Stahl Header Clearance Issue

[ollie]

Hi all,

I have finally installed my Stahl header and one set of 3 primaries runs within 1/4" of the foot well. I have 2 questions for those who have installed these headers; 1. did you have the same clearance issues and if so, how did you deal with it? Banging in the floor isn't an option as the car has been totally restored.

I don't see any way that I could heat up the pipe and bend them over without wrecking the header. I'm also hoping I don't have to send this back to Stahl to be worked over but that is an option I suppose.

I could also look at bending the pipe which is closest to the floor too, and wrapping it in header wrap at this area only.

The other challenge I had with this header was the flange not being the same thickness as the intake manifold. This was resolved by having a machine shop make up some shims for the common studs but what a pain.

Any thoughts and feedback is appreciated. I would like to be able to use this awesome header but I don't want to cook up the floor.

Many thanks.

[LeonV]

You're going to have that problem on pretty much any long-primary header in an S30 (Stahl, Nissan Motorsports). As long as all of your mounts are good (engine, trans, etc.) and the exhaust is mounted properly, the header should not contact the floor. You might get some taps now and then, and even then only when driving hard. That's based off of my experience with the Nissan Motorsports header.

As far as "cooking' the floor, will you be tracking it? Otherwise, I wouldn't give it a second thought.

The easy way to go about getting good clamping on differing flange thicknesses (this will happen with any header) is to grind down the thick washers at the shared studs so that they become stepped, in order to accompany both thicknesses.

[ollie]

Thanks a lot for the note. All mounts are brand new, engine and trans, and it isn't so much the tapping the floor but frying the sealant, undercoat and paint since it is so close to the foot well. I may look at wrapping this area just before the collector as the checks written to the body shop for body work are burned in my mind still, call it vanity, and I would like to keep it looking nice. As you can likely tell, this car won't be tracked.

Any way I was very fortunate in that the machine shop made the stepped washers matched exactly to the intake and header, when both were off the car so clamping on both appears to be excellent. The one stud, which is not shared, next to the first primary was tough to torque but I think it is OK now, expecially since there isn't much tq needed to seal the gasket with the aluminum head.

[LeonV]

Thanks a lot for the note. All mounts are brand new, engine and trans, and it isn't so much the tapping the floor but frying the sealant, undercoat and paint since it is so close to the foot well. I may look at wrapping this area just before the collector as the checks written to the body shop for body work are burned in my mind still, call it vanity, and I would like to keep it looking nice. As you can likely tell, this car won't be tracked.

Any way I was very fortunate in that the machine shop made the stepped washers matched exactly to the intake and header, when both were off the car so clamping on both appears to be excellent. The one stud, which is not shared, next to the first primary was tough to torque but I think it is OK now, expecially since there isn't much tq needed to seal the gasket with the aluminum head.

Ah, the machine shop ground the washers. Shims would be a different issue altogether!

I can see your concern, although I'm not at all worried about my floor (more about the header, really) if contact is made. Since you don't want to clearance the floor and don't want it to have a chance at tapping it, bending the pipes would be your best solution unless you want to put a dent in the header where it is closest to the floor (I wouldn't).

Wrapping the area may help with heat, but it also expands the effective diameter of the piping, meaning that the wrap will be even closer to contacting your floor.

[ollie]

Agreed, well I think I have some thinking to do. I'm not sure that bending the primaries is much of an option either but if I could buy myself another 1/4" that would do the trick I think. Since the header is on the car I can't see a logical point where it could be bent easily other than reshaping the primaries at the flange. I'm also thinking of putting a sleeve into the collector to see if some gentle tq might help it along. This might be the easiest option at this point, short of hammering in the floor, which isn't an option at this point!

[John Coffey]

Make a stainless steel heat shield and rivet it to the body in the tunnell/footwell area. If done right it will look nice. You can also put a layer of DEI insulation on the inside of the car under that carpet:

http://www.designengineering.com/category/catalog/boom-mat-acoustical-products/floor-tunnel-shield-ii-heat-sound-insulation

FYI... do not start bending on your header.

Edited October 9, 2012 by John Coffey

[LeonV]

You can always leave it as is and hope for the best! The way I justified it to myself is that the engine spins counter-clockwise when looking at it from the driver's seat, thus the header will move away from the floor under torque. The only time I can hear my header tap is during a bumpy, hard right corner and I attribute it to poorly-done exhaust hangers.

[ollie]

Thanks for the wrap tip. As for bending the collector as a unit I don't think that's possible so worst case it goes back to Staph. Mean time I will wrap it and see how it goes. Thanks guys.

[ollie]

Quick update: I ordered the HP Shield from Verocious Motrosports. It is a 3" x 14" sheet comprised of stainless steel, ceramic and stainless mesh which can be timmred down. The length I need is about 7" in total so I might double it up. The wrap is attached with stainless straps which work the same as zap straps. I should have this kit in a few days so I update as to how it worked out. I don't have much space at all between the header pipe and the floor, maybe 1/3rd of an inch so it will be close. This seemed more permanent than wrapping it.