Engine/Transmission (1994 - 1998) Wastegate hose ?

[RedRamer]

On my 97, I got a small rubber hose going from the wastegate valve to the turbo neck on the pressure side.

Is that all there is to control the boost?

Doesn't the boost have something to do with fueling requirements?

thanks

 

[WadePatton]

That controls the wastegate. Pressure from the turbo actuates the wastegate to bleed off boost around 20psi-stock.



Restricting the wastgate through various methods allow more boost to be made. Adding fuel creates more boost more faster. Dunno 'bout 97's but 24v trucks must have computer "fooler" to make ECM think no more than 20# boost is being made.



Mine makes 34#--I adjusted it down from 43#.

 

[illflem]

In addition to what Wade said, you're better off to adjust your max boost up with the linkage on the wastegate rather than totally plugging the hose like some folks do. Boost over 35 psi will run your egts up and can blow head gaskets.

 

[Todd T]

the same applies. you will need to put in a tighter AFC spring to slow the AFC lever up and keep the smoke down. also if you have enough fuel to overboost the wastegate you should install a boost elbow to restrict the pressure to the wastegate to keep it from bleeding off your boost. you can get a boost elbow from TST products for $25



hope that helps

Todd



ON EDIT: i would caution telling people to mess with the wastgate adjustment. first of all most of them are rusted to beat the band and you could wind up bending or worse yet, breaking it trying to free it. secondly they are kinda tricky to fine tune and you could easily get yourself in a wad trying to do it if you never have before. a misadjusted wastegate is the easiest way to rob HP from these trucks.

 

[RedRamer]

thanks guys...

OK, I think I got it.

Boost is made up by the amount of fuel you pour to it. Directly related to intake air flow.

So, no matter what the intake air flow is, when the boost pressure gets to about 18lbs (Max on mine), the wastegate opens up.

Can I fine tune turbo pressure so that it kicks in with a bit more boost at lower speeds with that elbo?

 

[Hogan]

You guys are right on about the advantages and disadvantages, but I've never seen the wastegate hose attached directly to the turbo. I have a 1997 also and the wastegate hose goes to the AFC. There's a T fitting on the AFC where the wastegate hose and intake hose connect. If the boost at the turbo and intake are the same at the same time then I don't see a problem with it being either way, but if they're not then that could cause some fueling or boost problems.

 

[chrleb1]

If you want power a little sooner, that is all in your AFC housing and not fine tuning your turbo. The lighter your spring in the AFC (or moving the star wheel forward), the less amount of boost is required to start fueling hard. You can run more than 18lbs of boost, in fact i would put a boost elbow on so that you get some more. When you have more air you can clean up some of that smoke (not like smoke is a bad thing).

 

[RedRamer]

Hogan

I read about some lines going to the AFC.

Mine goes straight to the turbo pressure end of things.