Building a custom exhaust, need input

[edubb11]

The stock exhaust muffler on my 240SX looks to be rusting pretty badly, so I figured that it would be a good time to go ahead and replace the exhaust with an aftermarket one. The only problem is that most of the exhausts are N-1 style which I don't want (had on my WRX and was too loud), or single-tip mufflers which is almost equally as undesirable as the previously mentioned style. So, I figured that a custom exhaust is the way to go, I personally would like to have something similar to the stock setup with a twin-tip muffler, only with 3" piping which will be good for when I finally decide to go turbo.

Going to an exhaust shop is a no no, I barely trust some of the shops I have seen in Orlando. So, I looked around on the net for options and ran into some mandrel-bent piping systems on www.kteller.com, a site which has good reviews from the Acura/Honda crowd. They have a full bolt up, 3" mild steel piping system for under $260 and a full stainless option for $25 more. Pair this with a resonator and a Magnaflow muffler with tips of your choice, get hangers from stock muffler to work with Magnaflow one, and you have a decent alternative to the brand name systems offered.

A few questions:

- Are there any other options for piping kits from other websites/parts sources?

- For the KA-T owners, what diameter piping are you using for your setups? Is there any reason to go with a 2.5" system, other than possibly a gain in low-end torque?

Sorry for the long post, just wanted to cover all points!

[240Stilo]

You get more low end torque even with 3 inch piping.

[240Stilo]

Do you know if the piping is made from the cat on back or what?

Furthermore, if you want a muffler you need to buy that seperate. So about $360 before going to a welder to have it put together. Not too bad nice that there's a new option. If anything I would probably run a resonator or two and just tuck the end of the piping somewhere so there's no sign of it.

[edubb11]

Do you know if the piping is made from the cat on back or what?

Furthermore, if you want a muffler you need to buy that seperate. So about $360 before going to a welder to have it put together. Not too bad nice that there's a new option. If anything I would probably run a resonator or two and just tuck the end of the piping somewhere so there's no sign of it.

240Stilo, the piping is made from the cat back. You can go HERE (http://www.kteller.com/store/index.php/cPath/23_125_150_151) to see all of the piping systems they have for the S13 and S14. Also, your $360 quote would be before the muffler is welded to the piping and hangers are welded to the mufflers. All the other hangers/flanges are already welded on, so I wouldn't imagine that the muffler and hanger welding would be too terribly expensive.

Tucking the exhaust sounds like a good idea, but looking at the bumper and seeing empty space where the muffler should be would get to me.

[Jeff240sx]

I wouldn't.. I won't buy from any place that can't do simple research and list the correct years, for parts they're making.
86-93 and 94-99??! How about 89-94 and 95-98? Wouldn't you be pissed ordering S14 piping for your '94 s13 'vert?
Second, OBX/Boostevolution.com have a $250 stainless steel 3" setup. Either the website (there are others, that's just off the top of my head that carries it) or ebay. Paying $300 for something of less quality doesn't seem fun.
Finally, you'll lose low end torque with 3" piping. Sheesh. You'll gain high end. Most people planning for turbo get 3" exhaust, and bitch about the loudness until they put the turbo there. If you have moderate power goals when you go turbo, 2.5" will suffice, and help you now.
-Jeff

[edubb11]

Not getting the years correct doesn't bother me much, I have done research about them and found them to be very highly recommended amongst Honda/Acura enthuasiasts.
The exhaust on Boostevolution.com is of a style that I do not want to go with. However, they do mention at the bottom of the page that more exhausts are available upon request. Maybe I could give them a call and see what they could do along the lines of a stockish looking exhaust setup. If it is not competitively priced compared to what I figure I could get with the kteller.com setup then they will be out of the question.
Oh yeah, thanks for clearing up the misconception between 2.5" and 3" piping, I guess 240Stilo misread my first post. Truthfully, I doubt that the gains/losses between the two diameters would be very significant.

[Salty_X]

you'll lose low end torque with 3" piping.
DIE MYTH DIE!!

[brianglawson]

get an apexi N1 Dual

[Jeff240sx]

DIE MYTH DIE!!

WTF mate? It's pretty proven. Low end, you lose torque due to the loss of the scavenging effect, which takes place as the low pressure area of the moving car's tailpipe sucks gasses from the high-pressure area of the combustion chaimber. This is the difference between sucking air through a straw and sucking air through a paper towel holder. Or blowing that air, for that matter.
Hell.. look at Mav's dyno charts of stock vs. apexi n1, and you'll see the loss of a few ft/lbs of torque. For some reason, it doesn't affect the KA like it does to other motors, especially Hondas.
-Jeff

[RedlineRacer]

that isn't saying much about the company if they are praised by the honda/acura crowd.

for instance: I was at the local import shop the other day (cool guys, but their customers are complete idiots sometimes), and this kid comes in with this riced out pos civic saying he needs a Caber kit. I was like you mean camber kit? Then he said yeah, i need one of those. and he is sitting there talking about all the bullshit rice on his car and then says, how do you install that caber kit. What is it for? I was like, how are you gonna come buy one and have no idea what it is used for.

[Salty_X]

Hell.. look at Mav's dyno charts of stock vs. apexi n1, and you'll see the loss of a few ft/lbs of torque.
http://www.worldwidechang.com/Pics/Cars/MyCar/Dyno/NewDyno/IntakeExhaust1.jpg
I don't see any...

[Jeff240sx]

For gaining a couple ft/lbs at 2000rpm, he sure didn't gain any hp there. Something seems off.
Anyway, I was wrong about Alex's dyno chart, but I did end my post with "for some reason the KA isn't as affected."
So, now the whole debate is you and the "End the myth" versus fluid and thermodynamics. I vote for physics.
-Jeff

[sideviewcivic]

im building one rite now. im actually wanting to see if anyone had undercarriage shots of the buddy club specII and the greddy DD system. i can build systems similar to them quite easily. gotta love a miller machine.

[Phlip]

SSAutochrome, $260.00 shipped anywhere in the US, 3" stainless, found here (http://www.planb-attack.com/kyle/group-buy.htm)

[Salty_X]

For gaining a couple ft/lbs at 2000rpm, he sure didn't gain any hp there. Something seems off.
Anyway, I was wrong about Alex's dyno chart, but I did end my post with "for some reason the KA isn't as affected."
So, now the whole debate is you and the "End the myth" versus fluid and thermodynamics. I vote for physics.
-Jeff
I'm just trying to say that it is possible to use 3" piping and not compromise power. The KA is big for a four-cylinder and has a lot of exhaust gas energy. Even Alex admits that the best possible piping size is needed for gas velocity and scavenging, and considering the dyno I'd say it's at least possible that 3" is it.
Anyway, I'm not trying to argue, so don't take it personally. :) Maybe if I understood the physics better I would vote for it, but I don't, so I go with the dyno charts.

[Jeff240sx]

Some cars gain power with a large exhaust, others are very finnicky. Take a Ford 302, gains 9hp and loses 6ft/lbs when uncapping headers, while older (late 80s, early 90s) Chevy 350s would gain both power and torque. Some would say better header design on the chevys, because fords use shorty-style mostly. Same could be said about Nissan versus Honda. We have a 4-2-1 header stock, and honda have a 4-1 header that wraps around under their engine. Header design would change alot, and allow the use of larger exhausts for more power gains and less torque loss.
I'm changing my mind. I think headers are responsible for the scavenging effect, using the exhaust pipe as an intermediate low-pressure area.
-Jeff

[orion::S14]

For gaining a couple ft/lbs at 2000rpm, he sure didn't gain any hp there. Something seems off...

So at 200rpm, he's making 47rwhp BEFORE and 48rwhp AFTER...

Let's do the math:

HP = (TQ X RPM) / 5250

So TQ = (HP X 5250) / RPM

BEFORE: 47X5250 / 2000 = 123.4

AFTER: 48X5250 / 2000 = 126

Looks about right to me...

I vote for empirical evidence...(as long as it's repeatable, which on the KA...it has been).

- Brian

[240Stilo]

orion::s14: Are you an engineer or is that your favorite formula? :D

[orion::S14]

It's my favorite, but the "XX size injectors can do XX HP" is a close second!

:D

[Phlip]

I saw that formula on howstuffworks.com (nerd paradise, I swear) a while back and forgot about it until I saw it here

[240Stilo]

I saw that formula on howstuffworks.com (nerd paradise, I swear) a while back and forgot about it until I saw it here

Look at this guy acting like he's smart too. Ha!

Had to say something for my 1000th stupid thing said...wee! Eventhough PHLIP has me by 1000. :Ownedd:

[bkfill]

http://www.mr2oc.com/showthread.php?s=&threadid=57156&highlight=Hydes+new+exhaust
3" in 3" out
ran 11s and still running 11s same #s with exhaust and wideopen open exhaust
http://www.jekylhyderacing.com/images/hyde_muffler1.jpg
had a 3" in/out Borla installed this week-^
I ran 11.78 the weekend before the muffler was installed (just had and open pipe) and I ran 11.78 the weekend after.-^

[g81981]

I have one for sale. May be what you are looking for.
http://www.zilvia.net/f/showthread.php?t=63060

[96twofourty]

dont buy from boostevolution, theyll shiest you

[S14DB]

WTF mate? It's pretty proven. Low end, you lose torque due to the loss of the scavenging effect, which takes place as the low pressure area of the moving car's tailpipe sucks gasses from the high-pressure area of the combustion chaimber. This is the difference between sucking air through a straw and sucking air through a paper towel holder. Or blowing that air, for that matter.
Hell.. look at Mav's dyno charts of stock vs. apexi n1, and you'll see the loss of a few ft/lbs of torque. For some reason, it doesn't affect the KA like it does to other motors, especially Hondas.
-Jeff
Um, even by your example bigger piping scavenges better. You want to pull as much of the exhaust out to make room for the intake charge. Header design is more critical than exhaust size.

I had a 60mm 5Zigen Fireball, I switched to a 80mm Cannonball. The low end response and throtle tip in have improved. I have not had the time yet to dyno the new exhaust. When I do I'll make a thread. The Cannonball is quieter than the Fireball with a silencer