Sunday, January 29, 2006 - 03:41 pm, by: Michael Sztyk(Sli1)
Hi guys, just wanted a few opinions as what type of setup to get. Im looking at either a single conversion or leaving it a duel setup. i want to go 3" from the turbo back to a cannon/cannons. With a 3" twin would i lose any pressure as i have heard talk about this. I do like the twin look but i dont want to lose any performance. I have heard the single a more efficient. I couldnt find a post in the forum already so i this is ok.
Any opinions would be appreciated as i am looking at getting this done either tomorrow or the day after.
Ben Evans TryHard Qld "Master Power" Turbo 1J With Xtras
Sunday, January 29, 2006 - 07:07 pm, by: Troy Baker(Sincity)
I would be very doubtful that a twin set up would be less efficient, just more expensive. I have a single 3' but if you have the cash twins look the goods.
Monday, January 30, 2006 - 06:58 am, by: Damian Ware(Frozenpod)
I have spoken to some exhaust places and they all said that a single is better. Single is lighter and cheaper and depending on the setup they can be quieter.
What I don't know is if the setup is quieter if there is a loss of performance. I am planning to look further into and think very carefully before making my final decision.
Monday, January 30, 2006 - 08:09 am, by: Paul Irwin(Rival)
The flow of two 2.5” pipes is around 140% that of a single 3” pipe if my quick preliminary calc is correct.
After taking into account the extra skin friction losses of the dual setup the single 3” pipe will still only do about 70% of what the dual 2.5” is capable of (as opposed to 72% based on cross sectional area alone). Just by doing a check on the cross sectional area of each tells you the single 3” is going to be much lower in volumetric flow.
It has been proven by a number of people on these forums that there is no advantage to going bigger than dual 2.5” so this would really be the max you would shoot for, however in the end the decision of whether to go for a dual or single should come down to the following:
Single 3.0: Pros: • Cheaper • Deeper tone (usually) • Gives you that N1 Dorifto look.
Cons: • Louder (almost always, though can be reduced with a good quality muffler and a good quality resonator, but will always be louder) • Will scrape on a lot more stuff if your car is low • You wont have two sexy tips at the back of your soarer’s wide rump. • Less flow based on a rough calc and assuming the comparative dual 2.5 system has a well made splitter.
Dual 2.5’s: Pros: • Wont scrape on quite as much as the 3.0”… quite as much... • better volumetric flow (provided exhaust shop makes the splitter pipe nice and streamlined) • You get that sweet dual exhaust look out the back.
Cons: • exhaust tone wont be quite as deep (usually) • more expensive (two resonators, two mufflers, twice the pipe from the splitter back, twice the mandrel bends from the splitter back).
Back pressure should not be a concern to you as you drive a turbo and the less back pressure you get the better the turbos breathe. The turbos themselves are considered to provide enough backpressure for the engine.
In the end the decision really comes down to cosmetics, what do you prefer the look of and also cost as both options should give you ample flow.
The argument of loudness really depends on the system, generally a 3.0” will be louder just because the cross sectional area is bigger and a lot of the sound seems to blast straight through missing the packing and exhaust perforations. But with a good quality set of resonators and a good quality pair of mufflers (or a single) <cough> Rival Performance<cough> you can get it sounding quite respectable without sacrificing virtually any flow (so long as they are high flow straight through units).
Don't forget the extra turbulence you're creating when the turbo dump splits from single 3" to dual 2.5" or whatever. I believe that is where your power loss will occur. Don't forget, all of these gases are originating from a single pipe to begin with, and depending on where they split, gas expansion to "fill" the 2.5" pipes may be negligible.
Monday, January 30, 2006 - 10:41 am, by: Benjamin Burgess(Jampac)
The cat is just before this so turbulence shouldn't be a problem. I have a dual 2.5" setup on my soarer, but I have 4 mufflers on it, so probably not the best for flow. However I've opted for a 3.5" pipe setup off the turbo to just before the external gate flow joins back up again, which would probably help the most in the whole setup. We tried to put in a 4" dump pipe but just isn't enough room to work in.
Monday, January 30, 2006 - 04:01 pm, by: Benjamin Burgess(Jampac)
Problem but is 3.5" will hit the road a lot more often, just have a look at your stock exhaust how much its dented up. I'd have 6" pipe dia if clearance wasn't a problem, but you gotta work with what you got. You could try some of them mega expensive square pipes just so you have more cross sectional area.
Weight isn't really that much of an issue when your talking soarer weights. Maybe if it was an atom, mx5 or something like that then you'd be more concerned.
Monday, January 30, 2006 - 09:20 pm, by: Callum Finch(Sigeneat)
Benjamin Burgess wrote on Monday, January 30, 2006 - 10:41 am:
The cat is just before this so turbulence shouldn't be a problem. I have a dual 2.5" setup on my soarer, but I have 4 mufflers on it, so probably not the best for flow.
Sounds like mine.. I have 4 mufflers but she still manages to build up 1.1bar and 280rwhp (~210rwkw for the unedumacated)
Monday, January 30, 2006 - 11:34 pm, by: Michael Sztyk(Sli1)
WOW Thanks for the quick feedback guys! Some interesting points brought up.
Well i did some thinking and booked it in for the morning.
Full 3" sports exhaust system with a cannon. Brand of the cannon i cant remember but it comes off the same line as Magnaflow. Stainless steel mandrel bend system. Cannon will point slightly up and out.
Place: True Fit, Warrigal Rd Moorabbin in Melb. Price: $1515 with cannon $1315 with out cannon with tip.
Rep is pretty good with those guys and i have seen their work. Most likely will do my cooler piping there too in the near future.
As Chris mentioned above about single turbo's, that is a future plan so i guess this system will apply well.
I hope this will not drone. I want the flow but as least noise as possible. I told him that and he goes he know's exactly what i want so see how i go. Apparently he did someones there already and the car was pretty quick with a few other mods. Anyone from this forum?
Tuesday, January 31, 2006 - 09:39 am, by: Michael Sztyk(Sli1)
Get much power gain from the cat back Ryan? That is a pretty good price you got but these guys got a good reputation and i am happy to pay the extra to get it done right. Also if i am not happy with it they can change the configuration for me as long as they dont have to re-weld it from scratch.
Sitting at home now waiting to go pick it up. Was there for a bit telling him my requirements.
Tuesday, January 31, 2006 - 11:02 am, by: Benjamin Burgess(Jampac)
I paid $300 for my cat back. It was mistaken for a standard exhaust that was slightly modified. I've made up to 220rwkw with it, just cat back, still stock front section, but I'm building a single turbo setup at the moment, so all that shock stuff is going.
Saturday, August 18, 2007 - 08:58 pm, by: Juan Hutinel(Juanted)
My 2 cents worth. Performance wise dual or single shouldn't really matter. The exhaust gases should be cooler by the time they are exiting the rear so there should not be much of a problem with back pressure. Size mostly matters from the turbo back as the gas is hotter (therefore expands more, more pressure). Personally I prefer single. The reason for twins is purely for looks on an inline six. Dual exhaust on a V6 or V8 makes sense. Personal preference though
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Silly idea perhaps?
That is if you don't intend on going single anytime.
