I need some opinions on the American Thunder Flowmaster exhaust system. Ive taken a long time looking at all the cat back systems and Ive looked at two SS's, an A4 and M6. I drove both and was able to really tell a difference. Also upon deceleration, it sounds like engine breathes better and the re-gurgle doesnt hang up with minimal (if none) backfire. Both systems also opted for the Flowmaster Y pipe. Need some more opinions on this.

 

I had the flowmaster system on my previous car (99 Cobra). I was not impressed with the power gains (if any). I decided to go with Magnaflow on my 02 Z-28. I am very happy with it.

The general feeling on this board (from what I have noticed anyway) is that the flowmaster is not a good choice for performance. It uses chambers to alter the exhaust note. Magnaflow, Borla and most others use a straight thru design which allows for bettter airflow.

If your only concern is the exhaust note, go with flowmaster. If you want a good sound and performance, get something else.

Mark

 

That system sucks on LS1s, just dont get it. Sounds almost stock most of the time for one. I absoutly hate mine. Get the SLP Loud Mouth, Borla, GHHM, or anyother system with a straight through design for the muffler.....

 

Yea, Flowmaster is towards the bottom of my list.
There are a LOT better systems out there. Just look around

 

Infact, all other systems are better.

 

Get a Magnaflow, Hooker, or Dynomouth...

 

Ditto. I noticed a big difference with the Magnaflow and the sound is perfect (not too loud)- and it didn't hurt my dyno numbers either.

 

I was not in it for just the power gains. I love the sound of Flowmaster. I am thinking about taking the muffler out of the system though and replacing it with a 40 series. We'll see.

As far as sounds, my vote is for Flowmaster!

 

The flow master cancels out the bad sounds, and it does sound quiet , but it roars pretty good up high, it's not loud as others, but it sounds nice, and it will give you power gains. If you want straight though flow you might as well just get a cutout, the thing i don't like about the flow master is how low the muffler is mounted with the caback system, i painted mine black to hide it.

 

When i got my car, Flowmaster was already on it. I don't like how quiet it is at idle, however it does sound nice when you get on it. I usually have my cutout open anyway. Flowmaster does outflow stock. Flowmaster may not be the best for performance, but if you think about it, the stock muffler sucks. So if flowmast outflows stock, it will pull more power. Maybe not much, but i'm not complaining. Anyway, next year i'm gonna get a Corsa so, i'm good for now.

 

I have Flowmaster on my car, but the previous owner installed it. If it was stock, I would not of gotten Flowmaster. But anyways, my exhaust sounds great, and nothing like stock, to whoever said that. I heard my friend's stock against mine and mine is much lounder and sounds much better. The system doesn't rattle while driving, pretty reliable. I might want to exchange it soon for Borla or something close to it.

 

One Word Dynomouth...

 

If you absolutely must have the sound, then do it, if you want performance then Flowmaster is not the way to go - unless you put a cutout on there. This has been proven by a good deal of drag cars, gaining .2 when going to almost any muffler BUT a Flowbee.

Or, get a Flowmaster single in/out system and swap the muffler out with something else, if you dont feel like buying the peices seperately for about $90 or so.

 

spintech is awesome sounding and a good performer too.

 

I read an article in Popular Hot Rodding Magazine that showed a before and after Dyno on a 98 Trans Am. The before was stock at 292 hp and the after was an American Thunder Flowmaster System at 305 hp. For as bad as everyone on this message board claims that they flow, I don't see them posting much better gains.

But if I had it to do over again I would probably have got the GMMG Exhaust. I think it has a better muscle car sound with less interior drone.

Good Luck!

Al Kraft