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Figured since it was performance related, and could be applied elsewhere as well it should go into the performance forum.

It's called a "Banjo" turbine discharge. It's used where there isn't space for a straight piece of pipe.

I scanned in a page from "Turbochargers" by Hugh MacInnes. Here's a link to the image I scanned in. It'll show you what it looks like, and why it would be so nice for a C900. But I'll quote the pertinent parts here:

"Sometimes turbocharger installations end up with the exhaust very close to the fire wall or some other obstacle. When this happens there may not be enough room to get an elbow between the turbine outlet and the exhaust pipe. A banjo-type turbine discharge, Figure 8-4, can be used for routing the exhaust in close quarters.

Bristol cars ran into this problem with their turbocharged Beaufighter, which uses a Chrysler 360-CID engine. This car has close clearance between the turbine discharge and the engine-compartment fire wall.

Dennis Sevier, Chief Engineer of Bristol, said a short-radius elbow was tried but the car lost power on accelleration and top speed. He replaced the elbow with a banjo-type fitting and found it worked at least asl well as a straight exhaust.

This car accellerates from 0-100 mph in 13.8 seconds-not bad for a four-passenger car with a family car-sized trunk." [Note this was written in the late 70's early 80's. Back then that really was quite impressive.]


See the link for pictures of what it looks like.

Because the exhaust gasses spin as they come out of the turbine I could see this type of dischage being very effective if done properly. So far I've never seen one on a C900, which is an obvious application in waiting.

Dubbya~
 

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I think it would be hard to justify the cost of fabricating something like this when there are other solutions available. You'd probably need to weld a compatible bracket onto the turbo side and you'd need to do something with the down-pipe to get it attached to the other side of the fitting.

The c900 does not really have a shortage of space. It's just that the battery is in the way. Once you move the battery you can buy a nice gently curved, large-bore down-pipe straight off the shelf. There are also some uprated down-pipes that will fit even if the battery hasn't been moved - I guess this is a bit of a compromise though.

It'd probably be as much hassle moving the battery as it would be to develop this sort of solution.

Having said that though; if someone were to develop one and start producing them as a direct replacment for the standard elbow - that'd be a good thing. Obviously it would have to increase the performance.
 
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