Headers Glowing Red

toyman · Jul 21, 2009

I wanted to open this thread again as someone mentioned not too long ago about his headers glowing. As I have been experiencing higher than normal engine coolant temps I was curious about my headers glowing. In daylight it isn't obvious but at night they are glowing slightly on both sides just upstream from the mid pipe flange. The earlier discussion centered around both lean and rich conditions as a likely reason for this to happen. Since I can monitor AFR I see nothing that would account for rich or lean conditions being the cause in my case. At idle and under low load the AFR is between 14.3 and 14.7. As the load increases the AFR drops and at WOT runs about 11.6. Plugs look good, timing max is 28* and the car runs strong. So, maybe this is more normal than expected, especially with boosted engines. How many have popped the hood at night after putting your foot in it and checked.

Stanger007 · Jul 21, 2009

toyman said:
I wanted to open this thread again as someone mentioned not too long ago about his headers glowing. As I have been experiencing higher than normal engine coolant temps I was curious about my headers glowing. In daylight it isn't obvious but at night they are glowing slightly on both sides just upstream from the mid pipe flange. The earlier discussion centered around both lean and rich conditions as a likely reason for this to happen. Since I can monitor AFR I see nothing that would account for rich or lean conditions being the cause in my case. At idle and under low load the AFR is between 14.3 and 14.7. As the load increases the AFR drops and at WOT runs about 11.6. Plugs look good, timing max is 28* and the car runs strong. So, maybe this is more normal than expected, especially with boosted engines. How many have popped the hood at night after putting your foot in it and checked.

Glowing headers are fuel burning in the exhaust or thin walled headers. It is more common on turbos where you have a slight backpressure.

I would verify that ignition timing is indeed where you think it is.

Is the cam position verified?

Wes

ProKiller · Jul 21, 2009

i had the problem when my distributor was going out and wouldn't hold proper timing. check that to make sure.

toyman · Jul 21, 2009

I spoke with the engine builder this morning and he's of the opinion that lightly glowing stock headers are normal. He also suggested that if you run the engine on most vehicles at 1800 rpm for 2 minutes and check the headers they almost certainly will glow.

Wes, how do I verify cam position?

The timing is locked at 28* and is managed/controlled by the AEM-EMS ignition map if I'm not mistaken. The car was dyno tuned 2 months ago.

After I got home tonight I looked at the Ignition map and noticed that from the last dyno tune timing was advanced from about 17* to 28* for most of the cells in boost to max rpm. I seem to recall that when they were doing the dyno pulls they were picking up significant gains in HP with this change. I don't hear any pinging or knocking but that's not to say it isn't there.

Stanger007 · Jul 22, 2009

toyman said:
Wes, how do I verify cam position?

The timing is locked at 28* and is managed/controlled by the AEM-EMS ignition map if I'm not mistaken. The car was dyno tuned 2 months ago.

After I got home tonight I looked at the Ignition map and noticed that from the last dyno tune timing was advanced from about 17* to 28* for most of the cells in boost to max rpm. I seem to recall that when they were doing the dyno pulls they were picking up significant gains in HP with this change. I don't hear any pinging or knocking but that's not to say it isn't there.

The cam would have to be degreed at install time.

28* seems a bit on the high side to me for an 8psi motor on 93. If the car was making nice jumps in power as they were adding spark then that is _usually_ a great indication you are quite a ways from finding knock. An odd one for sure!

Wes

revhead347 · Jul 22, 2009

My headers were glowing when one O2 sensor went bad. The computer was dumping in too much fuel, and it was burning in the exhaust.

The exhaust on my turbo MR2 used to glow, but that is normal for a turbo car.

Kurt

turbogt · Jul 22, 2009

If your afr seems to be right, then it definately sounds like a timing issue, OR, very thin headers... I've never noticed mine glowing before, but I'll check it out tonight for you

toyman · Jul 22, 2009

Stanger007 said:
The cam would have to be degreed at install time.

28* seems a bit on the high side to me for an 8psi motor on 93. If the car was making nice jumps in power as they were adding spark then that is _usually_ a great indication you are quite a ways from finding knock. An odd one for sure!

Wes

It's a '94 if that makes a difference and we are talking about a custom built balanced roller cammed engine. Tomorrow I'm swaping out the T-stat for a 180* high flow unit to see if additional flow keeps it in the 195* +/- range.

toyman · Jul 22, 2009

turbogt said:
If your afr seems to be right, then it definately sounds like a timing issue, OR, very thin headers... I've never noticed mine glowing before, but I'll check it out tonight for you

Thanks, that will be great. Are you running OEM headers?

turbogt · Jul 22, 2009

toyman said:
Thanks, that will be great. Are you running OEM headers?

no glow at all.. I'm running bbk 1-5/8" Ceramic coated longtubes... the ceramic coating may prevent them from glowing though..

toyman · Jul 23, 2009

toyman said:
It's a '94 if that makes a difference and we are talking about a custom built balanced roller cammed engine. Tomorrow I'm swaping out the T-stat for a 180* high flow unit to see if additional flow keeps it in the 195* +/- range.

Well that didn't work either. Driving in traffic will still see it climb into the 220* range and more quickly if the A/C is on. I stopped and let it idle for about 15 minutes with the hood up and the temp fell to 205* before I turned off the ignition. Tomorrow I'll take it on the highway for half an hour or so to see where it settles in. Thinking that I might just turn the rad fan on high from 180* instead of 190* where I have it set and turn off the low speed entirely.

Guero · Jul 25, 2009

I was under the assumption that glowing headers was caused by a lean condition, not a rich one.....

ej95cobra · Jul 25, 2009

What plugs are you running? I agree with some of the above possibilities (timing off, gas igniting in manifold) though another cause could be too hot a plug. This happened to my brother-in-law when a stealership put the wrong plugs in. His manifold was glowing red as you describe. In any case, it is not normal, something is off.

toyman · Jul 25, 2009

I don't recall the plug # but they were one step colder. They were recently pulled to check their condition and regapped. They were all fine and did not show any abnormal operating conditions. I was reading the AEM manual last night and it reference either a too lean condition to too much timing retard. Since the AFR appears good and the WOT timing is was set while on the dyno I was looking at the timing under little or no load and idle and advanced it by 4*. Idle seems slightly better, not that it was bad before, so I'll see if that changes anything. As I mentioned, the glow is only visible in the dark and it's very slight so I'll have to wait until later to see if that worked.

Headers Glowing Red

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