I have decided to go with the Flowmaster after hearing some sound clips. What series should I go with, 80 series or American Thunder? I want the deeper sounding of the two. Where should I buy the Flowmaster? Thanks.

 

i used to have a 40 series on my S10....it sounded pretty nice..it would probably be pretty loud on the LS1 but it would definatley have a nice low rumble

 

I really wouldnt go with the FM if I was you. I have one, and yes it sounds nice, but its one huge f-ing restriction. When I first got the car i had the flow on it and it dyno'd 294hp. I later added a cut out and with the cut out i put down 310hp. Only difference was cut out and clean paper air filter. Same weather, same gas, same oil.....the Flow hurts power.

 

i've got the flowmaster american thunder kit on my Z28 and I really like it. it is a full 3 inch system not like the 80 series muffler which has a 2 3/4 inlet and two 2 1/2 outlets. I also have the slp y-pipe on my car and I really like the sound it makes. There is an awesome sounding rumble to it when you get on it, but quiet enough to hear yourself think when you cruise. If you get the American Thunder System, you won't be disapppointed. You can get the American Thunder System from Summit Racing for $300 + $15 for shipping.

 

I too have the "American Thunder" Flowmaster cat-back system (full 3" system from cat back) and I love the sound of it. It's not as LOUD as some systems, but the SOUND is pure quality! Flowmaster definitely knows how to make a car sound good.

In comparison to other aftermarket exhaust systems / mufflers, maybe the Flowmaster muffler is more restrictive. But in comparison to factory 2-3/4" exhaust, it's gotta flow better just based on the fact that all the pipes are a full 3" diameter, and mandrel bent. Also, if the factory exhaust is quieter, doesn't that mean it's more "muffled"........meaning MORE restricted?!

You can't compare ANY exhaust system + muffler with a cut-out. I'm sorry, but that's no different than comparing to open headers. Obviously a fully open exhaust system will flow better and give you upwards of 15 rwhp as you claimed (Aklaim) but for an actual exhaust system, I don't think you can go wrong with the Flowmaster if you're looking for sound.

 

All I am getting at, is that you can get less restrictive cat backs, like the LM, or Random Tech, Magnaflow, Hooker, Etc. in the same price range that flow well and you will see a power increase, NOT a decrease. A LM or Random Tech cat back will flow just about as well as a cut out. Yes I agree, the Flowmaster does sound badass (i have one i know) but it is a big restriction.

 

i went from no cats and two 40 series flows... to cats and bullets on my duals and picked up at 1mph in my trap....


take that for what its worth

 

if u are dead set on getting a flowmaster muffler, get the 40 series. it sounds the best of them IMO. buddy of mine has it on his 98 LS1 and it sounds pretty mean

 

i have 40 series... no IDEA on the restictivness but.. sounds nice...

 

I read an article a couple of years ago in Popular Hot Rodding where they did a before and after Dyno on a 98 Trans-Am with the American Thunder Flowmaster and it showed a 13 hp gain. I had this exhaust with headers on the 95 Camaro I used to own and it sounded great.

On my 2001 Camaro I have a LM and it sounds like crap. I added a Dynomax Muffler and it help a little but it still reminds me of a dump truck.

This spring I plan on switching to a Hooker Catback with Hooker Long Tube Headers. I heard Bob's Camaro from EPP in Ft. Wayne and it had a refined muscle car sound. You might also think about the Hooker Catback.

Good Luck,

Al

 

There are alot better mufflers out there than FM, Im not saying they are bad , But if I was doing a muffler like you the magnaflow is one of the better flowing ones for the money and it has a nice deep sound to it.

 

In terms of pure V8 sound, I think Flowmaster is one of the better sounding mufflers out there. I just love that deepbass rumble it makes (especially on LT1's). It is not really loud, but far from quiet (right in the middle). Some people complain about the drone, but many other systems do this too (like the SLP Loudmouth). As for flow, it is at the bottom of the barrel compared to other systems available for our cars, but that only really matters if you are a avid drag racer (which most of us are not!).

And here is a tip when running a Flowmaster muffler: Using bigger tips (stock Z28/TA style or 3.5"+ slant cut) will actually amplify the rumble and make it sound louder, especially after the muffler breaks in...

Mike

 

That's where I think you're wrong. Look what Al (95TealLT1) posted..........he said he gained 13 HP on a '98 LS1. That's gained, NOT lost.

I think what you mean to be comparing are all the aftermarket exhaust systems. YES, I agree with you, maybe Flowmasters do not flow as well as LM, Magnaflow, etc., BUT compared to the STOCK, FACTORY EXHAUST SYSTEM, they DO flow better.

I don't think it's fair to mislead people this way. While I can't say I noticed a huge power increase from the cat-back install, the SOTP meter definitely felt a slight bump in high RPM power (trust me, the tires seemed to break free a little easier even while on a roll at low speed after I put on the cat-back ).

 

No, he said he read it in a magazine. It wasnt his car, and I believe magazines just about as much as I trust politicians. I think a 16hp from an open cut out is a bit high, so all that does is leads me to believe that yes in facr, the FM does kill power. I didnt do a before FM dyno test so I cant say for 100% certain but with my own case, and from what Ive heard from others, the FM does hurts more than it helps.

 

Quote: No, he said he read it in a magazine. It wasn’t his car, and I believe magazines just about as much as I trust politicians. I think a 16hp from an open cut out is a bit high, so all that does is leads me to believe that yes in fact, the FM does kill power. I didn’t do a before FM Dyno test so I cant say for 100% certain but with my own case, and from what I’ve heard from others, the FM does hurts more than it helps.
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I think you guys have been brain washed. So you think they would lie about there results in a magazine article. What do they have to gain? Just how much SOTP feeling do you think you will see from 13 hp? That would only give about 0.1 seconds improvement in the ¼ mile. When I put on the LM exhaust on my car I didn't feel any difference. Does that mean I didn’t gain any HP. I’m sure I did but it still sounds like crap.

Look at there design from an Engineering point of view. Flowmaster's design only deflects the sound. There is not much if any restriction. The stock muffler actually restricts the opening and is muffled with fiberglass. How can you justify saying that a Flowmaster won’t give you gains or make you loose hp compared to having a stock muffler.

Keep in mind, the gain from a more free flowing exhaust is in the top end or high rpm range. I don’t have a Flowmaster on this car and it’s probably not the one that would give you the most gain but don’t let you ignorance mislead others.