exhaust for a 2004 2500HD

smokinspartan · March 20, 2004

im looking just to replace the muffler. i want a nice aggresive sound, what flowmaster should i get? what size will weld right in place with the stock pipes. i want it all to look stock, just swap out the muffler. i got a 04 2500HD 6.0litre.

LikeaRock14 · March 20, 2004

Here's where I come in

A 70 series will be almost identicle to stock size, a little narrower and a little bit shorter i'd have to say. It would give out a nice, sweet low mellow tone, hopefully no resonance. Everyone says a 6.0 resonates really bad, but I have't heard one resonate yet. I looked at my friends truck, it's a 70 series (though he said 50 seeries), and it sounds good. A nice, deep mellow sound when he;s crusing, a more mellow tone under accleration, and he has minimal interior sound he says. I have 70's on my 454, I love it. The only con I have about it is that I wish I did dual out the first time I had it done lol

Go ahead with the 70 series, I would if I were you. It's perfect foe waht you're looking for

Silver Bullet · March 20, 2004

The direct replacement for the 6.0 in our truck is the Flomaster 530513. I have not heard it in person, but they have a sound clip on their webiste www.flowmastermufflers.com. It is under the 70series big block II section. I called flowmaster and ask their opinion of the interior resonance, and they told me it was bad. The guy suggested waiting on the new muffler they will be making for the 6.0. He said that the 6.0 is a very loud motor, louder than the 8.1. He also said that the interior resonance on that muffler on the 6.0 would be worse than original 40 series on a strong small block with no cats. So that might be a little much to listen to on a long trip with the windows up and trying to talk to some one in the truck with you.

I also called magnaflow and asked what they suggested. The tech suggested leaving it stock. He said that their mufflers can not quiet the resonance down.

The worse resonance is from 2000 rpms and down also. So you don't have to have it floored to get the bad vibes.

So do some research on this forum and see other opinions before you spend the dough. I am hesitant to spend money on an exhaust that you are basically taking a chance on.

LikeaRock14 · March 20, 2004

Everyone says they have problems with resonance on the 6.0's with any motor. I have VERY minimal interior sound with the 70 series.

Basically the direct fit for the 6.0 is a 70 series anyways. I have yetr to hear a 6.0 drone inside, but all the one's I've heard have 70 series too.

d2bnorman · March 20, 2004

Silver Bullet is right on with his anaylisis. Hopefully the new Flowmaster will address this problem.

Silver Bullet · March 20, 2004

I think the 70 series are sweet sounding mufflers. Its hard to believe that a muffler meant to kill all resonance still resonates on the 6.0 Trucks, but that is what I keep hearing. I wish I could get in one and take a ride to find out. Everyone's opinion on loud and how much is too much is different. I don't know if the SUVs with the 6.0 are having the same problems.

I had a 40 series delta flow on my '02 Ext-Cab with the 5.3, and when first installed the guy talked me into a 18" glass pack resonator in front of it. He said that the 5.3 resonated really bad. Well it was way too quite for me, so I got it cut off. With no resonator it was still not that loud to me, and I had it dumped over the rear axle.

So the suggested muffler might not be that bad to me, I am just hesitant to pay $200 + to find out. I know the stock muffler has a small low resonance when just creeping around, so the 6.0 has got a little more going on than my 5.3 did.

RC ALLOYS INC · March 22, 2004

I'd wait and see what FlowMaster does for the resonating troubles with the 6 liter trucks. I can tell you first hand, it is true. I dropped $700 + on a full stainless cat back set up. Once installed and I hit the road for the first time with it I about lost my lunch. Horrible resonance and drone in the cab, not what I wanted in a $35,000 truck. Two days later I cut the new system off and fitted the stock pieces back on the truck. Money well spent eh? Dunno, could have just been my experience but I'd do some major research before doing any type of exhaust upgrades. Just my two cents :-) Good luck.

apache sierra · March 22, 2004

I went with the magna flow cat back with the single 4" out and don't have any resonance. The guys that installed it said that the single outlet reduces that pitch, and it seems to. Everyone that has heard this 4" outlet say that its the best they have heard because of the deep sound and not too loud(until you stomp on it). I have talked to several who say the duals for some reason sets up that harmonic pitch that is especially bad on 6.0's so for a lot of guys they have gone to the single and not noticed any loss in performance.

Machine · March 22, 2004

I too put a high $ catback on my 6.0 and it resonated at 2000 - 2300 RPM - right where you hit 68 mph - 80 mph. Drove me nuts. I had to calm it down by removing the Borla muffler and installing the biggest free flowing muffler Magnaflow makes...it's working great. It now has a small drone at 3100 RPM but I'm never really in that range for long.

Silver Bullet · March 23, 2004

apache,

Do you have the 6.0? Is that 4" catback made for the 6.0 or did you have it made at local shop? Thanks.

solariz007 · March 23, 2004

hey there fellas new to the board. i just wantedt o ask that i too have just bought a04' 2500hd wth 6.0l and wantedt o know that it seems that right before my muffler there seems to be a type of canister with a 2 sides into my muffler then a 2 piece also coming out of my muffler i was wonder i wanted to buy a 40 series old school muffler adn was wondering since stock size is 3" should i keep stock 2 inlet to 2 outlet on it or switch to only 1 3" inlet to 1 3" oullet for keeping stock torque i pull alot of quads adn stuff not looking for alot of performace but low end pulling no drag truck here fellas adn i might add the the type of canister dones seem to have a O2 senser on it just wonder what that poses with just buying 40series muffler thnx in advance for the help and good luck to all and takr easy

thnk

solar

04' 2500HD 6.0L W/T

apache sierra · March 23, 2004

apache,

Do you have the 6.0? Is that 4" catback made for the 6.0 or did you have it made at local shop? Thanks.

hey silver bullet; yea its on a 6.0 when i bought it it was a dual in single out with a 3.5 outlet and 4" tip. But when it came in it had the 4" outlet and tip. It sounds a lot deeper than the 3.5" They said it was a upgrade for the 6.0.

mmayo · April 26, 2004

Anyone know if flowmaster has the new muffler out yet for the 6.0L???

AUTOGUY · April 26, 2004

Why is everyone so hung up on Flowmaster? There are other companies that make exhaust systems out there.

I had Flowmasters on my 89 Mustang GT and had the Drone...it was expected and not really a problem on that car. I also have Flowmasters on my 72 Malibu and they are very loud and obnoxious...but thats the way I like that car.....

I have a Magnaflow on my 2003 Silverado SS with the 6.0 and there is a drone at 2000 RPM. I just keep the truck in 3rd gear aroung town and this seems to help. Again, this is a fair weather performance vehicle so a little noise is acceptable.

As far as a daily driver, I had a 2000 Silverado EC 2500 with the 6.0 and I had a Gibson system on that and there was very little drone if any. I also had it on my 2002 Sierra 2500HD CC with the 8.1 and it sounded good, performed good and was not annoying at all.

If I were and of you guys...I would stay away from the Flowmasters on any daily driver and save them for a weekend performance vehicle.

Seriously look at Gibson. I do not work for them, just a very happy user of the product.

After the experience with Flowmaster and Magnaflow, I would not consider putting either one on a truck I drive daily. I would stick with the Gibson.

Just my Opinion.

mmayo · April 26, 2004

I'm not hung up on any brand.....I've always kept my stock exhaust, never wanted to be any louder - hard to sneak up on deer/hogs/whatever I want to shoot , with a loud exhaust.....but sometimes I wish it was a little more throatier (sp?), which leads to me my next question. My inlaws recently bought an H2 which has the same engine as my truck, but the exhaust sounds better IMO than my truck. Do these trucks use the same mufflers? or is this just a result of a shorter pipe/muffler setup???