Ok guys, I have been messiing with my car for a while trying to get a certain problem fixed/narrowed down. But my question to you guys is, Can I disconnect the compressor side (tube going into my TB) and run the car on a full RPM (alll motor) run without destroying anything (overspinning turbo?) I know that the wastegate will stay closed (7lb spring) and keep all the exhaust going to the turbo because of no + psi in the intake manifold. I have a speed density w/ AEM stand alone computer and I need to do an all motor run. Any advice would be appreciated.

Mike

1995 Mustang GT
347 stroker
T67 GTQ @ 7 psi

 

You'll horribly overspin the turbo. Tie the wastegate open if you're going to do that, but even then you might still damage it.

 

So the wastegate needs to be open eh. Could it over spin even with the waste gate open?

Thanks

Mike

 

cap the turbo? lol

 

Even with the WG open, with no resistance, the tubo can still overspeed.

 

it will overspeed the turbo, probably even with the gate disconnected, and especially if the turbine side is small or the turbo is small.

 

You pretty much NEVER want to do that!

 

Dont do it I killed my turbo doing that.

 

I used to believe that as well but was corrected by an engineer from one of the major turbo manufacturers. He indicated that they never saw a turbo overspeed when the hose blows and infact what happens is that the turbine runs out of power. This might seem backwards but bear with me.

When you blow a discharge hose the look where you go on a compressor map. You will head to the max flow at a pressure ratio of 1. As the compressor heads to the bottom right side of the map the efficiency is dropping quickly which means it starts to really consume a lot of power to keep moving. At the same time the airflow through the engine is dropping therefore the exhaust energy is dropping. What ends up happening is that the the turbine eventually can't generate sufficent power to keep speeding up the compressor and it hits a steady state point where the turbine can't generate enough excess power to speed up the turbo.

I know it sounds counter intuitive (I had a hard time beliving it too) but once you sit down and actually calculate the power required to drive the compressor at that low of efficiency and then calculate how much power the turbine is generating it makes sense.

Steve

 

I dont think you will have a problem. I do it all the time when I have to tune an engine using alpha N to get the engines map right. Never hurt anything!

 

All due respect to those that have posted.

I do know a couple of guys that did that
and bought new turbos shortly after.

IMHE

 

I haven't taken the time to think about everything you said.. But it is true.. When you blow off a compressor hose.. The power does drops dramaticly ..

 

From my experiences working on diesels, I have seen turbo damage when a CAC hose blew off. It's true that it will run out of power and eventually not beable to generate enough to spin any faster, but that point can easily be at a much higher rpm than the max rpm of the turbo.

 

So to sum this up? It isn't guarenteed to kill your turbo but why risk it. Turbos and engines aren't cheap or easy to replace.