Dyno results: Flowmaster CB vs. E-cutout!
Yes, I read your post and it's full of holes.
I'd like to see the A/F ratios in order to see what is really going on here, and it would also help to see the entire power curve and a picture of the exhaust itself, showing all bends and such after the cutout.
I'd also like to see that same muffler run, only with a 4" inlet on a 4" exhaust system since that muffler in a 3" was not designed to be run behind a 600bhp+ motor. Any 3" crossflow muffler will choke down some horsepower at that power level. It's not even remotely fair to stick a muffler designed for a car rated at 305 horsepower behind a car making literally twice that, then to call that muffler a restriction. No **** it's a restriction, it's a 3" crossflow muffler stuck behind a damn race car motor that would NEVER be found on a production car stock.
I'd like to see the A/F ratios in order to see what is really going on here, and it would also help to see the entire power curve and a picture of the exhaust itself, showing all bends and such after the cutout.
I'd also like to see that same muffler run, only with a 4" inlet on a 4" exhaust system since that muffler in a 3" was not designed to be run behind a 600bhp+ motor. Any 3" crossflow muffler will choke down some horsepower at that power level. It's not even remotely fair to stick a muffler designed for a car rated at 305 horsepower behind a car making literally twice that, then to call that muffler a restriction. No **** it's a restriction, it's a 3" crossflow muffler stuck behind a damn race car motor that would NEVER be found on a production car stock.
I agree with you man. That thing wold have had the same results with any cat back that was on it. I had flow master before my td's and it sounded great and ran awesome. My has a 01 ta with a 224/224 cam in it and dynoed 380 hp. He recently changed to a dyno max muffler off the Y pipe and it "feels" like he gained 8-10 hp. He hasnt put the car on a dyno since the exhaust change. But I drove it a bunch of times and agreed with him about the small gain. And by the way he only changed it so it would be louder not get a 25 HP gain.
Tech Resident
Joined: Jan 2006
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From: Philly
Tech Resident
Joined: Jan 2006
Posts: 5,117
Likes: 3
From: Philly
Right, 305 is underrated, but the muffler was used to support the horsepower that the engine was rated at. If the LS1 was rated at 500bhp, Flowmaster probably wouldn't have used the catback they did. LS1's make 340-350 horsepower, and the motor in question is making something like 600-650bhp. That's roughly double the power of the LS1. You can't compare rwhp numbers because more rwhp is lost through the drivetrain as the power level of the motor goes up. A car that puts down 300rwhp has roughly half the bhp of a car that puts down 520rwhp.
Tech Resident
Joined: Jan 2006
Posts: 5,117
Likes: 3
From: Philly
I agree with you man. That thing wold have had the same results with any cat back that was on it. I had flow master before my td's and it sounded great and ran awesome. My has a 01 ta with a 224/224 cam in it and dynoed 380 hp. He recently changed to a dyno max muffler off the Y pipe and it "feels" like he gained 8-10 hp. He hasnt put the car on a dyno since the exhaust change. But I drove it a bunch of times and agreed with him about the small gain. And by the way he only changed it so it would be louder not get a 25 HP gain.
The Flowmaster 80 series obviously doesn't have the flow of a straight-through muffler, and I'm not claiming it's the best flowing muffler out there. It's not. It's restrictive compared to other makes, but it's not as bad as the crowd on this site will have you believe. I'd never trade my Corsa for it, but it's not a bad buy for the money.
Last edited by Red99TA; Mar 27, 2008 at 07:30 PM.
TECH Fanatic
Joined: Jun 2006
Posts: 1,220
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From: Nashville, TN
I do not car how much hp the flowmaster costs. When I had my t/a with an X and single chamber flows it was the best sounding exhaust hands down. I would be more than happy to trade 20hp for the sound. A cut-out makes the car sound like a redneck straight piped 4x4. On a stock car, the flowmaster 80 is not going to cost more that 5 to 10, not a big deal. Like I stated the sound makes up for the hp loss. I wish my Z06 could sound like my t/a, but thats not going to happen. I am a sucker for the flowmaster sound.
On The Tree
Joined: Apr 2007
Posts: 149
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From: Houston, TX
I loved my Flowmaster, loved the way it sounded. But, when i replaced my exhaust system for a Magnaflow CB i gained 12 hp. BEFORE YOU GO NUTS, the flowmaster had all kinds of leaks and was making me throw codes. Overall, i was actually very pleased with the flowmaster. IMHO i think its one of the better sounding CB's out there. But, magnaflow puts the smack down on anyone with the WOT sound. *shivers* It sounds segsay.
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I replaced my flowmaster with magnaflow. Just looking into the mufflers, is a no brainer which flows better. Magnaflow has the same size hole as the opening. Flowmaster had a much smaller hole. Reminds me of huge tips on Hondas that go into a pea shooter.
Tech Resident
Joined: Jan 2006
Posts: 5,117
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From: Philly
What is that supposed to mean? Do I work for Flowmaster? I clearly don't, so how is it "straight from the horse's mouth"? Or do you not even know what that phrase means? On top of that, where's the rest of the quote? It's easy to selectively quote and distort what I actually said. I could write the phrase "I'd **** your mom if she was the last person on Earth to save the species" and you can quote me for saying "I'd **** your mom" and leave the rest out, but I still think she's ugly 
the flowmaster 80 series definately sounds good. that muffler only and a lid ONLY NO OTHER ENGINE MODS at all on the woman's 99 m6 ws6 trapped 108-109 consistently @ 2500' da. it has to be better than the stock muffler, there's no way this car was that fast in stock trim. it's full weight + at least 50 lbs of her ****. car runs strong and i think part of it is the muffler. i almost **** a brick when we went from a ~35 roll and her stock t/a was at my door - with her driving haha. my auto turd had headers, true duals, lid, udp and ls6 intake boohoo.
Not really flowmaster related but I'll throw it out there anyway. When I dynoed my car with just a lid and cutout (stock exhaust) I did back to back pulls with the cutout open and closed. HP and TQ gains were both less than 1. Soooo, unless a flowmaster is worse than stock, I don't see a cutout helping much on a stockish car.
Tech Resident
Joined: Jan 2006
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From: Philly
TECH Senior Member
iTrader: (1)
Joined: Apr 2005
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From: Vancouver,[KITSILANO].B.C. Canada *WestCoast*
Don't be surprised. There are a lot of Flowmaster haters that just jump on the bandwagon for absolutely no reason on this site. The Flowmaster isn't as bad as advertised. There are plenty of people pushing well over 400 rwhp with them out there. Sure, they're not the best out there, but they're not going to destroy your car by running one.
Nice gains with the tune!
Nice gains with the tune!
