Fuel cut to limit power

[diracdeltafunct]

I have a 3S-GTE running with the EMU standalone ECU.

I want to limit the power for street use, I know this is probably not the ideal solution, but will it hurt my engine to set the fuel cut to 4500 RPM?

The 3S-GTE has a stock redline at around 7000 RPM. Will it be dangerous for the engine to suddenly have the fuel completely cut at 4500 RPM under full load? I'm assuming this is okay, but I'm asking just to be sure. I imagine it is possible that the engine would run extremely rich for a brief period when the fuel is cut, is this a problem? Any other considerations?

I need some easy, temporary way to limit the power that doesn't require me to make a new fuel map or do something else that I don't understand.

[samvel]

On turbo engine You normally limit power with boost level.
But You can also shift earlier and/or not using full throttle.
Is it so powerful?

[astra vxr]

Would it not be Easyer to turn the boost down ? Or run gate pressure for street

[diracdeltafunct]

I'm not sure it will be low enough to meet regulations for street use. The lowest boost setting is too much. Not that the car makes an incredible amount of horsepower, it is just a matter of regulations for street use. Cutting the power at at particular RPM would let me easily pick whatever target horsepower I want based on prior dyno graphs. I just need to know if this will harm the engine in some way that might not be clear to me.

[astra vxr]

by rights it should cause any damage as its no differnt if its 4k or 9k i just dont see the logic in building a car that you carnt use on the street if its ment for the street

what are your regs on street use and what sort of hp do you have ?

also say you make yours cut power at 4.5k and you drop 1 k between gear changes its not going to be very nice to drive around like that and you will be forever in the limiter driving the thing

i would look for another way of reducing power instead of the limiter

[Jadzwin]

I suggest to make the 2nd tables set, limit boost to minimum, retard ignition little a bit.

[diracdeltafunct]

by rights it should cause any damage as its no differnt if its 4k or 9k i just dont see the logic in building a car that you carnt use on the street if its ment for the street

what are your regs on street use and what sort of hp do you have ?

also say you make yours cut power at 4.5k and you drop 1 k between gear changes its not going to be very nice to drive around like that and you will be forever in the limiter driving the thing

i would look for another way of reducing power instead of the limiter

I need to limit power to 170 hp before I can drive it. The car has about 300 hp at the moment.

I think it makes more than 170 at the lowest boost settings. I don't have the experience to change the fuel map nor the ignition timing.

[ATS_Scott]

If you think it will make under the 170Hp with boost at minimum, just remove any boost control you have, and replace with a hose from boost source to WG actuator.

Is your TVIS still in place? You could activate that to cause an intake restriction, if boost alone is not enough.

[Karel]

Or switch 2 cilinder off .... like Mercedes does

[diracdeltafunct]

Thanks for all the suggestions.

But since no one has pointed out it would be harmful to the engine it seems fair to assume it is not harmful?

As for the two latest suggestions:

I'm pretty sure it makes above 170 hp at the lowest boost settings, I was told around 200. I'm not sure if the TVIS is still in place (this also shows how low my skill level is, so it would be nice with a simple solution).

Is it safe to switch off two cylinders? How would I do that? Could it be damaging if I only turn off the fuel to the cylinders, but it keeps attempting to ignite the spark plugs on these cylinders?

[samvel]

Revlimiter is harmful in my opinion. Maybe not so harmful on 3s type of engine, but valvetrain will not like to drive on limiter continuously.

Whats minimum boost with actuator direct connection? You can install weaker actuator for even lower boost in case of internal WG or weaker spring in case of external WG.

200 vs 170 is not so big difference. I wouldnt change anything, just make lowest possible boost and just adjust power with pedal and shiftpoints. You can also limit max throttle mechanically.