Is two 2 1/4" exhaust pipes the same as one 3"

[oddiesGN]

Back when I bought this car I had the exhaust redone and I was wanting 2 1/2" duals, but instead he put on 2 1/4". He thought thats what I was wanting, so he gave me a good price on it so I kept it since my car was just a stocker, I figure no big deal. Well now I'm not stock and was wanting to know if the 2 1/4" duals have the same, less or more flow then just one 3" down pipe? If its the same or a little better I'll just keep it since its still new, lucky if it even has 2,ooo miles on it. If its a big restriction I'll have to replace it with the 2 1/2" duals.

Thanks, Otes.

 

[UNGN]

A single 3" will flow more than 2.25" duals. assuming the same small boundary layer next to the pipe for each, the 3" pipe would have slightly more flow area.

The restiction in any exhaust system is the first mufflers/cat, then the bends in the pipe.

You want straight through, smooth mufflers. My car picked up almost .4 seconds and 3 mph when I went from 2.25" Cherry bomb glass pack system, to a non mandrel bent 2.5" system with ultraflows. No other changes. A cat would have been another .4 seconds if I had had one.

 

[ZNix]

If you are looking to replace your system, what are you looking at budget wise? There are systems anywhere from 350 to 700, single shot or dual. What would you prefer?

Nix

 

[oddiesGN]

I don't really know what my budget would be problably like to stay under $400. I would be looking for dual 2 1/2's and I'll probably have some one around here do it because its cheaper unless some venders have some for a good price. Whats a good flow through muffler? I don't want one thats loud, I like it quiet.

Otes.

 

[ZNix]

http://www.kirbanperformance.com/pr...TEM+(Non-Polished+Stainless+Steel)+#6996.html

 

[oddiesGN]

Will there be much to gain when going to a 2 1/2" from a 2 1/4"? Found a formula and it says that two 2 1/4" are bigger then one 3". Two 2 1/8" is the same as one 3" and two 2 1/4" has 1.76 more volume. I know thats not alot and I will probably just go with the 2 1/2" exhaust, because with the bends in the pipe I could have as small as 2" at the bends.

Has anyone tried the 2 1/2" from pypes? How loud are they and did you notice any difference in performance? How was it to install and has any one had trouble lining up with your down pipe?

Thanks, Otes.

 

[ZNix]

Get a mandrel bent system whatever direction you decide. More flow.

 

[charlief1]

Will there be much to gain when going to a 2 1/2" from a 2 1/4"? Found a formula and it says that two 2 1/4" are bigger then one 3". Two 2 1/8" is the same as one 3" and two 2 1/4" has 1.76 more volume. I know thats not alot and I will probably just go with the 2 1/2" exhaust, because with the bends in the pipe I could have as small as 2" at the bends.

Has anyone tried the 2 1/2" from pypes? How loud are they and did you notice any difference in performance? How was it to install and has any one had trouble lining up with your down pipe?

Thanks, Otes.

Pypes have been posted about quite a a bit and there's a huge thread about them. As far as your math you're partially right here. Since the pipe's are joined there flow will be disrupted at the joint, which causes turbulance. The 3" won't have this issue so it will actually flow better.

 

[motorhead]

Save your money and sanity by running a dump off of the downpipe. There is no reason to needlessly throw away a good exhaust system, which you have already paid for, that isn't bothering you (low noise) for many hundreds of dollars for moderate/no gains. A simple dump pipe and electric cut out will net you excellent gains with minimal work. Also they can be retained when the time comes that you need to replace your exhaust again.

 

[bison]

A Dual 2.25" is less cross sectional area than a single 3". The smallest area needs to be considered. Dual 2.5" is a little more than a 3" if I remember correctly. Just google the formula to get the
Area of a circle. Pi(radius squared)=cross sectionalal area of a circle.

 

[pacecarta]

maybe this will help
i forget the source but it isnt mine

 

[~JM~]

Does the system that is on your car have mandrel bends or are they the traditional muffler shop crushed bends? If they are smooth mandrel bends I think I would keep it & consider the dump pipe idea. If they are crush bent you may be better off with the Pypes 2.5" system. I have a kit still in the box waiting to go on my car if you have any particular questions. Another option is the 3" system from RJC. I almost went in that direction, but chose the Pypes instead just because I had the chance to see the system mounted up. It fits fairly nice & sits up pretty high. I also liked the way it sounds. I went with the straight through "Race Pro" mufflers.

Good luck
~JM~

 

[canadian nascar]

Hi I have a 81 turbo trans am, I have a 2.5 dp then to dual 2.25 according to the chart above my max flow hp is 232 hp?

sorry for the highjack

thanks

 

[SloGN]

The average car cab run into the tens with a 2.5 inch exhaust .. I personaly like the pypes system as I have that on my t type . Great fit. Decent sound . Summit has the best price

 

[turbofabricator]

Unless you are running faster than 10.30 there would be ZERO gain in going bigger. A local racer runs 9.70 on dual 2.25" old ATR system. Dennis runs 10.03@136+ on a three muffler 2.5" system. On his StageII race car he did a test and it had a three muffler system in 3" and after uncorking the down pipe it gained only 6 hp. It had a 3.5" down pipe. (9.1@149 mph car) Bigger is louder, too.

 

[Fast Farmer]

I have the Pypes 2.5" kit with the race pro mufflers. I absolutely love it. Picked up .4 on a stone stock car with it. Air conditions were also worse when I ran it with the Pypes kit. Got mine from Summit. The first exhaust system that I put on the car was a set of Flowmaster mufflers. They slowed the car down .3 from the stock system. The right exhaust system can make or break these cars. They do not like chambered mufflers at all.

 

[Roger]

I have dual 2 1/2" & considered it to be too loud & I then installed a third muffler as Denis to make it quiet.
Fast with class I believe the class is quiet.
3" are much louder than 2 1/2".

 

[Steve]

I had a dual 2.5" crush bent set up on my 10.60 T-Type with good mufflers and it ran the same with the dump open or closed. I would think that a non mandrel best 2.5" system would be about the same as a mandrel bent 2.25" system. The last setup I made was a single 3" mandrel bent system with two mufflers. I put a Dynomax Race bullet in the cat location then a Dynomax Ultraflo in the normal muffler location and it worked great with very little drone and saved a little weight also. I first made the set up with just the one Ultraflo muffler and there was too much drone but adding the Race bullet pretty well fixed that. The best part was I made the whole system for less than $200 including the mufflers and everything was stainless. I just can't make myself pay $600 or more exhaust, I would spend that on other parts!