It’s been awhile since posting on F Chat. I have a 99 355 GTS that I have owned for nearly 20 years. My question is the color of the exhaust outlet. I haven’t driven the car that much in the last few years, but I don’t remember exhaust outlets having the appearance of being lean. The car runs perfect and doing nothing out of the ordinary. It presently on cat bypass pipes with a Tubi. Again, all vitals are perfect. It is going in for a belt service in the spring, however, it would be good to know if something is amiss prior. Maybe this is normal and I haven’t paid attention in the past. Any thoughts? Regards, Matt Image Unavailable, Please Login Image Unavailable, Please Login
Depending on the type of multi weight oil you are using, some additives cause a white tailpipe color, because of a high ash content when the oil burns. Gary Bobileff
If in doubt put a sniffer in the tailpipe and check CO (most shops have one), or borrow an LM-1 and run it through the gears to ensure proper AFR's.
Doesn't the 355 exhaust tip sides share the same can, meaning left exhaust tip contains emissions from both banks?
Everything is mixed inside the muffler can but to what extent who knows, so I would sniff both sides just to be sure.
The whiteish tail pipe coloration has nothing to do with mixtures, if it was extreme leanness, it wouldn't have a whiteish residue, but have almost no residue at all, as leanness burns mush higher than the normal thermal temperature of a proper mixture in the exhaust, and would burn off any residue. . A dark color would denote excess richness. Gary Bobileff
After more careful reading, no cats. I did change from Mobil one 0-40 to Pennzoil Euro 5-40 last year
My outlets are usually whiteish after I’ve given the car a good thrashing eg. long high speed running on a highway or hard climb up a mountain pass, especially in warm weather. If i’m driving in traffic in cold weather then they tend to be black. I’ve also had my car nearly 20 years and has been like that since I got it. I have a 95 GTS it’s running well, currently on factory cats and factory muffler. Personally, I don’t give it a second thought.
