I was thinking a 3" DP and either a 3 1/4 or 3 1/2 inch y-pipe to a pair of the new Racing Beat mufflers.



Does that sound about right for a FC with a mild port engine and a To4B, FMIC, etc..??

my thoughts were if I ever upgrade to a larger turbo the exaust would be set up already

is the turbine outlet 3"?



if so I'd just stick with that down to the Y, like your saying. I'm not sure what you mean about the 3 1/4" "y" Maybe if I saw the mufflers it'd make more sense.



I think the Idea is anytime you "Y" you want to step down in diameter to keep exhaust velocity up. My setup is 3" dp to borla xr1, and jr modified the apexi n1 Y (opened it up and added a couple wedges) to accept the 3" now, and it's not restrictive at all. So it goes from 3" to 2- 2 1/2" pipes to the n1 mufflers. Can't really say if it's helped or hurt because this is the only exhaust i've had on this turbo, but it sure sounds good.

turbo out is 3", so I guess a 3" DP, then a 3.5" pipe that splits into 2 3" pipes, then steps down to the RB mufflers that I believe are 2.5"



I can have 3" inlet put on the RB mufflers if I want as well,I want to keep the dual muffler layout of the FC along with the use of the RB mufflers



Kooks has developed thier own mufflers that are all stainless but I know they will be even louder then the XR1s I have on there now

The bigger the better; pressure guages don't lie.

Reducing restriction/backpressure is what you want.

I got a a 3 to 4 inch transition coming right off of the turbo to two 3 inch out the back. Going up to a 4 inch system made a big difference in just about everything turbo related. Power, boost threshold, lag, boost creep lol. I recomend going bigger after having a straight 3 inch system and going to 4 inch.

Below is my opinion. I base it upon the fact that most factory exhaust pipe diameters reduce as they get farther from the engine.



Hotter is bigger. Duh.



Big at the end is a sales tool either as to show a big pipe or to have a certain sound.



After right after the turbine, the need for a larger pipe than the turbine exit is diminished. The farther away from the heat, the smaller the pipe can be.



Larger than needed is more loud than it could have been.



I think a 3 to 4 is fine right after the turbine.



I think that two 3's to the mufflers is a lot more than is needed and much louder than it could have been.



My opinion is just that.



[quote name='Crusader_9x' date='Mar 12 2005, 04:50 PM']I got a a 3 to 4 inch transition coming right off of the turbo to two 3 inch out the back. Going up to a 4 inch system made a big difference in just about everything turbo related. Power, boost threshold, lag, boost creep lol. I recomend going bigger after having a straight 3 inch system and going to 4 inch.


[/quote]

I think opposite of Mike https://www.nopistons.com/forums/pub...IR#>/smile.png Hot gasses flow easy, cold gasses don't. The hotter the exhaust is the smaller it can be.



I think factory exhausts get smaller towards the tip to keep velocity up and heat in.



My thinking anyways.

Where are the engineering students when we need them? https://www.nopistons.com/forums/pub...IR#>/smile.png



I was told once by an engineering graduate, that a 3" pipe is good for about 550 hp.



If so, and you don't have twice that hp with two 3's, noise is the result.

Mike



[quote name='setzep' date='Mar 24 2005, 09:07 PM']I think opposite of Mike https://www.nopistons.com/forums/pub...IR#>/smile.png Hot gasses flow easy, cold gasses don't. The hotter the exhaust is the smaller it can be.



I think factory exhausts get smaller towards the tip to keep velocity up and heat in.



My thinking anyways.


[/quote]

I have read .025 in^2 of cross sectional area per hp recommended for rotaries in aircraft. I think 0.020 in^2 per hp is a little closer to ideal for a car given packaging constraints.



Now, keep in mind this is an ideal cross sectional area. It wil take a good bit more hp(flow) for a given pipe size to start to become restrictive in any measurable amount.

unless you know an excellent exhaust shop or can do it yourself, I have no seen that many well done exhaust systems in toronto area. If i were doing a custom exhaust, i would buy the turbo back racing beat system, sell the downpipe, and have that part custom made to fit your needs.

[quote name='Cheers!' date='Mar 25 2005, 07:35 PM']unless you know an excellent exhaust shop or can do it yourself, I have no seen that many well done exhaust systems in toronto area. If i were doing a custom exhaust, i would buy the turbo back racing beat system, sell the downpipe, and have that part custom made to fit your needs.


[/quote]



who is that directed at? https://www.nopistons.com/forums/pub...1047683561.gif

How are you guys tying in a muffler with a 4 inch pipe. If a 3 to 4" DP is made then who sells the muffler?

I'd have to get one of those Yellow Bus mufflers.

If you just wanted a straight 4" system then look into getting a diesel muffler or two.



On the two 3" pipes out the back, yes they are alot louder than i would have expected. I am gonna be getting another set of mufflers to put inline right before the ones i have on there now to help quiet it down. Personally i dont care about how loud it is, what bothers me is all the new attention the cops give me for jsut driving. I would hate to see there reaction if they heard the open wastegate.



I wanna leave it vented to the atmosphere but might look into a little exhaust system of its own to help reduce noise, cause it carries a ways!



For future reference i would recomend a 4" to 2.5" if your concerned about noise. Oh and also i wouldnt recomend the N1 style mufflers of off ebay either.



But if noise isnt a problem then go with exactly what i got. Even my Vette friends say my car sounds good now.



edit: Oh and if you have the time and money buy a welder and the exhaust tubing online and make a system your self. Thats the only real way i found to get what i wanted.

well I ask cause it seems the 4 from 3 is all the rage and yes i get tired of not hearing my three amps and subs.

geting ready to make the piping and was wondering what I will replace the Drager with.

i plan on using a couple extra magnaflows. As for wanting a straight through 4" system, if you had the room you can order there diesel mufflers anywhere from 20" to like 36" i think. Check out magnaflows website for details but i believe you could make it plenty quiet with there selection. If worse comes to worse then just buy two and put them inline.

http://www.geocities.com/crazymestiz...oofexhaust.MPG



This is a S4 13BT mild streetport, 60 trim turbo, 3" DP > 3" MP. The exhaust is GP Sports. The flange on the Y-pipe is stock sized because it was sold as a cat-back. But the Y-pipe is 80mm or ~approx 3 inches. I guess it's kinda loud, when I crank it up I can hear loud pulses. But I gassed it in front of a cop (he was 2 cars behind me, I didn't know), redlined 1st, and for some reason I just decided to put it in 4th. My speed @ redline was ~approx 40MPH, and the speed limit was 40MPH. The cop just drove beside me and looked at me funny. So I guess its not as loud as I think. I'm going to weld a Borla XR-1 muffler in there to see what it does tho.

You'll have to right click and save as. BTW the camera was like ~approx 2.4 feet from the muffler.

Why not go 4 inch downpipe with a 3-1/4 to 3-1/2 split in the y pipe? I always thought you wanted to have larger down pipe and then a smaller diameter for split duals.

[quote name='spooliNrx7' date='Apr 16 2005, 06:52 PM']Why not go 4 inch downpipe with a 3-1/4 to 3-1/2 split in the y pipe? I always thought you wanted to have larger down pipe and then a smaller diameter for split duals.


[/quote]



The outlet on my turbo is 3 inch. There's no point in putting a 4" DP. Plus it's more work, and I'm lazy as ****.

My turbo outlet is 3" as well. Although when i went up to a 4" downpipe i did see a huge difference in turbo response and overall power. All i did was get a long 3" to 4" transition from burnsstainless.

[quote name='Crusader_9x' date='Apr 17 2005, 03:05 PM']My turbo outlet is 3" as well. Although when i went up to a 4" downpipe i did see a huge difference in turbo response and overall power. All i did was get a long 3" to 4" transition from burnsstainless.


[/quote]



Maybe it was in your head? I think it's pointless going from 4 to 3 inch. If I'm getting 4" DP, then my entire exhaust will be 4" as well.

[quote name='BoneT2&Harmony' date='Apr 18 2005, 07:41 AM']Maybe it was in your head? I think it's pointless going from 4 to 3 inch. If I'm getting 4" DP, then my entire exhaust will be 4" as well.


[/quote]



No it wasnt all in my head. I saw earlier turbo response by about 200-300 rpms and loss of traction in 2nd gear. Where as before the 4" exhaust i had full traction in second. Also i got horrible boost creep after 6krpms with the 4" exhaust where as when i had the 3" it would hold steady whatever i wanted.



I think you missunderstood something, i didnt go from 4" to 3", i went up to 4" from 3". I have a 4" downpipe all the way to my 4" y pipe and then after it y's off it goes down to 3".

[quote name='Crusader_9x' date='Apr 18 2005, 11:33 AM']No it wasnt all in my head. I saw earlier turbo response by about 200-300 rpms and loss of traction in 2nd gear. Where as before the 4" exhaust i had full traction in second. Also i got horrible boost creep after 6krpms with the 4" exhaust where as when i had the 3" it would hold steady whatever i wanted.



I think you missunderstood something, i didnt go from 4" to 3", i went up to 4" from 3". I have a 4" downpipe all the way to my 4" y pipe and then after it y's off it goes down to 3".


[/quote]



Alright I thought you meant a transition from 4" then back to 3. Anyways I already bought this super expensive GP Sports exhaust, I'm not going to spend any more money.