VGT off?

[jordan572]

So the duty kind of acts like an upper or lower limit?

 

[drunk on diesel]

I don't know what the actual logic path looks like, but yeah, the duty cycle is essentially the vane position. BUT, the desired backpressure obviously have an effect on vane position as well.

I don't know which trumps which or how the tables work together, but Brayden Fleece taught me not to peg out the vnt solenoid on the older style. I ran mine at 97%. I have my current self-imposed limits at 5% and 95%

 

[TD-5]

Under the Turbo values heading there are the minimum & maximum duty cycle limit settings. I figured these would limit the actuator from bottoming full stroke at either end. H&S has lowered the minimum limit from 7% to 2%.
d on d makes a very good point, probably a much better idea to set the table values inside these limits for added insurance. I will change my 0.0 % to 3-5% just to be safe.

 

[drunk on diesel]

you could probably peg them out without any issues, it's just old habits die hard... 2-3% should be safe. I would imagine that the 6.4's controller is far stronger/more advanced than the old style solenoid

 

[jordan572]

If you bottomed them out on the older style would the actuator put constant pressure on that bottomed out position or something? I will take your word for it and set them a few percent off 0 and 100 but I like to always know why.

 

[grimrippy23]

Has anyone had any problems with messing with the vanes? Also i don't think you can but just wondering is there a way to make the vanes be open on one tune and my other 3 tunes be the normal h&s tunes? I am new to the mcc tuning and trying to feel my way around it.

 

[B585Ford]

Has anyone had any problems with messing with the vanes? Also i don't think you can but just wondering is there a way to make the vanes be open on one tune and my other 3 tunes be the normal h&s tunes? I am new to the mcc tuning and trying to feel my way around it.

I have never had any problems when adjusting them. They cannot be adjusted by shifting on the fly.

 

[TEXAS6.4]

got my mcc today and trucks out of the shop...
looking at doing this because now i have upfitter #3 hooked to a relay that kills power to the vgt actuator and id like to do that in the tune instead. i set all backpressure tables to 0 at <1000rpm done deal, but while im in here i need to adjust some things on top end i wish the truck would just make 40psi instead of hitting 40 and turning down power levels because boost still climbs and so do egts. it seems better now with the manifolds and up pipes but i can only have my foot in it for about 6 seconds and the tuner is backing down to stock at 1600EGT. its hard to win a race when you lose power as soon as you hit 65mph. from what i see theres no boost control only backpressure control i would always want minimal backpressure but from what i understand it'll never spoolup if you dont have it there right?
from what i see daily driving my truck, i only need the vgt from 1000-2000rpm or say 0-40mph i feel pretty confident the atmosphere charger has it all by then, and i should be able to disable the vgt by making desired backpressure 0 in the higher ranges?
or will that not help and i need to adjust timing or duration?
is it possible to have a 550hp truck with stock turbos and egts that arent thru the roof at high speed?

 

[drunk on diesel]

without a wastegate, you're probably not going to be able to limit boost to 40psi on a race tune

H&S sets it to 5% on their hot tunes in on the top end.

to answer your last question? no

 

[TEXAS6.4]

figured that nature of the stock setup im running H&S 250 tune im not worried so much about boost as i am egts tho, any way you think just to make it more manageable i mean if h&s was the best, there wouldnt be custom tunes out there now would they

 

[powerstroked08]

In my opinion yes H&S is the best tuning device. They have some good canned tunes, but NOTHING is better than a custom tune for YOUR truck. And no you don't want to set desired back pressure to 0 after 2000 rpms. That won't solve your issues. The VGT is all about throttle response. You want agressive bp at low throttle and for it to level off later on in the rpm range. Topping off at around 60-65. Setting the minimum duty cycle to something like 2% vs. 7% will help, but the ansewer is bigger chargers.

 

[drunk on diesel]

Yup, turbos are the answer to the EGT question

 

[B585Ford]

You need boost to keep EGTs down like everyone is saying. You need EBP to make boost. You can watch your trucck and RPMs and then lower your EBP at those RPMs. The only way you are going to get EGTs down without more boost is to cut the PW at WOT. But that will be happening thruogh every gear. With enough time and tweaking you could probably get EGTs to stay in check for your setup but that will take a lot of tweaking.

 

[TEXAS6.4]

You need boost to keep EGTs down like everyone is saying. You need EBP to make boost.

correct, but in a compound turbo system your ratio of boost to drive pressure should be near 1:1.
boost is great but excessive back pressure isnt, and i could see with a turbo as small as the vgt on a 6.4 it would be easy for the engine to be pushing more exhaust at it than its getting in return on the intake, nature of an engine designed for EGR who'da thunk it. cant believe theres not even a table in here for boost pressure
have you changed your duration? do you see much loss of power with just a couple millisec?

 

[TEXAS6.4]

You want agressive bp at low throttle and for it to level off later on in the rpm range. Topping off at around 60-65.

max backpressure in the h&s canned 250 tables is 50psi

 

[drunk on diesel]

1:1 is great and all, but it's not necessary... and it doesn't matter if it's compound or single, 1:1 is a great ratio to shoot for.

Bottom line is the factory turbine wheels and housings can only flow so much. The only ways to bring down backpressure is to reduce fueling (thus reducing exhaust volume), add a waste gate, or open up the turbos

 

[B585Ford]

1:1 is great and all, but it's not necessary... and it doesn't matter if it's compound or single, 1:1 is a great ratio to shoot for.

Bottom line is the factory turbine wheels and housings can only flow so much. The only ways to bring down backpressure is to reduce fueling (thus reducing exhaust volume), add a waste gate, or open up the turbos

:whs: I didn't have a EGT issue but I did have a EBP issue with my setup (I would hit 70 (actual EBP) and still climbing when I would let off (and that was on a stock valvetrain). With the help of Dustin, I tried manipulating the EBP tables, then the vane tables and it didn't help much cause when the RPMs get high enough (and the airflow is great enough) compounds can't overcome the restictions in the system (HP turbo, poor low of heads, etc.). The only way I got that down was to cut the PW. Again, with a lot of trial and error, you might get to a point where your power loss from cutting the PW would be minimal.
For the quickest spool up, 1:1 is not optimal. On these trucks with relatively stock fuel and turbos, I would say 1.5 to 2:1. Once you light the atmo turbo, then 1 to 1.2:1 would be a great ratio.

 

[Stroked777]

In my opinion yes H&S is the best tuning device. They have some good canned tunes, but NOTHING is better than a custom tune for YOUR truck. And no you don't want to set desired back pressure to 0 after 2000 rpms. That won't solve your issues. The VGT is all about throttle response. You want agressive bp at low throttle and for it to level off later on in the rpm range. Topping off at around 60-65. Setting the minimum duty cycle to something like 2% vs. 7% will help, but the ansewer is bigger chargers.

What would changing the minimum duty cycle change? Allow the vanes to open further?

 

[B585Ford]

What would changing the minimum duty cycle change? Allow the vanes to open further?

My experience has been that it wouldn't do much. My very first attempt at lower the EBP as well as making an exhaust brake was to change all the tables related to vane position. It did not do anything I could appreciate. As soon as I changed the EBP tables, I saw a difference. During my exhaust brake experiments, I couldn't get the EBP as high as I wanted...I set the EBP table to 50 but could only get about 30 at 1700 RPM. Then I changed the vane tables which did give me a little more. My point is simply that it seems like the EBP tables took the "priority" over the vane tables. When I was trying to lower EBP, doing all the adjustments helped, but once I got to certain RPM, even with the vanes set at 4%, the EBP would continue to climb beyond way beyond the desired EBP (because of the air flow restrictions in the system). That is when I found only by cutting the PW did I reduce EBP.

 

[Stroked777]

Instead of starting a new thread about it I'll ask it here seeing this thread is named vgt off

Has anyone made a pulling/racing tune to use at the tracks that turns the vgt off? What I'm getting at is would it help lower ebp because essentially it would be just like running a single. I know the lag would be bad off the line but in both sports you gotta brake boost anyways, anyone give this any thought or kinda get at what I'm saying