6.5 Waste gate

[farmerson]

This question has probably been asked many times before, but can you switch the vacuum waste gate on a 99 to a mechanical waste gate? Does it give you as much boost as everyone says? Is it even worth doing? Thanks for any help.

[Robyn]

HI there

The issue of BOOOOOOOOOOOOOOOST is beat around and around and around.

Boost is only useful up to the point at which the available amount of fuel is completely burned and has produced all available power it can.

Boost simply for the sake of having high manifold pressure does nothing.

FUEL is the source of POWER and in order to burn more fuel, it takes MORE air.

More boost equals more intake air temperature too and is the enemy of power, but thats another can of worms and really is not too much of an issue as long as the levels stay below 15 PSI


The systems on our GM trucks were engineered to meter a maximum amount of fuel and to also deliver a coresponding amount of air to allow for about 190 HP and reasonably clean emissions.

The system is controled by the onboard computer (ECM) and it does a fair job at it.

ECM controls boost to about 7-8 PSI max

The issues with this system are that the vacuum system that controls the Turbo wastegate are funky and do give troubles.

The mechanical replacements that you have heard about (Turbo master) are a fine product and do exactly what they were intended to do.

The Turbo master is a spring controlled device that replaces the vacuum wastegate controller.

A large nut is tightened down against the spring until the effort required for the exhaust pressure to BLOW open the waste gate is such that the coresponding manifold pressure rises to whatever level is desired.

Now, all this said, the only way to reap any real benefit from this system is to install a large free flowing exhaust system, have the computer reflashed (or in 94 and 95 trucks install a power chip) and then adjust the turbo master to reach a peak boost of about 12-13 PSI under a hard pull.

The other thing with all this is that NOW you are the only thing that stands between POWER and melting the engine.

The computer can no longer manage the fuel and boost levels as the new programing has changed all that.

You must have a Boost gauge and a Pyrometer in/on the dash/Pillar or ??
so you can monitor things.

YESSSSS these things can make boost and they do exactly what folks say they do.

Hope this helps


Missy

[farmerson]

Ok thanks, is there any way i can add more fuel without changing injectors (basically im out of money). I put a cold air intake on it, and for some reason made it smoke black like if you had a small chip in something. And it did not change much other than you can hear the turbo whistling now when you put it to the floor, im going to take the muffler and converter off today and make it just straight pipes. And eventually going to put stacks in. I have also heard you can make these 6.5's a really powerful engine for not a lot of money.? Is this true and what does it require?