Holset VGT 5VZ-FE turbo build

Well since I'm gonna use the wastegate to regulate pre-turbine pressure, and therefore boost pressure, the vanes will really only need to be set to "follow" the turbo speed as it increases. Basically match the flow velocity to the radial velocity of the turbo. That will basically be a matter of testing.

I do have a GM MAP sensor wired in and working that I use as the boost gauge. So there's always that option to experiment with.

 

Well since I'm now having to use a wastegate to regulate pre-turbine pressure, I'll be essentially controlling max boost anyway. The vane control will now just be a matter of having the vanes "follow" the turbine as it speeds up - trying to match the velocity through the stator to the turbine speed at all conditions to maximize the acceleration. But that'll take some trial and error to dial it in.

MAF voltage would actually be harder to work with than TPS since the signal is far messier in the MAF. The TPS is just a potentiometer.

 

That's a a nifty way to mount it for sure. I like.

Still have the stock engine mounts (262k). I clocked the compressor housing a little more to help it clear and stuck about .4" worth of washers under the hood and now there's no rubbing at all even under heavy engine braking. For now I'm happy.

 

Problem with that is, when you mash the throttle, your vanes will go wide open. If you can, I would map the vanes with either the engine speed or boost levels.

 

Right, but I wasn't saying I'd use that as the control input, we were just talking about those inputs purely from a signal processing standpoint - see previous posts. You would be right though.

If the max nozzle area was big enough to keep the max speed down around 70000 RPM, then I'd just take in MAF, TPS, and RPM to create a load vs RPM table of a target shaft speed for all load and RPM conditions, but since the max nozzle area isn't big enough, I'll have to use a wastegate to regulate the top end speed Vane position will just do the job of speeding transient response by opening up in proportion to the turbine speed. So boost pressure will be controlled mechanically and spool speed will be controlled by the VGT.

 

I don't see the point now that you're adding a external WG really..why not just leave the vanes closed all the time to have the fastest spool possible and let the WG do the rest. seems over complicated.

 

Gotcha, sorry, was skimming your posts.

Agreed. Not to be a rain cloud in your build thread, just not sure why you are stuck on making this particular turbo work vice getting a better suited turbo.

 

I mean he gets boost plenty fast with the vanes closed..and it'll be a very efficient turbo...just...don't see the point of actually utilizing the VGT part now..

 

I was looking into why variable vane turbo charges and found this:

https://www.youtube.com/watch?v=J06nj5-B_AE

Now this guy can probably write a dissertation on how a hammer works but its a pretty cool technology.

 

Wow. That pretty cool. Very simple.

 

Sure, I could bolt on some boring 35 lb/min turbo and get my power goal and reasonable spool. But it wouldn't be ridiculous.

It will be a very inefficient turbo if the vanes were to be closed fully all the time. Leaving the vanes closed just creates tons of excess back pressure that chokes the engine and reduces total power output.

The reason why variable-nozzle turbos exist is so you can constantly be changing the the flow angle and throat area to suit the turbine as it increases in speed. I have a textbook on radial turbines on my desk right now. I'm not an expert on radial turbines, but it's straight outta the book.

 

Why is everyone bagging on OP when it's pretty clear he's tinkering around just for the sake of tinkering around? Everyone on the forum has tons of ridiculous shit on their trucks that is 100% unnecessary. Seriously, every other post in this thread is some pessimistic and completely unwarranted bull shit.

I've seen ever single one of you make the comment "it'll never be a race car." Why don't we stick to that mantra and quit trying to hijack or back-seat OP's build and let him build his truck the way he want's, optimized OR otherwise.

Fuck.

 

This is probably the most pessimistic post in this thread if you ask me

I was just curious; "it wouldn't be ridiculous" is a very sufficient answer.

 

no

 

Uhh..what??

I think most of us have been asking questions and he has been answering to his ability and tinkering like crazy.

God forbid we ask questions and point of stuff we ourselves don't understand.

Gtfo.

 

Whoa fellas, it's all good. People are asking valid enough questions.

I know people don't necessarily agree with my approach with this whole build. Just believe me that spent a lot of time planning and considering how to best use a variable geometry turbo on this platform. This is, like it has been said, a learning exercise that will also increase the power a bit for towing and driving on our highways in CO that routinely go over 10,000 feet in elevation.

 

Any fuel mods planned bro?

I've seen some people go boosted in Colorado without running any fuel mods because of our elevation.

 

For now I'll just limit to whatever the stock injectors can handle. I just installed a wideband so I'll be able to find that limit then back off a bit.

Anyway, back on topic with updates:

APSX wideband installed:


Precision PW39 wastegate and dump pipe
(fits, surprisingly):




Anti sieze so I don't go postal if I need to unbolt the wastegate later:


I can't wait for mountain season...

 

Neat build.

 

It will be a Race Truck!