Rev limiter: fuel cut or spark cut?

[encomiast]

Hi all,
I tried the search, but I didn't come up with anything useful. I wondered if the rev limiter on the 7M-GTE cuts fuel or spark.....
I'd guess it should be fuel cut since excessive fuel because of spark cut might damage the cats, but I'm not sure.
Can anyone tell for sure?
Thanks!

 

[lagged]

IIRC the rev limiter randomly cuts pairs of injectors.

 

[mk3ukr]

I think it cuts ignition first, then at rpm level 100 or 200 higher cuts fuel. To cut fuel only is dangerous, you can lean out and melt pistons
Vladimir, 89T

 

[figgie]

i think don't count

think of it at a logical standpoint.

If we have ignition cut. Fuel will still come out of injectors and out the tail pipe unburned. What does the EPA NOT like?????
Also what would happen the MINUTE we turned igntiin back on with UNBRUNED fuel in the exhaust?... 2 step anyone

we have FUEL cut rev limiter.

 

[figgie]

I think it cuts ignition first, then at rpm level 100 or 200 higher cuts fuel. To cut fuel only is dangerous, you can lean out and melt pistons
Vladimir, 89T

no

completely cutting fuel will not do anything

zero fuel means ZERO combustion.

 

[gixxer750]

I would think it would be ign.... I usually get flames out the exhaust on the rev limiter...... Gotta be some unburnt fuel there for flames... However, I could have no idea what I'm talking about also!

 

[figgie]

I would think it would be ign.... I usually get flames out the exhaust on the rev limiter...... Gotta be some unburnt fuel there for flames... However, I could have no idea what I'm talking about also!

think about that... what would the good ole EPA say about that much unburnt HC coming out the tailpipe??

Trust me it is not igntion cut. There was a thread where one guy controlling the injectors with a haltech went up to 10k rpm. Stock ecu was still controlling the ignition

 

[mk3ukr]

no

completely cutting fuel will not do anything

zero fuel means ZERO combustion.

When I said about leaning out I meant stupidly keeping gas pedal down and bouncing on - off rev limiter.
Just now checked AEM base calibration file for mk3.
Ignition cut - 7200rpm
Fuel cut - 7400rpm
I am not sure if they imitated rev limiter parameters from stock ECU, but it is way more higher than stock 6500rpm
Vladimir, 89T

 

[encomiast]

Thanks for your replies guys, even if they're rather controversial, lol.
I'm just asking because I'm probably getting an e-manage ultimate, which is supposed to be able to disable the factory rev limiter IF the rev limiter is only cutting fuel.
So if it's possible to increase the rev limit by controlling injection with the Haltech, I guess it should also work with the eman (provided that I get it to work with the 7M-GTE at all).... woot.

 

[figgie]

When I said about leaning out I meant stupidly keeping gas pedal down and bouncing on - off rev limiter.
Just now checked AEM base calibration file for mk3.
Ignition cut - 7200rpm
Fuel cut - 7400rpm
I am not sure if they imitated rev limiter parameters from stock ECU, but it is way more higher than stock 6500rpm
Vladimir, 89T

there is a reason why AEM, Motec, Haltec, electromotive all put a DISCLAIMER on the stand alones that basically states:

"This part is for OFF ROAD USE only."

Again standalones do thing differently hence why NONE of them can legally be used on the street.