not_my_z

iTrader: (1)

I'm thinking about upgrading the exhaust of my 99 FRC.

What would be the result of installing longtube headers and X-pipe but keeping the stock C5 catback (non-z06)? The stock catback isn't restrictive, is it? Would the LT's give a nasty note at WOT, but the stock catback would keep it nice and quiet at idle?

I know, a Ti exhaust is probably the answer, but I'm looking at all the options.

Last C5

Yes, your stock C5 system is restrictive, especially if it's trying to handle the flow of a nice set of long tubes. Long tubes, X pipe, and a stock Ti system is only 86 Db at 50' WOT so a stock C5 catback is going to be really quiet, even at WOT. Get the Ti system to go along with the new LTs.

corvetteandsilverado

iTrader: (3)

yea I would def do a cat back before doing the headers I don't think you will be very happy if you do it the other way around you will gain power by just changing the cat back. What kind of header system are you planning on running? with cats I assume?

kerryt1

iTrader: (10)

1. Get a new aftermarket catback of choice. I like GHL bullets for their deep musclecar tone.
2. Get a stock Z06 Ti catback. $300-400 or so. Flows fine and sounds better than the C5 one.

If you do a search on youtube for "Corvette Exhaust" there is a video of a red C5Z with headers that compares the Ti system to the GHL. Pretty good stuff.

itsfast

iTrader: (1)

Long tubes + high flow cats + Borla stingers = One of the best sounds imo.

Long tubes + no cats + Ti's = Another great combo

twospeed

Installing LTs and keeping the stock C5 cat back exhaust set up = putting a cork in the exhaust system! Forget the sound issue for now. If you are wanting to keep the costs down this is not the way to go about that. You will not be happy with the results.

99FRC

iTrader: (5)

Yep!

99 FRC

06cobaltSS

I agree.

David Gordon

iTrader: (1)

I ran a heads cam and headers with a stock catback for quite a while. We strapped it to the dyno and it made about 420 throught the stock mufflers, then we unbolted the catback and made a few pulls. The best we got with no catback was 9 rwhp very little tq. I would say an aftermarket catback would be worth 3 to 4 rwhp for big bucks.
I say leave the stock exhast in place till you are ready to make big big power!!

Steve01SS

iTrader: (43)

YUP... :iagree: I made 446rwhp through Borla stingers and really lost nothing (other than noise) when putting on a stock non-z06 catback. Running sleeper mode now.. It's not as restrictive as you think.

There is a thead over in the FI section on corvetteforum where they dyno tested a 600hp s/c'd C5 with stock catback and then open. Didnt lose much.

will82

ABSOLUTELY do NOT get a cat-back first.

You will gain your solid 25rwhp or so from the headers either way. Get the headers FIRST, and see if you like the combo. You may, so there is no sense wasting money on a cat-back until you are sure you want one, because it is the headers and not the exhaust that will really improve power and performance. Unless you've got F.I. or a stroker, a cat-back will not make a huge difference.

I don't know why people equate sound with flow, they're not the same and it is quite possible to make a good flowing muffler without being loud. The stock mufflers flow well. That is evidenced by the fact that cat-back swaps on stock c5s literally gain almost nothing.

Get the headers, see if you like the setup, and THEN if not buy a cat-back.

Trust your instincts on this one, you were on the right path.