| incident was just a few months back with a customer's car, Pete Conguindi of Pensacola. He has the Sport500s and they have about 3000 miles on them. He installed downpipes and testpipes into the car when he rebuilt the engine and the turbos didn't smoke right off the bat, but around the 2700 mile marker, they started smoking on deceleration. He had them removed and replaced with another "new" set of sport500s from JWT and around 3000 miles, they bagan smoking horribly on deceleration after boosting AGAIN. He still had the original testpipes and we reinstalled them in the off-chance that they needed this backpressure and they stopped smoking completely. We were both VERY amazed to see this. When I say the car was smoking, I dont mean by little puffs either - the car is white and when he would let off of the gas after a short boosted pull, the car would literally disappear into the cloud. It was one of the most embarassing things for him and he let the car sit for a few weeks until I made my trip up to see him. Just recently the same thing occurred with Stacy Watson's convertible TT that he recently did a TT swap on. I went through the car here and took it to the dyno to find that it was just puking TONS of smoke on deceleration after boosting. I aborted the tuning session at the time and he got ahold of some hi-flo cats from Greg D. and brought teh car back down. I installed the cats and the smoke was pretty much non-existent, however, the car was already smoking less for whatever reason when he brought it back than it was when we originally took it to the dyno. Sport500s are NOT new turbos. They are simply stock turbos that have been rebuilt with slightly larger wheels. Granted, they use a new turbine wheel/shaft, compressor wheel, seals, and bearing groups, however, the center housing, compressor housing, and turbine housing is typically reused. In the machining process of rebuilding a cartridge, the rear turbine shaft seal sits into a precision bore at the rear of the housing and this bore is typically honed out to clean it up. When this is done, a larger turbine seal is used to make up for the difference in the bore size. Because human hands are involved in this process of honing, mistakes can be made and if this bore is honed out too much, the rear turbine seal will have too much of a ring gap and allow leakage. Not all Sport500 turbos will smoke when you install downpipes and testpipes onto the vehicle. Only some of them have had this problem. It is my opinion that what is creating the inconsistency in behaviour is the fact that these turbos are remanufactured from stock turbos and slight differences due to the machining processes involved are likely the culprit here.
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