Stock twin vgt

[little luke]

To begin with, assume fabrication is not an issue.



I know there are plenty of proven setups for reliable power out there, but this is more or less a "I did it!" thing.



Ok, so the setup in question would be using to identical stock vgt turbos, preferably 2006 models since I already have one, in a twin configuration. Without knit picking the smaller issues at the moment, what would be the downside to this setup? My knowledge on turbos is limited.

 

[drunk on diesel]

downside would be never being in the compressor map...

 

[little luke]

I'm reading up on the Garrett turbo website on compressor maps. Honestly I'm not following you at the moment.

 

[drunk on diesel]

it won't work...

 

[shmoozer]

They will constantly be out of their effective operating range

 

[strokin6L]

The turbos would need to be smaller than the stock one in order for it to work.

 

[Mwilbur516]

downside would be never being in the compressor map...

They will constantly be out of their effective operating range

The turbos would need to be smaller than the stock one in order for it to work.

Yes, yes and yes.

Can you do it, sure. Will it work, probably not worth a crap.

You would need two smaller turbos than stock. Plus, the stock VGT's would present the issue of figuring out how to control the VGT solenoids of two turbos. I guess there is the possibility that since they are in a twin setup as opposed to a compound setup, that simply piggybacking a second VGT plug off the harness MIGHT work. In theory they should actuate the same all the time.

I'm all about people trying different things. In in for the build if you decide to try, though I think you'd be better served going a different route. If you need anything on your journey, let me know.

 

[drunk on diesel]

definitely not worth a crap...

turbos are not magic. you can't just up and double the size of a turbo and expect it to work

 

[SSpeeDEMONSS]

What are the inducer and exducer measurements on a stock charger? Compressor and turbine.

Garrett

 

[KCTurbos]

Are you talking actual twins... or compounds...

for twins... what everyone already stated is correct. Study compressor maps a little more and mess with these two websites... they will help out.

http://www.squirrelpf.com/turbocalc/
http://www.not2fast.com/turbo/gloss...p=21&SFC=0.386&AFR=21&maxInjectorDutyCycle=85


Here is a screen shot of what a gt3582 turbo would look like on a 3.0 liter motor making 250hp (basically 1/2 of the twin setup). Multiply it by 2 and you end up with a 500hp 6.0 liter motor. This was done assuming an 18:1 A/F ratio (semi smokey). It was also assuming boost does not even start till 2000rpms (really laggy setup).


You can see that you are basically left of the surge line the whole time. That would basically just surge the whole time and run like crap. It might JUST BARELY run if you are taking it really easy the whole time. Add any more fuel and try to spool the turbos any sooner and the setup would be un-driveable without surging.

I hope you don't take any of that as "bashing"... I only know because I myself looked into the idea and was told it would run like crap... So i researched the heck out of it until I understood why it would not work.

Hope that helps

 

[TheReelMuhcoy]

I know there are plenty of proven setups for reliable power out there, but this is more or less a "I did it!" thing.

That being said, I say "do it!" so you can say "I did it!"

I don't know how far you would want to take the build, but you could consider over-boring the pistons for more displacement which may help get you closer the compressor map that's being referred to, although that may be a far stretch.

I like outside the box thinking, and I just feed off of everyone else's negativity, so.... Give 'em hell!

POST THOUGHT: controlling the twin VGT is rather simple due to the way that 6.0's work, it's a voltage signal. If you do proceed let me know and I'll help you out with that.

 

[swinky]

That being said, I say "do it!" so you can say "I did it!"

I don't know how far you would want to take the build, but you could consider over-boring the pistons for more displacement which may help get you closer the compressor map that's being referred to, although that may be a far stretch.

I like outside the box thinking, and I just feed off of everyone else's negativity, so.... Give 'em hell!

POST THOUGHT: controlling the twin VGT is rather simple due to the way that 6.0's work, it's a voltage signal. If you do proceed let me know and I'll help you out with that.

Most horrible idea ever. Hell why don't we just have a stock turbo for each cylinder while we're at it.

 

[drunk on diesel]

that's just plain mean!

can't tell you how many times I've seen people try this in the 15+yrs I've been in the diesel performance community...

EVERY time somebody proposes this people try to talk them out of it... every 5th or 6th time, they don't heed the knowledge and go ahead and build it. and it NEVER works. I will say that every time I've seen it done, it's been on a Cummins. Probably because they're easier to work on?

But it doesn't matter what engine you try it on, physics is physics. Think outside the box all you want, but realize that sometimes that box is there for a reason.

That being said, I say "do it!" so you can say "I did it!"

I don't know how far you would want to take the build, but you could consider over-boring the pistons for more displacement which may help get you closer the compressor map that's being referred to, although that may be a far stretch.

I like outside the box thinking, and I just feed off of everyone else's negativity, so.... Give 'em hell!

POST THOUGHT: controlling the twin VGT is rather simple due to the way that 6.0's work, it's a voltage signal. If you do proceed let me know and I'll help you out with that.

 

[little luke]

Ok, after some reading I believe I understand the surge line, left side of the map thing. Those web sites are pretty neat, still have a lot to learn though. Thank you all for the info.



Stupid question, but is this the equivalent of running a single turbo twice the size of the stock one?



Yes, my idea for controlling the turbos was to splice a second plug into the harness.



I did try and search for some others experience before posting this, but mostly what I found was "it won't work". The idea is brought up mostly in the Cummins forums. Was kinda hoping to find someone who said "i did it, it worked out." or "i did it, please don't do it"



Ok, so entertain me for the moment. Take a step back and forget using the stock turbo. If you still wanted to utilize a vgt turbo, what size would "work". Or am I still missing something completely.



This whole thing is further down the line. I've got a tdi to finish building, 4 sets of traction bars, a 600^2ft two story steel porch to build, and a nursery to build due to a little one on the way. So I'm proboly only going to be able to think and plan what I want to do come spring.

 

[drunk on diesel]

yes, it's essentially the same as putting a turbo on that's twice as big as stock...

go get you a VGT off of a big Cummins 18 wheeler and put it on... the truck isn't going to do anything. if you tighten the **** out of the VGT to try to get boost, it's just going to surge

I had a powermax VNT with a custom controller on my '06 Cummins. You can't magically overcome a compressor map with a variable turbine section, if you try to come up on boost early and you're on the wrong side of the surge line, the turbo will just sit there and bark.

as far as going with smaller turbos? the obvious first question is "WHY?"

beyond that, the problem with smaller turbos on a diesel is you typically run into less and less efficiency at high pressure ratios. a 6.0 is going to want 35-45psi or more. looking at tons of compressor maps, you'll note that as you go smaller on the compressor side, you typically go lower and lower on effective pressure ratio. Why that is, I don't know...

I'm not trying to come off as a high and mighty know-it-all, but in the 10+yrs the 6.0 has been out and with the countless numbers of performance minded enthusiasts that have owned them, I assure you that you're not the first person to consider this. I honestly feel the reason that you don't find many posts on the forums from guys saying "don't do it, I tried and it didn't work" is because they're embarrassed.

I have read a couple of those posts over the years, and while I commend a man for getting out there, getting dirty, and DOING something, I just kinda shake my head because it's painfully obvious how it's going to unfold... I'm lazy and hate wasting time/money/energy. I will admit that I've never been a front runner in this industry. I like to sit back and let other people burn the money on development. Then once there's a clear path as far as what works and what doesn't, I get on board! LOL

At the very least, this will be a great lesson for you in learning more about turbochargers, compressor maps, etc.

cheers

 

[Mwilbur516]

There was a TRUE twin setup on a 6.0 in some old iron (60's Ford wagon of some kind IIRC), in Diesel Power mag about a year ago. Dude had upgraded fuel, done the twin setup (one turbo feeding one bank) and spent tons of time and money in the build. The car was awesome and the engine was very clean. But for all the work and money he had in it, he ended up with about 425RWHP. you could get that with a tune on an otherwise bone stock 6.0. I'll look for the article later. Just some food for thought.

I'm not bashing you or your need to do it yourself at all. Your attitude is admirable, but it's like I tell guys all the time , there's a LOT more to it than just throwing fuel and air onto an engine.

 

[swinky]

200 frame charger may work. Like a s258 or something.

 

[SSpeeDEMONSS]

Would someone like to say what the inducer and exducer is of the compressor and turbine?

Garrett

 

[little luke]

I'm not taking any of this as bashing. If I didn't want the opinions I would have just said **** it and built it. The fabricating and controlling the turbos didn't seem like an issue, but if it was that easy I figured I was missing something. Proboly would have made it all the way to the turbos coming apart and then got on here and asked what happened. Honestly I'm not interested in it if stock turbos won't do it, just because I was figuring I could do it for less then a grand. Already have one in perfect condition and decent stockers can be had for $300. Back to the drawing board.

 

[little luke]

I think its a 58mm/82mm