I have an 04 Silverado SS with a Radix (3.0 pulley, 6-7psi) and I currently have JBA Shortie headers going to 3" true duals w/ dual Flowmaster 40's exiting the side.

My question is, if I ditch the 2 Flow-40's for a single Magnaflow 3" Dual in/Dual Out muffler (part 12599) that has the integrated X pipe (Tru-X or some ****) and dump it, do you think I will gain any power considering the Magnaflow is straight thru with the x-pipe, vs. the chambered flowmaster-40s? Keep in mind I have the Radix, so I am thinking the chambered design will not flow as well with FI compared to Magnaflow.

Should I swap em' out, or would I be wasting my money?

Thanks!

 

 

Hey, don't look so sad...

I've been looking at PN 12599 too but all I have is an '02 K2500HD with a NA 6.0L. I'm pretty sure it'll flow better than the stock GM muffler but I'm worried about resonance at cruising speeds.

Why are you considering convering to a single muffler? To save weight? Going for a different sound?

I believe that a straight through design will flow better than a muffler that's chambered. (it may be louder as well) But I guess the question is; Does a single, 3" dual in/dual out unchambered muffler flow better than two 3", single in/single out chambered mufflers?

Too bad Magnaflow's website doesn't state the diameter of the X-chamber within their muffler. (Area of a circle is, radius squared x pi (3.14))

With two, 3" pipes going in, you have about 14 sq. in. of total area. If the largest diameter of the middle of the x-pipe is 4", that works out to about 12.5 sq. in. of area at the narrowest point. If the middle of the x-pipe/chamber is 5" in diameter, the cross-sectional area becomes 19.6 sq. in.

But I don't know what the x-chamber does to exhaust gas velocity. It may be that even if the area of the x-chamber is slightly less than the pipes leading in, it may not act as a restriction if the exhaust speeds up as it passes through.

I suppose it boils down to a question of back-pressure. Which system would have less? An exhaust shop may be able to install a probe upstream of your current mufflers and get a reading. But that won't answer how the Magnaflow 12599 will perform.

Maybe someone on this forum can answer that.

Good luck.

Nick

 

Good info man!

I am just wondering if I should stick to 2 mufflers instead of going to a single DI/DO muffler.. hmm I would hate to spend the $$ for the muffler and install, just to find out it loses power.

 

I tried the di/do magnaflow and i hated it. I would rather lose power if i had to instead of hearing that nasty sounding muffler at 2000 rpm's. I now have true dual pipes with mac flowpaths. It's still loud as ****, but at least it doesn't sound like a 70 camaro with glasspacks. Just my .02

 

I've noticed that there's really no love for Flowmaster around here, but alot of folks really like Magnaflow and Hooker AeroChambers on this site. I'm surprised that alot more guys haven't posted up saying to "do it". There was a thread a while back listing a bunch of different mufflers with their flow numbers...Magnaflow was near the top while Flowmaster was almost dead last. I'd say go for it (going by what I've learned here), but I don't have any hard evidence to give you unfortunately

 

As much as a hate hearing the same trucks with the same flowmasters around town, I'd say just go with whatever you want. If you like how the flow sounds, go for it. It's your truck, not someone elses. If you get tired of the flow and go get a magna or spintech or whatever, all the better. Everyone likes a different sound.

 

Why does everyone hate flowmaster? It does have a good sound. Is it because it doesn't produce as much HP as others? Even if it didn't, it would only be 2 or 3 HP wouldn't it?

 

I'm curious about this too...I've always like the Flowmaster sound. How bad can their flow characteristics be...as you mentioned, would the difference even be noticeable?

 

the only reason I got rid of my flows was of the drone in the cab, I now have the IMCO DI/DO and love it, sounds great and no drone.