What is the size of the D-Max's factory turbo? Isn't it internally waste gate'd too? Any info you guys know, like A/R ratio, inducer or exducer bore size would be helpful too. Don't the newer turbos have variable turbine area as well?

I'm just curious as to how the factory sizes the turbos for these beasts.

 

The LB7's have the fixed vane turbo and have a wastegate. The LLY's use a VVT (variable vane turbo) in which the vanes position themselves according to how much boost is needed, and no wastegate is used. I don't know the size of either.

 

Yeah, the one on the LLY is the one I'm thinking of. I don't understand how they don't use a WG on it though. That must be one finely tuned turbo!

 

The exhaust turbine uses adjustable blades/"vanes" to control the boost instead of a normal wastegate.

The turbine blades are not fixed like on a standard turbo.

 

I understand that, but just like Aerocharger's old VATN turbos, they should utilize a wastegate.

 

When the computer reaches max boost it will change the vane angle to limit the amount of available boost just like a wastegate. It is very responsive, in fact the LLY turbo is much harder to bark than the wastegated one on my LB7. When the blades are commanded fully flat you loose all boost in a hurry and it seems to bleed off much quicker than a wastegate setup.

 

The technology must be to the point where a wastegate is not necessary now.

BMDMAX - Thanks for the explanation.

 

Wow! The computer controls the angle of the vanes!!! Damn that's sweet.

Thanks for the info, but what does it use to control the angle of the vanes? What does it use to KNOW the angle of the blades?

 

There is a vane position sensor on top of the turbo that reads where the vane angle. The ECM then uses the APP, ECT, GEAR, LOAD, MAF, RPM and BARO to control boost. It uses the vane position sensor as feedback on what position the vanes are in at any given moment. It uses the boost sensor just to make sure the boost is at a pre calculated # based on load, rpm, ect. The vane position sensor is 1 volt when open and 3.5 volts when closed. One thing that the tuners are working on is if the ECM thinks the vanes are open a little more than they really are it should make more boost. Just don't fool it to much or the pressure sensor is going to tell the ecm that there is to much boost for this rpm/load and cause the sytem to throw a code or punt.

Gotta love technology.

 

Wow! That's awesome! That's about as good as it gets for turbocharging.