6.5 TD Exhaust System

[pgoldstein]

I purchased a 97 K3500 4X4 Crew Cab a few months ago and am very happy with it, with the exception of the exhaust system. I have heard several different opinions about what is wrong with this system. Some people tell me that the down pipe must be replaced and some say that it is fine and to just get rid of the catalytic converter and replace from the down pipe back. I would be very intrested in some feedback on this.

Thank you,

[moondoggie]

Good Day!

If you had the downpipe from your truck laying on the ground, you'd be absolutely convinced that it fell off & was run over several times. It wasn't, that's how they come from the factory.

Look at the various Page advertisers, many offer good solutions to this problem. I have John Kennedy's on my Sub. I love it, with only one exception. I have a decidedly different idea about sound level that almost everyone else on the Page. His muffler allows enough noise to make virtually all who buy it happy, but I really would like it closer to silent, without taking too much away from the performance.

In my experience, the Page advertisers are not just selling stuff, they're enthusiasts. They have to eat, but most of them would probably do this as a hobby anyway.

Blessings!

Brian Johnson, #5044

'82 6.2 1500 4X4 1/2T pickup, 4spd man w/ OD, bone stock, 335K+, "In Rust We Trust"
'89 6.2 4X4 1/2T pickup, bone stock, 145K+
'95 6.5TD 2500 4X4 heavy 3/4T pickup, Gear Vendors Aux. OD, 182K +
'95 6.5TD 1500 4X4 3/4T Suburban, Kennedy exhaust, 200K +

[Big Red Suburban]

Moondoggie,

I am looking at installing Kennedy's 3.5" exhaust on my 95 sub as well. Could you elaborate on the level of noise it creates inside the Suburban? Is it just more noticeable, alittle loud, or can't hold a conversation while driving down the highway? I want to make sure my Wife won't hate me for installing an exhaust kit on the Suburban that increases interior sound levels too much.

Did you remove your Cat as well? Or follow the directions to gut it and install the 3.5" pipe with holes drilled in it? Does this help quiet it down some?

Thanks...

[pgoldstein]

I am also considering Kennedy,s system. I would like to know what kind of power increase I may expect with it on an otherwise stock engine. My truck currently will make about 7 psi boost up to about 2000 rpm under a heavy load but above about 2400 it will only make about 3.5 psi. Could this be caused by excessive exhaust backpressure or is this normal?

[charliepeterson]

7 psi of boost is normal for stock systems. The larger pipes will lower EGT's and might add small boost increases. I've read where it can also add up to 25 HP. These trucks work much better the faster they get rid of the exhaust with no restrictions.

[Dvldog 8793]

Howdy
I have JK's 3.5 pipes, free flow muffler, new down pipe, and ceramic cross over. I can't say for sure on power gains but it was like driving a whole different truck! MPG was about +2. I would get rid of your EGR intake also.
Have fun!
Conley

[pgoldstein]

Thanks for the info. My truck has the "F" engine which I don't thing has an EGR system. If someone knows different I would like to know so I can put it in the same box as the cat.

[moondoggie]

Good Day!

Big Red Suburban: With the windows up, you can still always hear the exhaust. It's not loud, but it's always there. B4 installing this exhaust, I couldn't hear the exhaust, just the normal diesel noise. Now I don't hear the diesel noise, but the exhaust. Lower the right front window, & it gets louder; lower the right rear window, & you can clearly hear not only exhaust noise, but turbo while. I'm probably the only DP member that doesn't really want to listen to this. Am I happy with my purchase? YES.

Remove the cat? Was that the bulge in the pipe? Surely I'd NEVER do such a thing! (Yes, it's gone.)

Power? I have no idea. I had John install it (he needed pic's for his website) because the exhaust was shot when I bought the truck, & exhaust is the 1st mod generally made.

Blessings!

Brian Johnson, #5044

[BuffaloGuy]

I ordered one of JK's exhaust kits yesterday. I already had the new downpipe put on a few months back. It did look like it was run over with a forklift!

I'll let you know how it goes.
Ken

[dslpwr]

THERE IS AT LEAST 2 MEMBERS THAT DONT LIKE NOISE.
I HAVE JOHNS EXHAUST WITH BILL HEATH MUFFER THAT MAKES IT QUIET.
I COULD ALMOST STAND IT UNTIL I PULL A TRAILER.

[triggerman]

For what its worth, I think I got a great deal on a muffler that is just SLIGHTLY louder than stock. the unit OAL is 42" it is 3 1/2" in and out, straight thru with the exception of a single ring baffle in the center which forces most of the flow through 80 scoop holes, then back out 80 holes in the rear and out. I did drill 4 extra holes in the center ring for more straight through flow. The PN is A491985 for $33.49 at Value built tractor parts (1-888-828-3276). It is intended for a Case Turbo Diesel farm tractor. The quality of this muffler is as good as any I'v seen and the tone is perfect. By that I mean the engine is what you hear at steady cruising untill you step in it, Then you know you have something extra! :D

[pgoldstein]

I just purchased Kennedy's 3.5" exhaust system. Where I live in KY. I am required by law to keep my cat. I, along with Big Red Suburban, would sure like to know if John Kennedy's home made cat resanator, that he describes on his web sight, really helps quiet things down. I don't really care what the system sounds like, but my wife will.

[patrick m.]

i have JK's 4inch system, 3inch down pipe, 3.5inch to the muffler, and 4 from muffler out.
i took off my stock down pipe, no cat, 3inch pipe to a 3.5 inch straight thru muffler. the muffler is 9inches in diam, 36inches long, and gap in the middle between the straight thru baffles. then on out with a 3 inch pipe.
the 4 inch sys is louder than the system i took off, but not a whole lot.
JK explains on his website, the 4 inch sys is really not necesary, but sure looks cool :D

The sys did not add any noticeable power, but it sets the stage for further power inhancements ;)
I did get a slight decrease in egt