Rpm Drop

[17gt07]

I’ve had some weird driveability issues since I bought my 15 gt but I hardly drive it so I don’t get bothered by it too much. But one thing that annoys me is how the rpms seem to drop too much while shifting into certain gears. 1-2 and 2-3 is usually fine but 3-4 and sometimes 4-5 the rpms drop a little too much so once I let the clutch out it’s like when you push start a manual. The rpms jump a few hundred rpm or so to match the speed of the engine. I know it has an aftermarket clutch but could it have a lightened flywheel too? Maybe a tuning issue? I bought it from a dealer so I don’t know the history of this car.

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[John S]

Good luck finding a solution. My 2022 Mach 1 is just the opposite, the factory tune has deliberate rev-hang anticipating the up-shift RPM drop so it will hold too much RPM if I skip up-shift. Ah, the wonders of drive by wire.

 

[robvas]

Maybe you're shifting too early? I mean when you shift a manual the rpm's are going to go where the gearing makes it go

 

[17gt07]

It doesn’t really matter if I shift early or not. I’ve owned 3 other s550 gt’s and this is the only one that does it. I read that lightweight flywheels can cause strange issues like that since they have less inertia. It has a McLeod sticker under the hood so I was thinking maybe it has a McLeod clutch and lightened flywheel but I have no way of telling. It’s not a huge issue but it is annoying nonetheless.

 

[robvas]

i never noticed a light flywheel other than at takeoff from a stop

 

[17gt07]

What does it do in that instance? With mine, I pretty much have to dump the clutch so it doesn’t stall. And when getting on it from a stop, I can hear a small misfire a few times before it really takes off. I’m sure that’s another issue altogether but I thought I’d mention it.

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