exhaust ?s
 

right now my car has a flowmaster muffler on it. the guy just chopped off the old one and welded the new muff on.

what's the proper procedure here? i need a high-flow cat-con? what diameter piping? what's the deal with dual exhaust? i'm totally a noob.

also pricing if you remember how much it cost when you got yours done.


thnx
mike

Its been quite a few years for me. let me see if i can help you.
Cat back would be a good start. 2.5 inch is I beleive the largest that will fit over the axle from the cat to muffler. There are 2 different types of dual exhaust, true dual using 2 mufflers, and then the dual which our cars are more set up for, 1 muffler layed sideways, single inlet, dual outlet. The factory mufflers are not dual out, but just like the corvette, grand am, CRX, and I am sure there are some others, I have an SLP exhaust for a grand am, my welder needed to shave a couple inches off but other then that it fits perfectly, I cant find it on SLPs website, but I did find this which is a how to for that exhaust http://www.pfyc.com/supportfiles/ga5004install.pdf

I think mine cost me about 6-700 and my friend installed it dirt cheap, maybe 50-100

As far as a cat, I dont think it is necessary to get a high flow, unless your looking for more performance off the bat, I do not have mine done, becasue I am not sure of yours but it is illegal in Maryland to remmove a cat that is working fine. So a shop may not do it for you.

Borla also makes an exhaust for the Alero, and since SLPs grand am worked, I assume any grand am exhaust could work on the alero with some minor cutting of the pipe. Or you could buy 2 mufflers and do that way.

hope that gets u started, good luck

^ to be more specific on the true dual....there would be 2 exhaust pipes running directly from headers to mufflers without combining. So on a 4 cylinder (or pretty much any common inline engine), with how most headers are manufactured, it is very uncommon to see true dual exhaust. however, on V6 and larger V* engines, true dual exhaust is quite easy and common (not from the factory though).


and to the original post: if it is properly hung, he is using the stock hangers, so that the exhaust has a little bit of flex. (if mine had flex to it, the muffler probably wouldn't have just fallen off). if the new muffler has the same size pipe, you shouldn't need any more modifications at this point. The stock cat is a decent flowing cat as it is, and should only be upgraded if you have more power flowing through, OR if your stock one is shot and you just want a nicer new cat on there. (check your state's laws for emissions regulations, as a high-flow cat may be restricted)

when I had my Borla ProXS (camaro style, dual out muffler) put in, it cost me $400 total for parts labor and taxes. They had to fab up some bent pipes, cut out a spot on the bumper cover for the new pipe, welding, and the tips. The tips were the bulk of the parts cost, being $75 each.

I would start off with a cat-back exhaust and a high flow muffler.
You can ditch the stock cat for a high flow cat for more flow and power. If you're doing this, I'd also make the downpipe (from the manifold to the cat) the same size piping as the cat-back exhaust.
What size engine do you have? 2.5" should be good.
True dual exhaust would be hard to do on an Alero, and may not be any better than a single exhaust anyways. It could only be done on the V6. Each bank of cylinders gets it's own exhaust path to the tailpipe.

If you want dual tips out back, you can just run the single exhaust pipe and spilt it to two mufflers and tailpipes, or run a Camaro style muffler that runs one pipe into the muffler and has two pipes that come out for the tips.



Speaking of exhausts, Albino - you get your new exhaust done yet?

It has been done before, the original aftermath (Robbie) I believe had true duals

i have the 2.2 eco

well what I been telling you is for the 3400, unless you plan on getting a supercharger or turbo and some major modifications, the 2.5 in diameter will be way to much for you. Its actually too much for a stock 3400 but at the time i was planing on s/c it.

nope, not yet. because of my coil towers, spark plugs and wires and ignition module misfiring, burning and melting, and dumping fuel into my old cat, I had to put on my new cat with the new ignition stuff, thus spending my exhaust money. so I have new headers and a new muffler and my old one (gonna try to be quiet for a change lol) ready to go...with no funding.

I never said it couldn't be done. I've seen the pics. I was just saying no one knows if a true dual system on an Alero is significantly better than a single for the extra effort spent on it.

For a full exhaust, I'd go with a header, to a high flow cat, to a cat-back with a resonator and straight through muffler, using 2.5" piping for the entire exhaust. To start out, go with the 2.5" cat-back with a straight through muffler and you could always upgrade the rest in the future.

2.5" piping is a good size for both the Eco and 2.4. It's small enough to retain low RPM exhaust velocity, yet large enough to allow for high RPM flow. The 3400, being a full 1000cc's and 2 cylinders larger than the 2.4 would actually benefit more from a 2.75" or larger exhaust for N/A. That's a lot of exhaust to flow through the same little 2" stock piping that the 4 cylinders get. A fully free flowing 2.5" exhaust could also be used since the V6 doesn't rev as high as the 4's.

Going turbo, at least 3" is best for all 3 engines.

If I recall nothing thicker then 2.5 will fit over the rear axle. If thats not true, then mine is thicker then a 2.5, becasue I remember when my buddy and I installed it we would not have gotten anything larger over the axle, it was a tight fit, the first place I went to said 2.5 was to big.

Well I can tell you for a fact that's not true. I have 3" piping going over the rear axle. I fabbed it all myself.

well maybe the SLP had 3.5 in then, like I had said previously it was back in like 2001 that i had it installed so i have forgotten quite a bit, I am pretty sure whatever I had was the largest that could go over the axle, (without major modification)

3" is pretty much the biggest you're going to get over the axle. Mine rattles a little at idle as it is. Any bigger and you'd have to run it under the axle instead.

i thought mine was someting.5, but i dunno

i know with mine i get some backfire every now n then, and my friend who has bult a couple turbos says that my exhaust is a bit much since i dont have a turbo or s/c

I guess it's possible on a 4-cylinder with a 4-2-1 header and just omitting the last "Y". not that it would be worth it.


That's not really that valid. The 300SL Mercedes I picked up last summer has a 3.0 inline 6-cylinder (~220HP) and they run a DUAL 2.5 on it until the rear axle where it goes to a 3.0 single into the muffler. I'm pretty sure they didn't do that for no reason.

well thats what I was told by a friend of mine who built several turbo cars, but again I may have a larger diameter piping now that I have been talking to some of you guys, I cant really remember, it was almost 10 years ago, lol

Some people aren't as knowledgeable as they may think, whether they've built cars or not.

a resonator is to reduce sounds? i love the deep n throaty sound my car makes.

i have a header, so i should be looking for high flow cat (if legal here) and cat-back?

this is how the not-so-common true duals on a 4-banger are though. boosted applications which don't require a whole lot of back pressure would definitely benefit from a 4-2-1 header, minus the 1.

Your right but this guy I believe, becasue he actually has/had a shop that built them for some circuit, plus he is like 34 and been doing it for well over 10 years.

The shop I think he worked for is this myspace page
http://profile.myspace.com/index.cfm...id=210 517188

and one of his cars is Lamar's 95 civic twin turbo (not street legal)

and I dont know much about exhaust or turbos, so of course someone could probably debate his knowledge.