I know this has been talked about a lot but Im hoping you guys can help me out in my situtation. OK, right now I have a Flowmaster Super 40 SI/DO setup. It sounds pretty good and all but I seriously think I lost ALOT of low end torque...even with my mods I can just barely squeek the tires when I stomp on it. Heres my question...should I buy a Magnaflow SI/DO mufler and swap it out? Do you think this will help me in anyway? Also, I dont know much about Magnaflow but which muffler will give me the loudest and most aggressive sound while giving me the most gains?

Thanks for any help...

 

I'm in the same boat you are. With just the AEM intake and Spintech 3" exhaust I could spin the tires at a dead stop no problem. With the addition of the Edge Evo, 285s, and changing out the exhaust to the IMCO Extreme (Flowmaster 10 series clone) I get NOTHING at all when the pedal is hammered. Sure the tires are a little larger than the factory 265s, but with my mods getting the tires to spin some at a dead stop shouldn't be an issue. I already purchased the new Magnaflow muffler but will just have to wait to have it installed this next weekend.

As far as the loudest Magnaflow, I'm sure it would be one of the 14" long round bodied version. I went complete opposite from the IMCO and purchased the 5x8 oval 18" long model to significantly reduce the interior noise especially when pulling the trailer.

 

Let me know if you gain low end torque back...Im seriously considering this and I dont think it would cost to much to just swap them. Anyone else?

 

I wouldn't expect the change to be that extreme as in Adam's situation but damn, I guess it is!

I don't think I could spin the tires of my 06 SCREW 4.6L if I was on oil.
3.55 on 20's (from factory 17s) S&B intake, Magna catback.

 

Hmmm....even if the magnaflow muffler flows a bit better than the flowmaster and will maybe give you a couple more horsepower, I can't see it being that much of a night and day difference on a heavy truck....with only possibly a few extra horses. I'm gonna eventually do true duals with no mufflers and see if there is a power difference from my 40 series to that.

The other thing I can't understand is why alot of people say you need a muffler for backpressure....when some of those magnaflow mufflers have such a straight through design that its like running a straight pipe only it quites it down alot. So instead of wasting money on mufflers I'm just gonna have true duals with an X Pipe and no mufflers.....and maybe 2 1/4 pipe to help keep some torque.

 

Let me know how that goes!

Well anyways...I talked to 2 different muffler shops around my area and they dont see why I want to change. They both sell Magnaflow and flowmaster and they say don't do it...I wont see a change and they talked very highly of flowmaster saying they could even be better?? So for now I guess I will stay...Maybe in the future Ill throw some headers on and maybe go true duals with an X pipe....

 

I had the same prob.I put true duels with flows and it wouldn't break the tires loose anymore.I switched to maggies and it spins em fairly easy now.
I think the flows switch the power band alot higher in the rpm range is what i found.The flows pull good up top but you need to get the rpm's up.
The maggies pull great down low where you need it as soon as you hit the gas.Pics of what i did in gallery

 

I think your dead on with that assumption...I got a real good top end but my bottum is end is lacking a little.

Kevin...I like ur exhaust setup...so do you think it would be worth it to go Magnaflow true duals w/ an X? Thing that sucks is that I paid like $450 for my setup about a year ago...idk what to do Might just have to keep it this way for a while. I mean dont get me wrong the thing does still have some low end...if the road is just a tad slick with rain I could do donnies all day but Im thinking a could have more....

 

Ya i noticed the same as you,could only spin em good when the roads are wet with flows.Once the rpm's get up to about 3500+ pulled extremely hard but until then it really does not go well.I saw your vid awhile back with your truck and it's identical to how mine used to run with exhaust and edge.My truck actually pulled better with stock exhaust down low then it did with flows.Stock exhaust sucked up top compared to the flows though.It was enough dif over stock when i did the flows that i had actually thought something was wrong with my truck when i first took off.

Thanks, still need to put my x-pipe in then weld it up,that's why the clamps are on there.I have true duels w/o x-pipe now and love it.I relly need to put the x on to balance it out better.A ton more low end and great top end with maggies.Pulls great for what it is all the way to red line.I was in the same situation as you had new exhaust for a year but didn't like it so i switched.What you could do is just swap mufflers for now until you do what ya want.That would be an easy swap for $100 tops for the muffler you need.Or just leve it until you have enough $$$.If i was in your shoes i would just do a muffler swap.
Kevin

 

24# injectors anda custom tune will cure that right away

 

Ok...now this swapping mufflers thing has got me thinking. Im also looking into borla. Do you really think just swapping si/do mufflers will give me gains? Also, does anyone have a si/do borla exhaust...if so how do you like it?

 

Well the flows took it away pretty easily I guess another brand could atleast give you back what low end you had. Im in the same boat, the flows killed my low end, im lookin at the magnaflow dual side exit infront of the rear wheel, basicly lightning style cat back.

 

The maggie is going on Thursday...Ill let ya'll know how I like it

 

Cool...I'm interesting in knowing the difference seeing as your leaving everything else (pipes and tips) the same and just swapping out the muffler. I've always wanted to know from someone if they could feel a noticeable difference. Also let us know how you like the sound compared to the flows.

I've thought about it for a while and im keeping my 40 series for now until I get some more cash...then im going true dual straight pipes with 2 1/4 pipe, X-Pipe, and tips out the side lightning style. I know a good shop in my area and it shouldn't be too much considering no muffler cost. Just tips and piping.

 

Ill definately let you guys know how I feel about them once I get them on. Ill also take a video clip and I can post up my other video of my flowmasters and compare. I just really hope I see more low end after this.