quick Q on mufflers

[alfalfmarkie]

I have a 02 SER and I wanna get an aftermarket muffler for my car and the universals have a 2.25" inlet to them. I was just wondering if anyone knew what the stock muffler inlet is? Would I have to get a adapter to fit the new muffler on or will it just clamp on like the old one? Also are there any opinions on which muffler i should get i want a uni with tips but im not sure which one to buy

Thanks Bill

[nametakennow]

The old one is welded in. The stock exhaust system is closer to 2in, so they may have to weld some kind of widening piece.

There are a lot of mufflers out there, though, personally, I think you'd be better served to get a full catback exhaust system. Just putting on a muffler may cause it to sound buzzy.

[nissantech06]

The old one is welded in. The stock exhaust system is closer to 2in, so they may have to weld some kind of widening piece.

There are a lot of mufflers out there, though, personally, I think you'd be better served to get a full catback exhaust system. Just putting on a muffler may cause it to sound buzzy.

Or have zero tone whatsoever. The stock resonator will still be in place.

[alfalfmarkie]

hahah so wat u guys are sayin is i should stop being my cheap self and just buy the ful cat back. Ok that does make sense i was thinking about by pasing the resinator but if im gonna do all that might as well get the whole nine yards. Thanks guys

[nissantech06]

hahah so wat u guys are sayin is i should stop being my cheap self and just buy the ful cat back. Ok that does make sense i was thinking about by pasing the resinator but if im gonna do all that might as well get the whole nine yards. Thanks guys

The only thing I'll tell you about welding a muffler on is you will notice almost NO performance gains and, it's kinda ricey.

[nametakennow]

Any time I've heard a car with a muffler added onto the stock exhaust, it's just been a buzzy version of the stock noise. That's why I said it'd be buzzy.

There would be no performance gains. Catbacks add only a little without a header, for that matter, but they do change the sound a ton.

[nissantech06]

There would be no performance gains. Catbacks add only a little without a header, for that matter, but they do change the sound a ton.

That all depends on the size of the engine. The bigger the engine, the more the performance gain. Sure, an exhaust on a 2.5 might ONLY add 6 or 7HP, but an exhaust on a 5.6 Titan will add almost double that.

[nametakennow]

Axle-back? Nada or practically nada on any car.

With a catback, you'll see a few ponies and maybe a couple more on larger-engined vehicle.

Think about it: Tossing a catback on makes roughly half the exhaust larger. Unfortunately, the other half is still stock sized, so the added room after the cat really isn't utilized much. Yes, I know with fluid dynamics the whole deal about smaller volume/higher velocity emptying into a larger volume, but anything I've ever seen has shown that a catback alone won't do much.

Anyway, yes, at a basic level, the bigger the engine the more gain from a bigger exhaust.

[jbarbaresi]

what size piping do you think i should go with for an '07 spec v, 2.5L QR25? should i be safe and do a 2.5" pipe or would i have too much back pressure going with a 3"?

[VMPhil]

Any time I've heard a car with a muffler added onto the stock exhaust, it's just been a buzzy version of the stock noise. That's why I said it'd be buzzy.

There would be no performance gains. Catbacks add only a little without a header, for that matter, but they do change the sound a ton.

CO-Signed. when i first bought my car (used) it had an Apexi Muffler Welded on to the stock echaust system, it was buzzy as hell. i didnt like it. i went Greddy Evo 2 and have loved the result, adding a Header is a MUST on the 02 SE-R/Spec because of the Precat break up issue. not only does it add more HP it also preserves the life of your engine by doing away with the stock header. With a stock header, your engine may be a ticking time bomb....

[nametakennow]

2.5in is plenty if you're staying NA.

[jbarbaresi]

2.5in is plenty if you're staying NA.

NA? is 3" piping too big?

[VMPhil]

NA as in Non turbo. Naturally Aspirated

[nissantech06]

NA? is 3" piping too big?

3" = Honda VTEC = no low-end torque PERIOD.

[nametakennow]

3" is wasteful. The car definitely doesn't need that much room. It'd probably sound a bit hollow too.

The whole losing torque because of big exhaust thing is almost completely bunk. The header is the only place it could possibly matter in terms of scavenging effect, and the evidence for it is wishy-washy at best.

[jbarbaresi]

yeah i'm just gonna stick with the 2.5 and if a turbo kit comes out in a couple years i'll figure something out then. i haven't really decided at what point i'm gonna stop modding. i know i'm definitely doing exhaust, probably brm (just waiting to hear back from greg), intake either injen or nismo since they are similar in cost and will probably the first two cai released (injen will be released late nov/early dec), eibach pro-kit(released late november), new wheels/tires, front strut tower brace, maybe headers and hi-flow cat/s at some point. we'll see how things go.

[nissantech06]

The whole losing torque because of big exhaust thing is almost completely bunk. The header is the only place it could possibly matter in terms of scavenging effect, and the evidence for it is wishy-washy at best.

Tell that to my Lancer when I put 2.5" exhaust on it. I noticed an IMMEDIATE drop in torque. I also have noticed on cars I dynoed in school when I used no muffler or too big of an exhaust the torque dropped off.

[nametakennow]

I'd love to see these dynos.

I've seriously only seen one dyno that ever showed a loss with a large exhaust, and it was 1 ft/lb at a low rpm, there were gains everywhere else.

Your butt dyno was probably fooled by the gains you get in the mid and upper range. It feels slower because, compared to the middle and top, the bottom end doesn't gain much, if any. It's the same phenomenon when people run very high angle cams. They don't lose anything, it's just the gains that are all up top.

Again, with a header, this scavenging-effect-related torque loss makes some physical sense, but with just a catback I'm unconvinced.

I'm kinda confused why you said 3" = Honda VTEC. VTEC is valve timing, and Hondas' lack of torque has nothing to do with the VTEC system itself, but with out the cams and other aspects of the engine are set up.

[SER96VET]

is 3" piping too big?

yes, it would be a complete waste. the only people running 3" on 4 bangers the turbo folk like myself. 2.5" should be fine for your 2.5 and will go along with all the other NA bolt on stuff. You should probably measure you stock piping since that's a revised QR25 pumping out around 200hp (at the flywheel)

[nissantech06]

I'd love to see these dynos.

I've seriously only seen one dyno that ever showed a loss with a large exhaust, and it was 1 ft/lb at a low rpm, there were gains everywhere else.

Your butt dyno was probably fooled by the gains you get in the mid and upper range. It feels slower because, compared to the middle and top, the bottom end doesn't gain much, if any. It's the same phenomenon when people run very high angle cams. They don't lose anything, it's just the gains that are all up top.

Again, with a header, this scavenging-effect-related torque loss makes some physical sense, but with just a catback I'm unconvinced.

I'm kinda confused why you said 3" = Honda VTEC. VTEC is valve timing, and Hondas' lack of torque has nothing to do with the VTEC system itself, but with out the cams and other aspects of the engine are set up.

That was me being sarcastic. The VTEC system on Honda (which I worked with for 5 months when I worked for Rohrman's Schaumburg Honda) has all upper-end power. Hondas traditionally have very, very low torque numbers, usually just enough to get the car rolling and once you hit the "VTEC area", or about 5500 RPM+ on most cars, the horsepower takes over. The reason they redline so high is because when you shift at 8000 or so, the next gear brings you right up to 4000 and allows you to keep the powerband in the VTEC range. I know what VTEC is, I went to school for it and had to study it to work with it.

As far as the dyno numbers, most of the cars I saw on the dyno with too big of exhausts were small displacement 4 cylinders. As far as me actually using a dyno, I went to Universal Technical Institute, and every campus of the school had a Power and Performance course which included a Street Legal Performance section. We would learn the positives and negatives of bolt-on parts, and in lab, we would do a baseline dyno on the project car we chose, and for the remainder of the course, bolt-on parts and see the effects on the horsepower/torque numbers.

As far as a butt dyno, I'm relatively experienced in knowing what effects a modification has on a car. I've worked in the industry long enough and worked on enough cars, both stock and modified, that I can tell when I'm losing torque. Yes, my old car had a HP gain when I bolted the exhaust on, but I lost significant low-end power. I ended up cutting the old muffler off (the one the exhaust system came with) and put on a Magnaflow (for all you nay-sayers about my disliking for them) that had a less "wide open" design, and I gained my low-end power back.

Yes, doing a 3" exhaust on a car won't kill the torque TREMENDOUSLY, but you will lose a significant amount of back-pressure, and, over time, will eventually start burning the valves because the old exhaust gas won't scavenge out of the cylinder head.

One thing I like about this forum, unlike the Mitsubishi one I was on previously, is that we all can have educated conversations like this. There were so many people on that forum that didn't know a throttle body from a hole in their head and tried convincing me otherwise. I don't know everything, but there's a reason I get paid to do what I do. I hope that you guys don't take anything I say as sarcasm, but just another point to consider.