performance exhaust question

[redlava]

I did a search and I didn't exactly find what I was looking for. Without sounding like an idiot I was wondering what the main difference was (performance and sound wise) between a cat-back exhaust and just a regular performance muffler. I was thinking about getting a magnaflow exhaust and didn't want to spend money on something that wasn't needed or didn't improve anything. Any input would be helpful. Thanks

[dmitri]

the only real catback is magnaflow. for 350 bux u cant go wrong. All the rest are axle back, and more expensive.im not spending any more money on my vibe. tho, its all going in my civic

[Psychobroker]

According to www.ptuning.com, Borla's Exhaut Kit is also Cat-Back

[dmitri]

i swear some of u never read these forums those arent true cat backs, they dont eliminate the resonator and arent from the cat.

[redlava]

OK so let me try and put 2 and 2 together. A true cat-back exhaust will not have the resenators that the stock exhaust has. Which is the reason why they are less restrictive. Therefore getting back to my original question, if I just put a performance muffler on my car and not replace any of the other components I will not be gaining much power. And if I put a cat-back exhaust on my car then I will be getting rid of the resenators in the stock exhaust to make the flow less restrictive. Am I correct in my thinking?

[MadBill]

Hey Red, here's a bit of data to go with all the preceding opinion :Per my Dual Exhaust -Check it Out thread, I built a cutout ahead of the muffler on my base Vibe. I also fitted a pressure tap ahead of the second cat, to take exhaust back pressure readings. At 6,300 RPM with the stock system, the back pressure was 4.4 psi. With the cutout open, it was 2.0 psi. Since the second figure represents the combined back pressure from the second cat and the resonator, I conclude that most of the restriction is in the main muffler, and not much more could be gained by deleting the resonator, especially since it would then be much too loud without substantial muffling/back pressure in some new sport muffler.

[Stang2Vibe]

redlava, you are trying to gain HP on the wrong end of the engine. By most accounts, you could reduce backpressure all you want and only achieve a HP gain that could be counted on one hand. If you are looking to pick up some easy HP, get a Cold Air Intake. They have proven on the dyno to pick up much more HP than tinkering with the exhaust. There is also a lot of debate that too much of a reduction in backpressure of small 4 cylinder engines actually takes away HP, not adds to it. I know MadBill doesn't go for this theory, and my jury is still out. I'd have to see more proof. But anyway, bang for the buck, the CAI is the much better option. Change the exhaust for the looks and the sound, you're not going to pick up much power from it.I want a louder and deeper exhaust tone, so I want to eliminate my resonator and swap out my muffler for a Flowmaster 60 Series. The 60 series is specifically designed for small displacement 4 cyl engines and has the delta-flow technology so it effectively muffles the loudness without increasing backpressure. That is the way to go for me.

[Thxalot]

Stang,I wouldn't mind getting into a little CAI vs. Exhaust debate with you. Take a look at my CAI rant on the bottom of this page:http://forums.genvibe.com/zerothread?id=6855I put a GMD exhaust on my GT, and I noticed a clear improvement in power throughout the RPM range. Unfortunately my (removed)-dyno doesn't give good numbers, but since I have gone back to stock I was able to make a decent comparison. George said he saw 8-10 HP improvements using his exhaust on a dyno.It's an axle back like the Borla, not a true cat back like the Magnaflow. I would like a true cat-back, but I need to keep it bolt-on. No metal cutting or welding for me. Nonetheless, the GMD uses bigger 2.5 inch stainless tubing, it's mandrel bent, and there is a real short glass-pack muffler on the end which runs longitudinally with the car. Around town it had a nice low rumble to it and gave the car a nice sporty tone and look. It wasn't too ricey.Unfotunately, at highway speeds the sucker had a very loud drone in the 3000-4000 rpm range which is where I like to cruise in 6th gear. I actually took out an SPL meter and measured the before and after, when I put the stock back on. On the freeway the GMD is an average of 10dB louder than the stock setup. (Incidentally, I think the GMD is actually a couple dB quieter than the TRD and Borla setups.) 10dB is a lot of extra noise. It means the exhaust is putting out 10 times more acoustical power. It really made conversations and listening to tunes intolerable.I understand the stock resonator is at fault for all the axle-back exhaust systems freeway drone. Since the Magnaflow replaces the resonator, I'd love to put my SPL in a car with a Magnaflow system. Anybody near SB, CA volunteering?I do miss the extra power that GMD exhaust gave me. Speaking of which, it is available for sale. Too heavy for shipment, but I drive down to LA pretty regularly. I paid $400 installed. Make me an offer.-Burt

[Thxalot]

Say, Stang, where'd you get the Momo sills and how much were they?-Burt

[Psychobroker]

quote:Anybody near SB, CA volunteering?SB as in Santa Barbara? I cruise up to Oxnard/Ventura all the time and live in L.A. Unfortunately, my VibeGT is 100% stock (still) until further notice.As for:quote:i swear some of u never read these forums those arent true cat backs, they dont eliminate the resonator and arent from the cat.Of course I read these forums, but I wasn't going to perform a search on exhausts when I thought I could rely on ptuning AND Borla for reliable information. Are you saying that they are misadvertising their product? If so, you should let them know. According to Borla, it's a cat-back system. :shrug: I have no idea.

[Thxalot]

Psychobroker,You got the SB right. If you want a bolt-on exhaust that can easily be put back to stock, drop me a line.As for the false advertising of Borla, etc. It's almost forgivable. The ony break point for a bolt-on exhaust is at the rear axle. The stock cat is welded to the stock resonator. They can't really make a bolt-on cat-back system. Axle-back is the best they can do for the Vibe, but nobody has heard of an axle-back exhaust system, so they call it a cat-back for marketing purposes.-Burt

[Stang2Vibe]

quote:Say, Stang, where'd you get the Momo sills and how much were they?-Burt www.ltbmotorsports.com has them the cheapest that I could find. They have a MOMO outlet store online where they sell MOMO stuff that has been discontinued or they are overstocked on at a pretty good discount. All kinds of MOMO stuff there, steering wheels, shifters, pedals, wheels, etc. You have to check it once in a while because the supply is always changing. I got the Course Tuning aluminum pedals back in the summer. They're still on the Vibe, but I'll probably take them off for the winter to protect them from road salt, etc. I never got the door sills yet, I dont know what happened to them. I have to go back and check my credit card account data to see if they refunded the money for them because I never got them. I still want them, though. I found that MOMO makes 2 different lengths of sills, long and short. I measured the Vibe's door sills and compared them with the MOMO specs. The short sills will fit well in the front doors, but I think are way too long to fit in the back. So I guess that I'd have to have them in the front only. They are currently $25 for a pair. Pretty good price for MOMO stuff, I think.