Check your boost sensor on the fire wall near the drives side. There should be a vacume line attached to it. What makes you think the rear turbo is no good? They are sequesntial and on one shaft so if one is bad the other could be on its way out too if there is any play that will deteriorate the seals. Check from the intake side, pull off the lower hose the connects to the front of the turbos and pull back and forth on the nut that holds the compressor wheel in place. This would tell if you have any end play. If your not smoking like crazy your trubos a probabley fine. I bet that the clogged melted cat is the culpret of your problems. I could also change becasue of that messed up cat becasue the O2 sensor will be getting readings that fluctuate from the exhaust not working properly. I bet there is a lot of back pressure being built up from the cat too slowing down the flow out of the turbos.

 

yes, the turbos work great and the problem was the cat we knocked it out about a week ago....but when we take off the turbo kinda bogs then goes....kinda like flooring a diesel engine (basically there is no acceleration for about 2 sec.)

 

Turbo cars always have a certain amount of lag, the stock sequential turbos have less lag but it's still there, You have to have enough rpms for the exhaust to be there and spin the turbos.



and actually the front turbo usually wears out sooner because its always being used, and the rear one comes on after 4500 rpms so it gets less use.

 

ya i know...but could tha lag be from the empty pre cat? i knocked everything out of the pre cat...all the crap inside, and put it back on/

 

well the precat is still smaller then an aftermarket downpipe, so you could gain so you could reduce the lag some more with a downpipe. And then even more with a midpipe, and more with a catback. The less back pressure you have the less lag, but the more noise and emissions. the precat is bad for the car though and stores extra heat so its good you at least knocked it out. If you're cruising at 4500 rpms is there any lag when you punch the gas? Or is it only coming from a stop light or somthing? Do you have a boost gauge?

 

no its only from a dead stop, it works pretty good when were going, we never really floored it at a constant speed. we kinda have a boost gauge but it really a pressure gauge, still works. it only seems to lag when we floor it off the line, like the turbos are delayed.

 

thats normal. at idle there isnt enough exhaust gases to spin the turbine thats why there is a lag. New turbos would be the same way.

 

no its not like what you think, its like flooring it in a stock van and then after about 3 sec it kicks in. i know theres a little lag but you can really tell the difference.

 

hmm i'm running out of suggestions. maybe the main cat clogged?

 

My NA was exhibiting similar symptoms. Check all of your cats. If one has failed it might have caused a chain reaction.



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My exhaust system became a virtual potato canon after I flooded the motor. Once I put fresh plugs in and got it running it backfired violently five or six times. Platinum plated strips of metal were propelled out of the tailpipes like a shotgun. Afterwards idle was high and no amount of adjusting could bring it down consistently. Amazingly it still ran and could squeal tires with cat as pictured.