to see how I could improve my exhaust system 'on a low budget', the first shop wanted about $300 to do a 3.5" duramax with 'glass pack' straight through muffler,... not a deal as we know a 4" sys is only $325 on the auction site... so the next shop says... buy the muffler $150 3.5" or $80 3" and I'll throw in the take off mandrel bent pipes... so what I'd like opinions on,...is... staying 3" to the muffler and 3.5" on out(he's good to go on that)... I know I'll probably upgrade to 3.5" later but having just gotten the '99 burb about christmas there's other priorities in the works and IMHO this thing needs to breathe...

I paid $110 for my 3 inch straight pipe. I dont think it is very loud. But then again I'm just a 20 y/o. But I think i'll go to a 4 inch this summer if I get the time. I'd go 3 inch unless you plan on going all out with mods.

I agree with Z-man on the 3" straight pipe and i'm 48 yr old. :D Mine is 3" straight through until a little before the rear axle, then i have it split into 2 2 1/4" pipes out behind the rear tires. Nice rumble.. :cool:
Don

4" from the downpipe back....... not to loud........ put your foot in it and you got a 454 with glass packs! :D

All of the above posts talk about "staying" with a 3" to the muffler.

You can't "stay" with 3". You don't HAVE 3". What you have is 2.75" from the turbo to the cat/muffler. 2.75" that has been horribly deformed, squashed, and generally made into a 2.25" in places.

IMHO, you can do whatever you want from the muffler on back, but if you don't do something about that front pipe, you are not going to see the benefits you're looking for.

BTW, my system includes a 3" downpipe, a used resonator off a DMax, and then a take-off 4" from a Dodge. The only part that really cost me anything was the downpipe, and the muffler shop did the rest on the cheap, using parts they would have thrown out anyway. (recycle, reuse, reduce, right?)

The resonator is because I pull a 5th wheel, and without it, the straightpipe was either really cool (me) or extremely annoying (wife), depending on who you ask.

All of the above posts talk about "staying" with a 3" to the muffler.

Do not! ;)

thanks, to all opinions,... a lot depends on what comes into the shop, and the condition... what's on the truck now is a terrible design and opening it up like I'm doing is going to help,... when... and that is later this year I'll go 3.5 or 4" complete, but this gets things rolling and the costs... not much when you consider the install is free, probably when I do up grade to the larger pipe I'll get this guy to put it in... (I'm tired of laying on the drive putting this stuff in), and this opens up the buying of pmd/heat sink and cable and so on... one step at a time....

Buy the Flowmaster kit $110(auction site) - 3'' downpipe and upgraded crossover. Cut right before stock muffler and bore out cat = 3'' straight pipe! And the basics are covered!!

All of the above posts talk about "staying" with a 3" to the muffler.

You can't "stay" with 3". You don't HAVE 3". What you have is 2.75" from the turbo to the cat/muffler. 2.75" that has been horribly deformed, squashed, and generally made into a 2.25" in places.

IMHO, you can do whatever you want from the muffler on back, but if you don't do something about that front pipe, you are not going to see the benefits you're looking for.

BTW, my system includes a 3" downpipe, a used resonator off a DMax, and then a take-off 4" from a Dodge. The only part that really cost me anything was the downpipe, and the muffler shop did the rest on the cheap, using parts they would have thrown out anyway. (recycle, reuse, reduce, right?)

The resonator is because I pull a 5th wheel, and without it, the straightpipe was either really cool (me) or extremely annoying (wife), depending on who you ask.

I don't see any mention of "staying with 3"" in my post, i stated 3" pipe. Mine uses the SSD downpipe, then 3" to the splitter. Hope that clears that up.
Don

Yeah, sorry about the generalization, daustin and cr. I wanted to make the point that the gatherer was only talking about staying 3" to the muffler. When I first got my truck, I thought it was 3" too... it doesn't look too bad, back by the muffler.

Then I pulled the downpipe out and <whoa!> "what happened to THAT pipe?"

Up until then, you couldn't have convinced me that a 3" downpipe was that much of an improvement. After that, it's my first recommendation to anyone.

...I already had the kitty cut off (not required here in FLA) and a 3" pipe put in place,... now I have to deal with the small pipes front of the muffler to the end...


I once had a '711/2 ford P/U 360 gas which I could nearly figure 'gallons-per-hour', I had 2.5" straight duals with an 'H' pipe to balance it out... so the state trooper said at a check point, "rev it up", so I gave a little varooom,... and he said, "no, really rev it up!", so I did a wopppoow!!!!, he smiled as he wrote a warning ticket giving me 48hrs to fix it and said "I love that sound!"
My girlfriend took the truck to get mufflers on it and they put what looked like 1.5" glasspacks on it, l took it to a shop and changed them for 2.5" turbos not much restriction...but enough back pressure for gas...

...I already had the kitty cut off (not required here in FLA) and a 3" pipe put in place,... now I have to deal with the small pipes front of the muffler to the end...

The issue actually isn't the pipes from the cat back... I guess I didn't ask the question properly.

Have you changed the pipe that comes down from the turbo to the cat? The very first pipe in the exhaust system?

If you haven't, you may want o look at doing that first. That pipe is only 2.75" at its biggest point, and there are several restrictions in it that cut the effective diameter down to nearly 2.25" in a few places.

Changing that pipe (called the downpipe or frontpipe) and replacing it with a 3" mandrel-bent one is the first performance modification you should do.

(mandrel-bent tubing has constant diameter, even in the bent parts. Pressure-bent tubing is considerably smaller in the bends than in the straight sections.)

If you haven't changed that front-pipe, then don't even THINK about putting in a chip, high-flow injectors, or raising your boost pressure.

If you haven't changed that front-pipe, then don't even THINK about putting in a chip, high-flow injectors, or raising your boost pressure.

Oops....:D

Oops....:D

Living dangerously, are we?

That's my truck ... When she gets hot enough, I roast marshmallows on her!

We were.....I was running 12 psi boost on the stock exhaust system before I blew out one of the donuts and cracked the crossover tube....now I've got the Warpspeed 4" system....it was a little bit of an upgrade...

We were.....I was running 12 psi boost on the stock exhaust system before I blew out one of the donuts and cracked the crossover tube....now I've got the Warpspeed 4" system....it was a little bit of an upgrade...

oh yeah, I remember that. The turbos on these things really don't work so good when the crossover cracks, do they?

You guys have been happy as can be with those warpspeed systems, eh? Nice to find somebody that can work with Canadians on shipping issues!

I agree with jifaire on the 3" mandrel downpipe, that along with a new mandrel bent crossover and removing the darned snorkle was the first set of mods i did to mine. The factory downpipe is squashed in several areas and the crossover wasn't very open either. :eek: Mine didn't come with a cat (or so i think but i bought it used..so...) and i junked the muffler asap. :D With mine exiting behind the rear wheels and being "split" before the rear axle it's louder than stock but not obnoxious and dosen't drone in the cab. Currently i'm adding guages and modifying the factory mechanical actuator for more boost. (and new injectors, glow plugs, little porting on the intake..etc.) Good luck with your mods.

Hey Dustin, Is it possible to put up some pictures of your exhaust? The part I would like to see is where and how you split it in two just before the rear axle.

Right now i've got the truck partially torn apart, i'll take a couple of shots of the splitter area that's not apart. The front downpipe and other stuff is off at the moment.
Don

Buy the Flowmaster kit $110(auction site) - 3'' downpipe and upgraded crossover. Cut right before stock muffler and bore out cat = 3'' straight pipe! And the basics are covered!!

DMDK described exactly what I did. This was a very cheap upgrade, and the breathing on the Tahoe went up markedly. I went from 11.5 0-60 to 9.5. I am NOT kidding. OK, I did open up the intake manifold, and I recently went with a '97 air filter setup. In my opinion, this is the best low-cost (+ reliability) mod you can do, outside of actually buying a complete stainless-steel 4" exhaust from the downpipe back.

I have nothing against getting a completely new exhaust, I'm just saying that it was maximum ROI for the $110.

Sincerely,

Rob :)

... o'kay, here's the plan so far... after all this info and talking to a 'few' shops that have repeatedly told me they 'can bend me a tailpipe and it doesn't matter about the crimps'... so I listened to all here and the multitude of posts I've read in the time I've been a member and I'm ordering the complete warpspeed 4" system (I hope that's not a conflict with vendors on this site) and will put it in myself,... "she who controls all" (at least at my house) has given the 'go ahead' blessing... "after all dear,... I need it..."

LOL!

You won't be disappointed...neither will the wife...

Hey Dustin, Is it possible to put up some pictures of your exhaust? The part I would like to see is where and how you split it in two just before the rear axle.
I didn't get to it yesterday before it got dark, i'll get some pics this weekend.
Don

get the three inch down pipe, run a piece of 3inch back to the muffler. Magnaflow makes straight through muffler with a 3 inch input with two 2 1/2 outlets. The longer the muffler is, the quiter it will be. Local muffler shop can bend two tailpipes. 2 x 2 1/2 will flow more than the input on the muffler, and you have cool duals for less than 300.00

Down pipe about 100.00
3' pipe, abot 30.00
Muffler about 40.00
Tailpipes 50.00 per side.

Worked great on my 97, and sounds better than a flowmaster imo. Sorry, no photo's. The truck is gone.

Well, I do want some noise when I get on it. Will the flowmaster cut down on the noise much? I want to hear it bark a bit when I get on it. :D

I meant magnaflow. Sorry.

It will be louder than stock under power. The lenght of the mufler will determine how loud it is. I bought the longest I could get to keep noise down, and it was probably about halfway between stock, and string pipes under power, but relatively quite when just poking around.

Well mabey I will just run straight, no muffler, then if it is too loud I can just put a muffler in? Sound okay? Any one running straight and like it?

Its alright, but my ride to work is 1 1/2 hr. Drone is a little much. I hear though that if u have a Turbo Master and run 2-3 psi at hyw speed it cuts it out.

Well, I just want a good sounding loud bark when getting on her. :D I was behind a 6.5 at the stop light the other day and it had two pipes out the back, one behind each real wheel. Like stock gas motors have. When he left the stop light in front of me it smoked alittle and sounded great. I should of stopped him and seen what he did if anything for a muffler. I liked the sound of it. Crisp and loud.

Mine is straight pipe'd and with it exiting behind the rear wheels there is little drone and it's not too loud. I've got the 3" downpipe and 3" to the splitter. Then 2 1/2" to about 1" from the exits, and 3" crome end pipes. My wife dosen't complain about it being loud, it has a nice tone to it and i'm very happy with the sound. Not too loud but you can hear it.
Don

Okay, has anyone tried both the duel pipes, like daustin has on his? And then switched to single pipe? Or visa versa? I just want it to sound nice and crisp. Just trying to figure what way to go here.

I thought about starting a new thread but figured I'd tag on to this one... I just had my Pinnacle 4" system installed w/ 3" downpipe. I've had the system for a month or two now but haven't had time to install it till yesterday. It's a single exhaust out the back with a straight-through muffler on it. At idle it actually has the sound of a gasser motor that has a nice cam in it. Very enjoyable, had it on the highway doing 70 with the cruise on and the sound was there, but not an annoying "drone". Can't wait to see how it hauls the car to the track Saturday.