1999 6.5L Performance upgrades [Archive] - TheDieselPage.com Forums

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scot5146

11-29-2010, 13:47

Hey everyone-

Ok well this is the story I have moved from the 6.2l diesel section because my 1987 Suburban blew up and i am tired of dumping money into it so its going to be a parts rig...

Anyway my NEW (at least to me) 1999 K2500 suburban 6.5L diesel with 100k on it just pulled into my driveway and shop...

Now I am excited to put on some upgrades to get the best combo of power and towing ability as well as mpgs...

SO ANY SUGGESTIONS ON WHAT I SHOULD CONSIDER DOING TO IT....?

It was regularly maintenance and has no issues, the past owner is the original and a good friend of mine...:D

I was thinking of 4 inch down pipe/ exhaust, cold air intake... And curious about water/ methanol injection (has anyone used it and is it safe for a diesel)

Maybe a upgraded cpu from heath or ssdiesel etc... Any ideas? oh and a special thanks to everyone who helped me try and fix my old 87 6.2L...:D

6.5 Detroit Diesel

11-29-2010, 19:01

Do the four inch. It will make a world of difference along with a good d/p. sounds like your on the right track to start.

following the exhaust, get a program done for the truck in conjunction with some sort of turbo control.

personal opinion is to use heath or kennedy. ssd sucks.

i am working on a different intake system for our 6.5's, but if you are keeping the stock box, get a good filter. current CAI on the market are pretty crappy. they will work if you port behind the marker light, otherwise, they draw air from a hot area.

w/m injection can be used safely. i ran a system on my truck that made a huge difference in cooling and with a 30-35% methanol mix made a very noticeable difference in power. most guys would run like a 10% mix on the 6.5's.

If your still looking for some more power, then hi-performance injectors in conjunction with your program.

while your doing all this, don't forget your cooling. w/m injection will take care of that, but if you don't do that, look at upgrading your cooling system.

good luck with the burb'!

6.5 Detroit Diesel

11-29-2010, 19:02

oh, and i didn't ask, but i am guessing the PMD is relocated?

if not, you can extend it.

make sure the ground remains running to the pump or you won't get a start.

i moved mine in behind the drivers headlight. keeps it cool and out of the way.

Kennedy

11-29-2010, 19:34

Gauges first, then exhaust, chip/programming, and injectors.

A 4 " exhaust will gain you nothing but noise over a 3.5" system.

Make sure that the raidator is clear.

ted2020

11-29-2010, 21:25

What is the advantage of relocating the PMD?

6.5TDTahoe

11-29-2010, 22:04

Not made ! 3 in. mandrel bent is is the largest down pipe made & will fit.. The rest can be 3 or 4in. STANS in washington state has the complete kit. Enjoy your new ride.

AllThumbs

11-30-2010, 13:06

I'm currently in the middle of a project, I'll let you know how my stuff turns out and maybe a help to you in deciding what to do. The good part is, all this stuff bolts on and you can do it one at a time and see how each part helps. I do have a pickup instead of a burb, but I don't think that makes a lot of difference.

scot5146

11-30-2010, 13:54

:D

Thats all great ideas, just what I am looking for, but bare with me because I am still new to diesels...

Q: what is the PMD and what does it do? why do I need to move it?

Thanks again

Mike

AllThumbs

11-30-2010, 19:33

PMD - Pump Mounted Driver. It is the electronic controller for your fuel injection pump. They generate a terrific amount of heat and if not kept cool will fry. One of the biggest problems with the 6.5 TD. Moving them to a remote, cool location extends their life (good since they are expensive). You can't run without one and anything that will extend their life is good. Costs to move them to a cooler place. Costs more and is less convenient to replace if you don't.

6.5TDTahoe

11-30-2010, 19:43

The 99 Suburban, trucks has the best & final cooling system up grade courtsey of GM The cooling fan,fan clutch & f an blade was the final 6.5 upgrade by GM. . check the thermostats to see what the part numbers are. Should be AC Delco/ or GM 192 degree version. Original equipment GM12559936 or Delco131-103 part numbers. These engines are intolerant of temps over 205 degrees. I Recommend a well lighted capillary tube gauge & you watch the gauge!!!!

6.5 Detroit Diesel

11-30-2010, 19:57

Not made ! 3 in. mandrel bent is is the largest down pipe made & will fit.. The rest can be 3 or 4in. STANS in washington state has the complete kit. Enjoy your new ride.

well aware of that fact. ;) only way to do a 4" is a completely custom system.

whether or not a 1/2" will make a difference is really up to you.

if you are just doing light towing, you shouldn't really have any issues with EGT's. i have repeatedly pulled 10K+ without any issues and only have a 2 3/4" straight exhaust and a GL4 program.

to each his own, just sharing what i have done to all my trucks and what has worked for me with EFI and MFI.

16gaSxS

12-09-2010, 14:49

Gauges first, then exhaust, chip/programming, and injectors.

A 4 " exhaust will gain you nothing but noise over a 3.5" system.

Make sure that the raidator is clear.

I'm with John........

scot5146

12-09-2010, 18:15

thanks everyone! I found a exhaust system and I am in process of relocating the PMD...

How about CPU upgrades and Cold air intake, any specific brands to buy/ watch out of etc...:rolleyes:

also my rig seems to be running very cool, maybe (180*) is this OK?

Thanks Again

Mike (New Guy)

93GMCSierra

12-09-2010, 21:47

scot5146

12-13-2010, 23:51

AllThumbs

12-14-2010, 01:48

I've had your same question on cold air intake and have been told the 1999 stock is a good as you can get. I bought one and can't believe the size of the filter. You might see what choices there are out there for filters, I'm putting an Amsoil on mine.

So far on my project, I have new injectors, new glow plugs and 4" exhaust. I have not had any real time yet to drive it, but what little I have, the difference is startling. I'm well pleased.

Performance chip and intercooler next. They are here but not on yet.

suburbanK-2500HD

12-14-2010, 13:35

Where du you plan to install the IC.

16gaSxS

12-15-2010, 20:34

:confused:

I am in Oregon/ Washington on the westside so it never really gets that cold... So is that still an ok temp for normal operations? 175-180* ish...

cold air intake... Suggestions on brands for a 6.5 TD?

Thanks

Mike
:D

HMMM, someone could have put 180 degree thermostats in, some folks do that for towing. If you replace them with standard 192-195 IIRC you'll get bit better MPG's and you'll run at the designed temps.

scot5146

12-16-2010, 09:06

HMMM, someone could have put 180 degree thermostats in, some folks do that for towing. If you replace them with standard 192-195 IIRC you'll get bit better MPG's and you'll run at the designed temps.

thank you very much thats what I was looking for, does anyone know the
AC Del-co part # for the thermostat for a 99 6.5 TD?

Thanks everyone for all the help, you all are fantastic!

Mike
;)

scot5146

12-16-2010, 16:37

:confused:

My 1999 Suburban that I have been asking about has 2 thermostats???????

I took it into Mac's radiator here in Vancouver WA and had all the coolant flushed and the radiator serviced...

I found out that I had 2 thermostats... SO are my temps correct or is something screwed up?

I am constantly running at about 170* it is not even half way on my gauge between 160 and 210* I figured it had lower temp thermostat maybe the owner before me put in for towing or something...

Come to find out it has 2 of them and after the shop replaced them with OEM stock (NEW THERMOSTATS) I am still running the same temps....

IS THIS NORMAL?

The main reason I am asking is because I am in process of lots of upgrades, but I dont want to overheat / underheat my motor...

1999 K2500 Suburban
6.5 TD, 116k miles

Thanks Again:
Mike
:D

aquaman0001

12-16-2010, 18:51

Mine runs closer to 190 year round but I am not for sure if there is an advantage or disadvantage to the lower temps. You would think for the summer or like you said towing, that a lower temp is better.
A

AllThumbs

12-16-2010, 21:59

This may sound stupidly simple (sometimes life is like that) but the thermostats may have been put in wrong. That does not sound right in this case since you have been running low temps all along. On my truck, I could not get it to warm up and when we pulled the thermostats, one had the rubber sealing ring stuck inside the throat and would not allow it to close.

scot5146

12-28-2010, 03:05

:confused:
This may sound stupidly simple (sometimes life is like that) but the thermostats may have been put in wrong. That does not sound right in this case since you have been running low temps all along. On my truck, I could not get it to warm up and when we pulled the thermostats, one had the rubber sealing ring stuck inside the throat and would not allow it to close.

Hey everyone... Hope you all had a great holiday...:D

Ok so the update to date on my 1999 K2500 GMC Suburban 6.5 diesel...

I got the cooling figured out, you were right the shop put in one of the wrong thermostats in my rig, problem has been fixed and i am running a consistant ~185* (about)...

I ordered the 4" exhaust kit and I am saving up for the AFE intake and a set of Sunpro Diesel Guages from Summit that are a good price...

I will post pictures as i go...;)

Questions:

1) Is there or do I need to replace the exhaust crossover pipes from each side of the exhaust manifold? I have seen a kit that claims smooth bends more flow, power, etc... Any truth to this?

2) Is there an exhaust "header" for the 6.5 diesel that will make more power, lower EGT's, etc...?

3) I want to relocate the PMD... is this by a longer wiring harness atachment or is there a bracket of some kind, because what i am seeing online is a bracket, but they are all really expenssive...$ 140 ish...

Well I am at work playing on the computer, sitting up after a structure fire at 2 am in the morning and all my words are running together, so I guess those are my questions for now! bed time (i love my job job but the long nights can be brutal):eek:

Ayway thanks everyone, I appreciate all the help so far! Pictures to come on my Suburban project!;)

Best Regards

Mike (New Guy)

AllThumbs

12-28-2010, 08:00

The information I gathered here was that if you wanted a different crossover pipe for performance purposes, you were wasting your time. Mine would have been very difficult to get out as the bolts were really rusty and the always terrible problem of breaking one off in the manifold was raising its ugly head. So, I simply left mine as it was and could still feel a terrific improvement. I don't think there is a lot there. The 4" exhaust is another issue. Mine was not difficult to put in and made an obvious, instant improvement.

scot5146

12-29-2010, 21:50

6.5 Detroit Diesel

12-29-2010, 23:00

it'a up to you really. with the stock turbo's, you really don't need an intercooler. it might make a little difference, but not much. if you were swapping to something different for the turbo, it could be a good upgrade.

as for the w/m injection. some say it works, some say it doesnt. others say it add's power and cools, some say it only cools.

from my own experience, it added power and resulted in dropping a couple hundred degrees on the pyro while at WOT. i was spraying to much, but the point is, it worked.

scot5146

01-12-2011, 18:49

Hey everyone-

My suburban project gave the service engine soon light yesterday...

I ran my OBD II scanner and got a code: P0251

(Injection Metering Control A- (cam/rotor/injector)

can anyone shead some light on this for me, I am confused and not sure what this means or what I need to repair...

thanks

Mike:confused::confused:

Kennedy

01-13-2011, 16:43

;)

Ok so the 4" exhaust is a go... I think I wont bother with the crossover pipes from the exhaust manifolds...

As for the other parts I am still planning on:

Gauges
Exhaust
CPU upgrades
Duramax cooling fan blade
Air Intake
re locating the PMD

What other considerations should I look into? maybe water/meth or an inter-cooler?

Thanks
:D

Mike

The duramax blade will gain you nothing. If heat is an issue when things warm up then consider my Special Calibration fan clutch and keep the stock blade.

We have a very nuce FSD cooler setup that attaches cleanly and simply to a vacant bracket already in place on the 96+ vehicles.

CPU upgrades require exchange ECM for this model year. I tune these myself in house.