# Turbo rpm at idle?



## NovRus (Oct 29, 2002)

As topic says: What is the rpms of a turbo (actual turbo, not car) at idle on a MK4 or any other stock car? Thanks!


----------



## turbojeta3 (Feb 23, 2002)

*Re: Turbo rpm at idle? (NovRus)*

900-1000.
any other than within reason you either have a boost leak or something isnt hooked up right. vac line etc....


----------



## Agtronic (May 14, 2001)

*Re: Turbo rpm at idle? (turbojeta3)*

I think he wants to know how fast the turbo is turning when the car is at idle ...
I would also like to know out of curiosity ...


----------



## BlkVentoTurbo (Oct 15, 2002)

*Re: Turbo rpm at idle? (Agtronic)*

(in a strange voice ) i will say....... 1 yes that is the aproxomite value
.... i would also like to kow this


----------



## Mike GP (Jun 13, 2003)

I'd say about 4-5000 Rpm ( Impeller speed)


----------



## StevenT (May 28, 2002)

*Re: Turbo rpm at idle? (BlkVentoTurbo)*

If your motor is idling, there is no load so there would be no boost. The wastegate would be venting most of the exhaust gases and The turbine would still be turning, but below the boost threshold.
Grab yourself a compressor map, calculate the CFM of air the engine would be pushing at idle then plot it on the compressor map, there ya go








Maybe it would turn at 15k RPM? dumbassed guess..



_Modified by StevenT at 11:29 AM 10-23-2003_


----------



## speed51133! (Aug 5, 2002)

*Re: Turbo rpm at idle? (StevenT)*


_Quote, originally posted by *StevenT* »_If your motor is idling, there is no load so there would be no boost. The wastegate would be venting most of the exhaust gases and 

true, no boost or load, but the wastegate will NOT be open. A wastegate's natural state is closed. I assure you of this.
the rpm of the turbo TOTALLY depends on what motor your dealing with, and WHAT TURBO!
not only what turbo, but what A/R ratio the turbine housing is. WHat kind of bearings does the turbo have?
I mean this is like asking what is the rpm of a guy's car when hes going up a hill?


----------



## garyw (Oct 17, 1999)

*Re: Turbo rpm at idle? (StevenT)*


_Quote, originally posted by *StevenT* »_If your motor is idling, there is no load so there would be no boost. The wastegate would be venting most of the exhaust gases and The turbine would still be turning, but below the boost threshold.


When I start my car in the morning, I can hear the exhaust venting out the wastegate. Not sure if it's suppose to be like this, but the engine is only at 1200rpm and aroudn 15in-hg vacuum. Once the rpm drops back to normal idling speed and vacuum going back to 20in-hg, the wastegate closes.
anyone know is this normal? I thought they only open when it reaches to a certain amount of boost, but not in vacuum?
My intake shifterrods is also engaged when its a cold start also cause I can see it move when it goes back down to normal idling.
Gary


----------



## NovRus (Oct 29, 2002)

*Re: Turbo rpm at idle? (speed51133!)*


_Quote, originally posted by *speed51133!* »_
the rpm of the turbo TOTALLY depends on what motor your dealing with, and WHAT TURBO!
not only what turbo, but what A/R ratio the turbine housing is. WHat kind of bearings does the turbo have?
I mean this is like asking what is the rpm of a guy's car when hes going up a hill?

I realize this and that is why I said I didn't care what car it was, just an approximate value would do. I mean the turbo can't be spinning 50,000 rpm at idle, unless it is a small turbo on a large engine, right? I was just interested if there were any factory numbers out there.
Any info is useful.
As far as a wastegate goes, isn't it a diverter valve that opens up when there is too much exhaust pressure? So in that case, if your wastegate is open at idle, then you have too small of a turbo on your VR6. Correct me if I'm wrong, because I don't have a turbo, but I love them. One of mans great inventions.
:edit: Actually, it wouldn't be too small of a turbo, it would be just right. It makes since that your wastegate is open since you probably have a larger turbo and it hasn't reached any speed yet, thus there is allot of exhaust pressure, thus the wastegate is open. So actually your set-up would be alright in that case.


_Modified by NovRus at 12:27 AM 10-24-2003_


----------



## garyw (Oct 17, 1999)

*Re: Turbo rpm at idle? (NovRus)*

Well, being the vacuum at 15in-hg, idling at 1200rpm and no load on the engine, I don't get why the wastegate is opening. I thought it should only open under boost, not under vacuum.
It closes off when the idle drops back to 800rpm.
Gary


----------



## Boragirl03 (Nov 23, 2002)

*Re: Turbo rpm at idle? (turbojeta3)*

yes, mine is around 900...real smooth (that stock feel)


----------



## GTibunny16v (Aug 12, 2001)

*Re: Turbo rpm at idle? (Boragirl03)*

Trying to figure out how fast a turbo is spinning at idle. You need to know turbo size, exhaust housing size, turbine wheel, motor size and flow. 

Just look at a 1.8t those tiny ko3's spin pretty quick at idle. But Ive seen a T72 on supras that just barely spun at idle.


----------



## nycvr6 (May 4, 1999)

*Re: Turbo rpm at idle? (GTibunny16v)*


_Quote, originally posted by *GTibunny16v* »_Trying to figure out how fast a turbo is spinning at idle. You need to know turbo size, exhaust housing size, turbine wheel, motor size and flow. 

Just look at a 1.8t those tiny ko3's spin pretty quick at idle. But Ive seen a T72 on supras that just barely spun at idle.

My turbo doesnt spin at all at idle.


----------



## GTibunny16v (Aug 12, 2001)

*Re: Turbo rpm at idle? (nycvr6)*


_Quote, originally posted by *nycvr6* »_
My turbo doesnt spin at all at idle.









lol http://****************.com/smile/emthup.gif


----------

