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Turbos which keep spinning long after the car stops

Bass Junky

By Bass Junky,
in Engines & Forced Induction

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Bass Junky Grand Master

Bass Junky

Posted
Posted

hey ppls.

I'm looking at a new turbo (high flow) soon, and I have seen a fair few turbos lying around in various forms over my time.

When you spin the wheels by hand, some spin heaps some not at all.

Plain bearing turbos dont spin at all after your finger comes off.

Ball Bearing turbos spin a few revolutions, but some keep spinning for a long time after the car stops.

This HAS to be a good sign that the turbo is free to spin as much as it likes.

So, is there a special bearing or something that makes this happen?

Is it a Ceramic bearing that does it?

Do the GCG high flows do it?

All Help Appreciated.

BASS OUT

SeriesIIGTST Mentor

SeriesIIGTST

Posted
Posted

Hi Bass, I know that my HKS GT2535 unit will spin for about 10-20secs after my car is turned off, even if i only turn it on for a min, move it 10m to make room for my housemate getting out of the drive then turn it off again. That's a ball bearing turbo but whether or not it's a special type of ball bearing, i have no idea.

Sorry, can't comment on GCG highflow.

PHaT MR30 Grand Master

PHaT MR30

Posted
Posted

Just a good garrett ball bearing i would say, i know that a guy down here has a ball bearing turbo on his S2000, and just b4 he shuts the engine off he give it a short rev and the thing spins down for about a minute!

Cubes Grand Master

Cubes

Posted
Posted

I've had a few turbo's in and out of the car. All stock Nissan items. VG30DET, RB20DET etc.

Off the car they spin freely but don't really keep spinning when I let go of them.

Once installed on the car and they get some oil pressure in to them if I pull off the piping and then spin them they will spin for quite some time if I give it a little spin by hand.

I often hear the stock item spinning down after idle.

Cubes Grand Master

Cubes

Posted
Posted

I've had a VG30DET on the old RB20DET and pulled it off because it laaaged too much.

But yes.. I've got injectors etc now so I can bolt the vg30 turbo on.

Uni's started back up so its finding the time. :P

This new years I'll be buying a GT30 SB8006A chra and .7 comp cover and have the vg30 turbine housing machined up to suit.

Should work well and be a little more efficient at higher boost levels due to the .7 comp cover.

SLY33 Mentor

SLY33

Posted
Posted

how a turbo spins when its off the car and you spin it with your fingers is not a good indication of how free it spins!

depending on whether its new, used, has a bit of dust in the core, getting dry, etc... you'll find many second hand turbos that have been sitting wround a while to feel gluggy and not spin very well, but get them on the car and you'll hear them spin down after shut off.

i believe any half decent ball bearing turbo that has steel wheel will spin for some time after shut down. not so much the stock ceramic stuff, maybe not enough inertia in the wheels to keep them spinning for long after you turn off.

Bullant47 Community Regular

Bullant47

Posted
Posted
hey ppls.

I'm looking at a new turbo (high flow) soon, and I have seen a fair few turbos lying around in various forms over my time.

When you spin the wheels by hand, some spin heaps some not at all.

Plain bearing turbos dont spin at all after your finger comes off.

Ball Bearing turbos spin a few revolutions,  but some keep spinning for a long time after the car stops.

This HAS to be a good sign that the turbo is free to spin as much as it likes.

So, is there a special bearing or something that makes this happen?

Is it a Ceramic bearing that does it?

Do the GCG high flows do it?

All Help Appreciated.

BASS OUT

Hi Pete. I don't know if GCG uses these all the time buy they built mine with Ceramic Angular Ball Bearings.

Ian

ferni Grand Master

ferni

Posted
Posted
Just a good garrett ball bearing i would say, i know that a guy down here has a ball bearing turbo on his S2000, and just b4 he shuts the engine off he give it a short rev and the thing spins down for about a minute!

So he revs it up, spins the turbo up and turns off the ignition which shuts off the oil pump/feed. Wow, really smart, hope he doesn't expect his turbo to last long :D

ferni Grand Master

ferni

Posted
Posted

spinning it with your hand would be alot slower than it spins when being pushed by exaust gas. Also doing it once or twice with your fingers wouldnt matter, but doing it everytime you turn your car off, can't be good for it?

GTRgeoff Grand Master

GTRgeoff

Posted
Posted

Not a great idea but these are more for longevity rather than response. The bearings add weight to the rotating parts. A good plain bearing should have no contact as it floats in the viscous oil pulled around the journal. It will not last as long though, but well cared for will give a good life.

Race__24 Experienced

Race__24

Posted
Posted

I would gesss that most ball bearing turbos would have a small amount of pre-load in the bearing so that when it has been run for a while it comes within optimum tolerance. Heat would also play a factor as only .01mm difference would be needed to dramatically change how well it would spin.

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