nice cavy man. dont take this the wrong way but that exhaust sounded like something out of a cartoon
I do have plans to purchase the LSJ header over the summer since it does flow better than the current pacesetter header that I have. As far as HPT, unfortunately the GM reflash for the ecotec motor is locked and cannot be tuned. If I wanted to use HPT, I would have to swap in a stock PCM and create a fake 2-bar tune and go from there. There is a ton of info on that in the tuning section of the JBO. Ultimately I’d like to do that, but right now I like having a “reliable” tune since this is my only car at the moment. I would swap to a smaller pulley, but I’m already seeing 10psi and if I push the car any further I will probably break something. It seems that the breaking point for superchargerd L61s is right around 12psi. Most people are either snapping rods or the ringlands are going.
Ideally, I’d love to build a motor for this car, but I’ve got other important things to worry about at the moment. I’m graduating in a week and a half and need to find an accounting job.
i’m not saying that it won’t support my car’s HP numbers, I’m saying that it will hurt the exhaust flow. On your 450+ HP application, the loss through the chambered muffler is minimal, where as on a 200HP cavalier, the loss would be more noticeable. I could be completely wrong in my theory there and if I am please go right ahead and correct me. I’m just speaking from my experience with straight through mufflers versus chambered mufflers on my cavalier. I know that when I swapped from a straight through magnaflow to the chambered dynomax super turbo, I felt a loss in power. That could all be in my head or there actually could have been a slight loss. Either way, I have no dyno proof to suggest either. I’m just going on my experience, thats all.
if you guys have any suggestions for mufflers that sound good on a 4 cylinder car I’m all ears.
Thanks everyone for the kind words and especially for the constructive criticism. I knew that I could come here and people would “tell it like it is” where on the JBO people just say “nice car” and things like that.
Yeah the JBO is a lively group, as is clubcav.com…
Nice, looks like it was done nicely, question though, why stay auto? And how long will the auto hold up?
Sorry, I wasn’t trying to be a d!ck or anything. I actually dig the car for what it is, other than the sound. Yes, you will give up a few HP, I’m guessing 2-3 wheel HP tops, going to a chambered style muffler. But honestly on a DD, and a Cavy isn’t it worth it to not sound like ass? Just for reference my car is putting out 450 RWHP, so let’s assume you have 200 WHP (I wasn’t sure if you meant wheel or crank when you said 200… probably crank but let’s give the car the benefit of the doubt). I’m making about 2.25 times the power. Assuming the same brake specific fuel consumption (probably not an accurate assumption me being NA vs you SC, but close enough for this discussion) I should have about 2.25 times the exhaust gas to deal with. My car is running 2 2.5" pipes (it’s 3" off the headers but necks down to 2.5" at the end of the X-pipe to connect to the factory tail-section of the exhaust) which have a lot of big bends at the back of the car, and run into factory, baffled mufflers.
Dyno testing has shown a Z06 at my power level will pickup maybe 8-10RWHP going to a good chambered aftermarket exhaust, and 10-15RWHP going to a straight through muffler and pipe routing (eleminating the big 180 bends both tail-pipes make before the muffler). Not a very big change between the chambered setup and the straight through. We’re talking about 1% change between the chambered aftermarket vs. straight through. And still only 2-3% between the stock tail-section all the way up to a straight through.
Apply the ~1% to your car at 200 wheel HP moving “down” to a chambered muffler (certainly not the stock one, but a quality aftermarket unit) shouldn’t cost you more than about 2 HP at the wheels. In reality each of my 2.5" pipes is supporting more HP though than your single 2.5", so the change would probably be less than 2HP.
-TJ
What about buying a 3" chambered muffler to help offset the backpressure that you want to avoid?
My DSM has 2.5" TBE, with a straight through muffler, it’s about as quiet as stock at idle, and comes alive a good bit when I tromp on it. I suppose that’s how you want an exhaust to behave, at least I do.
the 4t40e holds up pretty well with boost. i haven’t seen anyone break one yet. the auto seems to hold up better than the five speed. i went with the auto cuz i like a challenge. its really easy to take a 5 speed cav with the ecotec motor and slap on the hahn turbo kit and run 13s, but doing that with an auto is not as common. having a 13 second 5 speed jbody is nothing impressive to me. i have only seen 3 auto jbodies break into the 13s and they were all turboed. i have yet to see a supercharged auto in the 13s. thats where my project is headed.
you make a good point. so basically whatever i might lose performance-wise is negligible. i appreciate the help and explanation. most of you guys on here have roughly 8-10 years on me and you’ve all definitely been around cars longer, so you guys know what you’re talking about.
time to start searching for a nice sounding chambered muffler
hands down the cleanest cav i’ve ever seen!my buddy would :wackit: if he saw this since he has an auto cav lol. I know you’ve been asked this alot but any plans for a manual swap?just think how much faster it would be!
x2
any pics of ur old one ? & times with it ?