I purchased this Hass downpipe from a forum member a couple of months ago:
It is for the most part a standard T25 downpipe, but unlike a normal T25 downpipe, it came with a 3” j-pipe flange. The stock j-pipe is 2.5” and won’t bolt up. I knew fabrication was going to be necessary. Rather than downgrade the downpipe to a 2.5” flange, I decided to upgrade my j-pipe. I purchased a RWD j-pipe from ebay (along with some flanges, bungs, a reducer, and misc other supplies) with the intention of modifying it for FWD with a 3” flange.
Shortly after it arrived I stumbled upon a diamond in the rough on ebay. I won this downpipe for $75 shipped.
It arrived yesterday. I immediately had one of the guys on my team check it out.
In a previous post I made (before it arrived), Chriscar had some great suggestions and questions. He noticed that the flange lacked a divider to help ensure wastegate/exhaust flows were adequately separated.
Here is the RWD piece as a reference. Note the extra piece separating the exhaust flow from the wastegate flow.
Also note the divider on the RWD piece can be removed with 2 allen bolts. I’m going to take it off and have a local machine shop replicate it for the new downpipe. I’ll keep you posted on that.
Chris was also curious about the length of the wastegate tube. Apparently 18” is ideal. I used a string to measure. It turned out to be 14.5”. A little short, but I still think it will work great.
Once the divider is welded in, I’m going to cut it just after the wastegate tube re-enters and put a flange on it. Then I’ll cut and flange the downpipe to match. Something like this:
As for exhaust, I’ve got that covered as well, once again thanks to a forum member. It is a 3” VRS cat-back. It will be mounted up after I finish the downpipe.
More updates soon to come.
