It is that shape, simply because the turbo it is bolted to is that shape. It uses a twin entry ( twin scroll ) turbo, which is supposed to reduce lag whilst still retain good top end. The twin bit, is why there are 2 wastegate flaps, one for each channel. It is pretty much the same on the road car, except that bit isnt shaped as well, and its bolted to the catalytic convertor. These cars are a complete nightmare to work at. Even if it is of their Rally car, it musnt have worked that well, as it was a few years ago ( and AFIK on the celica ) that they were caught cheating, with restrictors that actually got bigger as the car went, or something along those lines! Not surprisingly, they got caught and banned for a year or so.

[Edited by ustolemyname??stevieturbo - 9/7/2002 2:06:12 AM]

 

This may be useful, this is the downpipe (well the first piece) of a Celica TTE Grp. A turbo:

 

 

 

 

????

 

Interesting downpipe design and vertually identical to the design by used by all WRC cars that use a similar turbo body

As for the cheat, it was so ingeneous that they were only caught when a disgruntled ex employee grass them up. The cars had been repeatedly stripped by FIA scrutineers and always passed.

The restrictor on the front of the turbo had a heavy spring loaded arrangement inside that meant it could not be detected when removed from the turbo. When it was bolted onto the turbo, the spring was compressed and more air allowed into the turbo housing.

Even the drivers did not know.

 

Regarding the design, it is basically a "bellmouth" design, but has a small separation between the wastegate ports and the turbine exhaust. Looks similar to the new APS turbos, although they use only one wastegate port.

 

APS turbo housing:

 

and this is a new downpipe made in the US by Vishnu Tuning:

 

LOL, spot how much bigger the pipe is than the flange.

"New 3inch downpipe!!!"

hmmm, yeah, great.

Also noticed ceramic coated turbine in the pictures with the toyota exhaust parts. I also noticed the toyota part looks like it joins the downpipe with a nice quick release clamp.

Paul

 

The turbine on the ( ST205 and I suppose later MR2's ) toyotas is ceramic, not just ceramic coated. They also break very easy ( not that I ever broke one...whoops ) Just need to be quite careful when splitting the turbo from the exhaust housing.

 

Stevie, I don't know if the Grp. A Celica uses the "same" turbine that a stock turbo ST205 (probably it is a modified version), but certainly this turbine produces a lot of boost ( > 2.0 bar ) and it's ceramic turbines don't break easily.

Carlos H.