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Discussion Starter #1
For anyone with a stock exhaust on a Elise, could I get you to measure the exhaust pipe OD and the center-to-center distance (or outer edge to outer edge) between the two pipes? I want to modify my current stage-2 exhaust to fit the stock non-cut diffuser tray. My plan is to cut-off the expanded stage-2 tips, and re-configure and re-center the outlets to match the stock outlets.

Why, you might reasonably ask? SCCA Auto-X stock rules prohibit body modifications, but allow exhaust changes. While I have my car apart, replacing the previously damaged diffuser with a stock (non-cut) one, I figured I may as well sort this. From an SCCA protest perspective, it's well along on the "truly nit-picking" spectrum of possible items, but I may as well address it while it's convenient as I've tried to ensure everything else is "correct".

PM me or post here if you can measure one up for me. Looked in the exhaust thread, but didn't see anything on this. Thanks much!
 

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OD = 25 mm. Center to center = 30 mm, give or take a few mm's :)
 

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Discussion Starter #5
Isn't there an outline in the factory shop manual for the cutout, meaning it is factory approved?
Not sure about that, but regardless, The stage-2 exhaust is an "aftermarket" part, not available from the factory (as factory installed on the vehicle) so the "body modification" necessary to install it technically doesn't qualify in SCCA stock-class unfortunately. I'm not sure I'll ever again compete at the level at which it matters, but it's one of those things that I may as well put right. Will be interesting to see if the change to smaller outlets alters the sound at all.
 

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Discussion Starter #6
OD = 25 mm. Center to center = 30 mm, give or take a few mm's :)
Just confirming - the stock outlet pipes are only 1" (25mm) in outside diameter? Smaller than what I thought. And 30mm center to center means they are only 5mm apart?

The stage-2 pipes are one 56mm pipe splitting into two 43mm pipes, then the larger diameter tips of course at the ends.
 

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I think JF got his MM and Inches mixed up.:grin2:

The outlet pipes on the stock muffler are 2.5" OD and 3" C-C. :smile2:
 

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Discussion Starter #10
Why not just cut off the wye with the twin tips and weld a single pipe with a 90 degree bend? Lighter and no added restriction.
Yes, I may do this - just maintain the one 56mm pipe to the outlet. Simpler for sure and I think it would clear the stock opening. I do wonder if the stage-2 expanded tips have any contribution to the sound and lack of resonance, but I'll shortly find out :)
 

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Oops, My bad.

61 (ish) MM outside diameter
76 (ish) MM outside to outside
 

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Oops, My bad.

61 (ish) MM outside diameter
76 (ish) MM outside to outside
Oops, you did it again. :grin2:

61mm OD is close, but 76mm outside to outside is way..... off. Take a look at the picture I posted and multiply the inches on the tape with 25.4. You should get something like 140mm. 0:)
 

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Diameter is 61 ish MM. Outside to outside (or center to center as the original poster asked) is about 76, or 15 MM between the pipes.

140 MM is to distance of both, including center gap.

I should have better clarified outside to outside as to mean center to center
 
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