How does the wastegate work on my 93 6.5? is there any way to modify it? And since Im running the stock exhaust(muffler cut out)would I be wasting my time? I plan on upgrading to a 4" system soon

yea you can put a spring on your wastegate...search around for some pics its easy...get a few gauges first... id suggest doin the exhaust and air intake before messin with the wastegate

how much more power can i expect? Does it hurt mpg?

i can also move the rod very easily while engine is idling with no effect to the way truck runs,,, is that a bad sign?

Before you mess with the wastegate, there are a few things you can do that will help mpg's + performance. Get a cold air intake(even a cheap one), manual boost controller, and remove the cat. Making the truck breathe will make a world of difference! Rigging a spring on the wastegate is a half-a**ed way to make the turbo spool sooner-not gain power. There are more costly ways to gain power on those trucks(intercooler setups, etc.), but you really can't make them produce too much HP. They only boost about 7-8lbs with the factory turbo-if that. Search around for a few secrets, you'll be sure to find them. As far as your w-gate rod is concerned, it's ok.

As far as your w-gate rod is concerned, it's ok.

No, it's not. You shouldn't be able to move the wastegate actuator rod at idle very easily, if at all!!!!!

The first things to do are make sure intake snorkle in the fender is removed and the downpipe from turbo to cat is not the one from factory that is squeezed or pinched off by close to 50%(mine was anyway). Install a boost gauge to see what it is running, my 93 was 4psi from factory but should have been 6psi. On the 93 with mechanical wastegate you can just add a light 6 inche spring to help keep the waste gate from opening up but don't exceed 10psi. You should see a little better fuel millage and I would guess about 20% increase in power and just all around better drivability and lower engine temps. at least thats what happened to my truck.

No, it's not. You shouldn't be able to move the wastegate actuator rod at idle very easily, if at all!!!!!

:exactly: With the truck running you should not be able to move the wastegate rod with the vacuum hose hooked up! I would check for vaccum at the wastegate solenoid, if good check vaccum at the actuator, if there is none replace the solenoid. If good at the actuator then the actuator is shot and if you get gauges put a turbo master on.

yea you can put a spring on your wastegate...search around for some pics its easy...get a few gauges first... id suggest doin the exhaust and air intake before messin with the wastegate

Can I get a liitle help for the pic's of the spring?
thanks

my truck (93 chev) Has no vacum pump. so i'm assuming i have a mechanical wastegate? so the rod being able to move easily at idle, what does that mean? and if bad how do i fix?
sorry i feel like im asking the same questions, but i got a mix of answers

redfish...look im my garage i have a pic of the one on my van turbo is different but the application is the same...

anvil....yes your wastegate is mechanical...and with out a vac pump you can move it slightly .... can you here the turbo working...when mine was stock i couldnt here the turbo at all after some easy mods it screams...as long as your not dumpin black smoke im sure its fine...

The 93 6.5t have no vac pump and have a mechanical spring loaded wastegate, the 94 and newer do have a vac pump. The lever should be a little hard to move (a little ackward to get your hand on it) but can be moved without to much trouble. The spring is contained in a round metal housing 2" dia. but has no vacumn line runing to it. If you install a gauge it will tell you very quickly your boost pressure and you will need one to increase boost pressure with a aftermarket boost controller like I think its called "Turbo Master" from Heath Diesel or Kennedy Diesel or SS Supply will carry one or similar.

Can't stress enough how important it is to remove air inlet snorkle and check your downpipe.

Sorry missed the 93 part.

Sorry missed the 93 part.

Me too.

yes, some of those trucks did have a mechanical wastegate. I belive that it shoud have sping pressure in both derections, i have three of those trucks but i think all of mine are vacume operated, i will look to be sure. I am all also a GM tech i will get you a for sure anser.

The class of 92/93 is a good sort but often over looked and misunderstood. LOL.

Ok i looked it up and the spring that holds tinchen on the valve is in the turbo. the actuator is basicly just a diafram has not spring in it.

gmbryan quoted(Ok i looked it up and the spring that holds tinchen on the valve is in the turbo. the actuator is basicly just a diafram has not spring in it.)




Thats why I don't let many GM techs near my vehicles anymore. They just don't read very well (or listen). Sorry gmbryan but I have had to many GM techs feed me BS in the past.

Again the external pot on the 93 is spring loaded.

I disected mine and its basically a spring. You can make your own wastegate Control or go easy and buy one. Make sure you get a boost guage, and keep it near stock unless your going to install a EGT guage as well.

Why do these trucks use vaccum to open the wastegate. I am more of an import guy, and use my truck to haul the car to the track, and go to work. All wastegate setups I've seen use boost to open the wastegate and a spring closes it.

My question would be, could I modify a wastegate and arm from a Mitsu turbo that opens under boost (and using a boost source of course), and use a normal bleeder valve controller to regulate boost. Then forget about having the computer mess with the boost?

What else in these trucks is affected by the vac pump? If I did what I said above, could I remove it, or is something else important relying on a vac signal? (fuel pressure, brakes,...etc)

Why do these trucks use vaccum to open the wastegate. I am more of an import guy, and use my truck to haul the car to the track, and go to work. All wastegate setups I've seen use boost to open the wastegate and a spring closes it.

its the way chevy designed it. Mine used a spring, and it wasnt adjustable. Now it is. The newer 6.5's had vaccum control so the computer could control the boost while increasing the fuel rate.


You could probaldy modify the setup to what your saying, but remember, more boost without more fuel isnt more power. If you wanted just a bit more boost and power, get a spring controll and a reprogram.

These trucks dont use vaccum for brakes, they use the PS pump.

Is the only way to control bigger injectors, fuel maps,... with a reflash or chip with these? Anyone sell a piggyback or standalone for them?

That I dont know, as I have a non computer controlled setup. I use a allen wrench!

Thanks guys for all of your input. I just found this site a week ago, and I've learned more about my truck in 5 days than I have in the 5 years I've owned the truck!!! I ordered an exhaust with down pipe(any improvment in replacing the crossover pipe?) and a boost gauge. I'll see where I stand before I start tinkering with the turbo.

Not vac to open the WG, vac closes/keeps the WG closed, venting of vacuum via WG solenoid reduces amount of vac holding the WG shut to control boost, more efficient than a fixed spring as you can meter the boost with a more finite control using PWM control of the boost solenoid. Necessary for getting best mpg, or meeting emissions.

Of course GMs wussily program vents the solenoid right about the time one needs boost the most, which is why you need to fool the PCM, or reflash if staying with vac operated, or mechanically disable it with a spring control, which can still code if not fooled or reflashed and you have too much boost "dialed in" mechanically.

Is the only way to control bigger injectors, fuel maps,... with a reflash or chip with these? Anyone sell a piggyback or standalone for them?


Go to the FAQ performance thread for more info for what one can do with the 6.5 electronic IPs