6.6 Gas - choosing Flowmaster exhaust

tbarn · June 11, 2023

Flowmaster on my truck 5 years and going strong.

KARNUT · June 11, 2023

I can’t imagine flow master being any worse than the others. At least in my use.

Jettech1 · June 11, 2023

On 6/10/2023 at 8:35 AM, Cheekster96 said:

You can probably get away with not cutting it. But I did and was alot easier to remove it around the rear axle.

About 3000 miles on it, still sounds good and I love it!

Say you are towing an 8k lb camper for 1500 miles one way. Would you recommend it considering some mild drone and inside overall cabin noise from the exhaust? Even if there is no drone, would you recommend it just from more exhaust noise while towing?

nards444 · June 16, 2023

just put the MBRP single exit, installer series on. Took about an hour. Ended up cutting it in a place that easily to put back together if needed.

Has a really nice sound. I was expecting a little more volume, but actually happy it wasnt. Has a great tone, and I would say its about a medium sound/volume. Havent hauled, but cruise set at 60-65 there is very little if any drone

Randal Scott · June 20, 2023

The Outlaw and American are stainless steel. The Flowfx is not. I think that's what I read.

They all are 3.5", flange to the muffler. And the duel tailpipes are 3". The Outlaw and American give you the option for the tailpipes to go out behind the wheels or straight out the rear under the bump. I think the American and Flowfx sound close to the same. These were my second choice.

Randal Scott · June 20, 2023

The Outlaw and American are stainless steel. The Flowfx is not. I think that's what I read.

They all are 3.5", flange to the muffler. And the duel tailpipes are 3". The Outlaw and American give you the option for the tailpipes to go out behind the wheels or straight out the rear under the bump. I think the American and Flowfx sound close to the same. These were my second choice.

Randal Scott · June 20, 2023

Sorry, don't know why it posted 3 times.

Edited June 20, 2023 by Randal Scott

Jettech1 · June 20, 2023

On 6/16/2023 at 9:07 AM, nards444 said:

just put the MBRP single exit, installer series on. Took about an hour. Ended up cutting it in a place that easily to put back together if needed.

Has a really nice sound. I was expecting a little more volume, but actually happy it wasnt. Has a great tone, and I would say its about a medium sound/volume. Havent hauled, but cruise set at 60-65 there is very little if any drone

Your comment of very little if any drone still scares me off. I think I'm just going to stick with the garbage can exhaust for now. I love the way it sounds and no drone at all. With our big towing trip this August of around 3k miles round trip, there is no way that I'm going to be kicking my own ass the whole way. Nope. Staying safe for now but I do appreciate your findings here. Thank you very much for that!

Edited June 20, 2023 by Jettech1

Jettech1 · June 20, 2023

13 minutes ago, Randal Scott said:

Sorry, don't know why it posted 3 times.

Not a problem. I'm pretty sure everyone has had that happen to them at some point in time, me too. Technical glitches with your provider can cause that. It's all good...lol...no worries!!

Jettech1 · June 20, 2023

On 6/11/2023 at 12:48 PM, KARNUT said:

I can’t imagine flow master being any worse than the others. At least in my use.

The only experience I had with flowmasters was horrible. Granted we are talking about back in 91 on my 5.0L mustang. I first tried the 2 chamber ones. I couldn't even hear the radio or hear myself think a bit, I do that at times and it always scares me...lol.... Took it back, had them weld on the 3 chamber ones, better...but still lots of drone. Then I had them install Walker mufflers....Those were the key to a great sound, no drone at all. I used to get many compliments of how they sounded. I can't remember the exact name of them, they were Walker high flows maybe???? Anyhow best damn mufflers I've ever had. I had them installed on my 2003 Titan, sounded amazing. I had them installed on my wifes 2003 Lincoln Aviator....Amazing....the Walkers have never let me down. Perhaps.......maybe....I will try them again...maybe....lol...

Randal Scott · June 20, 2023

On 6/3/2023 at 10:32 PM, Jettech1 said:

I think my perfect exhaust would sound exactly like the factory system but getting rid of that huge muffler. Does that exist?

I installed the AFE system. And after adding a resonator muffler, it's better. I like what it has done. Better throttle response and fuel mileage. Still has some drone in the 1500 to 1800 rpm range. Sounds good when pulling the rv. If I had to do it allover again. I would just change the OEM muffler. Walker's Dynomax 17517 and you need a piece of pipe. Walker 43366. I found these on Amazon. There is also

Magnaflow 12909

Flowmaster 953558 and 74151.

These are all 3.5" inlet and outlet.

Jettech1 · June 20, 2023

5 minutes ago, Randal Scott said:

I installed the AFE system. And after adding a resonator muffler, it's better. I like what it has done. Better throttle response and fuel mileage. Still has some drone in the 1500 to 1800 rpm range. Sounds good when pulling the rv. If I had to do it allover again. I would just change the OEM muffler. Walker's Dynomax 17517 and you need a piece of pipe. Walker 43366. I found these on Amazon. There is also

Magnaflow 12909

Flowmaster 953558 and 74151.

These are all 3.5" inlet and outlet.

IF I ever take the chance, it will be with the Walker's......IF I take the chance....I'm waiting for you younger risk takers to answer my question about them....lol...

KARNUT · June 20, 2023

8 hours ago, Jettech1 said:

The only experience I had with flowmasters was horrible. Granted we are talking about back in 91 on my 5.0L mustang. I first tried the 2 chamber ones. I couldn't even hear the radio or hear myself think a bit, I do that at times and it always scares me...lol.... Took it back, had them weld on the 3 chamber ones, better...but still lots of drone. Then I had them install Walker mufflers....Those were the key to a great sound, no drone at all. I used to get many compliments of how they sounded. I can't remember the exact name of them, they were Walker high flows maybe???? Anyhow best damn mufflers I've ever had. I had them installed on my 2003 Titan, sounded amazing. I had them installed on my wifes 2003 Lincoln Aviator....Amazing....the Walkers have never let me down. Perhaps.......maybe....I will try them again...maybe....lol...

I had flow masters on my 94 impala ss last. All my vehicles until I hit 60 had exhaust done by the same bender. Unless the were factory tuned exhaust like my trailblazer ss. Since cross over or equalized exhaust became the preferred exhaust you had drone. The RPM varied. My Impala had drone at 50 in overdrive something awful. It rarely saw 50 so it wasn’t a problem. As far as not lasting I had the impala for 8 years the flow masters never needed to be replaced. It was going to our forever classic until we realized the Acura Intagra type R was going to be worth more so it stayed. If you want loud exhaust without drone? True duals without the cross over unequal exhaust is the answer. My favorite exhaust sound came from my 307 impala fastback. 2inch true duals glass packs. Probably because it had a power glide transmission and wasn’t especially fast. But it sang a song that started low. Slowly reaching perfection at its only shift at 60 mph.

CT Chevy Connoisseur · June 20, 2023

On 3/22/2023 at 1:47 PM, NWSierra said:

There are three kits:

1. Outlaw - Most aggressive https://www.holley.com/products/exhaust/exhaust_systems/flowmaster/flowfx/parts/718111

2. American Thunder - mid aggressive https://www.holley.com/products/exhaust/exhaust_systems/flowmaster/american_thunder/parts/817933

3. FlowFX - least aggressive. https://www.holley.com/products/exhaust/exhaust_systems/flowmaster/outlaw_series/parts/818112

Who has had the FlowFX? Does it drone bad? I know, it's all relative, give me some feedback.

On Friday afternoons after a couple beers I'm more along the lines of, "F-it. I'm getting the Outlaw kit". The 6 other days, I'm thinking FlowFX. I hate my moments indecision.

Went with MBRP and haven't been disappointed. The main selling point of any exhaust I was going to put on was that it had to be 304 stainless. Only going to do it once. Most of the others are regular steel or 409 stainless, both of which will rust here in CT

Randal Scott · June 21, 2023

21 hours ago, Jettech1 said:

IF I ever take the chance, it will be with the Walker's......IF I take the chance....I'm waiting for you younger risk takers to answer my question about them....lol...

I don't know about being a younger one. I turn 64 next week. Somedays I like it's going to be 84. One thing that I have been learning is that the OEM mufflers no matter what make. Are one of the main reasons exhaust Manifolds Warpand break bolts. Causing too much back pressure.