I was thinking about making a new downpipe alltogether. The 3" tubing is excessive and I think there may be problems with boost creep (in this low-pressure system) because the path through the turbo will have far less restriction than through the wastegate.
Also, there isn't adequate room under the car to run a full 3" exhaust all the way to the tail, especially around the rear sub-frame, so it will have to be reduced at some point along the way anyhow! I'd also like to integrate the wastegate dump into the downpipe because the wastegate will probably be dumping from about 2500 RPM up, and it'll just be too damn loud to have a straight wastegate exhaust all the way from 3000-7000 at full throttle...
Are you going to use the stock cat?
Are you sure you need the scavenge pump on the oil return? Looks like the bearings may be a couple inches above the oil line. What if you rotated the center section about 25-30 degrees clockwise (as viewed from the rear). I know the drain wouldn't be vertical, but it doesn't have to be exactly vertical. Corky Bell recommends +/- 30 degrees max.
Keep up the good work!
