Teardown and Rebuild

[CSM]

How much faster did the twins spool off idle compared to the single?  I am thinking of off reducing off the line smoke without driving like grandpa.  

[TFaoro]

Ah that makes sense. They spool a ton quicker! Especially when the engine is warm. You need to come drive mine to actually see the difference. It's hard to quantify the numbers

[BBHD]

 

Might even start looking for a TS MVP as it's one of the few I haven't run.

I wish mine would work on your truck you could run it for a while to see if you like it. 

[NightHawk]

8 hours ago, TFaoro said:

I finally got a DP gauge installed and am not experienced in this area. As you'll see in my sig, I've got tight housings and small wheels on both turbos to keep fast spool (elevation ) I expected a very high ratio, but it isn't as bad as I thought. So onto the results.....

Smarty only on level 1
Boost: 50overall didn't look at primary DP 60
Opened the gate wide open
Boost: 42overall primary at 25 DP 55

The next test was a bit more difficult because I kept breaking the tires loose in 4th on dry pavement and didn't want to be doing 90+ in 5th.
TST on 7 smarty on 1
Boost: 70overall didn't look at primary DP 90
Opened the gate wide open
Boost: 62overall primary at 35 DP 80

So, given that what do you guys think??

I will say EGT's are sky high with the TST on and the exhaust is less than clear. The gate on the secondary could be opening early as well because the gate is set to open at 25ish on shop air. (meaning drive pressure might be opening it) The secondary's gate doesn't seem to be an issue though.

Discuss......

Its late and forgot if thread/form sharing is not liked (sorry if it is), friends at CompD can add some help. See post #01 &#12....

http://www.competitiondiesel.com/forums/showthread.php?t=107957

Edited January 17, 2016 by NightHawk

[AH64ID]

 

 

25 seems high for the secondary to be opening, but maybe it's not as bad once you throw drive pressure into it.

How much boost is the primary making when the secondary opens?

I have always liked the idea of the primary boost opening the secondary WG, but it takes a lower pressure WG to work. This way the secondary opens based on the primary being spooled, which varies based on rpm/elevation/etc.

Hook a load up to the motor and go find a grade. Then look at boost/primary/DP at a fairly fixed rpm. Partial, 3/4, and WOT. That will give you a good indication of settings.

16 hours ago, TFaoro said:

Unless you're above 25-2800 all the time, I don't think the cam is worth all the hype. That's a lot of work and money that can go elsewhere.

 

While 2nd gens are a different beast than 3rd gens, in terms of OEM cams, I disagree. I am on my 3rd cam so it's not just a OEM 3rd gen vs aftermarket.

I think a cam is a great mod, especially for towing and spooling.

It is a TON of labor thou.

Edited January 17, 2016 by AH64ID

[TFaoro]

The primary is so tight and spools so fast it's hard to tell exactly when the gate is being pushed open. From what I read, drive pressure is pushing it open well before the 25psi it's "set to"

I'll have to do that when the weather comes back up a bit.

I did pull the smarty and do more testing... what a difference. Exhaust cleans up much better and egts don't fly up quite as fast. I lost a few psi of boost without it but drive pressure is WAY too high above 2500rpm. It's around 58psi of boost and 85-90 drive pressure. I'm not sure if the secondary's housing is the worst restriction or the primary's.

[AH64ID]

If the secondary's WG is big enough it shouldn't be a restriction, but that's all dependent on the WG flow.

So without the Smarty the DP goes way up? That tells me you need more timing, but there could be other factors.

The 12cm housing is tight but at your elevation it may not be. Thou with the twins, cam, and injectors a 14cm may work better across the board.

Even at 3000' my GT3782R (64/65/.89) pushes above the 1:1 above 2600ish rpms WOT. It doesn't get as high as 1.2:1, that I recall (haven't monitored it in over a year), but at 2000 rpms it's around 0.8:1 so there is a decent rise.

[TFaoro]

I figured it needed some timing. I wish the smarty didn't make it run so dang hot at WOT but I'll put it back on a different setting for now.... unless I pick up something new.

I do wonder how well it flows. It's just a run of the mill phatshaft... can't find much info wastegate wise.

Drive to boost is 1:1 up to 40psi, and from there it goes pretty lopsided.

Do you think the small wheel and tight housing on the primary could be causing a decent amount of restriction? I've considered the 14cm housing, but I like fast spool!

In my thread on CF one of the members is suggesting tightening the gate down so I have more control with the boost elbow. In his experience he said my gate is being pushed open way early by drive pressure. I figured I'd try it... I don't see why not. If it doesn't work I'll just change it back.

[CSM]

I wonder if there is some tuning in the REVO settings that would help.  There really is no good documentation on how the REVO works, but I wonder if you reduced the duration and increased the timing... ?

On my auto, I find that the revo settings do make a big difference when it comes to the Tq Management.  My transmission shifts like crap and is VERY hard shifting with tq management off.  I haven't messed with the other settings much.  

Edited January 18, 2016 by CSM

[NightHawk]

11 hours ago, TFaoro said:

I figured it needed some timing. I wish the smarty didn't make it run so dang hot at WOT but I'll put it back on a different setting for now.... unless I pick up something new.

I do wonder how well it flows. It's just a run of the mill phatshaft... can't find much info wastegate wise.

Drive to boost is 1:1 up to 40psi, and from there it goes pretty lopsided.

Do you think the small wheel and tight housing on the primary could be causing a decent amount of restriction? I've considered the 14cm housing, but I like fast spool!

In my thread on CF one of the members is suggesting tightening the gate down so I have more control with the boost elbow. In his experience he said my gate is being pushed open way early by drive pressure. I figured I'd try it... I don't see why not. If it doesn't work I'll just change it back.

Well at-least you found the transition point, now gotta figure out what happens past 40psi (total boost assumed).   Have you measured the boost between stages and then drive between stages?  That's a sure way to find out how the system is working together. 

Never dealt with twins personally, but from the build threads I read, my is that you are relying on the primary for too much of the load.  I have always read (maybe wrong) the goal is to have the secondary carry the truck once up to boost levels, run as big of gate as possible on the primary to dump into the secondary to keep the power going.

[TFaoro]

11 hours ago, CSM said:

I wonder if there is some tuning in the REVO settings that would help.  There really is no good documentation on how the REVO works, but I wonder if you reduced the duration and increased the timing... ?

On my auto, I find that the revo settings do make a big difference when it comes to the Tq Management.  My transmission shifts like crap and is VERY hard shifting with tq management off.  I haven't messed with the other settings much.  

I never noticed the settings being "fine" enough to "tune" it in right. To me they seemed like a go or no go. I can always try though....

6 minutes ago, NightHawk said:

Well at-least you found the transition point, now gotta figure out what happens past 40psi (total boost assumed).   Have you measured the boost between stages and then drive between stages?  That's a sure way to find out how the system is working together. 

Never dealt with twins personally, but from the build threads I read, my is that you are relying on the primary for too much of the load.  I have always read (maybe wrong) the goal is to have the secondary carry the truck once up to boost levels, run as big of gate as possible on the primary to dump into the secondary to keep the power going.

Just for reference, the primary is the large atmospheric turbo, and the secondary is the small turbo 

I do have boost between the stages, but I don't and will never have drive pressure between stages. 

I know it sounds lopsided, like the secondary (small turbo) is working to hard when I say the primary (large turbo) is building 35psi and the overall is 62 BUT let me try to explain.

The compressor maps for each turbo are given by the pressure ratio. That's how you determine how hard each turbo is working.

So if we take the large one and calculate the pressure ratio we get   (35+12) / 12 we get   3.9167 

(35 is the boost the turbo makes, add the 12 because that's what atmosphere is here in Denver, and divide by the pressure the turbo is being fed at, which is atmospheric)

Then we calculate the small turbo:    (62+12) / (35+12) we get 1.5745.    

As you can see, the small turbo isn't even doubling the pressure it receives, while the large turbo is compressing almost 4x the pressure it receives. This tells me the primary is getting it's tail worked off while the secondary isn't doing much. Hopefully that makes sense.....

[NightHawk]

2 hours ago, TFaoro said:

I never noticed the settings being "fine" enough to "tune" it in right. To me they seemed like a go or no go. I can always try though....

Just for reference, the primary is the large atmospheric turbo, and the secondary is the small turbo 

I do have boost between the stages, but I don't and will never have drive pressure between stages. 

I know it sounds lopsided, like the secondary (small turbo) is working to hard when I say the primary (large turbo) is building 35psi and the overall is 62 BUT let me try to explain.

The compressor maps for each turbo are given by the pressure ratio. That's how you determine how hard each turbo is working.

So if we take the large one and calculate the pressure ratio we get   (35+12) / 12 we get   3.9167 

(35 is the boost the turbo makes, add the 12 because that's what atmosphere is here in Denver, and divide by the pressure the turbo is being fed at, which is atmospheric)

Then we calculate the small turbo:    (62+12) / (35+12) we get 1.5745.    

As you can see, the small turbo isn't even doubling the pressure it receives, while the large turbo is compressing almost 4x the pressure it receives. This tells me the primary is getting it's tail worked off while the secondary isn't doing much. Hopefully that makes sense.....

Well the build between close friends has always been larger then stock singles (my preferred due to simplicity) and it shows !  However displacement and configuration (v8 vs inline 6) play a role as well.

The explanation makes sense, tighten up the secondary gate to drive it harder sounds like a solution to try forward but a drive between stages (temp) would help you tune the setup.  As someone who looks in from the outside on a twin setup, seems getting the turbos to play along is 90% of the uphill battle.

 

Edited January 19, 2016 by NightHawk

[TFaoro]

I did some more "playing" with it tonight. This time I set the smarty to level 3. Funny thing, the overall boost didn't change when I messed with the boost elbow, but the primary boost did. 
Boost elbow closed: Primary 20psi, overall 62, drive pressure 95
Boost elbow opened: Primary 30 overall 62 drive 90.

Not sure what the heck to think about that....

[CSM]

The smarty confuses the heck out of me...  I love how my truck drives with it compared to any Edge product I've tried...  I like the TST a lot, but some of the changes in how the truck behaves with minor Smarty changes make you really wonder what in the holy hell is going on.  

 I really wonder if you shouldn't call Marco at Smarty and pick his brain a bit... You might get lucky.  

If I could have one document for the VP truck truck, it would be a treatise on how the Smarty works and how to tune to it by the makers of it.  I think it is amazingly powerful, but sadly untapped. 

ETA:  

I found it fun, and helpful, to take a dead hour on a saturday road trip, and stop every 5-10 miles and reflash my ECM.  I eventually found a tune with the REVO settings that works quite well at 300ft agl.  Zero lag, lots of boost, and the TST just makes things crazy.  

I have yet to find the "tune" for high altitude. 

Edited January 20, 2016 by CSM

[AH64ID]

What does the TST do and what is adjustable on it?

[CSM]

1 hour ago, AH64ID said:

What does the TST do and what is adjustable on it?

Fueling box that has a set of 1 - 10 power levels.  It seems to control fuel more off boost pressure than other fueling units and is much smoother than say an edge.

[AH64ID]

Does it do anything with timing?

[TFaoro]

No, it's a fuel only box.

[AH64ID]

Ok... so let me think out loud. Caveat is a I am not a VP guy, but a diesel is a diesel right!!

 

So what is the highest TST setting you can run on your airflow with good EGT's and only a greyish haze?

[TFaoro]

I'll have to check but probably level two, maybe level three.

Thanks for the help BTW!

Edited January 20, 2016 by TFaoro