Fuel cut options

[John Hartman]

Razor's not withstanding, I pose you this:

Supra's also have fuel cut. At least 3g Supras.  I suspect other cars that work this way do too.

I pm'ed you about this, so whats the cause??

[Fraser Cassells]

There is no relation to quantity of fuel, it is mass issue. The ECU does not care if you are going to run out of gas, it just see's a specific density of air entering(in relation to the set boost level) and shuts off the fun to prevent theoretical damage from a higher then expected stoichiometric ratio that it has calculated.....  guh.

[Chris Andrews]

Ok, Supras are a totally different car.  

John, you have PM.....

Fraser, thats right out of TMO's web site.

I want proof.  Not what Todd Day says........

[Fraser Cassells]

TODD ROCKS! he is one fart smeller. Keydiver is quick too, he needs more recognition

[Chris Andrews]

I agree that Todd Day is smart.

Show me the PROOF!

[Fraser Cassells]

He is smarter than me AND that Mike J dude is too, they both agree on the same basic premis behind fuelcut, AND Blaha, AND Dave B... on and on. I can see this turning into another raging debate that has resurfaced numerious times in the old digest.  My 2Gmass hit fuelcut ( i tried hard but it managed to do ti for a test) so the blanket statment doesnt fit.



must aquit

[John Hartman]

hmm, Fraser hit fuel cut too, must ammend PM to Chris

oh, here it is, just popped up

/edit, sorry just Robin about a HUGE turbo/

[Chris Andrews]

There you go, raining on my parade.  

But seriously, I want someone to prove that ECU induced fuel cut happens at xxx air mass.  That is, at say  2000hz at -10'C as an example.  

Just what is the limit?   Nobody knows......

[John Hartman]

The rain in BC falls mainly in Terrace...

Soooomebody does...

He just works at Mitsu, and is not allowed internet access

they gots to keep thier secrets somehow

Someone will figure it out tho, people are workin on this here ECU lots lately.

Jamey Sibley wrote his own code for his own home built translator, I saw it with my own peepers.

There is at least 2 other guys out there working on thier own ECU.  Not Todds, totally new code.

It would be nice to have it as a quantitative analysis tho so we can be sure, but we do know that it happens and mostly what makes it happen.

Jovan, go block off part of your upper plenum in your MAF, and take er for a rip, its cool out

[Fraser Cassells]

I am sure it is a variable that is dependent on lots of conditions. We see the proof in how often we see actual FC. No preset value but a preset "X" set of conditions that must be met, that initiates cut.  ?? ~!!!

[John Hartman]

ahh,screw it, I'm gonna hook up a Holly 750 double pumper!!

Fuel cut that, Biatch!!

[Chris Andrews]

So what conditions?     Alas, you guys have beaten down my spirit with your dogmatic adherence to the archives.....

Anyway, Todd says that you hit ECU fuel cut before you overrun the 1G mas.  He states this on his website, using a 20G at 19 psi on a 1G car:

After we removed this limit, we were only able to hit the MAF counting breakdown problem on a first generation DSM with a 20G set to 19 psi on a 3" exhaust.

When I put my 3" exhaust on my 20G turbo, turned up the boost and hit "fuel cut", I logged my car and only found mas overrun.

According to Todd, I should have hit this fuel cut before overrunning.   Never happened.  Put in the 2G mas to solve the overrunning, and no fuel cut since.  Evar.

Maybe my car is special.   Or maybe you guys are doing something wrong.   But I come by my skepticism honestly.   ECU induced fuel cut has not been in my experience.

[John Hartman]

I'd say there are "super" Ecu's out there.  I believe I have one and so does Chris.

I have only hit fuel cut once.  It was cold, I had 20 psi dialed up by mistake, and I had the tunes going so loud that I couldn't hear clearly and floored it in 1st.  As you all know 1st runs out mighty quick with the right foot flat!!  I logged 7500rpm.  Oh, wait, I just had another thought??  Maybe rev limiter??  

So maybe I hve never hit it??

I have sometimes a soft, gentle fuel cut I think.  It sorta gently bucks, my head will rock back and forth, but no BAMMM!!  like some people say.

[Mike Schmid]

I know I bounced the talon off the rev limiter in 1st at 7500rpm... it was definitely rev limiter too.  From what I've heard real fuel cut is like hitting a brick wall.

[Jovan Ceklaj]

John, log your car and TRY to get fuel cut. You'll be able to see the injector D/C spike down to zero when it happens.  Thats how you know what it feels like. I find I don't feel the gut wrenching, wall smashing drama that everyone seems to come up with.  The best way I can describe it for me was kinda like a chattering clutch (basically bucking kinda hard).

I'd actually like to know what formula the ECU uses to calculate when fuel cut happens.  It cant just be Karmen frequency and air temp, what about if I was getting 1600 hz and 10 deg. C at sea level and then I went up a huge mountain and was getting 1600 hz and it was still 10 deg. C. The air would obviously be less dense.  Knowing this magic equation would solve this.... :?

Jovan