Rev Cut - Fuel or ignition?

[spetz]

Hi guys,

Just wondering on the 6A12 MIVEC how is cut off controlled?

[Shane001]

Fuel

[spetz]

So an e-manage ultimate can raise the rev limiter?

"Rev Limiter Cut - For vehicles with a fuel cutting controlled rev limiter, this feature will drive the injectors past the factory rev limiter. *This feature will not work on vehicles with rev limiter controlled by ignition cut."

[Shane001]

Yes

[spetz]

Would there be a map though beyond the rpm limit of the ECU?
ie, after 8,200rpm what will happen?

[Shane001]

Don't know, tell you tomorrow

[spetz]

You have an ultimate on your car?
If so how did you set it up, as I thought they were model specific?
And is it worth it over the blue?

[Shane001]

You have an ultimate on your car? - yes, racecar.
If so how did you set it up, as I thought they were model specific? - they are, long story...
And is it worth it over the blue? - never used a blue.

[spetz]

Have you found any site that outlines the differences? Preferably in simple terms.

Also, the map on the ultimate is 16X16, same as the blue right? Which is 16rpm points, and 16 different throttle positions?

[BorepYano]

Would there be a map though beyond the rpm limit of the ECU?
ie, after 8,200rpm what will happen?

valve bounce

then eventually boom piston through the bonnet/firewall i guess

[spetz]

No it'd be fine for a little bit more. 8,500 definitely would not cause problems.
But my question was more in the context of what would happen in the sense of engine control, ie, once it is above the factory rev limiter would there be a map on the ECU?

[Shane001]

Well I didn't get this to work today but with passengers in the car all day I didn't have any time to be playing with it. I'll fine tune this next time I'm at Wakefield.

Stock ECU map won't matter as the Emanage controls the fuel during the rev cut rev range you program in.

[spetz]

Will it control it? As it doesn't control as such, it just alters, and if there is nothing to alter, what will happen?

Also, the map base, is it 16 X 16 in the sense of 16 rpm points and 16 throttle positions per rpm point?
Or am I way off?

[Shane001]

The rev cut map is based on duty cycle, you set the starting rpm and duty cycle, and the ending rpm and duty cycle, so yes I expect it controls it based on this information that you enter.

Yes 16 x 16.

[spetz]

16X16, but is it rev ponts X throttle positions, or something else?

[Shane001]

U can tune on throttle position, airflow pressure or absolute pressure.

For a GPX you would use throttle position or absolute pressure (ie manifold pressure).

Download and install the software and have a play

[merlin]

Perhaps I can chime-in here with some details:

The stock rev-limit (8117rpm) and stock speed-limit (184kph) are both fuel cut and both can now be re-tuned in the stock ECU if it is post 1998.

The stock fuel map rpm scale runs out to 8000rpm.
The stock spark map rpm scale runs out to 8000rpm then jumps to 20,000rpm.
These scalings can be re-configured to something more appropriate to higher reving engines.

[Shane001]

To remove the stock speed limit all you need to do is cut the wire

And are you sure the rev cut is 8117? The rev cut on my GPX is definitely up around 8250.

[merlin]

I have examined only one ROM, a GPX (UK) and it was set to 8117rpm. For sure others may be different and I dont know how many varients there are.
Cutting the speed input wire will affect several routines, one of which is definately the fan control.
Mitsubishi also sometimes do some gear-based calcs which need the speed input. I have not worked out if thats the case here, but there are a number of spark maps so its a possability.

[Kustom]

See.. this is where I shine and go right up to 10k easy if I increase the rev limit. Don't have to worry about pistons and shiz.