i'm looking around trying to come up with a pretty good ehaust system to replace the double CAT infected one on mine thats about as loud as a public library. Mr original plan is:

NO CAT, 3" crossover, 4" downpipe to bed, then 5" custom stacks off an old semi. Essentially open headers.

So what say you? Will it be loud? I've seen a few vids. with people running 6.5L TD's with a smiliar design, just smaller crossover and downpipes. I'm looking for pics and videos and ideas for this.

Good luck with 4" downpipe. Do some searching and you'll see why.

i'm looking around trying to come up with a pretty good ehaust system to replace the double CAT infected one on mine thats about as loud as a public library. Mr original plan is:

NO CAT, 3" crossover, 4" downpipe to bed, then 5" custom stacks off an old semi. Essentially open headers.

So what say you? Will it be loud? I've seen a few vids. with people running 6.5L TD's with a smiliar design, just smaller crossover and downpipes. I'm looking for pics and videos and ideas for this.

I don't think you can fit a 3" crossover or a 4" downpipe on these trucks.

SS Diesel Supply says "This kit contains, a 3" downpipe (largest OD that will fit)" and "Mandrel bent 2 piece 2.25" (stock is 2.0") crossover pipe This pipe only handles the exhaust of 4 cylinders and is not restrictive in any way. There is no hp or flow benefit to using a larger crossover then this beautiful mandrel bent piece. Also included is a 2.25" clamp.

Oh, and are you going to cut holes in the nice topper for the stacks to go through? :)

A 3in crossover won't work ether. The biggest that will fit is 2 1/4. The ports on the exhaust manifolds are 2 1/4. A 3in. downpipe is the biggest that can fit betweed the engine and frame. Take a look how tight the factory pos downpipe is. I believe it is 2 3/4 before they smashed it to bend it.Going bigger than 3in downpipe and 2 1/4 crossover isn't going to make any more power or noise. If you want loud buy a gasser and straight pipe that.

my crossover is a 2.5" crossover from warpspeed if i remember correctly. The biggest downpipe is a 3" unless you do custom fabricating like 67c30. my truck's got the fully upgraded exhaust(downpipe and crossover) into a custom exhaust(3 to 4 inch adapter, to 4 inch flex to the single exhaust stack). my truck is straight piped and its got a good roar to it, but its nothing to make your ears bleed. if you want that you'd have to straight pipe a gasser. :D:eek:


http://www.youtube.com/watch?v=QYf2lGTwnsA

http://www.youtube.com/watch?v=T4WuG_4JuoM

Hey Dave, I couldn't tell but did that honda accord have a stack too?? :D

Nice sounding stack.

I kept waiting for some kid to steal yer camera after you drove off.. heh heh

loving what im hearing. I'm not looking for those obnoxious teenager exhause pipes that make your ears bleed when they accelerate, and are so big that you could fit you foot in it. I just wanted a very rich, and deep done without the high decibles.

And with what im seeing and hearing from a few videos i found and the 2 hear. Thats about perfect. It sounds incredible. No way am i every going back to a gasser. Love my diesel WAY to much. Ask the lady. hahaha

So a 2 1/4" crossover with a 3" downpipe. I'm def. sticking with no cat. So i guess next question would be who recomends what? i've heard alot of good with the mandrel bent pipes compared to the double wall origninals when they bend and destroy the inner wall. Warpspeed and SS diesel supply seem to be the top ones.

Oh, and are you going to cut holes in the nice topper for the stacks to go through? :)
-Actually yes i was. I'm thinking whether or not to go through with it. I think it would look sick, but im not quite sure. If i don't do that im going to go to the end of the cab before the bed, then use a 45 to angle the ehaust down and cut it there.

Also, does the sweet sounding whistle from the turbo come as an added bonus with this? cause the video's i have seen/heard have all madesuch a beautiful whistling noise. My turbo can be heard, but barely.

Also, does the sweet sounding whistle from the turbo come as an added bonus with this? cause the video's i have seen/heard have all madesuch a beautiful whistling noise. My turbo can be heard, but barely.

Depends on the condition of your turbo, exhaust/muffler and your air intake/air filter.

Opening up the exhaust will give you a lot of exhaust howl from the turbine, and opening up the intake and throwing on a free flowing filter and blocking the turbo intake muffler will help with compressor whine.

You have a 98, so you should have a GM-8 factory, they get pretty vocal when you open things up, that has a few meanings ;)

here are my stacks, i made a "smoke box" to reach accross the bed, much cheaper to build then to buy...there noticably louder in the cab but i like it, it reminds me of a baby semi

i think most guys here will agree, the whistle on these trucks come with a diffrent wastegate, mine is a homeade job made out of ready rod, a spring, a few washers and a lock nut....search around the FAQ thread i belive you will find alot of info. (get rid of the vaccum wastegate, you'll love the truck even more)

as for the topper, let me know how that works, i was thinking of doing the same thing when i head off the diesel school(i'll have to take the headache rach off of coarse) i figured a guy would have to put some type of plate around the stack to protect the fiberglass in the topper?

http://c1.ac-images.myspacecdn.com/images02/34/l_b8679107e32249ca93992593220e6b78.jpg

http://c1.ac-images.myspacecdn.com/images02/2/l_55588a52ad214145adca39125e37b854.jpg

Scott

Check out the Jardine Straight thru system, Great fit, Great sound, even better price!!
Also go to Here: http://www.kennedydiesel.com/ and look up the 6.5 tech tips,, in the air mod section, it will show you how to open up the factory air box,, and remove the snorkel in the inner fender. Open up the air in/ air out,, will increase that lovely turbo sound.

I am still running the stock cross over, with a 3 in ss diesel down pipe and a 3 in straight pipe. I really like the sound, but I'm still a punk. The ss intake makes it so you can really hear the turbo. not a true cold air though :(
pretty loud at any rpm

thats awesome, thanks for the help. the tips from kennedy where great too, gonna try them out tomorrow at first light. now the wastegate vacum. is that the tuna can that is conected to the intake jsut before the tubo? how does that work, what does taking that out or disabling it do?

nope, thats the CDR, leave that alone for now... the vacuum pump is needed for now, until you get a reflash. it is located far down on the pass. side of the front of the motor, underneath your alternator.

alright thanks. I'm not going to mess with that. Intake muffler maybe? where is that. cause if there is something blocking my turbo from whistling its def. coming off. Now that there is light outside im taking a bunch of the tips from kennedy and putting them to use.

Stacks through the canopy wise im stilling pulling together ideas. Essentially yes i would need a ring or protector of somesort to not only protect the fiberglass from the hat of the exhaust, but also to keep rain out of my bed. I'm going to take a picture of the truck looking at it straight on, then photoshop in different idea's for stacks and see how it comes out. post them here and maybe add a pole to it to find out who likes what the best. bull horns are what stick out best in my mind right now.

If you have a "homebrew" ram air intake, it's unlikly you still have the turbo silencer, it is located right in front of the turbo and is a thin tube of black plastic about 14(i think?) inches long and runs over to the top of your alternator. It is attached to the intake tubing.

ah so that thing is useless. Go figure, actually no its still there. The actual intake from the airbox to the turbo inlet is still stock. But i ran a 2 inch pipe from the airbox to below the bumper line. Essential a very crude, but effective Ram Air intake.

Time to go rip that piece of junk out. stupid silencer

dropped the Cat converter and Muffler. end result? open headers. nothin after the downpipe. The most incredible sound i have ever heard. like, bystander pissing there pants jawdropped while staring is it goes by incredible. I'm going to post a video for the sound tomorrow.

I just saw a dual stack kit that heartrob exhaust makes . You might want to check out their web site. I have 2 of their exhaust systems. Good quality so far.

Can anybody tell me the first year Chevy put Catalytic Converters in the diesel pickup?

I think is was 94 with the fly by wire system. but i could be wrong, it has happened before. :rolleyes:

dropped the Cat converter and Muffler. end result?
I wonder if the end result isn't new exhaust valves and seats? I know Harley's don't like a wide open exhaust for very long (been there - over & over :D) but do diesels have the same problem?
Scoot now has a muffler - sorta ;)

I wonder if the end result isn't new exhaust valves and seats? I know Harley's don't like a wide open exhaust for very long (been there - over & over :D) but do diesels have the same problem?
Scoot now has a muffler - sorta ;)


the turbo provides all the backpressure the engine needs. after the turbo you want the exhaust as wide open as possible.

Amazing how a turbocharger throws a wrench into everything we know about engines eh? :D

The less restriction after the turbo, the faster it'll spool up, better it'll flow... And no burnt valves ;)

My 95 2500ld HAD one. Not shure if the 94 does or not ,havent been under it yet.

my 94 had a cat

neither my dads 99 are my 93 has cats on them. I think it depended on where you were in the country and what size vehicle you got like 1500 vs 2500 or 3500.

Mine has a cat on it, 94 im pretty sure is the first year of the cat, and mine is going to "accidentally" get cut off after this next paycheck comes. If i was to say purposely my gf would kill me. I want to buy some pipe and make my own "inserts" of where the cat and muffler would be and keep my tail pipe. I dont know how im going to do it because you need to bend the pipe to get over the tranny cross member. Has anyone done this? and if so give me some tips on fitting it together... thanks

If I can chime in on exhaust as this is a subject I love. My 99 burb has a 3" down pipe and the SS Diesel Stainless cross over. I had a 2.5" cross over and see no difference with the SS diesel piece. The stainless steel makes all the difference to me for longevity.

After the down pipe I stepped it up to 3.5" and fabbed my own mandrel exhaust out to a 5" stainless tip and used a FlowMaster RV Big Block muffler in the stock location. The exhaust sounds great. I can hear the Turbo spool under acceleration and then the awesome spool down whistle when I come off the throttle.

If I can share my 2 cents:
I would make life simple and run the exhaust in the stock fashion, maybe even shorten it to exit in front of the right rear wheel. But I would caution regarding stacks through your fiberglass cap. First off, what keeps your cargo from melting against the pipes?

Do you have an EGT gauge? Its amazing how quickly temps get up into the danger zone just with normal acceleration.
Plan on installing Water/ Methanol injection. Awesome.

nope. no egt or boost gauge. I'm def going for an EGT, 0-15psi boost gauge and tranny temp gauge soon. one more thing to show off in that truck. glad to know im not breaking anything with the exhaust so open. ha i think short of a bigger crossover and downpipe its about as open as it gets.

I'm not sure about the stacks and canopy. i want to but not. i can always build a smoke box of sorts to protect the cargo should it come in contact with the hot pipes. but the stacks will wait should i actually go with them. exhaust after the front wheels maybe not. prolly farther back. maybe towards the end of the cab. eh, i'll see what comes up and roles along.

Hey Scott, I know, I know, OT, but who makes that brushguard? It looks sweet. Kevin