new here first post

[Herman_Bolger]

We are new here. This is a post to see how this works out. We just purchased a very used 1993 gmc dually ext cab 4x4 auto. It is also our first diesel, our other big trucks were gas. The truck has 350k km about 275k mi. The previous owner just put in a rebuilt engine. I am asuming stock,he replaced a lot of external parts also,pump, injectors, glow plugs etc. He did not replace the stock exhaust though and the down pipe from the turbo broke the other day. My question is, finally, would an aftermarket exhaust be benificial, ex,larger down pipe, larger pipes front to back. Would eliminating the muffler help. We do some heavy towing sometimes,we pull boats that wiegh up to 15,00lbs. We would like to improve the low to mid range power but still keep it reliable for the longer hauls that we do. We have never owned a diesel before so any help will be welcome.Thanks

[rjschoolcraft]

First of all... Welcome to the Diesel Page. You've stumbled onto the best source for GM diesel information on the internet... especially 6.2/6.5. This topic would be better served over in the 6.5 forum. I'm working on moving it.

The first thing you should do is read about The Diesel Page.com's 6.5 Project Truck (http://www.thedieselpage.com/finale.htm) to see what it has accomplished. It was the inspiration for many of the modifications that I have done to my Suburban, except that my Suburban uses an electronic DS4 pump and the Projet Truck uses a mechanical DB2 pump.

There really is a lot of un-tapped potential in these engines. I tow between 8000 and 12000 pounds with relative ease now compared to stock form.

Good luck.

[Herman_Bolger]

Thanks ronniejoe for pionting me in the right direction, i will check out the project truck. is this your truck? There is a lot of info on this site and i was not sure where to post this. Thanks

[rjschoolcraft]

The Project Truck was done by Jim Bigley for the Diesel Page and is now in the possession of Chris Bigley. My Suburban is discussed in detail in my6.5 Performance (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=006650) thread and at SchoolcraftPowerTrain.com (http://www.schoolcraftpowertrain.com).

[rjschoolcraft]

This topic was moved from the Members Forum to the 6.5 Forum. Please offer additional advice to Herman, thanks.

[65turboman]

Welcome Herman, and congrats on the truck. There is a ton of good information on this forum. If you use the search feature you can pull up some very informative posts that may answer some of your first questions. To answer your exhaust question, YES, it would be quite beneficial for you to install a free flowing exhaust system (no smaller than 3 inch diameter) and also install Exhaust Temperature and Boost pressure guages. These things would be a great first mod. Many folks here are great for answering questions, so I hope they will soon chime in.

[DickWells]

Hi Herman, and welcome to the DP.
Just read my profile, and you can see that I have sort of been through the mill. Take the time to work your way through all the abbreviations. I tried to get a lot of info in a limited space.
It's good to get all the publications from Jim Bigley. They're well worth the money.
You will note that there's a wealth of data from Jim and Dr. Lee Swanger, as well as many others like John Kennedy. He (Kennedy) sticks pretty much with the electonics, and that's good. I got tired of having my engine miss beats at random moments, and changed to a marine mechanical DB2 pump. I'm very please with the results, but, it's a hard row to hoe, to get there. Lots of DIY
with the throttle, etc.
Just stick with the guys in the DP, and you will learn more than you can ever believe possible.
Good luck, Dick Wells.

[Herman_Bolger]

Thanks for the welcome. We scanned the many posts here, there is a lot of information some of it gets kind of confusing, so any clarifications will be welcome. we have quite a bit of experience with gas engines namely the 7.4l that we had in our other trucks. i am thinging of useing those priciples with the diesel. the first mod made is usually exhaust, you can't get more fuel in if it's not going out. I found a link to kennedy's site, and found that he has a ceramic crossover pipe and a 3in down pipe, and was thinking of starting there, any experience or recomendations there? then possibly getting a new chip.We have a stock so far, engine,4l80e trans, 4x4,and 4.11 's. we would like to build a hauler with better low to mid power, but it needs to be dependable, we use this as a work truck. thanks

[65turboman]

For the exhaust many members here have had good results with Kennedy's entire 3.5 inch system. This has a down pipe included. If you install a mandrel bend down-pipe it will be better, but the kinked after cat piping is also quite restrictive. Flowmaster offers a cross-over and down-pipe kit with mandrel bends if you want to upgrade just the down pipe first. On my truck I removed the cat. converter and muffler and then welded in a 3 inch section. A few inches past the cross-member I stepped up to 3.5 inch piping that was taken off of a Duramax truck. I don't mind a little noise, so I removed the muffler and inserted straight piping. The complete down-pipe back systems are probably superior to my setup, but it just depends on how much you want to spend.

[rjschoolcraft]

Herman,

Your truck is mechanically injected... the computer has no control over fuel delivery. You can turn up your pump, though. Others here would be better for advice on that.

You are right on the exhaust being the first place to start. Next would be air inlet system.

[Herman_Bolger]

We did find that our truck has the mechanical pump but did not know if it is all mech or electrical/mech I had no idea. I do know that we do not have a cat on our truck, and right now the down pipe is broken where it meets the rest of the exhaust, and compared to the 3in flowmaster exhaust i had on the gasser, this is not that loud. I will e-mail kennedy's to day about a complete exhaust without a muff. I would like to start with the basics first since I am on a budget and have a list of things to do this truck. I do not have a pile of dough to spend and I still need to paint this thing over the winter. It will only be on the road 'till dec 30. Then the real work begins. Keep the tips coming. Thanks