what's the normal heat exchanger tube temp on a 964

[silver911rdb]

Just wondering what normal temps are measured at the tube exiting each cylinder. It's a '91 964 with a 3.6L engine. I'm getting around 750 deg F at idle once it's stabilized. Seems a bit high to me but not sure what's normal. I was having an issue with glowing headers at idle, but did find a vacuum leak. I'm hoping that fixed it but still worried temps are too high.

Thanks

[RedCoupe]

If you're measuring the heat exchanger tubes right where the exhaust gasses leave the exhaust ports in the head, then 750F is probably normal. Remember, the 3.6 has a ceramic liner in the exhaust ports so that less of the heat of combustion is absorbed by the head on the way out. So, compared to earlier engines, I would expect the heat exchanger to run hotter. How about taking the car to a dyno where they can measure AFR under load just to be sure that all is well?

[silver911rdb]

Thanks! I forgot about the ceramic liner. I'll check tonight to see if any of the headers are glowing. I couldn't see anything during the day so it looks promising. The car runs so much better now that we found the vacuum leak.