I'm getting hedman shorty headers from a friend along with his piping straight back to a 01 SS muffler (no cat). I want to go without a cat but have on a dynomax superturbo muffler now. I love the sounds of a flowmaster and am thinking of putting on an 80 series, definately want to go with the dual outlet. What does everyone think? I'm looking at both sound (i like to hear the rumble of the engine) and performance.

Not a big fan of flowmaster, is's louder than what you have now for sure though. What about hooker or Spintech? Oh, and it's a safe bet to say that all of the choices you have now will out-flow the flowmaster.

I love my flowmaster catback but you may want to check out hooker if you are worried about price they sound great and are a little cheaper.

none, just get a cut out and put that in ,one of the electric ones, keep the exhaust you have and get that and youll be set.

I want to get a muffler at least, I see that people are leaning towards flowmaster and they're a lot less than i thought, only 75 + shipping on summit. Still, I don't knwo if that's what i want to go with. Keep the opinions coming. I want to hear from people who have exhaust without the cats, hopefully running hedman headers, but let me know what you think of your exhaust.

Flowmaster is probably the worst flowing out of all the aftermarket "performance" mufflers. Even the Dynomax superturbo outflowed it in tests. I would look at the Hooker, I had it on my '85, and it sounded great.

Thanks for the info. Got the test data to show us?

yeah, just look inside of one.

Oh ok phewwww. I knew flowmaster were the only chambered mufflers.

Flowmasters (including the 40 Series) are so lousy, that nearly every single 10-12 sec. musclecar (Camaro's, Chevelle's, Nova's, Challenger's, and fast cars in general of any year or Gen) that I know of almost all run them, dual 40's especially. Guess I'll go tell these people to take them off so they can actually be fast now and that their mufflers are holding them back at least 40 HP and TQ. The difference in just not significant between brands, if there even is one in some cases.



(BTW IROC5.7, if you would change your muffler to something else instead of Flowmaster it'd be guaranteed that your 14.8 would suddenly become a 14.4 )

I will never post anything that I don't have data to back up.

The best flowing Flowmaster muffler is the Delta Force 54040-10. It flows 634 CFM.

The Flowmaster 40 series 435409 flowed 576 CFM, which was the best flowing 40 series.

The best flowing Borla XR1 flowed 1450 CFM.

A Dynomax Race Magnum 17220 flows 2200 CFM.

A stock style turbo muffler flows 225 CFM, just for comparisons sake.

Any Questions?

I have flow data on almost every muffler made, so when I post something, I'm not just saying something I heard somewhere else, I'm offering first hand information from years of research and experimentation. I'm not here to put anyone down because of what the choose to put on their cars either. I'm just trying to offer real data for people who believe too much of what they see on TV.

i may have this wrong but arnt flowmasters suppose to help the scavagening effect? they arnt intended to have air just pushed throught them you have to pulse it like a motor and then they will perform. just what i thought they were inteneded to do i know they arnt a straight through but straight through has almost no scavenging.

Scavenging is handled by the headers (and y-pipe, if you run shorties). If someone can explain how a muffler mounted 8 feet away from the cylinder heads can effect scavenging, it'll be a new one on me. Flowmasters create backpressure, which stock or mild combos need, but most high end engines do not respond well to backpressure, and the length of pipe before the muffler, and the number of bends before you get to the muffler on a typical third gen should create enough backpressure for mild engines, so I'd get a fairly freeflowing muffler. I ran a Hooker Cat-Back before the engine swap, and it performed really well. I also ran a true dual setup with two single chamber flowmasters and high flow cats for a while, but because of the mild engine combo I had at the time, the true duals had no effect on performance.

Rich, can you scan that data and post it? I'd make it a sticky for people to reference.

Muffler CFM Comparison

Brand/Part Number CFM

OEM STYLE TURBO- 225
GIBSON SUPERFLOW 788200- 311
TTS BULLET CAT CONVERTER- 324
FLOWMASTER 40 SERIES 42540- 352
FLOWMASTER 50 SERIES- 362
FLOWMASTER 40 SERIES 43040- 392
DYNOMAX SUPERTURBO- 410
FLOWMASTER 62631- 435
CARSOUND CAT CONVERTER- 436
FLP CAT CONVERTER- 440
EDELBROCK VICTOR 5535- 562
FLOWMASTER 40 SERIES 435409- 576
EDELBROCK RPM SERIES 5511- 579
FLOWMASTER DELTA FORCE RACING 54040-10- 634
EDELBROCK 304 SERIES 5560- 640
EDELBROCK GEN APP 5505- 708
DYNOMAX RACE MAGNUM 17216- 711
BORLA XR-1 40600- 836
BORLA XR-1 40615- 854
DYNOMAX ULTRAFLOW SS 17263- 1000
DYNOMAX RACE MAGNUM 17218- 1000
BORLA XR-1 40575- 1100
DYNOMAX ULTRAFLOW- 1133
EDELBROCK VICTOR 5537- 1400
BORLA XR-1 40450- 1400
BORLA XR-1 40741- 1450
DYNOMAX ULTRAFLOW SS 17396,17268- 2200
DYNOMAX RACE MAGNUM 17220,17224- 2200
DYNOMAX RACE MAGNUM 17225- 2600

All the numbers were lined up nice and pretty, but when it actually posts, they group together, the last number in each set is the CFM

I also have some Magnaflow numbers around here somewhere, I'll try to post them when I can find them, but if memory serves me correctly, they flow around 650 CFM. I'll try to get more numbers as time goes by and add them to the list. Just remember, these numbers are given for comparison, all were done on the same flowbench, and different flowbenches might read a little different, it's just to give you a base idea on what mufflers flow what.

By looking at the chart, I've found it interesting that most people will break the law and delete their cats, to gain flow, but then put a Flowmaster 50 series muffler on their car, when a good high flow cat outflows the muffler. Today's exhaust technology is so far ahead, that you can run a full, legal exhaust with minimum power loss.

I didn't know there were so many different 40 series. Are the different part #s just different inlet/outlet offsets?

Although i love the sound of my 80 series flowmaster.. it is restrictive.. I have seen a Lt1 go from 12.7 to a 12.4 by dropping the exhaust and running open y-pipe.

On my car.. when i had the SuperChip for a stock L98 this is the difference in running through my 3 inch catback and 80 series flowmaster (dyno 1) and running open y-pipe (dyno9)..

Click here for difference

Keep in mind though.. that it all depends on the tuneing.. the best would be to run a good muffler for the setup and tune it for the whole intake/engine/exhaust setup you want.

Personally.. i don't have money for another exhaust system.. so cutout was just intalled today and i will post once i get some times and dyno's to show any difference in a custom chip tuned with the exhaust and then a cutout installed.

I agree with you. If you run too free of an exhaust, you'll lose low end torque. There's a conversion I have somewhere around here that explains the best pipe diameter for different HP levels. I was pretty surprised, on my Cougar, given it's current HP level, only 2 1/4 inch duals were recommended, which is what I got. This was for the 200RWHP level.

I'd be interested in seeing that conversion chart!

http://us.f2.yahoofs.com/bc/4029801a...GBtOABpoPoFjXY

There's the chart to help determine pipe size vs. engine displacement vs. horsepower.

Does anyone else have any evidence to back up what Shaun is saying. I knew flowmaster weren't great at flowing but 10-15 hp/torque loss, that's a decent amount. Would keeping the dynomax on give me more power? Can anyone pick me out the best idea for performance with a nice girthy sound under 125? I'm open to suggestion.

Still love that flowmaster sound.... that may win out overall.

keep in mind engine mods: www.madirocz.com/mods.htm

not sure the difference on other setups.. but mine was needing to lean out, it was running rich.

This may be a stupid question but does there seem to be a muffler that reacts better to TBI as opposed to TPI? Does that matter? Which mods would make the biggest impact on my choice of muffler?

back to the original question, I'd Vote for the Edelbrock Cat back, its the RPM, and its even on the chart above

Just out of curiosity, what makes people pick the dynomax, I haven't heard anyone really say much about it.

The Dynomax flows pretty well for the price, and it's probably to quietest cat-back on the market.

Yep. I've got a bit of a driving record, and the last thing I need is an instant cop attractant in town here. It sounds good when I need it to, and is nice and mellow up to about 50% throttle...

Then when the secondaries kick in, it's a totally different beast with a nice unique sound on an open element air cleaner My only mistake was not purchasing a system for future mods. On Stock LG4's and most 305TBI's a 2.5" system is fine. It'll be a real bottle neck when the mild 350 goes in.

As for the comment about cats, Mine's hollow because I didn't have money for a new one at the time mine plugged up, and I need to have something that resembles a cat on for the new visual inspections in parts of PA. I think headers with 3" collectors and a 3" y and 3" cat will really wake the 350 up... just can't do it now unfortunately...

I like the sound of the hooker aerochamber, I have flow now and I'm also disappointed in the sound.

Anybody know what the Gale Banks Muffler flows in cfm, the
Muffler that came with the Banks Cat Back kit for the third gen
camaro.