Turbo surging at low boost

[jbolt]

Ever since I got my truck back from the DTT upgrade my turbo will surge at the drop of a hat. If I get up to as little as 3-4 psi boost and back out of the throttle it will surge. Every time I accelerate across an intersection and let off it surges. Running on the highway if I accelerate at all and back off it surges. Running 75+ mph (which by the way is incredibly easy now ) with the boost up around 8-10 psi sometimes I get the same surging sound like it is fluctuating between loaded and unloaded.



Any ideas?



Jay

 

[BushWakr - RIP]

Jay,



When you say it 'surges' I'm not sure what you mean... to me, surge is a climb or increase in speed/rpm etc. Is that what you are referring too??



I can see were you might have a bit of compressor stall, but not surging... actually you shouldn't even have stall unless your really up there in terms of boost levels. .



A little more info ??



Bob.

 

[formula]

Jay,

I experienced the exact same scenario you're describing. I made a couple of posts about this situation in your "Diesel Dynamics pump kit first impressions" thread. There are several factors to the explanation of why your turbo is behaving this way.



1) The fact that you (and I) have a fully exposed air cleaner makes the noise from the turbo compressor much more audible.



2) Recent addiction to BOMBing the truck has given you an itchy right foot



3) More fueling, larger injectors, pump adjustments, drive the turbo to make more boost at a faster rate.



4) Your new torque convertor This is the biggest factor. The reason being is that the much tighter convertor will effectively slow the engine down quite fast when you back off on the throttle. When you let off of the throttle, you remove the turbo's drive pressure..... this coupled with a rapidly slowing engine will make the turbo unable to maintain boost..... then you get surge ("bark").



The root of this surging is, however, the turbo itself. It's the design of the compressor wheel, the compressor housing and the clearances between the two that will determine how the turbo will behave. The only way you're going to eliminate the surge is if you change your turbo.



Cheers,

Sean

 

[jbolt]

Originally posted by formula

Recent addiction to BOMBing the truck ... ... .

Hey I don't have a problem, I can quit any time I want to .....



..... oh crap... . forgot to hide those reciepts for the 4" exhaust and new steering shaft I ordered... ... .



I guess I'm just supprised at how little boost pressure is needed to make it "bark" 3-4 psi



Jay

 

[formula]

Those oil fumes will do strange things



What did you get for an exhaust system?



Sean