1996 Suburban Diesel Exhaust System Upgrade?

Discussion in 'GM Diesel & DuraMax' started by 2091B22, Jan 31, 2012.

  1. 2091B22

    2091B22 New Member

    I am a newbie to the truck club, and a newbie to my Suburban. I have a 1996 GMC K2500 4X4 diesel 6.5 L. Presently I am getting around 14 MPG in the city, and 20 MPG on the highway. I would like to upgrade the exhaust system. I purchased the vehicle used so I am not sure if the system I presently have is in fact already upgraded. The present system is a 2.5 inch crossover pipe, then a 3 inch down pipe that continues to the muffler. There is a 2.5 inch pipe from the output of the muffler to the rear of the vehicle. Is this system the stock system? If this is the stock system, what would be a good system to upgrade to, meaning what size pipes from where to where, including a better flow muffler? I do not want to go exotic, but I do want a better exhaust system. I know I should also upgrade the air intake system. Not sure if asking for recommendations for the air system should be in this thread, or generate another thread. Any thoughts on that?
  2. ChevyHD

    ChevyHD Rockstar 100 Posts

    With a diesel, the less back pressure the better. But no exhaust and cat does make it louder. Personally I would just do 3 inch downpipe back. But then again I love loud exhaust! lol
  3. rileyjr16

    rileyjr16 Epic Member 5+ Years 1000 Posts

    Air intake, go K&N. As per exhaust it sounds like its stock. I would go 3 inch all the way. A good system is MBPRD or MDRD not sure on the correct letters but not sure if they're for the older trucks.
  4. Asphalt Animal

    Asphalt Animal Rockstar 100 Posts

    Look at the downpipe, does it look like it was run over before being installed? If so, it's stock, replace it! The rest of the exhaust should be canned too, either buy a kit at least 3" or go to a good muffler shop and have one made. Don't use anything less than 3" or you're not gaining much of anything.
    Keep in mind, on a Sub, almost any exhaust you throw on that doesn't have a quiet muffler will likely resonate(drone) inside the truck.....
    Exhaust is a must for any diesel as they need to breathe, and the stock system on the 6.5L was horribly restrictive.
    As far as the filter, a K&N would be beneficial too.
  5. 2091B22

    2091B22 New Member

    Thank you for all of the information offered. It seems from the reply's I have received I have a stock exhaust system. Also MBRP does not make an exhaust system for the 1996 Suburban. Everyone also seems to agree that a 3" system is the way to go. Any thoughts on a 4" system with a 3" down pipe? Along that line, does anyone have an opinion on the Diamond Eye exhaust system? I will look into a K&N air filter system. Thanks
  6. Dukeschevy

    Dukeschevy Rockstar 100 Posts

    In my 6.5 diesel I went to the big truck store and bought 4" pipe and the elbows(to get over axle) and it cost me around $200 to do it all myself. 4" from the downpipe back. I think it sounds pretty good although I recommend getting an upgraded downpipe. I believe a 3" downpipe is about all you can fit. As for the filter, K&N is great. A good website is "ssdieselsupply" they sell just about everything you need for the six fives and have been pretty good to me, in my opinion. Their air filters are just like k&N, thats where I got mine. + the prices aren't too bad either. Good luck

  7. ChevyHD

    ChevyHD Rockstar 100 Posts

    I only said 3" because its an improvment but its not the best. IMO, to maximize performance, I would put 4 inch turbo back pipe. Ive don't know anything about 6.5's, just duramaxs. Dukes says you can only fit 3 inch downpipe, so I would do 3 inch downpipe and 4 inch downpipe back. Wasn't sure if you wanted the added exhaust because you could get annoyed of it especially if it drones. Like I said though, exhaust with me is the louder the better! lol
  8. SuperSport01

    SuperSport01 New Member

    If your crossover pipe measures 2.5" its not stock. If your downpipe measures 3" its not stock either. Diamond Eye is a nice exhaust just make sure to get the kit with a muffler.
  9. 2091B22

    2091B22 New Member

    Going With SS Diesel Parts

    After reading all of the great advice and input on upgrading the exhaust system on my Suburban, I am going with parts from SS Diesel. I am installing the complete 4" exhaust system. I am replacing the crossover pipe with a new one. Then a new 3" down pipe, then the new 4" system, with muffler to finish off. I am also installing the SS Diesel Performance Air Induction system. Once the system is installed, I am driving from Berwick, LA, back to Georgetown, SC. Then I will be driving back to Berwick, via Charleston, WV, and Atlanta, GA, so that will tell me if the upgrades made any difference. That should be enough road mileage to be a very good test.
  10. Asphalt Animal

    Asphalt Animal Rockstar 100 Posts

    I don't think you'll be disappointed there. I've heard and seen that system many times and it's a nice kit.

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