Engine/Transmission (1994 - 1998) Bad turbo bark, why?

[AMink]

We just got a new travel trailer that weighs in at about 7200 dry. When I was bringing it home I noticed that when the TC locks under load, the turbo barks pretty hard. The gauge kind of bounces down a ways, then steadys out. This also happened with our old, lighter TT. I was wondering why it barks so much when my foot is still in it. I know if I'm unloaded and pull my foot off the throttle, it barks some, but never had it do it with constant throttle. I understand (I think) the reason behind what causes turbo bark. I just don't get why it does with full, or close to it, throttle. It only started after I joined up here and started bombing :-laf :-laf . Any thoughts? Luckily, our first trip with the new tt will take us dangerously close to our Northern neighbor... hmm, Piers side trip?

 

[Devan Manis]

My theory (correct if wrong) is that at the boost the turbo is at before the T/C locks up that the engine is ingesting more air because of the higher rpm's then when the T/C locks up the same boost is there but at less rpm's so the engine can't ingest as much air as before which causes a surge/ bark

 

[AMink]

That makes sense. Guess I'll be really careful when I know that TC lockup is coming. Thanks

 

[Devan Manis]

On second thought if its barking way easy all the time... one time me and a friend were looking to buy a used 12v and when we were test driving it just under normal conditions that the turbo wouldn't usually bark it would and it seemed way laggy for a stock turbo, anyways come to find out there was two exhaust manifold bolts missing that caused a leak and resulted in slow spool up and easy barking. If it seems like its barking way to easy make good and sure you don't have an exhause leak BEFORE your turbo.