swappers, what did you do for exhaust? Options

[brianforster]

now we all know that 3" is pretty standard for all our swappers.

what did you do for exhaust? custom from a shop close to you? make it on your own?

whatd the shop quote you?

how much was it if you did it yourself?

looking for general price quotes here, trying to plan out the finishing touches of the swap and the only exhaust shop i called said "theyd have to look at the car".

to cut down on costs i think im going to buy my own cat and muffler from summit (43 bucks for cat, 18 bucks for muffler, summit turbo muflers for the win!) i just wanna know if you guys have any idea what it will cost. i already have a downpipe.

i tried searching, but everyone just says they have 3" exhaust, not where or how they aquired it, and since they are all custom, was wondering what everyone did for it!

thanks as always
-brian

[CheesyLobster]

im pretty sure that 3 inch is too big... most swappers want more like 2.5, and i think mainly they do custom exhaust.

[presure2]

im pretty sure that 3 inch is too big... most swappers want more like 2.5, and i think mainly they do custom exhaust.

cheesy, if your not sure, dont post.
basicly you'll need to go to an exhaust shop, or someone like dave (DG PERFORMANCE) and have at the minimum a custom b-pipe made to mate your stock exhaust to the 3s dp.
however, doing it like that is extremly restrictive.
the MINIMUM size pipe i would use on a 3s would be 2.5"
with a turbo setup, the best exhaust is no exhaust.
depending on where you go, who does it, kind of piping used, ect, expect to pay anywhere from a few bucks for a custom b pipe, to closer to 500+ for a full stainless turbo back 3" setup.

[x_itchy_b_x]

i have 2.5 downpipe back. made at a local shop for 300. all mandrel bent.
high flow cat and no resinator. sounds sexy.

[Defgeph]

3 inch turbo back made by DG performance.

[Supersprynt]

Buying ToyCeli8's 3'' turbo back mandrel bent and I have an Aussie 3'' and an Apexi WS2

This post has been edited by Supersprynt: Mar 10, 2006 - 10:56 AM

[jgreening]

3" turbo back SS exhaust with two SS magnaflow mufflers.

I would go for 2.5" with power levels less than 250whp unless you like the extra sound.

[Rjb23]

I have a 3" DP back SS custome exhaust made by a local shop called autolab. Cost $550, they did a great job and if I ever have any problems with it they told me to come back and they will fix it for free.

[OrbitalGT95]

DG Performance is your man for exhausts

[lagos]

welll... this whole time i have been rocking the greddy SP exhaust with a dented 2.5in (more like 2in with the dent) mid pipe. it does ok and the car is still quick, but you can tell that i will benefit a lot when i got to a 3in.

[brianforster]

DG's exhaust looks great but I just dont think its in the budget right now, im hoping I can get a 3" down to about 300-400 bucks by using a cheap muffler and cat

[lagos]

dont cheap out on the muffler. its really hard to get a 3in ehxaust to sound good and not be so loud that you cant hear your radio. at the very least get a 100$ magnaflow. if u cant afford a few extra bucks for that, then what are you doing with a turbo motor?

[eggman40]

For my exhaust i got a 3in. downpipe then had a custom 3 in. mandrel bend exhaust system made for it. I got a 3in flex pipe near the oil pan, gutted cat towards the center. I went under axel towards the back (i have great clearance by the way, even with a 3in drop) I used a Vibrant flat black muffler 3in straight through. (great sound) i think the under axel clearance depends on how the piping is bent back there.

[Drocay]

not on my celi since its sold, but on my project car i'm going with 3inch downpipe to Electric Cut out, my friend has had it for over 3 years now and it hasnt given him any problems and its as close to no exhaust as u can get. Also because u can have stock piping u can pass inspections no problem and emmisions, o and if your messin around on hi way with another car and they got exhaust they'll get pulled over not u.

[burneeed]

3" Turbo back exhaust. 3" Is the best way to go. sounds the best + no back pressure. Make sure you get a decent muffler also.

[brianforster]

dont cheap out on the muffler. its really hard to get a 3in ehxaust to sound good and not be so loud that you cant hear your radio. at the very least get a 100$ magnaflow. if u cant afford a few extra bucks for that, then what are you doing with a turbo motor?

i had money planned out, however certain things came up (getting ripped off on my shell being the major one) that forced me to spend money on more important things (such as airbag and windshield, to pass inspection..)

[DG_Performance]

If i can get better deals on the products i need to make exhausts i could make the 3" 3sgte race exhaust cheaper but at the current time i cant do it for less than what i charge or i would be loosing money making my exhausts. If anyone out there can get super deals on mandrel bend pipe, flex sections, flanges, v-band clamps, canisters.... let me know cause at the curent time i have to spend 95$ just for the 2 vband clamps i use on my setups! That is crazy!!!
At least now you know why the total cost has to be where it is cause parts to make it are not cheap. I dont like to make crap parts, so i buy the best parts, but the best parts are not low cost items.
DG

[brianforster]

If i can get better deals on the products i need to make exhausts i could make the 3" 3sgte race exhaust cheaper but at the current time i cant do it for less than what i charge or i would be loosing money making my exhausts. If anyone out there can get super deals on mandrel bend pipe, flex sections, flanges, v-band clamps, canisters.... let me know cause at the curent time i have to spend 95$ just for the 2 vband clamps i use on my setups! That is crazy!!!
At least now you know why the total cost has to be where it is cause parts to make it are not cheap. I dont like to make crap parts, so i buy the best parts, but the best parts are not low cost items.
DG

trust me dg, i know your price is fair for your quality work, i just dont have it, i promise i would if i could afford it!

[Bigmeanbulldog55]

What would be the disadvantange to running something like a 4inch strate pipe all the way back? I thought the turbo would give the motor all the backpressure it needs at the lower rpm, and it's best to have free flowing from there back. Is this just for race applications or something?

[playr158]

LOL 4" thats utterly pointless....

[Fastbird]

Dr. Tweak is hooking us up with a 3" downpipe and custom 3" exhaust for the swap that he's doing.

[Bigmeanbulldog55]

LOL 4" thats utterly pointless....

Dang it man, I know no one uses 4inch pipe. And I want to know why. I don't want to here things like it's pointless, and that's it. If your going to respond to one of my posts, give me a reason. Don't act like a little turd and say "LOL 4" thats utterly pointless," without explaining yourself. Please, just explain yourself. It rude not to. Even if you don't think it's rude, I do. And for future referance, when replying to something I've said, please keep that in mind. You are a very knowledgable person, please share that knowledge along with your comments.

EDIT: I just want to add that part of the reason I am curious about this, is because of the fact that sometimes turbo guys will unhook the exhaust at the bottme of the downpipe when at the track. I know the WRX guys were saying that at least. They could have been BSing me. And I know you can get those electronic cut offs to dump your exhaust up by the motor. So I don't understand how having a huge exhaust wouldn't have the same affect. I don't know how to run the numbers to find out what size pipe the 3sgte needs for optimum flow.

This post has been edited by Bigmeanbulldog55: Mar 11, 2006 - 9:23 PM

[scothaniel]

Yeah, dont use 2.5" piping - thats like only good for around 400HP.

[lagos]

4inch exhaust are only a benefit on 6-8cyl turbocars. if u look at all the supra guys they all run 4in.

on a 4cyl car, 3in exhaust is plenty to allow no restrictions.

[playr158]

i run my turbo with an pretty much open downpipe (well right after the cat) makes spool time much faster..less restrictive

pure and simple you only exhale as much as you inhale...anything over 3" diameter on a 4cylinder motor is over kill because you simply don't move enough air..by the end of the pipe your exhaust is moving so slow that the newest exhaust is probably pushing out the rest of wat has slowed in the pipe

This post has been edited by playr158: Mar 11, 2006 - 11:34 PM

[jgreening]

LOL 4" thats utterly pointless....

Dang it man, I know no one uses 4inch pipe. And I want to know why. I don't want to here things like it's pointless, and that's it. If your going to respond to one of my posts, give me a reason. Don't act like a little turd and say "LOL 4" thats utterly pointless," without explaining yourself. Please, just explain yourself. It rude not to. Even if you don't think it's rude, I do. And for future referance, when replying to something I've said, please keep that in mind. You are a very knowledgable person, please share that knowledge along with your comments.

EDIT: I just want to add that part of the reason I am curious about this, is because of the fact that sometimes turbo guys will unhook the exhaust at the bottme of the downpipe when at the track. I know the WRX guys were saying that at least. They could have been BSing me. And I know you can get those electronic cut offs to dump your exhaust up by the motor. So I don't understand how having a huge exhaust wouldn't have the same affect. I don't know how to run the numbers to find out what size pipe the 3sgte needs for optimum flow.

A 4" exhaust is NOT utterly pointless - particularly on a FF or FR car where the piping runs the length of the car. However, if you are running less than 400whp, it would not be cost effective because you are not going to see much of a gain. Above that hp level, you are correct Bulldog, it will improve flow and increase horsepower - more the higher up you go. On a "high power" turbo application, the best exhaust is no exhaust since it creates no back pressure. Heck, I would actually be willing to wager that you would actually see gains from a 4" exhaust over a 3" exhaust at 300whp too - just something in the neighborhood of 1-3 hp. Like I said, not exactly worth the added expense.

[Kadett]

3" piping with the stock st205 muffler for now. When the money comes in again i will set my eyes on a nice Blitz muffler!

[jgreening]

anything over 3" diameter on a 4cylinder motor is over kill because you simply don't move enough air..by the end of the pipe your exhaust is moving so slow that the newest exhaust is probably pushing out the rest of wat has slowed in the pipe

I am too tired to type a long response but suffice it to say that this is incorrect.

[Patrissimo]

I did a 3 inch straight back from Down Pipe. No Cat.

Sounds really nice.

2.5 inches is a waste of money. Go all the way man!

[presure2]

LOL 4" thats utterly pointless....

dan, sometimes your posts are "utterly pointless"


do you wanna tell noshoes his exhaust is "utterly pointless"?

[lagos]

3in is plenty for 90% of 4cyl turbo cars that are in the 200-300 power range. 400+ is where you would probably want something as big as a 4in, and if u have that much power, you probably wouldnt be on here looking for exhaust advice...lol

[Supersprynt]

Doubt alot of ppl heard of no shoes 'round here.

[scothaniel]

anything over 3" diameter on a 4cylinder motor is over kill because you simply don't move enough air..by the end of the pipe your exhaust is moving so slow that the newest exhaust is probably pushing out the rest of wat has slowed in the pipe

I am too tired to type a long response but suffice it to say that this is incorrect.

Sorry, you'll have to type a long response now, cause I have to agree with his statement (depending on the size of the motor).

Oversizing the exhuast can hurt due to the density, weight and velocity of the air traviling through it. Smaller exhausts will maintain higher velocity, which keeps the temps higher (less dense, lighter). If the exhaust is too big, the velocity slows, temps decrease and the exhuast pulses collide.

The key is to have the correct size pipe - not too big, not too small. I have 2.5" on my wife's car, 3" on my car due to the orginal T04 60-1 ( seems to be good with the 20G L2 as well).

2.5" was fine on the 16G powered DSM without any problems, and we hit low 12's with that car.

[jgreening]

Oversizing the exhuast can hurt due to the density, weight and velocity of the air traviling through it. Smaller exhausts will maintain higher velocity, which keeps the temps higher (less dense, lighter). If the exhaust is too big, the velocity slows, temps decrease and the exhuast pulses collide.

The key is to have the correct size pipe - not too big, not too small.

Exactly correct, for N/A applications.

I have 2.5" on my wife's car, 3" on my car due to the orginal T04 60-1 ( seems to be good with the 20G L2 as well).

2.5" was fine on the 16G powered DSM without any problems, and we hit low 12's with that car.

I am glad you have had good results. However, this anecdotal evidence does not disprove that turbo applications improve as back pressure decreases.

I have never seen one serious tuner suggest that someone should use a smaller exhaust in a forced induction application. By this logic, a 2.5" exhaust could potentially be better than a 3' exhaust with a small turbo. That has been disproven as myth time and again by real world dyno testing. The well accepted rule of thumb is the bigger, the better (on FI applications). That said, as I typed above, there aren't many people on this board that will benefit from larger than 3" piping. I wouldn't even consider it if my goals were under 400whp.

[scothaniel]

The addition of the turbo doesn't effect the basic principles of exhaust flow - it only makes it more important since a poorly flowing exhaust will hinder the turbos ability to make boost.

Looking back at the previous posts:

with a turbo setup, the best exhaust is no exhaust.

Right, because a 6" long exhaust means the gases are instantly out of the way. No worry about pulses or scavaging or back pressure. Though no back pressure will hinder performance before the turbo spools up.

The next best thing to having no exhaust is having an MR2 - thier full exhaust is as long as our cat backs. That or an exhaust big enough to seem like there no exhuast - like a 12" diameter! I have no idea where anyone will find a muffler to fit it though.

Can you post some dyno graphs for 2.5" versus 3"? I spent a few minutes on google and only found debates on the DSM, 200/240, SRT, and Volvo clubs on the same subject! I guess this makes 6gc a real club!!!!!!

[playr158]

Oversizing the exhuast can hurt due to the density, weight and velocity of the air traviling through it.

sorry i should have been more clear..that was a long night..
4" is pretty utterly pointless on a motor thats not supporting the HP for it..like the above stated oversized pipe without enough power to move the air isn't helping at all...yea "noshoes" can run 4" cause his pipe is 3' long in a "2" and he has a pretty freakin nice HP #......a stock 3sgte in a 10' long celica with 4" i doubt would see any gains..so "noshoes" motor and setup really doesn't apply in a celica situation..

and j...even on an FI motor if your exhaust is too big and long the exhaust velocity will eventually have slowed by the end of the pipe..you'll have increased back pressure from having to actually push the spent and slowed gases out regardless of FI or NA

its about correct size for your correct horsepower and CFM...you have to keep restritctions to a minimum and velocity to a maximum

This post has been edited by playr158: Mar 12, 2006 - 4:04 PM

[NuclearHappineS]

about the 4" exhaust

one of the big supra shops, either titan or horsepower freaks (i think it's titan actually) sells a 4" supra catback ...

if u go to their webpage they'll provide their '1st hand' commentary on why/when you'd need it...

i think to4r also had a dyno run of most supra exhausts starting with the oldschool greddy SP and working up to the newer titanium/stainluss catbacks (so from 2.38" up to some 3" and maybe slightly over 3" catbacks) with dyno data for all of it...

as far as titan goes they saw something like a 40hp gain pulling off a 'high flow' air filter on a 600 hp car... their exhaust (4") was worth over 120hp or so on some 700+ hp car that came in with a 3" if i remember correctly...

i just want to say this though...exhaust has to do with area which is related to diameter squared

2^2 = 4
2.25^2=5.0625
2.5^2=6.25
3^2=9
3.5^2=12.25
4^2=16

so the next step up if u had a high hp 3sgte isn't a 4" yet...

[playr158]

alright thats a inline 6 supra.....not a 4cyl celica
so the obvious reasons why 4" works there is pretty clear..

but defenitly right on the area

This post has been edited by playr158: Mar 12, 2006 - 4:24 PM

[jgreening]

"noshoes" can run 4" cause his pipe is 3' long in a "2" and he has a pretty freakin nice HP #......a stock 3sgte in a 10' long celica with 4" i doubt would see any gains..so "noshoes" motor and setup really doesn't apply in a celica situation..

Actually, its even MORE applicable. Try this experiment. Blow as hard as you can through a regular straw. Now cut the straw down to 2 inches and blow as hard as you can. Tell me which one flows more air. A: the shorter one of course. Flow is increased when the pipe length is decreased. The benefits from a larger diameter exhaust are more apparent in cars requiring longer piping - not less. Noshoes actually recommended to me to go with a 4" exhaust for just these reasons. Since my goals were less than most of his customers, I stayed with 3".

Although this argument about exhaust gases cooling and slowing down has some logical appeal, I am just saying that I have never seen any evidence it is true in terms of real world experience or reading what recognized experts have posted in the past.

This post has been edited by jgreening: Mar 12, 2006 - 4:40 PM

[jgreening]

Can you post some dyno graphs for 2.5" versus 3"? I spent a few minutes on google and only found debates on the DSM, 200/240, SRT, and Volvo clubs on the same subject! I guess this makes 6gc a real club!!!!!!

I know for sure that ATS did testing to show that the KO downpipe (2.5") yielded lower gains than a 3" downpipe on the same exhaust with the tiny ct-26. It was about 5hp difference I believe and was for levels way under 300whp. I know a downpipe is not a full exhaust but the principles are the same. I have also seen comparison dynos of full exhausts on other forums which have shown similar results but I am not sure I could find them.

[playr158]

we've already established shorter is better? thats what we all agree on....

"it is easy to get overeager on fitting large-diameter pipes into an exhaust system. "the larger the better" is not always the case....there is an exhaust gas velocity that ought NOT TO BE EXCEEDED, this velocity is approximately 250 ft/sec.....to size a tailpipe, you can adhere to this exhaust gas velocity or to simple the guildeline of selecting a tube diameter approx. 10% larger then the turbine outlet diameter."
corky bell

a 3sgte @ 15psi makes 321cfm ruffly
just to make sure i'm correct
i got it by....((122.04cid x 5000rpm x .5stroke x .90ve)/1728)x(14.7x15/14.7) = 321cfm

a 2.5" pipe can flow more then 600cfm(ruffly 293ft.sec) adiquetly
but we all know that a 3" exhaust does prove gains over a 2.5"
but at the point of 4" it would seem too large for a celica

This post has been edited by playr158: Mar 12, 2006 - 5:01 PM

[scothaniel]

Interesting post by Dave Buschar on the evo forums with Dyno numbers on an 04' Evo:

snip----

3. BR 2.5" axleback muffler. 267.1 whp, increase of 15 whp!

4. BR 2.5" downpipe. 270.4 whp, increase of 3.3 whp.

5. Super AFC with BR settings, 289.3 whp, increase of 19 whp.

This with the addition of a boost gauge and the mount for the boost gauge completes our Stage 0 and costs $995. Overall gains with this kit while remaining emmision legal with the stock cat and with a very quiet car was 52.2 whp and 29 ft. lbs of torque. HP per dollar spent is $19.06.

This package really puts the car into a great spot to do further upgrades from. Actually I was surprised by the next test:

We left the 2.5" downpipe on, added a 2.5" offroad pipe and the 3" catback with the Magnaflow muffler. The horsepower jumped to 313 whp and 292.9 ft lbs. For further comparison we ran an open exhaust system from the back of the offroad pipe, in other words no catback at all, the car only made 1 more whp. The open exhaust numbers were 314.4 whp.

We then went to the full 3" turbo back exhaust using the Magnaflow muffler and an offroad pipe. The car layed down 314.9 whp.

--- snip

[jgreening]

Out of curiosity Scott, what lessons do you take from that post? Somehow I suspect we may have different interpretations.

[scothaniel]

That 3" exhaust is better then 2.5"
I was wrong when I said that 2.5" is only good for 400 HP, now I'd say its fine for sub 300 HP range.

It does go along with velocity and cool-down expansion effect I mentioned earlier, since replacing the rear section with 3" gained a good amount of power and replacing the turbo back didn't make much a difference. Unfortunately the dyno graphs on his web site are for buschars kits - which includes more then just the exhaust changes. I'd like to see what the effect was on low/mid range torque with the larger DP.

This post has been edited by scothaniel: Mar 12, 2006 - 9:31 PM

[jgreening]

It does go along with velocity and cool-down expansion effect I mentioned earlier, since replacing the rear section with 3" gained a good amount of power and replacing the turbo back didn't make much a difference.

In this post, I am playing devil's advocate for purposes of discussion. Lets assume that there are no factors in these runs like improper cool down times, variations between runs, margin of error, etc. Under your theory, wouldn't the power have been less with the 3" downpipe since the exhaust gas velocity would have decreased? I recognize that it only made 2 more horsepower with the 3" downpipe but the fact that it didn't lose hp seems to contradict your theory. The big 16G is not exactly a large turbo.

[scothaniel]

Its a turbo that pushes over 500 CFM at 20 psi though, which is a lot more then a stock ct26 btw. 300+ HP. In fact, Buschar was almost able to hit the 400 mark with the stock evo 16GH turbo! A ct20b cant even touch that.

Like I said, I'd like to see the effect on low / mid range torque.

[CheesyLobster]

i just want to say this though...exhaust has to do with area which is related to diameter squared

2^2 = 4
2.25^2=5.0625
2.5^2=6.25
3^2=9
3.5^2=12.25
4^2=16

That would be if you are running a rectangular shaped exhaust. For area calculations it would be diameter * Pi (3.14159...) or volume=area * legnth of exhaust.

[NuclearHappineS]

That would be if you are running a rectangular shaped exhaust. smile.gif For area calculations it would be diameter * Pi (3.14159...) or volume=area * legnth of exhaust.

sorry but you're wrong ...and i was wrong too...

circumferance (sp?) = 2pi R = pi D
area = pi r^2 ... i just dropped pi because and forgot to halven D to get R

so 2" exhaust ~ 1*1
2.5" exhaust ~ 1.25*1.25
...etc .. .they all share pi so if you're looking for % difference it doesn't matter (Why i dropped it)

the guy who said that's an inline 6 ... forget that

my point WAS ... if you are making 700 hp or so (i don't care if it came from a single cylinder or 700cylinders) ...as long as it's a 4 stroke, then 700hp is going to be about 1050cfm of air no matter what type of motor (b4, I4,I6,v6,v8...etc) it came from...and if you are moving that kind of air i'd think about using more than a 3" exhaust.

[jgreening]

i just want to say this though...exhaust has to do with area which is related to diameter squared

2^2 = 4
2.25^2=5.0625
2.5^2=6.25
3^2=9
3.5^2=12.25
4^2=16

That would be if you are running a rectangular shaped exhaust. For area calculations it would be diameter * Pi (3.14159...) or volume=area * legnth of exhaust.

Actually, that would be a square (not a rectangular) shaped exhaust. Diameter * pi would be the circumfrance. To determine area of the exhaust, you use radius squared * pi. Therefore, the following would be the correct calculations to determine area of the cross section of the pipe:

2 inch piping = 3.14 sq. inches of area of cross section of pipe
2.25 = 3.97
2.5 = 4.91
3 = 7.07
3.5 = 9.62
4.0 = 12.56

EDIT: Nuke beat me.

This post has been edited by jgreening: Mar 13, 2006 - 5:18 PM

[Speedy2k]

Heh I see some people have forgot high school math

Do you guys know how to calculate the area of an oval (ellipse)?

Its useful when comparing oval mufflers to round ones. The bigger the volume; the quieter the muffler.

Lets say you have a

5" (height) x 8" (width) x 14" (body length) muffler - $128.42 MSRP
Oval Muffler

and a

6" (diameter) x 14" (body length) muffler - $127.47 MSRP
Round Muffler


Which of these would have the bigger volume?


Volume of Oval Muffler: 2.5 x 4 x 3.14 x 14 = 439.6 cubic inches

Volume of Round Muffler: 3 x 3 x 3.14 x 14 = 395.6 cubic inches

In this case the oval muffler has the larger volume for the same money! If you guys already knew this then take no offence

[playr158]

we need to work on pipe size before we get to the muffler part lol

so a 3sgte 5000 rpm at 15psi flows 321cfm (5.35 cf per second)

what is the pipe size that will keep the velocity of 321cfm exhaust gas around 400 ft/sec or so

This post has been edited by playr158: Mar 14, 2006 - 1:11 PM

[lagos]

i like my math better

3sgte + 3in exhaust = the right thing to do


hopefully ill be getting mine installed soon. going today to get an estimate.

[Speedy2k]

i like my math better

3sgte + 3in exhaust = the right thing to do


hopefully ill be getting mine installed soon. going today to get an estimate.

What downpipe and muffler are you getting?

[celicurr]

[playr158]

thats my scan!

(and it came from "maximum boost" by Corky Bell) to give credit where it be due

This post has been edited by playr158: Mar 14, 2006 - 3:00 PM

[jgreening]

That must be what HP level the stated pipe would "support". It surely does not reflect the ideal size to use since a single straight 2.5" exhaust is represented as 500 bhp.

[JFrost9]

This is going to seem completly random and all, but has anyone run a dual-exhaust on a 3sgte? Im sure its not recommended, i could see it more on a mr2, but i was just curious.

[lagos]

i like my math better

3sgte + 3in exhaust = the right thing to do


hopefully ill be getting mine installed soon. going today to get an estimate.

What downpipe and muffler are you getting?

i already have a 3in stainless DP on the car and ill be using a 3in magnaflow muffler.

looks like my exhaust will have to wait some more. went to get a quote today, lets just say that it was insane! i have another shop that is willing to give me a great deal, but the guy has almost no time to fit me in... sucks.

[Speedy2k]

How much was the quote? Mandrel bent? Stainless/aluminized?

[DG_Performance]

What happened to the topic ... you know that sentence at the top of the page that is supposed to be what all discussion under it is about HAHA
"swappers, what did you do for exhaust?" is no more!

We should rename the topic to "swappers... what do you think about different exhaust sizes?"

[CheesyLobster]

i just want to say this though...exhaust has to do with area which is related to diameter squared

2^2 = 4
2.25^2=5.0625
2.5^2=6.25
3^2=9
3.5^2=12.25
4^2=16

That would be if you are running a rectangular shaped exhaust. For area calculations it would be diameter * Pi (3.14159...) or volume=area * legnth of exhaust.

Actually, that would be a square (not a rectangular) shaped exhaust. Diameter * pi would be the circumfrance. To determine area of the exhaust, you use radius squared * pi. Therefore, the following would be the correct calculations to determine area of the cross section of the pipe:

2 inch piping = 3.14 sq. inches of area of cross section of pipe
2.25 = 3.97
2.5 = 4.91
3 = 7.07
3.5 = 9.62
4.0 = 12.56

EDIT: Nuke beat me.

Whopse. yeah a=piR^2, and i meant rectangular as in rectangular prism.