[Mk2] [Turbo] PROBLEM CT26's really bugging us

[Kai Performance]

Hi There

This is a bit of an odd one and to be honest it maybe just pure bad luck. we have a customers car in that we did the head gasket on. No problems.

Engine back in the car and no boost. Took turbo apart and the exhaust wheel had pretty much destroyed itself but wasnt visible when complete as the front of the wheel was intact.

Ok so we had a CT26 here that we rebuilt and put in the car. 5 mins later no boost. Dropped downpipe off and exhaust wheel sitting in down pipe.

Bought another ct26 that was apparently perfect. put on the car without touhing it and all good. next day customer back with no boost.

downpipe off and guess what, exhaust wheel in down pipe again.

Now the only thing different to the car is the customer supplied us an aftermarket tubular manifold and a boost controller.

Boost was set by customer to 1bar.

Is this just really bad luck ????? or a known problem ????

Thanks a lot
Warren
Kai Performance

[3S Service Centre]

Hi Warren

That sounds like bad luck mate.

Things to check! normal egt's and double check the 1 bar is 1 bar against another gauge. Also be sure there are no boost leaks causing the turbo to overspin to make that 1 bar.

James

[RobCrezz]

I wonder if its overboosting like crazy?

[JJ]

Couple of things to check... 1 maybe related :

Manifold - check the flange where it mates to the turbocharger... a cheaply welded flange on the manifold can potentially crack and loosen welds which as a result.. will bolt itself through the turbine and damaging causing the problems your'e experiencing.

The area it cracks and perished in is the area where the twin / dual scroll is created.. the area beneath....

I've seen a few on especially after market manifolds fitted to supras where they begin to deteriorate like this... and simply take out the turbine.

Solution is to grind / weld the flange up correctly.. smoothen off all the pigeon 5hiote welding that accumulates heat...

Other possible areas related to EGT's like James has advised... can have a old / lazy pump in it.. which will make the engine still boost but run lean at the high boost causing it to generate excess heat = failure.

Other culprets : Water injection !! A jet too large can cause turbo failure die to large particles not being atomised.. and effectively a solid object in the gas flow going through the turbo !

hth.

JJ