i'm gonna do a non mandrel bent Y pipe, to a high flow cat, all the way out to the back, where just before the tunnel ends, i'm gonna do a 1 in 2 out race muffler, then duals out to the back. I have 2 brospeed tips layin around, they're gonna go on. i haven't seen this done before, and i'm worried about backpressure. should i use a smaller size pipe? i was thinkin 2" after the muffler. and before 2.5" is that too big? anyone have any info on this? i'm worried about not enough back pressure. thanks guys.

 

Dont really beleive the hype. Sure some back pressure is good for some on the low end. But you dont really want back pressure it is power robbing. Brian V has the Y,high flow cat,etc...and he loves it. As long as you dont go 3" it will be fine.

 

I can't answer the question, but I'm glad to see someone in a car forum recognize the importance of back pressure in the exhaust. The same principle applies to air intakes. I think a lot of people are going wrong by opening their intakes too wide and sucking up hot air from under the hood with cones, and opening their exhaust too wide. When the exhaust is narrow the gases build velosity and pressure, imagine when an exhaust valve closes, a vacuum is created behind the fast moving gas. This vacuum practically sucks the exhaust out of the next cylinder when its valve opens. The reverse is true for the intake. I know this is poorly stated but you can get the idea.

You have to consider your use of the car, if you free up the exhaust and intake your high end HP will increase, but your car may be a dog on city streets.

 

Well on a engine with a turbo or supercharger a 3" pipe will make a nice HP output but on an N/A engine your just robbing the low end of what it can have with a catback that has normal size pipiing. with the set up you are refering to you might notice a loss in low end and it might not make up for it in high end either. stick with a nicely made 2.5 catback with free flow muffler and thats about all your gonna want or need exhaust wise form this car unless you boost.......

 

Stick with nothing more than 2.5" for exhaust. Unless you have V8 or NOS,Turbo,or S/C. And no matter what get a CAI if you do any intake changes. I think you know that though dude. I will let you know about the rims also.

 

i've just got a guy that'll do the duals fairly inexpesively. i have never seen a max with duals and it'll look really nice. i already have 2 tips layin around the shop, and now i'm just concerned with back pressure. I know the duals are gonna be all looks, but how many imports with duals are real duals? not too many, it'll be off a Y anyway, plus, this'll actually be cheaper than a catback. the guy's gonna charge me 150 for welding up the y pipe,cat, muffler, and running the pipe for the duals. should i stick with my oem cat? I REALLY want duals. and thanks bout the rims man.

 

by duals what do you mean? from one muffler to 2 pipe ends? and a tip on each? or two separate mufflers?

if you had 2 mufflers that would look pretty cool, the other way looks kinda cheesy in my opinion..

i went with 2.25 in piping instead of 2.5 (shop told me they had same car with 2.5 piping and lost a lot of low end power which the guy didnt like. so he recommended 2.25, and like the way it feels both low end and high end.. actually high end is really great compared to my low end now

 

see, my guy will run it real nice, i can't find a pair of mufflers that'll fit. the driver's side has such limited room. I need to put it up on the rack and dry fit a couple. if i can't find a pair that'll fit, i'm gonna use a 1 in 2 out muffler to 2 tips. i'll look nice, trust me.

 

take a look under the drivers side rear of your car.. there isn't that much room under there because of the gas tank and associated equipment. A true dual set up would be difficult with out using a narrow diameter blatty sounding cylinder muffler.

Fro

 

IMO, Dual exhaust is all looks. I think with imports a single is more effective. Besides you are adding extra weight to the car by adding more piping. So if you just want it for the look go for it. But for power gains I wouldnt.

 

oh yeah, i just want the looks bro. my car's fast enough

 

Dmontz and Fro are right. If it's looks, go for it. But you can get the same gains with one pipe. I got rid of my setup, it was too loud and performace was the same. It's been done, and there's a reason why it's not done more often or you don't see it. It was a waste of my time and is the only mod I regret ever having done. My 2 cents.

 

how did you have it setup? do you have any pics? how loud was it? did it sounds like bees in a can or what? any input would be very appreciated.

 

I was told it sounded like an V8 without a muffler, it rumbled. Of course it still does somewhat with my single, just quiter. There is no 4cylinder "bee" sound. That has a lot to do with the muffler you run too in getting a sound like that! My setup was flex pipe, glass pack, then straight pipe on back to the rear wheel on the passenger's side. Split there and the passenger's side run on back and the driver's side run between the spare tire and heat sheild. Both sides had tips. I don't believe or claim that this was an efficient setup, but I found that it was a waste. If you can run like 2" pipe and split it closer to midsection of the car and run the two pipes side by side till the rear wheels, then run them in different directions, it might be more effecient. I think you just need to climb up under the car, measure how much room you have from the rear of the vehicle to about 2-3 inches from where the second pipe will come around from the spare tire. This will tell you how much length you will have when looking for a round muffler, some are pretty long. Plan on getting a muffler or don't do it, it's just too loud! With my duals, if someone was talking to me while excelerating, the exhuast drowned out what they were saying, even with windows up or down.

 

ok thanks man, anyone have any suggestions on mufflers and where i can find em?

 

Borla has a set up for the Audi Quattro part #14951 that is one pipe running into one muffler, with the muffler having two outs and splitting the exhaust. Just for example of what you could do.

 

that's kinda what i was thinking. it has to have a muffler not a "glasspack" style, that way it won't be too loud.