OK, you're going to have to explain that one to me Sam. I know what parasitic losses are and I've been involved with about a half dozen supercharger installs. Not a single one of them had a raised RPM after the install to to account for the "parasitic losses".

At idle you are looking for smoothness and vacuum. Why does the RPM have to be bumped up to achieve that? Is the VQ so low on torque at idle that it needs to rev up in order to spin another pulley?

Another thought: The supercharger is not pushing any air at idle. The engine is under vacuum not boost from the sc. In other words, no parasitic losses (or at least very near zero).

 

Remember, at idle you're looking for some sort of equilibrium. You want to balance out the torque from the engine with all torque consumers (AC, Alternator, Accessory etc..)

Adding a supercharger only adds load to the engine at idle, remember the engine is still spinning the SC pulley and the compressor, even if it's not making any boost.

 

Yeah but the SC is in near free spin, it's not compressing anything. And it doesn't make sense that no other cars required a bump up in RPM after a sc install. I'll look into it more later.

 

Well something has to spin it at least lol

 

Yeah, but that's like saying, "if you add another idler pulley, you have to raise the rpm." That's not right.

 

Are you really comparing a SC kit with an idler pulley?

 

Man...some people on this forums either have huge egos or just want to argue....

 

Agreed. It would be nice to not have to filter through you two. I'd like to be able to open up this thread and read about how the install is going and nothing else.

Thanks.

 

Filter this...

Explain to me the reason for the increased rpm at idle. That's all I want to know. And it's not parasitic losses at zero boost. Contribute something to the forum instead of whining.

 

Grab a copy of EFI Advanced Tuning book and stop being stubborn lol

And besides, it's her car why do you care so much lol

 

same RPM with a higher higher output would compensate for the parasitic loss of the S/C.

I stand by the larger injectors being the primary cause for the higher idle. Of course, Sam (@GTM) could clear it all up with a firm answer...

 

GTM twin turbos run the same 600cc deatschwerks, but the car idles at 650rpm. Dont have any complications...

 

Yeah but Twin Turbo's don't exactly have a pulley connected to the engines crank do they?

 

Stock idle setting, no reason to change that, did not even have to le learn the idle .

Sam

 

I was responding to the post right above mine, which said