Hey guys im new here and i have a 98 sunfire se 5 speed as my beater car. Im thinkin about doin an ebay header for it but but have a question about bolting it up. in the pictures i see of the downpipe it looks like there is no flange at the end to bolt it up to the stock cat converter does this mean i cant run a cat with the header? if anyone can give me some info on this it would be much appreciated.

if it doesn't have a flange, you might have to buy aftermarket

Red2.2cavi wrote:if it doesn't have a flange, you might have to buy aftermarket

bight have to go aftermarket... post up a link and well be able to help you out a little better

The '98+ used a welded cat. You have to cut and clamp or even better weld the down pipe to the cat's inlet pipe. Better yet replace the cat with a newer high flow cat with the same outside diameter as the down pipe and a cat back exhaust.

damn well the car has a build date of 97 so maybe it still has the old style exhaust because it definatley has flanges on each side of the cat and they are rusted to hell lol. could i just cut the flange off on the inlet side and clamp the new downpipe to that will the piping size match up? thanks for the help guys,


98 Sunfire SE Coupe(beater car)
02 Monte Carlo SS - L67 Top Swap, 3.6 Pulley, VS CAM, GMPP Catback Exhaust, DHP Wideband Tuned 13.7@101.59mph

on my 2001 I just cut the factory pipe from the cat to length and welded them together. It was kinda tricky though, because the diameters were a little off. In retrospect, it may have been better to cut out more and try to put an adapter in the middle. Maybe try that route. I would definitely suggest welding over clamping though if you can.


"In Oldskool we trust"