MT-82 Question/ Normal Operation?

[2017-RS3]

Hey Guys, I have a 17 Roush with stock blower and tune. Im having an issue with my car idling at about 550rpms when in neutral and the clutch released. Idles at 700 when I push the clutch in. I thought is was slightly misfiring so i changed plugs and no improvemnt. I don't know much about how manual transmission clutches work but it seems like it is causing slight pressure when the clutch is out and causing the RPMs to drop slightly and the chugging noise from exhaust is just low rpm idle and the motor trying to compensate and catch itself so it wont stall. I know the Mt82 isn't meant for the amount of torque the superchargers add. Does anyone else's RPMs drop in neutral when you release the clutch and then jump up 150 rpms when you push the clutch in?

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[HoosierDaddy]

FWIW Depressing the clutch on my stock 2016 GT PP always raised the idle a little. It may be the computer making it a little less likely for a novice to stall from a stop.

 

[MrBD1348]

FWIW Depressing the clutch on my stock 2016 GT PP always raised the idle a little. It may be the computer making it a little less likely for a novice to stall from a stop.

my 22 does this too. Pretty sure it’s exactly this.

 

[2017-RS3]

FWIW Depressing the clutch on my stock 2016 GT PP always raised the idle a little. It may be the computer making it a little less likely for a novice to stall from a stop.

Thank you. Good to know!

 

[Grimmer]

My 2016 does this as well. If the clutch is pressed rpm goes up. Hold your foot on the brake with the clutch pressed for a few seconds and it goes back down. Release the brake and it pops back up. As mentioned above, likely a programmed anticipation of impending 'go time' . I've wondered if it isn't tweaking more than just the idle point since that small of an rpm increase probably wouldn't make much difference for launch. Perhaps the mixture as well...?

 

[Grimmer]

Mine also allows the rpm to drop during an upshift but hovers at the rpm needed for the next gear for a few seconds. Unless I touch the brake, then it drops to idle without pausing at the next higher gear's rpm.

 

[Tucker80]

Every manual car I've ever owned does this. I always thought it was due less rotational resistance once the clutch is no longer spinning the flywheel. Less weight to spin = idle rpm goes up. Didn't think the computer had anything to do with this since it's been happening on all my manuals back to the late 90's.

 

[Fetlock]

FWIW Depressing the clutch on my stock 2016 GT PP always raised the idle a little. It may be the computer making it a little less likely for a novice to stall from a stop.

Is it even possible to stall a Coyote? lol

 

[MrBD1348]

Is it even possible to stall a Coyote? lol

yes. I watched the lube tech stall my car 3xin a row when getting my “complimentary service” at the dealer I purchased from

 

[Grimmer]

Every manual car I've ever owned does this. I always thought it was due less rotational resistance once the clutch is no longer spinning the flywheel. Less weight to spin = idle rpm goes up. Didn't think the computer had anything to do with this since it's been happening on all my manuals back to the late 90's.

Mine will change rpm as soon as the clutch pedal comes off the upper switch, before any pressure is applied to the clutch. It will also go up or down with the brake pedal switch when the clutch pedal is down.

I suspect that they wanted it to idle at the higher rpm but are reducing the idle when expecting the car to be sitting still for emissions.

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