The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - What exhaust to use? Suggestions and pics

llowlife · 10-08-2010, 08:54 AM

Okay I will correct my statement. FM kill HP on Higher HP motors. THEy will flow ok for lower HP motors or lower RPM motors. I am not 100% certain why just that they do. They have a nice sound I will admit that and I haven't experienced every muffler FM makes but I haven't heard of one yet that flows much over 300 cfm. FM will tell you that the numbers means nothing when it comes to CFM so they don't rate them that way. CFM is one standard that I would like to see adopted so you can at least have some apples to apples comparison. Maybe it isn't the best but its a start. Irregarless though. If you can't get the flow out you can't use the HP you are making. FM used sound baffles to control their sound which is an excellent idea, just hasn't been perfected yet.

All opinions are by my own experiences or others I know. I have never tested all the combinations but if you look under my truck you will see Magnaflows even though I do like the FM sound. THey market the sound not the HP numbers. If you do searches I suspect you will see under FM I....love.....the ....sound.... NOT I am making big HP numbers. I am not knocking FM, if you want to run them run them I choose not too and if it starts to be a flame war. (which it is not currently) I will bow out of the subject matter at hand.
Our friend at the top has a 550 hp motor...FM will not net the same HP as Dyno's or Magnas.

Totally agree with exteriorizing the sound system. Now I'll open another can of worms. Run them to the backof the truck at a downward angle slightly tilted in towards the center of the truck

10-08-2010, 08:54 AM	#19
llowlife Registered User Join Date: Jan 2010 Location: Elgin Mn Posts: 112	Re: What exhaust to use? Suggestions and pics Okay I will correct my statement. FM kill HP on Higher HP motors. THEy will flow ok for lower HP motors or lower RPM motors. I am not 100% certain why just that they do. They have a nice sound I will admit that and I haven't experienced every muffler FM makes but I haven't heard of one yet that flows much over 300 cfm. FM will tell you that the numbers means nothing when it comes to CFM so they don't rate them that way. CFM is one standard that I would like to see adopted so you can at least have some apples to apples comparison. Maybe it isn't the best but its a start. Irregarless though. If you can't get the flow out you can't use the HP you are making. FM used sound baffles to control their sound which is an excellent idea, just hasn't been perfected yet. All opinions are by my own experiences or others I know. I have never tested all the combinations but if you look under my truck you will see Magnaflows even though I do like the FM sound. THey market the sound not the HP numbers. If you do searches I suspect you will see under FM I....love.....the ....sound.... NOT I am making big HP numbers. I am not knocking FM, if you want to run them run them I choose not too and if it starts to be a flame war. (which it is not currently) I will bow out of the subject matter at hand. Our friend at the top has a 550 hp motor...FM will not net the same HP as Dyno's or Magnas. Totally agree with exteriorizing the sound system. Now I'll open another can of worms. Run them to the backof the truck at a downward angle slightly tilted in towards the center of the truck __________________ In the beginning of a change, the patriot is a scarce man, brave hated and scorned. When his cause succeeds however, the timid join him , for then it costs nothing to be a patriot. I am a revolutionary...so my son can be a farmer...so his son can be a poet. If there must be trouble, let it be in my day, so my child may have peace... 72 short step w/ 388 /4l80e/ and 3.08 gears. Last edited by llowlife; 10-08-2010 at 09:05 AM.