So, I picked up a Gruppe-S unequal length header and a Grimmspeed up pipe a while back. Haven't installed them yet, waiting for all exhaust-associated parts to be in place.

Recently I was checking how well they fit up and, well, they don't. The bolt holes align, but there's an ugly step between the header and the up pipe, of about a fifth of an inch.

So I'm here poling for solutions. I looked around a while before posting this, and seems getting a Helix (says 2.25" diameter though...) or an Invidia uppipe was the only real option people had sugguested. I haven't found any specs on the Invidia diameter though.


Get a different header to match the up pipe?

Get a different up pipe to match the header?

Spooling/HP implications for them both?

Skip the header, and just PnP my stock manifold? (I've the tools for it)


I had otherwise been thinking about getting a step-down funnel spacer machined, as seen as the graphic herein. Too much work, another tentative point of leak/failure?

 

More poking around. This guy has some numbers.

 

I was picking the brains of the guys at Grimmspeed about port matching the up-pipe and collector, and they didn't have any real answers for me. I like where your head is on this, though.

 

I was gonna call GS about this tomorrow, hmm. Perhaps an a CYA measure, they've only had definite answers for their own products in the capacity they were meant for, when I've asked at least.

Good to know I'm barking up the right tree though.

 

If you decide the funnel shaped spacer is the way to go lmk.

 

Will do sir. I'll see if there's greater interest beyond me too, as a bulk order would save on tooling costs.

 

I was in the same situation, only I didn't buy the header yet. I was worried that the up pipe would not fit my header... So I went with a header up pipe from the same manufacturer. Perfect match!

 

Huh. Whodja get the set from?

Alternatively, I guess there's those all-in-one header and up pipes (you know, single piece), but those get $$$ iirc... [Edit: err, is that what you meant?]


When I got each of the pipes seperately, it didn't cross my mind that they'd not evenly match up

 

Groupe S v1... It's not one piece it's Seperate but same manufacturer. It's a 3bolt up pipe which is hard to find a replacement but IAG performance started making them

 

Hmm, good to know.


For me though it amounts to a parts hunt then. And like I asked earlier, iirc there are spooling implications to a wider up pipe. I might get a TD05 turbo down the road, but it's the stock TD04 til then, and a big bore pipe will have diminishing returns with that.

 

why a funnel shaped spacer instead of just grinding a ~10 degree angle into the flange?

stuffing ~1/2" of gaskets + spacer between the flanges isn't going to be fun if you ever remove one or the other and not both at the same time. Also consider that you're essentially putting in 1/2" into what many consider to be the most leak prone joint in the whole exhaust. I suspect that might cause issues.

Die grinder and an hour is what I'd do, at most.

 

The spacer solution seems neater, and much more reversible.

Is it just wiggling everything together that would be cause for grief?

I do have a die grinder, just want to see if there's other solutions yet.