quiet_storm98

iTrader: (48)

hmm i may have to pick up a set of these..i have dynomax bullet's right now and i heard they get raspy when you add a cam. Braincws6 your car sounds good..do you have any other sound clips?

BriancWS6

iTrader: (18)

We are concluding that the single chambers are not power robbers. They're also "race" mufflers, they're suppose to be loud. It's the nature of the beast. Although the sound level seemed to sound similar to open pipes, it's MUCH more refined, and actually a pleasure to hear. Never met anyone that heard the car and didn't like it.

I'm gonna have to raise a big BS flag on you losing 45rwhp with a 305rwhp setup, that's total non-sense. Oh, well maybe there was some apples wedged in the outlet or something? Or shop rags? Give me a break man, that's rediculous.

I sure as hell hope you don't lose power with a STRAIGHT threw muffler

BriancWS6

iTrader: (18)

I have one track pass video uploaded and hosted. I used a small dig camera and recorded it off my tv, so the quality isn't the best, and you'll need to turn the volume up.

Thanks for the compliment

http://s130.photobucket.com/albums/p...urrent=122.flv

engineermike

Ok, so maybe we should call them "race attenuators" or "race resonators" if their sole purpose in life is not to muffle, but to make the sound "more refined".

When we start talking about how "refined" something sounds, this all becomes a matter of opinion anyway. I prefer my 9 second car to be as quiet as possible, and with a smooth idle too. To each his own. . .

It's all very well documented. David at Thunder was there for it all and probably remembers if you want verification.

1989 Firebird coupe, stock weight: 360 cid SBC, 8.5/1 compression, AFR210 heads - Race Ready porting, 847 cam (234/242@.050), Victor Jr intake, Holley 750, SLP 1 3/4" shorty headers, TH700R4, Vigilante converter (locked), 3.42 gears.

Single 3" in / dual 2.5" out Flowmaster: 305 rwhp, 12.70 @ 109 mph
Muffler removed: 345 rwhp, 12.30 @ 113 mph
Single 3" in / dual 2.5" out SLP muffler: 350 rwhp, 12.20 @ 114 mph

When I first put together that combo, the car didn't perform like I thought it should. I chased my tail for a while, changing the headers and torque converter. Those helped, but it still didn't run like it should. One day at the track, I decided to disconnect the muffler and the next pass was nearly a half second and 4 mph faster! I went to the dyno and verified the 2 chamber Flowmaster was killing the power. This was several years ago, so a bunch of people were pretty shocked at the outcome. It's not that unreasonable, when you consider alot of guys are gaining upwards of 25 rwhp by bypassing one running camshafts with alot less overlap than mine. More overlap means that backpressure is that much more critical.

With the new muffler, it eventually went 11.96 at 114.5 in better weather with the accessory belt removed, then later with a short block swap (383 with 11/1) went 11.0 @ 123 mph.

Mike

BriancWS6

iTrader: (18)

I agree that sound is a preference.

I agree that people have picked up a significant amount of power when opening a cutout while running the 80 series cross flow on a stout heads/cam setup. I know a guy personally that went from 505rwhp open cutout, to high 470s IIRC through the 80, but 45rwhp is HUGE, especially with the better flowing muffler you had. And a 300rw setup is far from 500. The more power you make, the more the same choke point restricts you.

I'm not gonna argue with you. I would like to believe that you have no reason to lie about it, so I'll give you the benefit of the doubt. I'm sure stranger things have happened.

JohnFrazee02SS

iTrader: (23)

i took my cutout off and gained .2 in my time but i do like the sound i have a 40 series btw

engineermike

Yea I was certainly surprised by the results and mine is the worse case I've seen/heard of.

Don't get me started on the 3.5" single in/out offerings by Hooker Aerochamber and also Spintech. . .

Mike

ScreaminRedZ

iTrader: (3)

I don't think that most cars will gain anything near 45 rwhp at the 300 rwhp power level by removing their flowmaster muffler. I think that's gonna be a pretty isolated incident in general. Did anyone call Flowmaster and ask them WTF? 45 HP you think someone would have...

av6ateu

iTrader: (2)

You can add me to that list too.. I did a cam install this spring and couldn't figure out why my dyno numbers were so low. swapped out the flowmaster crossflow cat back for borla and never looked back. I do have to admit that I like the sound of flowmaster exhaust a lot though. Like everyone else already said, they seem to be pretty decent mufflers if you avoid the crossflow design.

JBIRD02

iTrader: (4)

Thank you for this! I have heard the same thing about the 1 chambers too. It pisses me off because people are going off hearsay about the 80 series, assume that it goes for all Flowmasters, and then spread it around as gospel. I also have Flowmaster TD's (in pic) with the 1 chambers and I love the power and sound. Not a day goes by I dont get compliments on it. I also put down the #'s in my sig with this setup.

AnotherWs6

iTrader: (17)

Back from the dead......

Anybody else have any dyno results with true dual single chamber flowmasters?

JDMC5

iTrader: (3)

Just so happens I still have the stock catback and crossflow 80 series muffler. I plan on testing it vs open headers on the dyno if I ever get done with my 4L80 swap. Not sure if I will end up going true duals or cutouts, I just love how it sounds lol.

JRENIGAR

iTrader: (37)

Im curious how the stock catback compares to the 80 series crossflow muffler. I had my combo dyno tuned and it only made 8rwhp more through the 3.5" cutout vs the stock catback. Surely the 80 series flows as good as the stock muffler. No???

1970camaroRS

iTrader: (8)

This?



Looks like it wouldn't flow any better than a 40-series. You know, the style muffler that everyone hates on.


Unlike the race muffler:


Or a straight-through muffler like a Magnaflow, Borla, Jones, Dynomax:


But nothing is as shitty as a 'turbo' muffler.

JRENIGAR

iTrader: (37)

Yes, the first one pictured is what I was curious about. How would it flow against a stock crossflow muffler? Do you have any pics of a stock muffler cut in half by chance?

1970camaroRS

iTrader: (8)

Yep, found a stock one cut-apart here on tech.



Similar to the 'turbo' style without any packing but with VERY small internal passages. Just about anything would be better, but the Flowmaster 40 or 80 series isn't a HUGE improvement.

JRENIGAR

iTrader: (37)

And the stock catback complete with 2.75" pipe was only worth a 7 or 8rwhp loss vs a 3.5" cutout with a mild cam and slightly ported heads with full boltons, Hmmm. I don't see how the flowmaster is any worse than the stocker looking at these pics. Anyone care to enlighten me?

1970camaroRS

iTrader: (8)

Because they both force the exhaust gasses to make multiple hard 90 degree or more turns or force them around objects in the flow path. Anything that makes the gasses have to bend, hit, or go around slows velocity and kills flow potential. 7 or 8 rwhp loss with stock cat-back versus a 3.5" cutout in a H/C car is BS. Something is wrong there. Big time. The stock muffler is very restrictive, but it flows enough to support the desired out-put for the stock vehicle while also passing sound-requirements.

JRENIGAR

iTrader: (37)

I guess the dyno is wrong? The pulls were within 10 min of each other right after it was tuned. The car dosent feel like it pulls any harder on at wot with the cutout open either. I will say that part throttle acceleration is alot stronger with it closed.