Turbo Stockers

[Rob Lloyd]

Originally Posted by Jimi B

I wouldnt be real concerned with it. You know you have a stock turbo. Just get the correct rebuild parts. As far as that dia of the inlet.. It says Turbocharger size will be verified by measuring the housing bore at the leading edge of the impeller wheel. So basically measuring the dia. of the inlet right at the front of the compressor wheel. If you are not aloud to change the wheel I dont see much need play with the inlest size.. Not 2mm anyway. Every little bit helps I suppose. But I would think that you would want the tolerance to be tight right at the wheel...

I'm not to worried about the compressor side. It's the turbine I'm worried about. I have a good turbine housing, but all of my turbines measure at least 0.04 smaller than the housing at the exducer. I think maybe my turbines are worn down pretty far. My guess is it should only have 0.01" clearance, but I don't know for sure what the turbine is supposed to be. I found some specs that say it should be 1.88" - mine measure more like 1.84". Ouch! But, again, the housing bore measures close to 1.88" So, I don't know if that spec is for the housing or the turbine.

You definitely do NOT want 2mm clearance around the compressor. It will cause a very slow boost rise. You want as small a clearance as you can run on the compressor side.

Related question - Art, did you have trouble seizing the wastegate arms? I seem to seize one up every single season. The 'good' turbine housing I mentioned above I shelved because it seized the WG arm. I took it apart and reamed it out, but I'm concerned it will just seize up again. I reamed it with a 5/16" drill (the arm measured 8mm, so there's alot of clearance now). Just gotta get the arm welded back up and put my 'good' turbine in there for Indy...

[art leong]

Originally Posted by Rob Lloyd

I'm not to worried about the compressor side. It's the turbine I'm worried about. I have a good turbine housing, but all of my turbines measure at least 0.04 smaller than the housing at the exducer. I think maybe my turbines are worn down pretty far. My guess is it should only have 0.01" clearance, but I don't know for sure what the turbine is supposed to be. I found some specs that say it should be 1.88" - mine measure more like 1.84". Ouch! But, again, the housing bore measures close to 1.88" So, I don't know if that spec is for the housing or the turbine.

You definitely do NOT want 2mm clearance around the compressor. It will cause a very slow boost rise. You want as small a clearance as you can run on the compressor side.

Related question - Art, did you have trouble seizing the wastegate arms? I seem to seize one up every single season. The 'good' turbine housing I mentioned above I shelved because it seized the WG arm. I took it apart and reamed it out, but I'm concerned it will just seize up again. I reamed it with a 5/16" drill (the arm measured 8mm, so there's alot of clearance now). Just gotta get the arm welded back up and put my 'good' turbine in there for Indy...

It happened to me a few times especially when the car sat for a couple of months. I would just free it up. Then put it back together.
It happened when I sold the car to Jim. Took it to Cecil County Went to the line, The car left like a garbage truck. I knew what the problem was but the look on Jims face was priceless I knew he was thinking what did I come up here for? Loosened it up, ran the expected number. And the car was on it's way to Fla.

If I were you I'd look for some heat resistant preoiled bushing And install that.
It seems to be the leaded gas that does it Jimmy Malone hasn't had it happen to him that I know of and he uses the VP unleaded.

[Rob Lloyd]

Originally Posted by art leong

It happened to me a few times especially when the car sat for a couple of months. I would just free it up. Then put it back together.
It happened when I sold the car to Jim. Took it to Cecil County Went to the line, The car left like a garbage truck. I knew what the problem was but the look on Jims face was priceless I knew he was thinking what did I come up here for? Loosened it up, ran the expected number. And the car was on it's way to Fla.

If I were you I'd look for some heat resistant preoiled bushing And install that.
It seems to be the leaded gas that does it Jimmy Malone hasn't had it happen to him that I know of and he uses the VP unleaded.

I suspected the leaded fuel might have something to do with it.

How did you free them up?

[art leong]

Originally Posted by Rob Lloyd

I suspected the leaded fuel might have something to do with it.

How did you free them up?

With a hammer (chevy tool).

[Jimi B]

Just ditch it and run an external wastegate ha.

[Rob Lloyd]

Originally Posted by Jimi B

Just ditch it and run an external wastegate ha.

The legality of that seems a little gray to me, so I think I'll stay away from them until it's more black and white.

[Mark Yacavone]

I suppose all of this applies to FWD cars where traction is a problem.
You won't melt stuff if you retard the timing appropriately.
Why not use an MSD Boost control?

[Mark Yacavone]

Originally Posted by Rob Lloyd

I'm not to worried about the compressor side. It's the turbine I'm worried about. I have a good turbine housing, but all of my turbines measure at least 0.04 smaller than the housing at the exducer. I think maybe my turbines are worn down pretty far. My guess is it should only have 0.01" clearance, but I don't know for sure what the turbine is supposed to be. I found some specs that say it should be 1.88" - mine measure more like 1.84". Ouch! But, again, the housing bore measures close to 1.88" So, I don't know if that spec is for the housing or the turbine.

You definitely do NOT want 2mm clearance around the compressor. It will cause a very slow boost rise. You want as small a clearance as you can run on the compressor side.

Related question - Art, did you have trouble seizing the wastegate arms? I seem to seize one up every single season. The 'good' turbine housing I mentioned above I shelved because it seized the WG arm. I took it apart and reamed it out, but I'm concerned it will just seize up again. I reamed it with a 5/16" drill (the arm measured 8mm, so there's alot of clearance now). Just gotta get the arm welded back up and put my 'good' turbine in there for Indy...

And what would be the reason for having movement in the waste gate arm?
Is that what they call "bracket mode" ?

[Rob Lloyd]

Originally Posted by Mark Yacavone

And what would be the reason for having movement in the waste gate arm?
Is that what they call "bracket mode" ?

Well, yeah. If the arm doesn't move, the boost is uncontrolled. I've gone fast that way, but consistency is non-existent.

[art leong]

Originally Posted by Mark Yacavone

And what would be the reason for having movement in the waste gate arm?
Is that what they call "bracket mode" ?

We delay the waste gate opening but not stop it. With the waste gate closed you melt the motor, but go fast.
Bracket mode would be lowering the total boost. Or running it rich. I've done both sucessfully
Bracket mode on my N/A car is just shift it 1000 rpms early.