bmylez

iTrader: (3)

Not sure how anyone could complain about Kooks. Great fit and finish.

Sssnake

^^^^^ Price and the supplied gaskets suck. Get the FelPro gaskets.

RabidStreetRacer

iTrader: (1)

I hated the FelPro gaskets, they leaked a bit at the head and I could never get it to seal right. I upgraded to the GM MLS gasket and locking bolts and have never had an issue.

raven154

iTrader: (14)

Stainless works are most deffinetly NOT equal length. But how much difference does it really make on a blower car anyway. Plus they are more compact than the Kooks which are pretty close to being equal length.

barrok69

The 1 7/8" Kooks Headers fit great. They are pretty compact and package better than the Pacesetters I took out. The Kooks Cat option with Corsa connectors on the other hand does not fit very well on my car. The cats are 1mm from the floorboard and touch when they are heated up. The corsa connectors angles are all messed up too and don't fit very well.

rand49er

Agreed. Sure don't look equal length to me.


My 1-3/4" primary Kooks fit pretty well as I recall. Not sure if that made a difference though.

Sssnake

On mine they seem to fit pretty well, however, I do have noise that could be exhaust leak that I am trying to track down. No issues with clearance though or angle differences.

Sssnake

I don't know the FelPros are holding up right now (recent change to the FelPros). I did coat mine with this stuff http://www.summitracing.com/parts/pt...MhBRoCROnw_wcB.

rand49er

Same here. Then, I had a mechanic install OEM gaskets when he did my LS9 clutch. Worked like a charm ... no leak now.

Sssnake

OK, I should have been more clear. The potential exhaust leak would be between the headers and the Corsa catback. There doesn't appear to be any leak with the FelPros at the header flange to head junction. Now that may change with additional miles.

barrok69

I noticed going from the 1 3/4" Pacesetters to the 1 7/8" Kooks that it sounds like my car has an exhaust leak at idle and high load/low rpm engine speeds, but I think it's just the nature of the bigger pipes that make that sound. I used stock GM gaskets and there are no visible leaks or smell anywhere from under the car. The pipe walls could be thinner and not isolating them as well compared to the "smaller" pacesetters.

Either way I'm still happy with them.

Sssnake

^^^ Maybe. I get the sewing machine sound from under the car and NOT under the hood. My corsa cat back had no hangers except at the very rear of the car (it was on the car when I bought it). I am assuming that these things are loosening up at the joints because of the lack of support elsewhere. I have a pair of exhaust hangers on order. We'll see how that works.

88BlackZ-51

I changed out the Magnaflow catback for the Corsa system yesterday and I lost around 1 pound of boost which I thought was very odd. You guys have any idea why? The 1 pound was on the same dyno that I used prior

I am also thinking of selling the boost a pump and getting a better pump in the tank.

The 2 systems sound completely different imo.

Sssnake

less boost is good (boost is really a measure of restriction). If you made equal or more hp & torque then all is good. The real figure of merit is cylinder airmass. If Cyl Air is equal or greater then losing boost didn't hurt you (likely helps with IATs).

On the difference in sound, the corsa uses helholtz resonators to get rid of the low freq rumble which contributes most of the drone at cruise. As the flow increases they seem to become less efficient and you pickup a LOT of sound. Magnaflow uses more of a standard baffled setup.

rand49er

^^^ Yeah that.

The conventional wisdom is that aftermarket exhausts do basically nothing for peak hp and tq on V1s. If indeed you lost boost, maybe you really did gain some and the CW is wrong.

Corsa exhaust is like Dr. Jekyll and Mr. Hyde.

88BlackZ-51

I hear you Randy but it wasnt the tensioner or the belt, and his boost gauge on the Dynojet is accurate. I know loosing a pound is very odd but I cant explain it otherwise then it being the exhaust.

barrok69

What were the new numbers you got with the Corsa?

88BlackZ-51

480 rwhp and 460 rwtq. Boost was down to 6.8 if memory served correctly. In saying this I do enjoy the Corsa better but it is a more expensive system.


I will be going back soon as we had issues with fuel pressure but I was in a hurry to further investigate. But if I truly lost just shy of 1 pound of boost and gained 5 rwhp or the same with less boost then a win in my eyes.

I have a feeling that if I did headers and high flow cats that I'd loose another pound of boost to around 5.5-5.8. A crank pulley might be in store then!

I would think both of those would easily push her into the 500's....

rand49er

That's where mine is.

88BlackZ-51

Yes and you have the stock 2.8 with full exhaust. We all have different boost numbers with the Maggie slapped on. Gil mentioned that he gained around 2 psi with the crank pulley installed which is interesting. 2 pounds is decent hp/tq gains for the money.