Ok guys, confusion reigns supreme, I have looked up jeg'* website for hi flow cats
and have found three part numbers.

1). 54305 Round

2). 94305 Oval

3). 94315 Oval w/air tube.


Which one do I need to order :?:


Tim

read here:
http://www.bonnevilleclub.com/forum/...ic.php?t=52522

Yes...aim for the cat that has the front flange on it already. Much easier to install.

Anybody know what the gain is for a HF Cat?. I have a 2000 SSEI all stock.

i feel a difference in my SE since putting it in, i also removed the resonator an dhave ported exhaust manifolds, but i think the cat made the biggest difference

I swapped one out on my 97 SSEi and felt no difference. Only thing I noticed was a slightly louder exhaust tone and the extra space in my wallet.

You won't normally feel it unless your cat was old/clogged to begin with. It adds about 5hp assuming your old cat was flowing to spec, and that'* a little low on the butt-dyno detection threshold.

Was wondering on fuel mileage, If 5 hp is it, is it worth it for the money spent. My 454 in my truck got 10mpg (3/4 ton 4x4) Installed 2 1/2 inch new exhaust and went to 15 mpg stil using Stock cast iron manifolds. Thats 50% gain in gas mileage. If you can install headers and hi flow exhaust on a Blown Bonni what could the gain be???

that type of an increase that you got on the truck does not seem typical.

I doubt you'd see anything more than a 1-2mpg difference on a bonne unless you were battling a clogged cat.