Stahl headers
- Thread starter D Calkins
- Start date
Ha, you and I are in similar positions - I installed my Stahls this weekend and the ends don’t match up with the current new system I had put in. I’m bringing the car Wednesday to local shop to have them to the cutting and welding that’s needed. That’s what you’re going to need to do. Find a place that does more custom work like for sports cars or hot rods, they won’t even blink at doing this type of job.
The end of my factory downpipe is a straight section (~1 5/8” OD) with no flare. It’s triangular flange is free-floating, and just slips over the downpipe. Next, the exhaust “donut” gasket is slipped over downpipe.
The downpipe then slips into the flared and expanded pipe of the middle muffler (~1 5/8” ID). The floating flange and donut gasket on the downpipe are then sandwiched against the mating flare & triangular flange using 3x M8 bolts.
The slip fit of the pipe, plus the compressed gasket are sufficient to seal the exhaust system.
I can’t speak to the Stahl headers specifically, but if you’re looking to avoid custom work, you might check to see if your exhaust is configured the same way. Custom work may not be needed.
The downpipe then slips into the flared and expanded pipe of the middle muffler (~1 5/8” ID). The floating flange and donut gasket on the downpipe are then sandwiched against the mating flare & triangular flange using 3x M8 bolts.
The slip fit of the pipe, plus the compressed gasket are sufficient to seal the exhaust system.
I can’t speak to the Stahl headers specifically, but if you’re looking to avoid custom work, you might check to see if your exhaust is configured the same way. Custom work may not be needed.
My downpipe had gotten itself pretty well stuck in the middle muffler, so I’m quite familiar with the connection point.
Here are some pics which may help illustrate how my factory exhaust is set up.
You can see the straight ends on the downpipe, plus the flared and expanded section of the middle muffler.
Note that I don’t have the triangular flanges installed on the downpipe in the 2nd photo, as this was just a test fitment of my repair.
Here are some pics which may help illustrate how my factory exhaust is set up.
You can see the straight ends on the downpipe, plus the flared and expanded section of the middle muffler.
Note that I don’t have the triangular flanges installed on the downpipe in the 2nd photo, as this was just a test fitment of my repair.
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The original downpipe connections used two different metal rings, one solid and one with asbestos or something. When they rust the pipes get loose and noise soon follows. These were hard to find.
I used 2x "Exhaust Seal Ring", #18101177313 from FCP Euro which is a steel, two-piece shell encompassing the outside of a compressible asbestos-like inner core that works a treat with the stock pipes & flanges. The picture on their website doesn't match what it actually looks like.
https://www.fcpeuro.com/products/bmw-exhaust-seal-ring-18101177313
Based on the shape of the Stahl headers, I suspect they'd bolt right into the factory middle muffler with a new sealing ring and the flanges carried over from the factory downpipes. This is, of course, assuming that the OD of the Stahl collector is the same as stock. @D Calkins, perhaps you can measure & report back?
https://www.fcpeuro.com/products/bmw-exhaust-seal-ring-18101177313
Based on the shape of the Stahl headers, I suspect they'd bolt right into the factory middle muffler with a new sealing ring and the flanges carried over from the factory downpipes. This is, of course, assuming that the OD of the Stahl collector is the same as stock. @D Calkins, perhaps you can measure & report back?
Yes, that is correct but one of the original pipes had trumpet ends and used the solid ring, maybe that is the tough one to find.
Yep, looks like it'll fit right into the factory middle muffler pipes.
According to RealOEM, the gaskets you'll need are:
- 1x Gasket ring asbestos-free, 18119067822- In stock @ RMeuropean: https://www.rmeuropean.com/Products/18119067822-MFG183.aspx
- 1x Conical Ring, 18111245489 - In stock @ RMeuropean: https://www.rmeuropean.com/Products/18111245489-MFG183.aspx
As you can see from my pictures, my stock downpipes did not come out easily. Despite being a dry CA car, my downpipes were pretty well stuck in the slip joint. I ended up cutting the downpipes off just before the joint, then used a short sawzall blade to carefully make a cut down the length of the remaining downpipe inside of the slip joint. That afforded just enough relief that I was able to pull the remainder out with a pair of good pliers.
According to RealOEM, the gaskets you'll need are:
- 1x Gasket ring asbestos-free, 18119067822- In stock @ RMeuropean: https://www.rmeuropean.com/Products/18119067822-MFG183.aspx
- 1x Conical Ring, 18111245489 - In stock @ RMeuropean: https://www.rmeuropean.com/Products/18111245489-MFG183.aspx
As you can see from my pictures, my stock downpipes did not come out easily. Despite being a dry CA car, my downpipes were pretty well stuck in the slip joint. I ended up cutting the downpipes off just before the joint, then used a short sawzall blade to carefully make a cut down the length of the remaining downpipe inside of the slip joint. That afforded just enough relief that I was able to pull the remainder out with a pair of good pliers.
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Only if one of the pipes looks like two trumpets facing each other, the solid ring fits between them. The other slips over as you know with that two part ring.
Oh, I see what you’re saying now.
I suppose I never saw the ends of both my downpipes since I had to cut one off. I assumed they were identical, and repaired both of them with straight 1 5/8” tubing.
In that case, a pair of the two piece 18119067822 gaskets should seal the Stahl headers suitably.
I suppose I never saw the ends of both my downpipes since I had to cut one off. I assumed they were identical, and repaired both of them with straight 1 5/8” tubing.
In that case, a pair of the two piece 18119067822 gaskets should seal the Stahl headers suitably.
I was surprised that there was no bung for an O2 sensor. For those of you with AFR gauges, where are you mounting the sensor?
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I have a bung in the collector at the end of each of the headers. For now, I only use them when tuning, otherwise they are sealed up.
I welded a pair of O2 bungs into my stock downpipes for tuning purposes, too.
This page has a good primer on placement.
This page has a good primer on placement.
Good idea. I’ll do that before install mine
Yes good idea I’ll ask the radiator shop to do that tomorrow
Here's what I did to my new ACP/Stahls when fitted. Not stock. Awesome.
V- clamps - easier to disassemble and increases ground clearance with no flanges
Flex coupler - will not fatigue over the years. Isolates motor torque from rest of exhaust
02 bung- mounted at end of an OEM center resonator
HTH!
-s
V- clamps - easier to disassemble and increases ground clearance with no flanges
Flex coupler - will not fatigue over the years. Isolates motor torque from rest of exhaust
02 bung- mounted at end of an OEM center resonator
HTH!
-s
W&N p/n A18111102405, includes both sealing rings : A18119067822, and A18111245489.
Please post some photos of your new setup.
My Stahl headers/Coupe King stainless exhaust were also cut and welded by a custom exhaust shop years ago w/o problems.