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I put in Corsa Cat Back Exhaust. What's Next?

1K views 4 replies 4 participants last post by  darkman 
#1 ·
I put in the Corsa exhaust primarily for the look and sound. I bought an 06-V last month that had 27K on it, in mint condition and totally stock from the original owner. So now I'm wondering what's next. i don't want to change the cam or supercharge it. But I thought maybe I should allow the engine to breathe better. So I was thinking about putting on Kooks long tube headers, a Holley 90mm throttle body and a K&N cold air intake. Does that sound worhwhile in terms of gaining some horsepower for the cost? I have heard that performance headers will up the sound level quite a bit and it will resonate in the interior of the car since they are right in front of you. Any truth to that? Any recommended mods would be greatly appreciated. Thanks.
 
#2 ·
I did a Corsa back in Feb '06 and was immediately disappointed in the sound ... or lack thereof. After a couple of weeks, I installed Kooks long tubes with the metallic cats. The sound now turns heads, but is not obnoxiously loud either at idle or at cruise. There's no drone. Removing the OEM cats is what made the difference. You will, however, need a tune to get the most benefit of increased horsepower from them. Figure ~25 rwhp from the headers.

Save your money on the Holley TB and CAI. Your stock TB and air box are not hindering your motor and changing them won't do a darn thing except lighten your wallet.
 
#3 ·
The stock 90mm throttle body is adequate for the stock heads and cam. The real restriction is the LS2 intake manifold. Once you replace the stock intake tube with the K&N, look at a FAST 102 intake for more air. The FAST 102 is a cheaper upgrade for your LS2 than for those of us with the LS6 (2004-2005 CTS-Vs) because it will work with your stock 90mm throttle body as well as your stock fuel rails. Finally, a good computer tune would help extract the benefit of your upgraded intake and exhaust.
 
#5 · (Edited)
a 102 isn't overkill?
No. With stock heads and cam, the relevant intake flow rates are those at, and below, 0.550 inch valve lift because the stock cam lift is 0.525 inch and the 243 heads essentially peak by 0.550 of valve lift. The stock LS6 intake (but not the stock LS2) is a reasonable match with a flow rate of about 255 cfm at 0.550 lift. A FAST 90 will flow between 270-280 depending on whether and how it is ported. The FAST 90 is more difficult to port than the new FAST 92 and FAST 102. The new FAST 92 and FAST 102 flow rates are almost identical at 0.550 lift, although the FAST 102 has more potential at higher lifts and on those applications where its larger throttle body capacity becomes a requirement. Thus, the FAST intake manifolds offer some headroom above the minimum requirement of 255 cfm, but hardly represent overkill. The suggestion of the FAST 102 was also based in part on relative cost/resale value. I think the installed cost of: (A) an LS6 intake re-snouted to accept a 90mm throttle body; (B) a used FAST 90 (if you can find one); (C) a new FAST 92; or (D) A FAST 102 is almost the same. I also believe of those choices the FAST 102 will have the highest resale value if one wanted to return the car to stock later. See Also: http://www.cadillacforums.com/forum...8692-ls2-dyno-results-headers-fast-102-a.html
 
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