I am trying to find out the most boost I can run before my ECU cuts it off.

I want to run race gas at the track and boost to 23 psi, but was told the ECU won't allow me to boost that high.

I am going to get a dynoflash and Greddy Profec B II. Trying to figure out which one I should get first.

Thanks

 

1) Fuel cut is not a function of boost, but rather a function of airflow. It just so happens that more boost means more airflow, so you usually see fuel cut at higher boost levels. There is no pre-defined boost level that will cause the ECU to cut fuel, though. I ran 23, 24, 25, 26 psi without fuel cut on race gas, but my SAFC was allowing me to fool the ECU into thinking it was seeing less air, so that basically delayed fuel cut to beyond what I was running at the track.

2) After you get Dynoflashed, there is no more fuel cut whatsoever.

 

What year is your EVO ?
My is 03 and I didn't have any problem boosting to around 22 maybe a little more running the XEDE without XEDE Flash , when I was going to run anything above 23 psi the boost cut off .

 

yeah i have run up to 25psi easily on my E7 with stock ecu

 

i m running 29psi on stock turbo no problem here!

 

me too

 

He didn't ask about the stock turbo. He's asking about fuel cut on the stock ECU.

 

Don't cry when you melt the turbo.


I have my settings on the Profec at 21 'lo' and 27 'hi'. Also I have the 280 cams, and many other mods. My warning is set at 28psi.

 

before i got the flash, i was getting boost cut at 23-24psi spike in my 04 with 10.5 hot side and intake. i thought that was way too early

 

he wont hurt that turbo my friend ran 32psi (not efficientally) but it did. he had no problems + a 75 shot btw this was an race gas.

 

Anybody who's smart (cough Warrtalon cough) could you answer me this:

If I just purchased an MBC, say forge... Could I turn the boost to 25 and run on 91oct day-to-day with NO OTHER mods?

 

No, I would not recommend that at all on 91 oct. Unless you are running alky/water injection, or race fuel.

 

 

25 psi with 93 octane is the ecu limit. well, on my car it was.

We've tested this on a dyno.

It'll start mis-firing, as well as limiters start coming in. (fuel cut/boost cut).

Your turbo turns red hot at that moment.

 

Every car reacts a bit differently! The only way to really know what is acceptable is to hook up a wideband and check your a/f ratio throughout your rpm range. If hooking up a wideband and reading the a/f data is too time consuming, you can always hook up an exhaust temp. gauge to see if things are getting too hot.

But one would think that 1 psi higher wouldn't be detrimental.