I know it's just one mod. But how many horses would I get say with a Dynomouth job. Single in, single out. Or say perhaps a Magnaflow installed on my car. Just muffler change. No cat-back.

 

Hardly noticable power gain if any.. Unless decibles = power in your world..
heheh

I think you are better off researching and saving then buying the right catback exhaust for you. I think I will be going with a mufflex 3.5" or 4" for my car when I do the exhaust. I just loved it when I saw it.

I used to have a Flowmaster Force II on my LT1 and it was great... but its alot to do with personal preference and not so much with power since catbacks will produce similar power gains.

How about a cutout? that will give you some power gain and louder note and cost a lot less.. plus you can cap it and uncap it as you wish.


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Psycho Cabbage
2002 Camaro Z28
(6 sp) Bone stock
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-Traded in- 1995 Camaro Z28 (A4 (#6 I might add!),ES tranny mount and torque arm bushing,SLP CAI,ASP 34% Underdrive,Strange 3.73's (shredded Auburn),1LE alum driveshaft & intake elbow,Yokohamas AVS Intermediates,160-stat,MAF screen removed, HPP+(for shift points only),Borla Y-pipe, Flowmaster Force-II catback, Gutted Cat, Airlift Airbag, !TB Bypass, J&M LCA's, Bosch Platinums, Moroso BlueMax Wires, Free RamAir, Meziere Electric H2O pump, MAC 3point STB, BMR Panhard, SCR SFC's
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best 13.44 @103.26
0-60ft 1.96
270 RWHP/296 RWTQ
0-60MPH 4.8sec
1987 Porsche 944S (waiting on LT1 mod)

 

Bullcrap!
I have a 98 with a lid and Dynomouth (stock exhaust with bullet) and I pull 318 rwhp/ 334 rwtq, not bad considering 98s pull around 280 stock.
I can link you to posts/sigs if you like of folks with expensive cat backs and lids that make the same or less than mine. Later model F-cars that are pulling 290 or better stock, are pulling close to 330 rwhp with Dynomouth... some of these posts have popped up on this site lately.

The fact is that the extra .25" of I-pipe diameter that you get from a cat-back over the stock 2.75" I-pipe (mandrel & stainless by the way) does nothing for your average F-car. Sure, put H/C to it and you should start looking at a 3.5" or 4". The 3" systems are worthless, they are just to close to the stock system.
Just dump that clogged piece of crap stock muffler and unleash some power. Don't go Flowmaster, they don't flow worth a darn, around 350 cfm. To compare, Borla flows around 900 cfm and the bullet in the Dynomouth flows better than 2200 cfm.
Good luck on whatever you do.
Dave

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[This message has been edited by ratio411 (edited August 28, 2002).]

 

So you are telling me that you whole heartedly believe that you 1 muffler gave you 38rwhp? thats like a 60+hp upgrade just with a muffler. Does that sound right to you?
I just know what I have seen at the dyno and what I have experienced. Perhaps if you had dynoed your car before and shown a before and after without any other mods, then yes. And I would be in line too. But jsut saying that the average car dynoes this and I dynoed that doesnt work for me.

If you have cold hard facts, I want to see them.

Nothign negative about this post, just that if you make a claim, please back it up.

 

Actually, with a muffler change, you can expect anywhere from 5-10hp change. Ratio411 is right about the flowmaster, they don't flow well, if you are using the 80 series. If you want to use a flowmaster use a 40 series 3" in 3" out with a single exit, of a 3" in and two 2.5" out the same side. If now, magnaflow, dynomax, and even the new borla pro x/s muffler's are straight through. And if the muffler is the only thing you are going to change, then I would recommend getting a muffler like this. Oh and the cutout alone will give you bout 10 hp, and and increased sound. I used to have a magnaflow 3"in and tow 2.5" out muffler with a cutout, and dynoed an increase of 14 hp with the stock I-pipe. rockls1

 

I have a 98 SS with the 2-into-4 SLP system. Is there a cat-back system I can install that will bump HP, and by how much? I am not looking to make noise--the SLP's sound fine--but to make more power.

Thanks.

 

I didn't say I got 38 rwhp with a muffler. I also have a lid. If you want to get picky, I have a Fernco, TB Bypass, Throttle stop mod, and an auto fan switch.

As for the flow numbers, they are fact. I pulled them straight from LS1.com, there are several other brands listed with their flow, but I made my point with those. The DynoMax bullet was the highest with 2200+ cfm, the next in line was 1100 cfm, then the Flowmaster was at the bottom with about 350 cfm. The stock system flows just under 300 cfm
Dave

[This message has been edited by ratio411 (edited August 28, 2002).]

 

So does that dynomax muffler have to be retrofitted to hookup to the dual out? Do you just install it in the intermediate pipe and then run a split after the axle. I wanted to do that one day with a 3rd gen Camaro but the crappo Firestone guy told me that the sound would be off because one of my pipes would be longer than the other . Are there any splitters I can buy just for that purpose. I would rather buy a good splitter pipe 2 and 3/4 in and dual 2 and 1/2 out than let the hacker local muffler guy make me one. They always use 2 inch pipe and that just sucks ***. Plus the pipe is that **** that will turn to rust in a matter of months. Whatever I do. I'll probably order aluminum coated pipe before I let these guys use there cheap pipe on my car. I have see one cool muffler setup and I think I could do that cheaper to. That's the dual chambered muffler setup. All a person would need to do is buy 2 of those mufflers. Then run a splitter behind the axle and weld up the dual chambers under the backin. I seen a guy do something very similiar with 2 cherry bomb mufflers and a true dual setup on his 82 Camaro.

 

I have had mine for almost 3 years. The muffler shop did it.
Here are links to some info on how the mod is done:

http://www.hhbc.com/justin96bird/exhaust.htm

http://www.ls1.com/forums/showthread...ight=dynomouth

http://server105.hypermart.net/jsgtp...outhupdate.jpg

 

You guys, the 40 Series and 80 Series are the same thing. The difference is the 80 series is made to fit the F-Body because it must be mounted transversely (sideways). They are both 2 chamber mufflers and should flow very similar.

Also, I have seen too many times when someone tries to compare CFM on them. It's BS, because the Flowmasters work on pulse flow from your exhaust to scavenge gases, and every other company that tests them uses constant flow to come up with their cfm numbers, making Flowmaster look bad.

Just something to think about.

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1983 Monte Carlo, 307 Stroker, TH350, 3.73 10-Bolt - SOLD 8/19/02

Future F-Body Owner

[This message has been edited by BlackHawk T/A (edited August 29, 2002).]

 

Yes,but look at the cut-outs of the mufflers.There is no way that a Flowmaster with "chambers" is going to flow nearly as well as a straigth-through design.All a Dynomax muffler is,is simply a 3" pipe with fiberglass stuffed around it.
Kevin

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1998 Black Z28 A4
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