Helix v3 downpipe
 

So , after 3 months of waiting, I got my helix downpipe (Gruppe-s).
It was supposed to be a v2 and they sent me a v3.

Well, I installed it and it is a problem. There is only about 1/4 in of clearance between the dp and the transmission corssmember. This causes very unhappy rattles at idle and when in reverse. I will try to fabricate a differet bracket at my work (solid works, mill, lathe, wellsaw, should be able to do it!). But just so everyone knows this is a problem.

You need the dent mod...

I threatened to do this to my BPM, but ended up just using longer hangers.

Not sure how the fit will be on the STI yet...

Call them and tell them they F'ed up, but some Kartboy Hangman hangers will probably solve the issue and if they would send you a set you would be very grateful. Of course, Gruppe-S has been known to let their customers flail about under the bus over trivial amounts of money, but you could get lucky.

What is the location of the cat in that downpipe? If it's up close to the turbo, you will probably have issues.

It's in the midpipe, and there is one post/review from a guy with an 04 STI on www.subarureview.com that says it fits, so I am hopefull. I think that cross member isn't there on the STI, so that issue goes away I hope. If not, I will see it when I test fit, and do the dent mod.

Yeah if it's 3" pipe all the way down to where it goes horizontal, you're probably okay with urethane hangers.

Its a catless dp and its 3in all the way down. I just pulled down and left on the pipe and loosened the mount bolt then retightened it. This solved all the rattle except upon starting and stopping the engine. It does look like my perrin catback pulls up a little on the dp so some lower hangers might help... Ill see if Gruppe-s is willing to cover this.

Siffer engine and diff mounts also help with the starting and other high engine torque situations.

This is a common problem when installing helix downpipes. This occurs based on how you installed it. Something about which bolts you attach first. Try reinstalling before you ship it back to gruppe-s and wiggle it around before you tighten to see if you can figure out what's going on.

Thats why I said you should stay with the same name brand you should have bought a perrin DP if you have a perrin Catback ect the fitment is always better!

Invidia from the turbo to the bump, FTW.

The problem isnt where the dp connects to the catback. I problem is where the downpipe mount is. With the mount in the position it is in, even with the dp pulled down and driverside as possible there is only 1/4 in clearance between the dp and the transmission crossmember. So when under load in reverse or starting and stopping the enmgine, the dp wiggles a little and hits the transmission crossmember, I could put a little flat spot in the dp and solve the problem. I installed it by snugging the turbo bolts first (as I dont want any exhaust leak at the turbo), then the dp to catback bolts then the mount, then tightened everything. This caused loud rattles all the time, so i loosened the mount and pulled the dp and catback down while tightening the mount bolt. This solved about 90% of the rattles.