Hey guys, I don't do a ton of exhaust fab, but I'm making a few parts again and needed a three inch donut flange to make a turn down for somebody on a WRX. He's got a three inch downpipe, the turndown is only for racing at big events where there is no noise restriction, and every last pound off the car helps.
Basically I need this in three inch instead of 2.5
I've seen 2.5 available from vibrant and kteller, does anyone have a source for three inch? Mild or stainless, either is ok.
edit: They're also called collector flanges, donut flanges, JDM collector flanges, ball and socket flanges, and probably have about ten other names too, which is probably part of why I'm having a hard time finding the part!
Are you sure that you need a 3" "donut" flange? Most wrx stuff uses two bolt 3" flat flanges and the downpipes made by Cobb and Fujitsubo use factory sized donuts at the flange?
Do you know who tha manufacture of the pipe is you are trying to mate to?
It's a turbo xs down pipe and cat back. I haven't seen the car yet, but I've got enough 3" and 2.5" lying around that I'll just go ahead and get some pieces flared for me at a local shop to use with flat flanges and spring bolts. I'm told it's a full 3" system, but it looks like TXS uses a flared pipe and flat flange as well.
Oh well, I thougth it would look prettier with a bowled flange like the one above, but I guess as long as it works, it works!
you could be very right in that the donut might be 2.5" I honestly wouldn't be surprised if that was the case.
Stock uses a bowled donut flange just behind the second cat after the turbo, the cat that's next to the transmission. I have my stock WRX STi parts in my garage from when I did my catback, it's the same style flange. I've done alot of work on my brother in laws 2.0l bugeye WRX as well, and it's the same.
Most aftermarket catbacks use a flat flange in place of a donut flange and then use a flex section. I think that's kind of dumb honestly. I'd rather avoid the extra cost, extra welds, chance of leaks, and a ribbed section in favor of a bowled flange like the OEM uses. It looks like for 3" donut applications flaring a pipe and then passing a flat flange over the back of it and using the OEM spring bolts is going to be the way to go. I've been able to find 3" donut gaskets no problem (the graphite/fiber ones) but apparently there is no market for the one piece flange.
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