Cats or No Cats???

[RussMcB]

I've never heard of non-cat cars getting smells into the interior of a car. Is there an explanation of how and why?

My initial gut feeling is there must be an exhaust leak for that to happen.

Or maybe it's because gasoline is formulated differently now? Still not sure how straight pipes in place of cats would cause a smell (much less going into the car's interior).

[WARP TEN]

Originally Posted by RussMcB

I've never heard of non-cat cars getting smells into the interior of a car. Is there an explanation of how and why?

My initial gut feeling is there must be an exhaust leak for that to happen.

Or maybe it's because gasoline is formulated differently now? Still not sure how straight pipes in place of cats would cause a smell (much less going into the car's interior).

No exhaust leak, Russ. Just an excess of hydrocarbons that the cats usually eliminate. If the car is just standing on a windless day or there is a slight tailwind, it is noticeable in the car. Or if you are just standing nearby or behind it. As noted before, I only notice it on a cold startup, and usually in my garage when I back out. And if I am driving my car it usually means the windows are open.-Bob