The case of the red-hot glowing header pipes...
#1
The case of the red-hot glowing header pipes...
Okay Scooby Doo fans and mystery sleuths, this morning as I rolled into my office parking garage, I parked, left the car running, and had a peak under the engine. I noticed that the B&B headers on the drivers side were glowing a light orange..all the way to the turbo manifold!! I had only driven the car a short distance (about 10 miles). It was pretty cool this morning (overcast and in the high 70s). I got on it a couple of times, but nothing too scary. I know that turbo cars generate a ton of heat, but is this normal? I follwed the proper cool-down routine before I turned the ignition off. The car is running better than ever! I plan to order the Innovate LM-1 this week to check my AFR. After installing my k27-7200 I didn't make any fueling adjustments. Could the car be running on the lean side...causing the heat? I guess there's no way to tell without the proper tools. Maybe I'll stay off of the boost until I can check the AFR.
I should also mention that the temp gauge was reading normal (right at the middle line), and oil pressure and level were all good.
I should also mention that the temp gauge was reading normal (right at the middle line), and oil pressure and level were all good.
#5
Sorry Sameer but that statement is 100% incorrect.
Running rich results in lower exhaust gast temps, running lean results in hot exhaust gas temps. Gasoline by iteself has a cooling characteristic, hence many manufacturers using side feed injectors.
This why most turbo guys run a little rich (naturally too rich is also VERY bad - for obvious reasons) too get some extra insurance when the boost goes up and also to compensate for not pulling back too much timing...also known as a "fat tune".
Sand_Man get that LM1 and do some hard runs....3rd gear in the power band is where you want to do the runs and then let us know what the AFRs are saying. Also you can buy a digital infra red Pyrometer very inexpensively and check hot hot those pipes are getting.
Yasin
Running rich results in lower exhaust gast temps, running lean results in hot exhaust gas temps. Gasoline by iteself has a cooling characteristic, hence many manufacturers using side feed injectors.
This why most turbo guys run a little rich (naturally too rich is also VERY bad - for obvious reasons) too get some extra insurance when the boost goes up and also to compensate for not pulling back too much timing...also known as a "fat tune".
Sand_Man get that LM1 and do some hard runs....3rd gear in the power band is where you want to do the runs and then let us know what the AFRs are saying. Also you can buy a digital infra red Pyrometer very inexpensively and check hot hot those pipes are getting.
Yasin
#6
Thanks, both of you! I'll go ahead and order the thing. I know where the AFR enrichment adjustment is, and which way to turn for rich and lean, but what does the actual adjustment screw feel like (that sounds kinky, I don't mean it to)? Is it spring loaded? Do I push down to engage the adjutment? I've also heard that it's very sensitive, so only small movements apply. Someone who has touched this thing, please advise.
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#8
yasin is correct - rich helps keep it cool - thus they wouldn't be glowing if it were running rich.
But lean will help them glow really quick.
Once we started up a V8 engine that a friend had built, and almost immediately after we started it the headers started glowing. Carbs weren't delivering enough fuel.
Brian
But lean will help them glow really quick.
Once we started up a V8 engine that a friend had built, and almost immediately after we started it the headers started glowing. Carbs weren't delivering enough fuel.
Brian
#10
Originally Posted by turbocarrera.
I've seen perfect AFR's glow red under boost on a dyno, but they stop glowing very quickly(two seconds) once off boost. They should never glow if idling.
What about ignition timing. I have a basic strobe timing light. My car is an'87 and I have removed all of the smog crapola. What's the methodology for setting timing. Remove vacuum advance lines and rev to 4000RPM? What mark am I looking for?
#11
My set of B&B headers used to do the same thing... a quick ten minute trip around the block and I had orange headers like a F1 car! I took it to the dyno and adjusted my C/O mixture to about 3.7-3.8% to correct an overall lean condition... It runs a bit on the rich side now but I get a nice 12.5:1 @ 6500 RPMs! (It drops down to 11:1 @ 3-4K) No more glowing headers... if I blast around in the car at worst my header turbo flange is slightly red, but not like it used to be... I have a 7200/Headers/Intercooler...etc.
#13
Originally Posted by turbocarrera.
I've seen perfect AFR's glow red under boost on a dyno, but they stop glowing very quickly(two seconds) once off boost. They should never glow if idling.
Certainly A/F mixture plays a role, but LOAD & boost level determine how much they change color on boost. Our 935's would glow bright orange-yellow at 1.4 bar with 10.5-10.8:1 AFR's.
Attached is a pic of a 3.4 964-cammed, twin-plug motor on our dyno at 1.0 bar (10.8 AFR) at full load.