I wanna do a si/do on my '06 5.4 screw. I have have 50 Big Block Flow on '03 H-D screw. Not near loud enough. Looking for agressive around town & not droning out on hwy.. Flows are my choice. Is Super 40 too loud? How about HD 50? Too little back pressure?

 

sounds like you want the 40 delta flow or super 40

 

If he gets the 40's will that decrease horsepower or anything at all. I am in the same thing trying get exhaust for my truck.

 

Get the maganflow, best for HP and sounds great!

 

You are going to lose torque with the Flowmaster. It sounds like an 18" Magnaflow would be perfect for you volume wise. Much deeper smoother sound than Flowmaster. And of course, with Magnaflow you gain rather than lose power.

 

i am getting tired of people making up stuff like this, were are your dyno numbers or track slips that show a loss with flowmaster to magnaflow? have you donr back to back testing with both systems on the same truck same day to get some acurate numbers? i say you lose tourqe with the magnaflow because it is a straight threw design and it aliminates all the bacpresure, with the flowmaster you gain low end tourqe compared to the magnaflow, now prove me wrong

 

bigtruck311, you're quick to defend Flowmaster but I have experience with them on two vehicles (including my current one) before switching to Magnaflow.
I have no dyno numbers but torque is helped by the fluency of exhaust exiting the engine. All those walls and baffles in th Flowmaster only cause turbulence and slow the exhaust's exit from the engine. This results in torque loss, which I experienced on my 1990 F250 w/ 351w (40 Series SI/DO out the back) and my current 2005 F150 (40 Series dumped.) I replaced the Flowmaster with an IMCO muffler (still baffled but less walls and "sound chamber" crap than Flowmaster) and gained slightly from the Flowmaster. Once switching to Magnaflow, my performance off the line is much better. My torque is much improved, and it holds OD on hills that it downshifted on before. The Magnaflow is dumped by the way. I have seen no Flowmaster dyno numbers at any point to prove they do anything to help a vehicle's performance. I am reporting this to explain that I have experience with both and am not a Kool Aid drinker. I am sold on Magnaflow products.

 

i dont want to start a war here, seat of the pants butt dyno is not a good measurement, really when you are talking anything less than 10hp or trourq, but if you get rid of all your packpresure you will lose low end tourq do to exuast scavenging, yes you will gain some on the high end of the rpm scale with less backpressure, if no backpressure really helped that much why not go straight pipes? if you want to lend me your magnaflow i will do the proper testing on a dyno i have the dyno time to do it and i will test any muffler back to back for you and post the results i have been saying this for along time and i have no takers, i have the dyno time

 

As a Ford engineer once said, "Without data, your's is just another opinion."

 

i agree 100% ^^^^^

 

I had a Flowmaster 40 SISO installed on my 2001 F150 4x4. It sounds and runs great!!! Have not bothered with a dyno test but it feels like it has a little more HP & definitely more Torque; mileage improved 1 mpg too. I can't speak for the others but I am very satisfied with the Flowmaster 40. :santa:

 

I went w/Flow 40, SIDO. Exited behind right rear wheel. Love it! No drone @ all. Good tone @ idle & accel..

 

Yall knew I'd get in on this sooner or later. (internet from Mexico costs to much) I agree with big truck. I have run this "debate" into the ground and have shown dyno results from a 99 mustang that showed between a 1-3 HP/TQ difference that varied in which was better in three runs. Wasting the money on a more expensive muffler that does absolutely nothing keeps you from getting other goodies.

 

Here's another possiblity: take it to a performance muffler shop that carries both Flowmaster and Magnaflow mufflers. Have them cut off the OEM exhaust system just BEFORE the Y pipe. Run dual 2.5" pipe into a 2.5" DI/DO muffer (Magnaflow makes one and it has built in X or crossover into the middle of the muffler), then of course run the dual 2.5" muffler exit pipes out to each side. Kick in the *** true dual exhaust! BTW, I prefer Magnaflow 10:1...

 

I have the factory cats and swapped to an "Original 40 series SI/2.5" DO - American Thunder" I have 2.5's back to the corners with 18" long 3.5" outlets with slash cut polished tips at 45 degrees on the corners on my 97' 4.6 and love the sound while on the gas and at idle but that spot at 2K just plain sucks. I had the 50-Delta and didn't think it was loud enough... My local "Custom" exhaust guy said the best route if I wanted to spend the cake would be lose the 4 cats, go with 2 "High Flow" units a crossover/H pipe and run true duals, one original 40, one delta flow 40. This would allow some noise cancellation and not be as deafening inside the truck. He also said I'll never be happy with the sound of the 4.6, It'll never make the sound of a 5.0 or 5.8 with headers and blah, blah, blah... That route on a stock 4.6 seems like a waste unless some how the entire system needed to be replaced anyway.

The current setup is custom bent, fully welded(no clamps) and came with a 2 year unconditional guarantee for $425. The tips need to be washed once a week and scrubbed clean with a fine plastic scrubby pad to keep them looking good (they catch all the spray from the tires where they are mounted).

I have a remote starter and can hear my truck start in a parking lot from 1000' feet away, awesome sound when starting and at idle...