No Frills/Custom Exhaust Thread

[dickie]

[Mikoriad]

I saw sombody mention the obx path.... Well, I took it with great results. I bought a 3" OBX can off ebay for 80 bucks. Then had a little shop put a generic 3" cat on with 3" pipping all the way back to the OBX. So the total spent was 120 bucks for everything. That was just about a year ago, and have no signs of rust, sagging leaks or looseness. Now for the sound... It's very similar to a WRX with an exhaust at idle and normal acceleration, then turns into this wild burbling roar at WOT (not at all buzzy). From about 4k and up it's race car like, and off throttle engine braking is wonderful. Bottom line, if you drive right it's fairly quiet. One downside is during long highway journeys the rumble get's a little annoying.

[A34D4ME]

Mikoriad, is your car N/A? Do you have a resonator?

[cwalke32477]

Will my car be better of with a 2.5" or a 3" exhaust system? It is a N/A ka24E engine bone stock. Anyone know where to find dyno results for a 2.5" and a 3" exhaust?

[InsanityInc]

3" is superior.

http://forums.freshalloy.com/u...art=1

Compared to

zerothread?id=147604

Clearly, the 3" is superior.

[pr240sx]

Next time I change my exhaust. will use a 4 dia. pie with a pipe heaterJust to keep the gas flowing fast and hot!

[A34D4ME]

I wonder what would happen if someone tested the same car with the exact same setups except for size. That would be a valid test.

Anybody know of someone who's done this?

[InsanityInc]

I wonder what would happen if someone tested the same car with the exact same setups except for size. That would be a valid test.

Anybody know of someone who's done this?

They both have the same mods besides the exhaust (an intake). The test is perfectly valid, just admit that you're wrong. It's not like one of the dyno graphs is all screwed up indicating a problem with either engine or something.

[Edub1]

They both have the same mods besides the exhaust (an intake). The test is perfectly valid, just admit that you're wrong. It's not like one of the dyno graphs is all screwed up indicating a problem with either engine or something.

A valid test can only have one variable. Two different cars could behave differently even with the exact same exhaust system. Plus subtle changes like a couple of tight bends or a bad muffler choice can have a big effect.

Even if we assume that a 3" flows better, it would stand to reason that we could expect diminishing returns. Something like the first 12HP when going from stock to 2.5" and maybe an additional 2-3HP when we jump from 2.5 to 3". That's just the way things ussually work, it's not a garantee.

But I'm wondering, InsanityInc. You seem to know an awfull lot about a number of complex subjects. Would you mind sharing with us your educational background? Are you an engineer or an engineering student?Are you in college? What year?

[YRUSOSLO]

Exactly what I did - well minus the 3" and OBX but still the purpose of this thread was - no frills

I'm glad that worked out for you. Despite Insanes rudeness I still pay attention to what he says because he does have some intelligence and I'm not going to argue with him about what he knows.

[Edub1]

Exactly what I did - well minus the 3" and OBX but still the purpose of this thread was - no frills

I'm glad that worked out for you.

Who are you talking too? What did you do?

[Silvia_Freak]

I have a HKS nock-off. Are there anyway to duplicate a header sound or cat. sound. ANy mufflers sound like that. I want something loud. and not ricey. BUT annyoning.

[YRUSOSLO]

Edub, Notice at the top of my post where it says re: (Mikoriad)

Also somewhere on pg1 or 2 I explained my el cheapo setup. Basically that is what the thread was looking for not is "2.5" better than 3" " or "what is the best muffler out there".

Now notice the top of this post will read re: (Edub) I still wish I knew how to quote certain things instead of complete posts.

[Edub1]

You know I always forget about that.

If you want to quote just one piece, just use "quote" and delete the portions you don't want. Just don't delete the [quote] business at either end.

I agree about the diameter business. It would be nice to see a true comparison. Maybe someone with a good 2.5" will post some good numbers.

[YRUSOSLO]

Edub, I love your sig. that's me exactly! You are a Libertarian do some research if you don't know about them. Check out Boortz.com

[Edub1]

Edub, I love your sig. that's me exactly! You are a Libertarian do some research if you don't know about them. Check out Boortz.com

I have. A lot of Libertarians have some pretty extreme ideas. I'm more of an independant, one issue at a time kind of guy.

[Edub1]

But I'm wondering, InsanityInc. You seem to know an awfull lot about a number of complex subjects. Would you mind sharing with us your educational background? Are you an engineer or an engineering student?Are you in college? What year?

Suddenly it got awfully quiet in here - was it something I said?

[Mikoriad]

Mikoriad, is your car N/A? Do you have a resonator?

Yes sir, it's definitly n/a.... for now and no resonator. I only have the OBX can on the back.

[sidewards]

What if I have a local hillbilly muffler shop put a flowmaster 40series on my stock exhaust system? would it be worth $100?

[Edub1]

Hell no, our cats are the old super restrictive honey comb design. The biggest advantage is going to be a free flow cat or test pipe followed by bigger pipe and a decent stright through muffler.

[sidewards]

will a highflow cat set off my o2 sensor. I have a 96 so it is obdII.

[eddiec]

it shouldn't. the second o2 only looks to see if there is any difference from the first o2 reading. and even the crapiest cat can catalze enough gas to keep it from getting an improper reading.

[Edub1]

I think in the SOHC it's before the cat, not sure about the DOHC.

[Neejay]

I think in the SOHC it's before the cat, not sure about the DOHC.

Yeah, its before the cat on a SOHC.

And I spent an assload on my exhuast by not doing it right the first time. But I basically have a magnaflow 2.5" hi-flow cat, 2.5" magnaflow resonator, tanabe muffler. All 2.5" stainless steel, mandrel bent piping. Sounds nice, not too loud, not too quiet, but perfect outside/inside. I get a lot of compliments on it when people hear it outside and inside the cabin.

If I decide to scrap it, or get another 240 down the line, I'll probably go with BRM dual-tips.

[InsanityInc]

A valid test can only have one variable. Two different cars could behave differently even with the exact same exhaust system. Plus subtle changes like a couple of tight bends or a bad muffler choice can have a big effect.

The 3" we're assuming obviously doesn't have anything bad about it, since it's the higher performing one. The 2.5" one has pictures to show it wasn't a POS, and I believe it was a BRM, which uses magnaflow straight-through perforated core mufflers.

Quote »Even if we assume that a 3" flows better, it would stand to reason that we could expect diminishing returns. Something like the first 12HP when going from stock to 2.5" and maybe an additional 2-3HP when we jump from 2.5 to 3". That's just the way things ussually work, it's not a garantee.[/quote]Yeah, at some point something will be worse, but nobody's really tested what that point is.

Quote »But I'm wondering, InsanityInc. You seem to know an awfull lot about a number of complex subjects. Would you mind sharing with us your educational background? Are you an engineer or an engineering student?Are you in college? What year?[/quote]I'm a software engineer. May not sound like much when it comes to cars, but I actually had to take an assload of physics and chemistry simply because software engineering is still considered an engineering degree. Beyond that, I had a minor in automotive engineering anyway. No degree for automotive, but I could probably take a few 300 level classes and get one.

And the reason I didn't respond to this earlier is that I haven't responded to anything in a few days. Search for posts by me if you don't believe me.

[A34D4ME]

I see, Software engineer - you ought to drop in on the guys over on hybridka.com and help them out with some tuning issues.

What area of software engineering are you involved in?

[InsanityInc]

I see, Software engineer - you ought to drop in on the guys over on hybridka.com and help them out with some tuning issues.

What area of software engineering are you involved in?

Really depends on what kind of problems they're having. The engineering aspect of the ECU/chipsets is generally out of the way, unless they're having some problem where they need an entirely new management system that utilizes a better/more precise map system or something.

And I'm not sure what you mean by "area". Currently I'm working for a company developing Information Visualization technology, if that's what you mean.

[HKSdrift3r]

well staying on the topic of cheap exhausts.. when i had my DSM I ordered a tubing kit from VRS exhaust and a Dynomax Ultraflo muffler from Advanced. I only paid 225 for the entire 3" setup and welded it with my friend. check out vrsexhaust.com as they do have the Tubing Kits for 240's as well. Only took a week for them to get it to my house. Great company!!

[Edub1]

How do you like it? Looks like I'm going turbo again so I'm wondering what I'll even need for a muffler.

[HKSdrift3r]

Well like with all turbo cars, the exhaust will never sound ricey at all. The ultraflo muffler sounded deep, throaty, and wasnt obnoxiously loud. The price at Advanced was great, $75, compared to $110 + S/H at Jegs/ Summit. I also had a VRS downpipe and it was of superior quality. It had nice welds (compared to mine) and also had a flexpipe that eliminated vibration. VRS exhaust is a great source for DYI guys. Check 'em out!