Is anyone going cat-less ?
I'm getting ready to do my exhaust system starting with a pacesetter header, a flex pipe, a 22" resonater, 2.5 tubing, not sure on the muffler yet, or if I want to run a cat.
Anyone not using a cat ?
what difference does it make?
How much louder will it be?
Is this a good idea at all ?
i dont have a cat...i have...long tube header,22"res,2.5pipe,and magnaflow muffler...............cant say on performance cus i didnt dyno before and after and i dont like to "butt dyno"
however i will tell you this..without the cat the exhaust made much more noise, not just loud but those other annoying noises as well....this noises went away after i installed my 22" res though....
so now i have the magnaflow res and muffler and i couldnt be happier with my exhaust tone..no pops or farts whatsoever ....i dont think you need 2.5" pipe though, not unless your boosted...
i would stick with 2.25......on reason i use 2.5 is cus my engine is a 2.6L , and i still think i couldve gotten away with 2.25
All cats are "free flowing" from the factory and are actually not that restrictive anymore, at least on most smaller cars. Putting on a full exhaust will gain you more than just chopping off your cat.
As proof...my car made 212WHP on 8PSI with a dumped side pipe. Came right off the turbo, went under the car, bent where the stock one did, and came out behind the door. 2.25in DP into 3in pipe.
With a 3in cat and full 3in exhaust the car made 211WHP on 8PSI.
I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26
2.25 is fine with me I'm using a header that is 2.5 at the flange that is the only reason I was saying that...
So... Cat or no cat ? I will be using a resonator so I wont have all the extra noise problems, but would it be better to just run a cat
Oh, I was not talking about just chopping the cat off for a gain in hp. I was just wondering if, since I'm starting from the front and going back, if it wouldn't be a good idea to just exclude the cat all together.
and if there would be a gain of any sorts, or just noisier ?
No real gains, and with the resonator to compensate as a pressure-wave chamber (Which is part of what a catalytic convertor acts like) deffinately more noise. Not to mention the ECM will be wondering were it went unless you trick it with a simulator. But then you'll have emissions testers on your case when you go in for the IM240 (IM: Inspection/Maintainance). So just more the cat forward a lil' to clear the resonator & you'll be fine.
Go beyond the "bolt-on".
Plus if you dont run a cat your computer throws codes and possably keep i t in open loop
I was just wondering, I will probably just run 1 of the high flow units from magnaflow...
Ive gone threw 2 magnafow cats in 3 years. They blow out wayyyy toooo fast.
Not having a Cat will trip your CEL, but will not affect anything else.
I have a Magnaflow High Flow Cat and it still used to trip my CEL light till i turned it off for good with HPTuners.
I will be pulling my Cat out soon when i get my header installed so i can run a cut-out where my cat currently is, then again I don't have emission tests where I live.
^Lucky dog.
Hey, what about the spun-shell metal-substrate cats?
Go beyond the "bolt-on".
I have a hollowed out cat that I can throw a straight pipe through, this is why I was asking.
you car will be louder no doubt of that. It will also be raspier. However I see you are running the prefered 22" resonator which will help with that. Running with no cat just throws CEL's however it will make little difference in performance. The only real reason stock cats aren't great at flowing is because there have small inside diameters. Upgrading the size of the cat to match the rest of your piping is most likely ideal however it depends on how you feel towards the environment and if there are laws about emissions.
We have the magnaflow high flow cats at www.TurboTechRacing.com they are less than $100 and have the extra O2 sensor hookup
-Aaron
www.TurboTechRacing.com
Performance Parts For Cavalier, Sunfire, Cobalts and More!!!
Hey... Remember what I said about "Pressure-wave Chamber"? It's true! In fact, awhile back David Vizard (One of the guys that had a hand in the design of the original Flowmaster) did an article in Popular Hot Rodding about custom exhaust design & spoke about how the expanded area inside the catalytic case acts like a pressure-wave chamber, and how the application of it is useful in designing a quiet, hi-flow exhaust system to help cancel unwanted soundwaves. The glass-pack muffler used as a resonator does the same thing (Canceling unwanted soundwaves), but since the catalytic case does the same (Only not to the same extent) it makes sense to use it with the resonator to help do the job.
Go beyond the "bolt-on".
itll def be louder after i s/c my car i hollowed out my cat at the shop, made my car alot louder and theres lots of fire balls comin out my muffler to.
That's 'cuz you just eliminated the one thing that'll cause whatever unburned fuel that's mixed with the exhaust as it leaves the engine to be thuroughly burned (To an extent)!
Go beyond the "bolt-on".
WOW.... I have actually gotten more dummer by readn this... you guys are funny though. It was just an idea though..
