11 degrees. i changed it one degree on the dyno and made worse numbers and was detoing like mad.


NEUMAN

[CaymenEGT91]

I ran 14-15psi on 14* and the only time i ever encountered boost cut was if i tried boosting in high gear, low RPM say floor it from 60 in 5th, it'd boost cut, but when i was ON IT no problems ever

[Mazda_Powered]

was your setup any different Tino?

[CaymenEGT91]

BP26 ECU,
BP26 mani/VJ20
stock U code VAF,
GTX injectors,
Stock FPR,
4 wire TPS,
CS Downpipe,
2.5" straight pipe from DP to muff.
8lb Flywheel
2.5" I/C piping
So pretty much the same other than the flywheel and DP/Exhaust

[drewhall07]

Nice work shawn. and yea, i still havent figured out the fuel/boost cut yet, but one thing about it is that my wideband is reading 10.0 at half trottle and will start cutting back, i have to barly throttle it(which is like 5psi boost) till almost 5.5krpms, then i can kinda go past half throttle till i shift. idk wtf it is, but is really aggrivating and i want it fixed. i think ima try and switch Vafs, and ECUs and see if i get any diff results


Drew

[bomdoutscort]

I think its because your turbo is a lot bigger than the vj20.

[drewhall07]

Well I wouldn't say A LOT bigger. I'd say barley. Lol. But even if it is runnin 10.0 on the WB, y would it b cuttin bak or not even throwin black smoke out. Its jus weird to me, but this is my first turbo build. :/

[Mazda_Powered]

10:1 is too rich. Typically you want to hit mid 12s

[drewhall07]

I kno its to rich, but everything I try won't change that. I tighten the vaf 12 clicks and doesn't cut bak as much, but still does on WOT and it won't idle right if I have it that tight. Idk wat to do

[bomdoutscort]

hopefully i get my other vafs in the next week.

[CaymenEGT91]

heres a video on the dyno of my A/F i was @ 8psi with stock exhaust @ the time, so the power wasnt great, but it gives a good idea of my A/F thru the RPM range @ WOT

http://www.youtube.com/watch?v=opWd_qq_52g

[neuspeedescort]

i ran an untampered Ucode VAM. i think that is your issue. don't play with it at all. just run it stock


NEUMAN

[cis2711]

hmm. I encounter the IDENTICAL problem as Caymen. However I believe it is NOT boostcut but rather a fuel related issue..LEAN DETONATION. My "boost cut" was triggered under heavy load at low rpms under 4,000rpms...my belief is that the bp26 ecu doesn't have the power enrichment values in it's map to handle 15psi from a vj-20 let alone a larger turbo. It requires more fuel to keep it from detonating at a lower rpm than a higher rpm.. I would assume that installing 460cc injectors and tightening the vaf spring would counter this issue but never get it perfect, but neuman claims one has to have a safc to do it..?

I can't run more than 10psi with an identical setup as neuman otherwise my air fuel ratio gets tooo lean below 4,500 rpms and it detonates....mine is not boost cut. Want to know how I know this??... with the mbc set at 15psi, I can floor it at 4,500rpms and my ecu & vaf can supply enough fuel to keep the air fuel ratio below 13:1 which is still dangerously lean however the car does not detonate/cut One should never, under high boost, go leaner than 12.5:1 and that rule of thumb becomes even richer, 11:1, in high psi/cfm applications.

[cis2711]

As far as drewhall is concerned having fat/rich air fuel ratio will douse out spark..causing a misfire which will seem like the ecu is causing a cut, in fact it is not. So vaf sounds like a culprit or maybe in combination with O2 sensor.

What I want to know/see is a video that shows exactly what each condition is.

Fuel cut. Spark cut. Boost cut. Spark blow out. Lean missfire/predetonation.

They all can seem similar but some more dangerous than others. I'm just afraid to run any higher than 10psi as what I might ASSUME is boost cut is actually killing my engine everytime it "cuts" because it's actually detonating.