red hot headers

[john walker's workshop]

goingsuperfast stainless headers, no exchangers. man, you wouldn't want to use these on a street car, would you? they're red at idle, brighter at higher revs. probably bake the engine as well as set any close debris/grass on fire, not to mention if any oil dripped on them. poof, goodbye 930. anyone using them on the street?

[WydRyd]

John, I'm running those on my daily driver... no such issues on this end. If you're seeing glowing headers even at idle, then EGT's must be way over the top... what's the AFR like on the motor? Aren't high EGT's directly related to A/F ratio?

As I said, I have no such issues with mine... very pleased so far.

[john walker's workshop]

the original factory exchangers, which are stainless, although a different grade i'm sure, did not get red. that's what bugs me. CO is 4% at idle. AFR unknown at this time. no dyno close by. i just spoke to alfred, who sells them, and he said that after a few heat cycles, they won't get red anymore. we'll see i guess. hate to waste all the installation effort and put the stockers back on.

[WydRyd]

Interesting, John. As I said, no such issues with mine and I've now had them on the car for ~4 months... car runs/performs great... I'm just battling with an overly rich issue right now, but I'm pretty sure that's an EFI related issue (e.g: AFM gone bad... AGAIN).

Headers glow red for only one reason, there’s fuel burning inside. The two main reasons are a rich mixture and late ignition timing - which doesn’t give the fuel enough time to burn inside the combustion chamber.

Well, there IS another reason why they glow... after you've just caned the crap out of the turbo

[Lukesportsman]

I'm not sure how an exhaust header could influence the EGT's beyond a leak. Certainly, you can add coating inside or out, but 304, 321 or 3XX are all going to radiate similar temperatures whether not the color they radiate is the same or different. 421 Pontiacs had aluminum manifolds for drag racing.....they are going to glow and melt much sooner, but not necessarily get any hotter than a set of Iconel headers.

Though I don't own a set of these headers, I would just check a few other things before I threw the headers under the carpet. Take surface temp or EGT and see where your really at...I don't know if color emmited is reflective or diagnostic. Certainly check timing and AFR's as Merv as suggested. You might have been on the fence before. You obviously/probably changed to headers for some reason. Probably to change/increase air flow...therefore your engine has a different set of parameters. Just my .02

[RarlyL8]

John - a freind of mine just went through that exact scenario whith a set of B&B headers. He posted the delima on Rennlist.
The car ran perfectly with a Euro exhaust. Nothing was changed but headers added.
At idle the headers would glow red. After much agony I suggested that the header material may be the culprit (thin tubing or metalergy problem) and the way to find out is by reading surface temperature. He bought a pyrometer and found the surface temperatures were slightly elevated, but not enough that it should cause the headers to glow.

Very long story short, the CO was in spec but the A/F ratio was not perfect. By not perfect I mean 0.5% off at idle. He retarded the cams, cleaned the fuelhead, and adjusted the WUR. Bingo - problem solved.

The point of all that is that in this particular case the header design exposed a "problem" with the engine tuning that manifested itself in a very odd way. The timing events combined with a slightly rich A/F ratio and new plumbing lit 'er up cherry red under moderately high surface temperature readings.

[beepbeep]

Yeah, what Brian said. Stock exchangers are continuosly cooled by air and probably made of thicker gauge metal.

BB's (especially those w/o heater boxes) will be more glow-prone in case there is slight missadjustment in AFR and ignition. I suggest leaning the mixture and advancing ignition slightly at idle.

There is probably lot's of unburned fuel that is continuously combusted in the tubing.

[Porschefile]

As others mentioned, I'd suggest checking your timing.

[911rudy]

I had the same thing and it turned out to be leaks around the flanges. Someone had replaced the studs with ones which had longer no thread zones. These worked fine for stock exhaust but did not allow me to tighten them enough to stop air leaks into the headers because the headers did not have as thick flanges as the OEM . If you did not have a problem before, then SS headers will not glow without some other problem. It's got to be an air leak. For insurance, put a washer on each stud, after the flange and then re-torque them to spec. Also look at the areas around the flanges and see if there is any exhaust blackening. If there is then that is the leak. Good luck.

[NathanUK]

Hi Rudy. I noticed that too about the stock studs on my car when I fitted my GHL's. I actually ran a die on the threads and cut them higher !

[911rudy]

Nathan,
I was going to do that but already had everything in place. I asked Stephen at AI if using washers on the top of the flange was ok and he said that it shouldn't make any difference. I also used the metal gaskets that have a raised area to transition the port to the header more smoothly.

[NathanUK]

I used a washer under each nut as well.

[930turbo]

Start with a simple test of your distributor mechanical advance. Be sure it's not hanging up. Late timing is usually the culpret on illuminated headers. I've experienced this on cars and motorcycles.

[hobieboy]

I second late timing... the 1st week after I EFI-ed the car, I retard the timing quite a bit just to be sure she won't knock. The end result was glowing headers. In fact, the exhaust temp was so hot that I can't even put my hand in front of the tail pipe for more than 2 seconds !