233/239 cam w/stock manifolds
 

im in the process of a TSP 233/239 @112lsa cam install and was wondering how much power do you think i will lose if i keep my stock exhaust manifolds and stock exhaust system?
I've heard that the exhaust manifolds changed in 2001 to flow better (i have a 2002 C5 with 241 heads).
was just wondering what ya'll thought of running with stock manifolds. think i can make it into the 11's (1/4mile) without LT's?
(241's w/upgraded springs, LS6 intake & 233/239 cam.... its an M6 car and im a very decent driver)

I am sure you understand that is not an optimal setup, or you wouldn't be asking, but that being said. I believe with M/T drag radials, you could probably sneak into the 11's with that setup. Auto or stick? Solid 12's are pretty common, so 11's with tires and a bit more power is do-able, but probably on a glory run, and not back to back to back. Good luck, and post the results for us nay-sayers. LOL Steve

I am sure you will keep an eye on those valve springs. What lift is that thing. You will have good power uptop, do you daily drive this car?

.598/.603 ...
For the most part its my daily driver (I alternate between this and my 88 c4). Im hopen to be pleased with the cam swap even without LT's

That is a very high cam lift for heads that really dont flow well above .575

Not changing to headers and high flows witll have you down at least 30 RWHP.. However, not upgrading the springs will have you on the side of the road.

The springs are being upgraded to double springs w/ max lift of. 650. Im aware they are more fragel when cold. 241s don't flow well over. 575 lift? I did not know that. So I guess I will be porting my 241s. Does everyone think unportred 241s wont properly support my cam?

No offense that cam is too big for 241s . It will work, but a smaller cam will get you much more HP out of the 241 heads.

Ported 241s really wont help. You need at least 243 heads but still really do not flow much above .600 so no need to have a cam with lift above .598 - .600

Too make more HP it is a whole package that makes it work. not just a cam or heads or LTs

Cam, Heads, LTs, fast 92/92 intake and CAI, with supporting parts and a great tune

Good Luck

I made 413WHP and 396RWTQ with my MS3 cam, 241's, and bolt ones. You will be just fine with the stock heads for now.

hey 0331marine i thought you had a ZO6?? But to the OP, i have this cam and im on 01 ZO6. I also have ALL the supporting mods. The springs i chose were PRC's EHT's .675. I wanted a spring with an extended life as i drive my Z often. I have LG Street headers, LG's X-pipe, Corsa Xtreme exhaust, SLP UD Pulley. All tuned on HP tuners and i made 412/380. IMO you will already be suffering a more than decent power loss w/o LT's and not to mention having 241 heads. They really dont flow THAT much better than the 899's you are reffering to. TSP's 233/239 is the largest i figured i could go w/o porting my 243 heads for more power...atleast for tq. I have a buddy with a 2000 who heard my car in its building stage at the shop and decided he wanted the exact same cam. He has LT's...now hes an auto but....he made 376whp

now from what ive read and please do correct me if i wrong on this but there are two versions of the 243 head,,, an early version that is almost identical to the 241 (except for combustion chamber size 243=64cc, 241=66cc). as i have read it the early 243's dont flow any different than the 241's but the later 243's outflow the early 243's and the 241's.................. like i said please correct me if im wrong.

Getting a cam that has more lift than where the heads flow max is definitely a good idea, think about it, you pass that lift and max flow TWICE, on the way open, and on the way closed. Anyways, looking at the lift of the cam means that you are worried about the wrong thing. You pick the rpm range you are running in, then pick the lobe, and let the lift fall where it falls. Lift is the least important of all the factors.

:crazy2: what in the world??

Thanks Bro :cheers:

I have the 233/239 cam, number in my sig, however you using 241 heads with stock exhaust is going to hold back about 50 RWHP over some ported 243's with full exhaust maybe a bit more.

thanks ya'll for all the info it is much appriciated. im going to port the stock manifolds (no nay saying i already know), hollow out the cats (i had a sick 383 stroker in my 81' vette with hollowed out cats, it worked), put the car on a dyno and post the results to this thread (might be a month or so).

Then i will add LT's :thumbs:

FWIW, when I had the 233/239 CAM ONLY with full exhaust/straight pipes I put down 380 RWHP, so with stock exhaust expect about 15-20 less than that.

your bummen me out man :toetap: but i appriciate the info... you picked up 50 or so RWHP from swapping heads?

Nope, just a little LS1. :cheers:

Those are some damn good numbers with 241 heads!:rock: Ill be more than bold when i say that aint the norm!