D90 cats

[greenmeanie]

Can anyone explain why they used different cats each side on a D90 exhaust? More importantly, what's the difference in construction?

 

[jatibb]

dont know about a 90 but both my classics had different cats on each side. clearance issues i believe

 

[UnfrozenCaveman]

IIRC all the ~'92 to '99 coilers use different cats right and left.

The tall oval section one on the right provides a little air space between it and the u-joint in the front driveshaft so all the grease isn't cooked out....prematurely

 

[greenmeanie]

You wouldn't happen to know if the passenger side has an extra skin would you? I have a friend with a D90 with issues that point to timing for me. Unfortunately only the driver's side CAT glows and I can't explain that away by anything other than the cats are different construction.

 

[stevenmd]

You wouldn't happen to know if the passenger side has an extra skin would you? I have a friend with a D90 with issues that point to timing for me. Unfortunately only the driver's side CAT glows and I can't explain that away by anything other than the cats are different construction.

Plugged CAT. Change it. You can just buy universal CATs. They are different due clearance issues.

 

[greenmeanie]

I had thought plug cat and that has been suggested by several people. Thing is the Y-pipe including cats is brand new. He might have driven all of 100 miles on the new part since he replaced the old pipe for the same issue.

I'd need to ask him who supplied the new pipe but I can't imagine it going bad that quickly. Having said that I think he had at least one leaking injector. How long does it take to cook a cat?

Thanks for the help.

 

[stevenmd]

Could be a defective CAT.