Exhaust Pipe Color

[bobh]

Back in the day we would look at the color on the inside of our exhaust tips to see if the engine was running right. Much like the color on spark plugs we looked for a light tan. If it was white it was running lean. Dark meant rich.... What color do you guys see now? Mine is dark which leads me to think it is running rich. However I don't know if modern fuels will produce a tan color on our non catalytic cars. Any thoughts. experience, comments?
BOBH

 

[macino62]

i've done similar tests, and no matter how much i lean the car, the exhaust is always black. my dad told me about how he used this trick back in the day (when he was racing GTO's)

 

[Harry_Ward]

I was wondering the same thing about a week ago because my exhaust has a dry sooty black look to it while the plugs are a perfect tan/brown. I'm not too sure about it but I think it has something to do with overall engine and exhaust temp and not entirely the air/gas mixture. Then again who knows what problems the additives in the gas we buy today are going to cause. This past summer I found out about the ethanol problem with the carb seals and rubber needle valves on all our gas mowers. I'm just glad the car still runs on this stuff. Someday we may all be buying black market gas to actually make our cars run.

 

[macino62]

...just head to your local airport FBO. i've bought 100 octane, low lead AVGAS before and monkeyed around with it in the TR4

 

[DougF]

I think it is the "environmentally friendlier" fuels that have been forced upon us.
A diesel exhaust pipe is probably cleaner and lighter in color than the one on my TR6.

 

[Don Elliott]

I used to use the tail pipe colour as an indication of the mixture, but then in 1990, Canada outlawed leaded gas. Since then, I've driven my TR3A over 94,000 miles and the tailpipe is always black with the unleaded "petrol".

https://www.triumphest2006.com/images/clubcars/30donelliott'str3.jpg