Boost and Control

[GMC Hauler]

I am still learning and reading all the posts about my new 6.5. What i have a question about is boost and how you control it. I have picked up that stock boost runs 4-6#. I also understand that when you install a intercooler, that boost levels fall about 2-3 lbs. When you send off the computer for a reprogram, does that adjust the boost levels? Do you need to have the computer reprogrammed again if you add an intercooler later? How do you compensate for this lost boost level due to the intercooler? I see that a lot of guys are running boost in the 12lb tange. Are you doing this with the turbo master boost controller, or is the computer capable of controlling it at this level? What is the most boost you would apply to this motor with the stock pistons in it (i read about the 18:1 pistons being used that allow for more boost)? I have noticed that my vacuum from my vacuum pump is at 15", and i see from the service manual that it is at the min spec. I understand that installing the turbo master boost controller is all mechanical and more reliable. What are the pros and cons to going this route (efficency, reliability, performace)? is it just easier and cheaper to replace the vacuum pump? Thanks in advance. P.S. this is a 96 Burb.

[rjschoolcraft]

My truck has 183,000+ miles on it. The engine has 120,000+ miles on it. I have now replaced everything in the boost control system: new vacuum pump, waste gate actuator, waste gate solenoid valve, boost sensor and baro sensor (the last two were unnecessary). I also run one of Kennedy's TDMax chips (mine is a 95, yours doesn't have a replaceable PROM). Now, under load here in the midwest, I see up to 13 psi peak and 12.5 psi sustained boost. I just found and fixed a major leak from the upper intake manifold. It seems that the threads in the intake manifold for the front, center bolt were stripped...this left a through hole to the intake plenum and I hadn't noticed it. Apparently, this has been this way since I installed the intercooler in July. I've been bleeding off boost all along and didn't realize it.

The boost level is controlled completely by the PCM with the new chip at present. Kennedy also sells electronic boost controls to provide adjustment beyond that, but I haven't gone that route yet. I personally do not recommend the Turbo Master for the electronic trucks...it seems a step backward to me. Others will jump in and say it's the greatest thing since sliced bread...and I think it is great for the mechanically injected trucks. The electronics retain quite a bit of flexibility. The TM is just an exhaust backpressure regulator. In other words, when ebp reaches a certain point, the waste gate opens and limits boost.

See my post "Significant improvement in towing performance" for more information on what my Suburban can do now.

I think your PCM can be reflashed to the 99 program, which according to Kennedy is about the best available even considering the aftermarket reflashes. Couple this with an electronic boost control and you could have a big improvment. I installed the chip before installing the intercooler. I was running 12-13 psi boost then, but could not effectively use it because the intake air temperature would cause the PCM to pull back on fuel and boost. Now with the intercooler, all seems well. I also upgraded my cooling system to eliminate my overheating problems.

[GMC Hauler]

Ronniejoe, Thanks for the reply. That answers my questions. Can i get a response from anyone using the Turbo Master and what they think about it? Thanks

[tom.mcinerney]

GMC~ A number of members like the simplicity, reliability, and lower price of the t-b retrofit. If no replies, click on "search" feature at top page; enter 'turbo boost' {don't enter any 'quote marks'}, there'll be plenty to browse.

[cruzer]

The TM was made for mech injection, which mine is. It allows me to set it at a max boost of my choosing. I have it set at 14psi sustained on hills or hard acceleration. I have stk pistons. The 18:1 pistons are really for building in durabilty, and to compensate for heat. They also will allow you to bump up boost pressures even higher.

I dont know the effects of added boost to the computer, but I know people have been successful w/the TM on these trucks. IIRC it also allowed them to eliminate certain items involving the wastegate operation.

The intercooler looses boost on the outlet side because of physics. Hot air expands, so if you cool hot air it condenses. A cooler more dense charge builds more power. The I/C needs to have approx 12psi to be effective. B4 I purchased an I/C, I thought who wants to loose boost? The whole concept sounds expensive and not worth it. After reading an article named "Pepto Bismol".(which is gone & we need to find or replicate. written by GMCTD) I purchased 1. After installation and some additional mods "WOW". I do use my truck to pull with. If you dont pull, I dont think a I/C will be much help.

The 1st mods I would do is gauges, a less retrictive exhaust or good downpipe, free flowing air filter and possibly a TM or chip for boost. Remember if you are putting more air in you need to get it out. Gauges are a must B4 for any mods.
The other things would be maintaining your cooling system and consider 97 cooling mods.


I started w/gauges, exhaust, K&N and TM. Theses
items really flattend the hills of KY, but I still had to make runs at some to keep a good speed at the top. Now w/all the mods I just set cruise w/minimal fluctuations in speed(1-3mph)on the same roads. I pull approx 7000-8000lbs+truck. Thanks, TDP

Hope fully someone w/electronic and a TM will chime in.

[HowieE]

My 97 is electronic with a BD computer and Intercooler. Prior to installing Bill Heath's Turbo Master the highest boost I would see was 13lbs, but that would decay very quickly as the computer will cut back on the boost over time while under power. Now my general boost levels are higher and remain at higher levels as long as I am calling for power. My Turbo Master is set to 12lbs. Bill has commented that that is the practical limit.
As for cost the Turbor master is less than 1/2 the cost of a vacuum pump to say nothing about the vacuum selenoid and wastegate control pot if you have to replace them.
But yes before you start adding power get those gauges installed.

[GMC Hauler]

Does the TM overide the high intake protection that the compuer implements?? Can it possible damage the engine due to an over pressure condition using the TM???

[MikeC]

GMC, I had a Kennedy boost controller on mine when the vacuum pump went. Put the TurboMaster on and left the boost controller in also. I'm figuring that it keeps the engine from seeing the higher pressures.

Too much boost can be damaging with and without an intercooler. Gauges are a neccessity when we start hopping these things up.

Mike