Duramax Stainless Exhaust Systems

[Tader Jack]

OK . . . Lots of you guys are running aftermarket exhaust systems. Who has the best setup . . . Banks, Magnaflow, Jardine, Kennedy, Professional Exhaust, others? I've looked at more web sites that sell systems the past two weeks. Quite a price spread from about $525 to $895 and even $1200+ for the 5" systems. Seems that most are 409 aluminized stainless, some are better. I'm looking for something that does not give a bothersome drone at highway speeds, but might sound nice when you get on it hard. I also like it to look good where it exits.

Are there any to stay away from?

Jack Schultz, McKean, PA
jackschultz@adelphia.net

http://photos.yahoo.com/bc/jack_schultz2001

2001 Chevy Silverado, 4-WD, 2500HD, Crew Cab, Short Box
LT Trim, Black Onyx w/ Tan Leather
Beltronics 980 Radar Detector • Blinder M-10 Plus Laser Radar Jammer
4 Rockford Fosgate FRC2206 Full Range Speakers • Husky Rubber Floor Mats
Lund Interceptor Wind Deflector • J&J Stainless Steel Tube Grill
Putco Stainless Steel Bed Rails • Access Roll-up Tonneau Cover • Pendaliner SR Bed Liner
DTA Stainless Running Boards and Mud Flaps • VentShades • Pop-Lok Rear Tailgate Lock
Lucerix Remote Control X-Mount Camper Mirrors • Unity Dual Door-mount Halogen Spotlights
Air-Lift Super Duty Ride Control w/ Dual Controller & Onboard Compressor •
Tekonsha Voyager Trailer Brake Controller • Uniden 510XL PRO CB Radio, Wilson Antenna
Kennedy Diesel Headlight Harness with 4 Lamp Mode • PIAA Platinum Super White Headlight Bulbs
Amsoil 2-Stage Air Filter • FPPF Total Power Diesel Fuel Treatment • FPPF 8+ Cetane Improver
Amsoil 15W-40 Synthetic HD Diesel & Marine Engine Oil • Amsoil Series 2000 75W-90 Synthetic Gear Lube (GL-5)
------------------------------------------------

[ 04-08-2002: Message edited by: Tader Jack ]</p>

[mackin]

This is going to be as bad as what brand oil to use, who tics who don't and lopey idle syndrome ..........I cannot wait for the results my self. I've juggling this one myself.


So I got question too.

Which fits the best? The Fit is real important.

I can say no "fiver" for me not worth it. Dose not need that big of an exhale.
MAC
On edit got the new Motor Trend's Trucking Trend Mag Sat.
Didn't look at till now and they got the Bank's Monster @ $659 with 5" chrome? tip. It IS aluminized. Muffler flow at same backpressure is a rate of 285 cfm to theirs at 965 cfm 238% more flow rate......... A little pricey. The muffler is straight through design Venturi inlet, expansion chamber high temp aerospace ceramic packing. What ever the hell all that means.......... lol With freight probably over $700 to me on the east coast........Yipes :D

[ 04-08-2002: Message edited by: mackin ]</p>

[Kennedy]

Unless you like it throaty, stick with 4" exhaust. The 5" with a perforated core muffler is LOUD. Louvered core isn't nearly as loud, but picks up some resonance around 1600rpms (45-50 mph) which isn't bad, but it is there nonetheless. 4" is much more civilized. I think it boils down to the yelling in a culvert thing...

[Tader Jack]

Thanks John.

I'm going to do something with the pipe pretty soon. Just don't know what yet. I heard a Jardine system last week. It was awful loud when my friend hammered his Dodge Cummins. But, he's got twin turbos and it has a strange sound anyway. Kind of reminds me of an Indy car sound, but slightly lower pitch. It was hard to tell how much the twin turbos contributed to all the noise but I suspect quite a bit.

[ 04-08-2002: Message edited by: Tader Jack ]</p>

[RichC]

I have the Kennedy 4" Exhaust. It is louder getting up to speed than the factory exhaust was, however at cruising speed ( 65 to 85) it is not any louder than stock. Response from the turbo is much faster. I had a Banks system on my 95 Suburban with 6.5 It was ok, but never felt much stronger than stock. Go with a good 4" Aluminized system and spend the rest of the money on other goodies for the Dmax. I think any thing above a 4" system is overkill anyway.

[csimo]

I think there's a bigger question here! Other than the stock muffler which most agree is crap, I have seen nothing to indicate the stock exhaust system is a problem at all.

I would love to see backpressure, dyno, etc. numbers that compare the stock pipes (after muffler change) to any of the aftermarket 4 or 5" systems. I'd be willing to bet there's almost no difference.

I have no numbers to back it up, but I don't think the stock system (except the muffler) is a problem. I could be proven wrong, but it would take real numbers to prove it. So far the exhaust guys don't want to release number compared to the stock exhaust, so there must not be much improvement.

[RichC]

I have the Kennedy 4" Exhaust. It is louder getting up to speed than the factory exhaust was, however at cruising speed ( 65 to 85) it is not any louder than stock. Response from the turbo is much faster. I had a Banks system on my 95 Suburban with 6.5 It was ok, but never felt much stronger than stock. Go with a good 4" Aluminized system and spend the rest of the money on other goodies for the Dmax. I think any thing above a 4" system is overkill anyway.

don't know how I posted this twice :confused:

[ 04-08-2002: Message edited by: RichC ]</p>

[Tader Jack]

csimo -

I believe that others have removed the muffler and tried aftermarket straight thru mufflers or eliminated the muffler completely with a straight thru pipe. I believe their results were less than encouraging with the 3" setup. I also remember a while back that someone posted the difference between our oem 3" pipe and 4" pipe. the differences were considerable.

I believe the need for a 4" pipe. I just want to make sure I get a good setup and not just a lot of noise. I had problems in the past with Gibson and want to get a little feedback before I spend.

[csimo]

I don't know about your truck, but I looked at mine today and it has a 3 1/2" pipe all the way back. I don't see any bad bends or anything that looks restrictive, etc.

I'm going to put a FlowMaster muffler on tomorrow and see what difference it makes. I just don't see that the exhaust (other than the muffler) can be a problem.

[Tader Jack]

If you search for previous posts in this forum you will find that others have already done the Flowmaster routine. Some have also eliminated the muffler completely and went the straight pipe route. Make sure you use a muffler designed for diesels and not just a typical "glasspack" type muffler. There is quite a difference. Yes the pipe is 3-1/2" o.d. I believe some still have the instructions they used to replace the muffler / pipe on their web sites. You may want to search for them and see if they are still running that setup. I don't believe that many are, if any.

Their results with the stock pipe were less than encouraging. I also remember some noise problems. I don't want a constant drone at 70 mph on the interstate that some of them give you.

I have to admit that when I first got my Silverado last April I thought about doing exactly the same thing, replacing the muffler. From what I've read so far, even though the muffler is huge, it's not all that restrictive, from what some of the aftermarket exhaust people have told me. The entire 4" system does improve flow and reduces back pressure considerably.

Right now I'm tossing around the differences between three systems. Kennedy's, Banks, and Magnaflow. There are several others out there, but the cost / availability is quite prohibitive. It's hard to find someone who has even isntalled some of these systems to get some feedback.

Is there anyone who can comment on the Magnaflow setup? Noise issues at cruising speeds?

[01_Duramax_Dually]

Hey Mr Dyno Psycho Kennedy.... :D
What's your thought on the 3.5" to 4" exhaust conversion? Is this really more of a muffler thing or is there significant gains to be had with a complete upgrade?

I am convinced that each of them will have a gain, let's say, 20Hp for the muffler and then 50-60hp with an entire exhaust including muffler. So from a stock muffler you could gain 5-7% where as an entire conversion could be as high as 20%. Am I close?

As we all know, these are big air pumps plain and simple. More air in...more air out = More HP...simple as that.

I know you have done the experiments...You are too much of a "I got to know" enthusiast not to have compared... :D

Can you state?

Regards

Jeff

[Tader Jack]

From everyone I've talked to and what I've read so far it sounds like the actual rear wheel hp gains are quite meager with any pipe. Yes, the flow and back pressure is helped, but as far as actual numbers, I seriously doubt you will see 5-10 hp at the rear wheels.

I've learned that these diesels are not like a gasser at all when it comes to pipes. I think that those who claim "big" gains might be smoking a different kind of pipe. Lots of unsubstantiated advertising claims with big hp from some of the aftermarket speed merchants selling exhaust setups. Ask any one of them for dyno sheets, I've done that. See what they tell you.

It does help the turbo spool up quicker and will lower exhaust temps considerably. It is also a necessity for those of us who will want to go further up the performance ladder with a box in the future. Those box gains will then be maximized with help from the pipe and quicker turbo spool-up.

Magnaflow . . . anyone try it yet? It's about the only one I have not received private feedback on.

Jack Schultz, McKean, PA
jackschultz@adelphia.net

http://photos.yahoo.com/bc/jack_schultz2001/rlst

Pipe – Pipe – Pipe – I need a Pipe . . . Whose should it be?

2001 Chevy Silverado, 4-WD, 2500HD, Crew Cab, Short Box
LT Trim, Black Onyx w/ Tan Leather
Beltronics 980 Radar Detector • Blinder M-10 Plus Laser Radar Jammer
4 Rockford Fosgate FRC2206 Full Range Speakers • Husky Rubber Floor Mats
Lund Interceptor Wind Deflector • J&J Stainless Steel Tube Grill
Putco Stainless Steel Bed Rails • Access Roll-up Tonneau Cover • Pendaliner SR Bed Liner
DTA Stainless Running Boards and Mud Flaps • VentShades • Pop-Lok Rear Tailgate Lock
Lucerix Remote Control X-Mount Camper Mirrors • Unity Dual Door-mount Halogen Spotlights
Air-Lift Super Duty Ride Control w/ Dual Controller & Onboard Compressor •
Tekonsha Voyager Trailer Brake Controller • Uniden 510XL PRO CB Radio, Wilson Antenna
Kennedy Diesel Headlight Harness with 4 Lamp Mode • PIAA Platinum Super White Headlight Bulbs
Amsoil 2-Stage Air Filter • FPPF Total Power Diesel Fuel Treatment • FPPF 8+ Cetane Improver
Amsoil 15W-40 Synthetic HD Diesel & Marine Engine Oil • Amsoil Series 2000 75W-90 Synthetic Gear Lube (GL-5)
------------------------------------------------

[ 04-10-2002: Message edited by: Tader Jack ]</p>

[Kennedy]

Im not sure if the old post still exists, but Dmaxer (Rick from Elgin Il) came in with a 3.5" straight pipe, and left with a muffled 4" system. He sent me the mpeg on my site. His reports were that the noise went away, and the power improved. Not completely scientific, but his nephew has a PSD with Hypermax chip and 5" exhaust. Before (3.5" straight) the PSd would best him by about 2 lengths in a race. After, he can now best the PSD by a similar margin. Rick's truck is essentially stock except IIRC a K&N :rolleyes: filter.

Will you find this on a dyno? I doubt it. I haven't. It is just one of those deals where improved turbo response, increased airflow, less back pressure, cooler EGTs combine to make a SLIGHT difference through the entire RPM range...

5 inch is just more boisterous IMHO. Come to RIII in May and Ill show you! :D

[Tader Jack]

Just got an e-mail from MagnaFlow. Seems that they have not yet shipped a system for my dmax yet. They are about 2-weeks away. That tells me they will not see my $$$ either. I'm not going to be a test case. No thank you.

[ 04-11-2002: Message edited by: Tader Jack ]</p>

[Silver Bullet]

Tader Jack,
Another system I was looking at was Rip Rook's
(http://membersites.nwbombers.com/riprook). I exchanged e-mails with him and found out this system comes in many sections...I think it was 2 more than Kennedy's (for crew cab). I see this is as more places to have exhaust leaks which is something I am considering in my search. Magnaflow and Banks are big bucks!!! I think for the money I am going with Kennedy's when I am ready to move on it.

[ 04-11-2002: Message edited by: Silver Bullet ]</p>

[Tader Jack]

Well . . . I'm not sure of what to do. the Magnaflow or Banks is $700 + freight. In my personal opinion I think the exit of each looks better than JK's. If he would chnage that, I'd like it. His exit angle looks greater and there is no polished tip either. It doesn't mean a damn for performance, but you know the deal . . . it has to look good too and will be on the truck for quite a while.

So, I'm still trying to decide. I may decide to start looking at all of them again. Even Gibson called and left a message for me while I was out today. So, I don't know . . .

[ 04-14-2002: Message edited by: Tader Jack ]</p>