i had flowmaster on my 00 z28 and it sounded good,but i just replaced it with the lm1 catback and it sounds awesome....im doing hooker headers and ory this weekend ....cant wait

 

Here's a quick sound clip of mine, it was early, no big revs, and that guy who posted the Camaro FM, lol, you shouldn't red line your car like that :p

http://www.youtube.com/watch?v=AW_9E9o4CYE

 

my only complaint about the 80 series i've got is that it is now 6 years old and falling apart and it's raspy as **** 2-3k (manifolds ory and stock catback) and getting louder. it is quite loud, i couldn't imagine it with long tubes and an ory. i think it would be obnoxious at that point. it is very loud in the car. i had a long tube 3" true dual (with x and 4x9 magnaflows) that was not near as loud in car. outisde...well, that td setup screamed at wot. i think the fm muffler i've got would be comparable in noise if this car had headers on it.

edit: as far as power goes...i don't think it's costing much if anything on cars that trap <115. at one point this car had a lid and muffler only, it trapped 88 in the 1/8. i really don't think putting the stock muffler or a different one (of any brand) would've increased that.

 

If anything, it's better than the stock muffler

 

My cousin had a flowmaster something on his ls1 and it sounded decent. I don't know if it was the catback or a 80-series welded in or what? Not powerful sounding enough for my liking.

IF I just loved the sound of the flowmaster on a LS1 I would get one. I would also have a cutout in the I-pipe though. At least when dealing with the 80-series.

Don't rain on the OP's parade. I wanted a 4th-generation Trans Am for over 10years. I finally got one when I hit 25 years old. I've got friends who love my car and some that say **** like "you live in Arkansas you need a truck". Or I can outrun you in the woods in my rusted **** truck. Freakin pisses me off. IDK.. its good to see people get exclamation point excited about an American V8. Good ole pushrod/single cam technology. Its just relaxing to say. I am so sick of seeing these Jap **** cars everywhere with bumblebee pipes on them primered all up with dents and stickers and then the "under construction" **** on the back glass.

OP- enjoy your car and whatever muffler you choose! Also, use this website it is a massive archive of information.

 

This is from JRP's sticky at the top of this section.

https://ls1tech.com/forums/generatio...e-posting.html

I highlighted the part discussing flowmaster.



A. Catbacks

What they are: Bassani Borla Corsa Hooker Magnaflow Random Tech Loud Mouth LM w/ quad tip center mount SLP Dual/Dual GMMG Mufflex


What they do: increase exhaust flow and alter sound


What to look for: depends on what kind of look and sound your going for. The premier ls1 sounds site here. Spend alot of time listening to the setups and hear as many setups in person as you can. Exhaust is subjective, so get what you like best in terms of sound since its you who are going to be driving the car around.

- Straight through setups like LM and magnaflow (pt# 14267 for just the muffler) are regarded as some of the top flowing catbacks. Flowmaster is one of the worst flowing catbacks for the LS1, it does sound good in its defense. Hooker, Magnaflow, SLP D/D are all great budget cat backs; Corsa, Borla, and GMMG round out the top of the premium spectrum.

- Loudmouth: LM is a love/hate exhaust, it sounds great on stock manifolds with few bolts on's. When you start adding LT's and ORY's it shows its ugly side. LM + ORY + LT = rasp and drone. Try and listen to various LM setups in person to know what your getting into. Time after time people get LM and end up swapping it out since they get tired of its annoyances. To reduce the rasp and drone you have a few options; install some cats, replace the resonator with a real muffler, or install a 12-18" dynomax bullet. This setup is referred to Dynomouth; Borlamouth is of the same concept but with Borla xr-1 mufflers.




Here is a link to pro stock johns thread where it shows flowmaster cmf consideribly less then hooker, magnaflow and borla.

https://ls1tech.com/forums/generatio...-mufflers.html



In this hp comarison flowmaster was number 15 out of 17.

https://ls1tech.com/forums/generatio...al-street.html



The 80 series has had a bad rap for years. If you do a search there is thread after thread of negative feedback. The general concensus is that the flowmaster 80 series sounds good but flows bad. Even the stickys back that up.

It'll still flow better then a stock muffler and sound really nice. So it's not all bad. Just not the best flowing muffler on the ls1 market.

 

They do tend to fall apart inside after a few years and then are super loud and sound terrible. Happened to a friend. He cut the muffler out and replaced it with a Magnaflow. Picked up some hp and couldn't be happier.

Darrensls1 sums it up pretty well for the OP though:

 

My god the guy in the first video is bouncing off the limiter

 

There has been plenty of threads showing gains of 15-20 rwhp with a cutout over flowmasters. Heres one from just a few days ago, i'm not sure what series flowmaster he's running but he picked up 21rwhp with the cutouts over the chokemaster.
https://ls1tech.com/forums/dynamomet...ideo-pics.html

 

i have read the sticky and flow/hp comparisons before. but on a stock car how much are you really losing 2-3hp? i could take a nice dump and the weight reduction would make up for that amount on the track. and remember these huge gains we are seeing are flowmaster vs cutout for the most part.

to me its like comparing 2 1/2 inch duals to 3 inch duals. there is less difference at lower hp numbers. a car pushing 450hp might show larger gains by switching.

in a 500hp car you would i be an idiot to think the flowmaster wasn't holding me back 20hp+. but in a 500hp car i would hope you have a cutout anyways.

to the OP: if you end up liking the sound of the flowmaster like many have, then enjoy it, and if you ever feel like it is robbing you of power just throw a cutout in there. i know i dont need all my ponies on my drive to work.

but to the people showing links i appreciate it. i have already read many of them but still thanks for going to the trouble and making this thread more informative instead of just a bashing.

FYI my setup is very soon to be 1 7/8 headers > flowmaster or vibrant 4" merge > 4" e-cutout > 4"to3" reducer > flowmaster catback.

 

There was a test done years ago by a magazine. It was open headers, flowmaster, and magnaflow, these weren't crossflow mufflers. Flowmaster was last just don't remember by how much. That's why I went with the magnaflow when I bought my Mufflex. I did have a flowmaster on a truck and it didn't last long.

 

If you look at the internals of a flowmaster and imagine water running threw it. You would know that they don't flow that well compared to straight through designs.

 

Not all mufflers are straight through, so that means flowmaster is not at the back of the pack. Plus, they have addressed this with the DeltaFlow versions of the mufflers.