Hello to everyone, so recently bought a 2001 lexus is300. It seems to run good from what i can tell, and previews owner changed the whole exhaust system it has catless headers and at the end of the Y-pipe it does not have the cat. frpm there it goes to a resonator and to a fart can muffler LOL. It sounds good and all but im concerned of like a raw gas smell i get when i stop at a light or just driving with windows open i smell it and it gets me light headed. so my question is, is it bad for my health? also since my 2 year old son rides with me a lot i would not want that to be harmful for his health. if so can anyone let me know so i can put cats back on before the summer since thats when i drive the most with windows down.

 

Not having cats is bad for the environment. If you are interested in getting a good performance manifold that has cats, look into a Dezod Green header or a Magnaflow header.

But if you're getting fumes in the car while driving or idling then you've got issues with the exhaust system that won't be fixed with just swapping exhaust manifolds. You've got at least one gasket, if not more, that is bad. If you're getting fumes thru the vents then it's the exhaust gaskets on the motor (most likely) or one (or both) of the gaskets where the header meets the y-pipe. If the fumes come into the car while idling then it could be any gasket from the header-y-pipe to the axleback muffler.

 

ill looking in to those thanks,
and well i dont smell it in the car when i have the windows up. but once i put them down i smell it and at idle too like at stops but just with windows down. i never smell it through the vents. and so i should check most of those gaskets you mention?
and thanks for your reply and information you provided, appreciate it.

 

Yes, I still think it's one of your gaskets. If the exhaust was functioning like it should, you shouldn't smell any fumes at all coming in thru the windows. Cats or no cats.