SM...

Today I was at the Orange County (CA) run, and Corsa's were demo'd...

From 2 drivers who had them installed, I asked the question...

How's the noise level in the cockpit?

Answer...

#1) No difference at all
#2) Well, I can't hear the radio

Neither driver had any sort of resonance problem, one driver had just-Corsa's, the other intake/cam/headers/Corsa's (REALLY LOUD but I must say mean) and that was the guy who said No noise difference from stock!

So obviously we have a difference of opinion, but to my (outside) ear the Corsa's were LOUD.

Regarding power, I can't quote the exact magazine article but from memory (paraphrase) cat-back exhaust systems by themselves add little --if any-- power.

 

Any performance gains cost $$. Going from posted owner dyno runs and rough calculations it looks like $75 t0 $80 cost for each 1 RWHP gain on bolt ons and even though it's early in the LS2 Edit the gains seem to be cheaper, $25 to $40 per RWHP.

The thing to remember is that gains aren't cumulative, the increase in RWHP isn't 40HP for headers + 15HP for catback + 20HP for CAI + 40HP for tuning. If it was there would be thousands of 515HP (437RWHP) C6's on the road today.

I'm doing the mods I listed above and if I dyno 385-390RWHP I'll be satisfied. A dyno really doesn't measure how the car actually responds to the mods, it just measures Torque and calculates HP. The 385-390RWHP I'm looking for will be on the same dyno as my other runs with the same SAE correction and the same smoothing factor.

I had runs on my SRT-4 that showed as high as 286RWHP by going to a smoothing of "0" and picking the highest run of three. Real world it was 270RWHP on that dyno.

 

and the latest vette magazine showed about a 20hp/20tq gain with b&b bullets

 

I believe it was about 10 Hp and 22 tq gain for the Bullets.

 

I posted this back on page one of this thread. It's both. The peak numbers are lower, but at certain RPM's it was higher.

 

I put Corsa with the Touring conversion in without any gain. Base line tested the day before under virtually identical conditions. There was an open bay beside the dyno and I switched back the factory "H" pipe in 30 minutes, retested and yet the same - no gain. When I say no gain it was within 1.32 hp and less than 1lb torque. The factory exhaust is not as bad as many think it is and therefore not much is gained on changing cat-backs alone. In my opinion, all brands are virtually the same except for the sound (and of course the price).

 

Can't say I understand how Vette magazine could have tested exactly the same exhaust and got 12.9 RWHP. Something doesn't make sense as to why some people see 10-20 RWHP while others see nothing. And the one in Vette mag was otherwise bone stock (no intake, no nuttin').

Mike

 

Mike, not sure if we are confused, or there are two different Vette Magazine articles. The one I referred to was B&B Bullets, not Corsa's.

 

I don't think we are talking about the same article. The one I saw was in the June issue. I don't have that issue any more but I'm pretty sure they tested the Corsa Touring in that issue and got 12.9 RWHP.

Mike

 

This does not agree with a posting you made in another thread saying that you took your dyno sheet to a manufacturer's rep and he noticed a "setting" that was off, presumably on the dyno. You said you went back and the dyno operator let you run it again and you gained 9.3 HP. Which is it? And what was the "setting" you were referring to? Your posts appear to conflict.

I guess they could be lying but Corsa claims that their system gives a 64% increase in flow. That's pretty significant and has to add up to some gains somewhere even if it doesn't occur at the HP/TQ peaks.

Mike

 

It was the June issue, and the RWHP gain was 12.9hp and the torque gain was 9.6 lbs.

 

It doesn't matter how well the mufflers flow, if you're choked by stock cats, exhaust manifold, and intake. Folks still don't get the concept that this works as a SYSTEM. All the componants need to be working TOGETHER to get any gains. Even if systems claim to increase flow by 64%, if the upstream isn't capable of flowing that much more, you might as well **** up a rope - you're not going to see any REAL gains.

Did the same dance with people around Harleys - add a nice big carb, and all you get it a bike that runs pig-rich (until you jet it down, and there goes the reason WHY you put a bigger carb on in the first place). Do the intake, heads & exhaust to match what the carb puts out and you get POWER.

Folks say GM didn't leave a whole lot on the table with the LS6 - that's just plain . Plan it as a system, and you'll get your money's worth.

Bone Stock - 336HP
Stinger/SuperMaxx/GHL/Tune - 371HP - on a 95*/95% humidity with 38lb wheels.

It would likely pull closer to 390 on a cool day with stock wheels. Bottleneck is now at the heads & cam (which would likely put it at around 420).

Rick

 

Mike, you're absolutely correct. Nothing (to speak of) on the first run when Smoothing set at 5, the gain was at a setting of 0. The freebie run on the dyno did show the above mentioned improvement then only to find yet again during a local cruise night talk with 2 other C6 guys that these results where not done correctly. I retested (for the last) time recently and this last post reflects what I (and a few others that know more than me) believe. I don't pretend to know much if anything about dynos, operators (2 operators) and their settings but I feel as though I am pissing away good money and my valuable time. Since I cannot track my vert locally I am stuck judging mod success by the local dyno and the seat of my paints. This crap is wearing me down and as a result I am just going to enjoy driving my car for what it is. I just put in the New Lingenfelter CAI (very happy with the fit and finish)it feels and sounds better; However I am not going to spend yet another $127 testing that - I'll be satisfied with letting others pay. I don't care if I ever see a dyno again! BTW, at Carlisle, a Corsa rep told me that they tested several C6s and all got 5hp gains. He said until someone finds a way to redo the onboard computer these intakes and exhaust mods wont amount to much as they could. I was with another CF member as a witness (PM me if you want the name).

 

i refuse to believe this is the case. if you know how the computer is going to respond then you can make mods. accordingly to make the computer do what you want. we know that the computer goes into wot mode at 4500 rpm and ignores the maf and o2 sensors. it uses the preprogrammed fuel settings for both wot and startup. once you know what the mix is you can add mods that will compensate for the fuel mixture and make it what you want.

without any tune (computer mod) i got 350 rwhp and 348 rw torque in my mn6 with 22k miles on it. my a/f ratio at 2000 rpm was 14.8 then at 2500 it was 13.0 then 4500 it's 12.7 and eventually drops to 12.1 at 5300 before it starts to climb back up.

but maybe this ain't all that great, once you add the 15% for driveline loss I end up with 402.5 hp and 401.12 trq at the flywheel. hhhmmm..

my mods are b&b bullets and custom intake.

i had it dyno'd on Jon Dega's DynoJet at Springfield Motorsports. He specializes in mustangs, has done numerous cars that ended up on mag. covers, articles, etc. maybe it's just me but it leads me to believe he knows what he's doing and his dyno is pretty accurate. all three runs were right inline. the first was 337/344 then 349.5/348.6 then 350.9/348.8 there was a 17 min. cooldown between the first and second run and a 9 min. cooldown between the second and third.

 

Save the time, money and aggravation – keep er stock

 

Actually 350 rear wheel is equal to 412 at the engine, as to account for 15% loss you divide rear wheel by 0.85, not multiply by 1.15.

 

I changed the exhaust for the sound more than the HP gain. I'm quite pleased, but agree if your motivation is massive HP gains then this is a lot of $$$ per HP.

 

Meee 2. Borla & I love it

 

I'll drink to that!

 

whoops...guess i forgot how to do basic math..... i heard einstein also had this problem.

that's for the clarification.