95' Junker Drag Truck

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CorneliusRox said:
Can you help me understand how these work? And they are in the OD housing, but they help control all shift points?

Do they spin and push back on the line pressure, and the heavier the weight the quicker they overcome pressure and allow flow in order to shift gears?

Also, where did you source them? I wouldn't mind 4000rpm shifts if you get it back together and it does shift higher!
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There are two hard lines on a RH tranny extending back into the tail housing from the main case. There is a sleeve they lead to that interfaces with the governor at the (3) orange seals pictured on the governor. Line pressure if fed down one line, through the sleeve, and into the governor assembly. There is a simple mushroom shaped valve (pictured above) that controls how much line pressure passes through the governor, to the other half of the orange seals/sleeve and back to the governor pressure circuit in the main case. As output shaft speed increases, the centrifugal force increases and the governor weigh pulls the mush-room shaped valve which allows more line pressure to enter the governor pressure circuit.

There are two ways to "raise the shift points" by mods to the governor:
1. Lighten the governor weights(or swap the diesel brass for gasser brass/aluminum)
2. Swap out the aluminum mushroom shaped valve for a heavier steel version.
 
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Big Blue24 said:
This is a different color, but same product, it is not SFI rated 45.1 but rated padding is not required till 9.99 ET. This was cheap and easy, great for figuring out how much to order, how it fits, etc. If/when this truck needs a certified chassis, then I'll get the better padding.

http://www.jegs.com/i/JEGS+Performance+Products/555/70003/10002/-1
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Yeah, I wasn't sure if you were planning to run 9s or not since you built a full cage instead of just a bar. I guess you're just preparing for the future.
 
Big Blue24 said:
GovernorSwap3_zps031646e7.jpg




There are two hard lines on a RH tranny extending back into the tail housing from the main case. There is a sleeve they lead to that interfaces with the governor at the (3) orange seals pictured on the governor. Line pressure if fed down one line, through the sleeve, and into the governor assembly. There is a simple mushroom shaped valve (pictured above) that controls how much line pressure passes through the governor, to the other half of the orange seals/sleeve and back to the governor pressure circuit in the main case. As output shaft speed increases, the centrifugal force increases and the governor weigh pulls the mush-room shaped valve which allows more line pressure to enter the governor pressure circuit.

There are two ways to "raise the shift points" by mods to the governor:
1. Lighten the governor weights(or swap the diesel brass for gasser brass/aluminum)
2. Swap out the aluminum mushroom shaped valve for a heavier steel version.
Click to expand...

Thanks for the lesson!
So is this only on an RH, and then on the RE's it is based on the offset between the gov solenoid and gov transducer (line pressure in that port)?
 
Maybe it is based solely on preference but wouldn't it much easier to go to a full manual valve body?

I guess what I am asking is there a reason a regular valve body would be preferred over a full manual other than ease of driving?
 
zfaylor said:
Maybe it is based solely on preference but wouldn't it much easier to go to a full manual valve body?

I guess what I am asking is there a reason a regular valve body would be preferred over a full manual other than ease of driving?
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Consistence I am thinking.
 
Have you thought of going to disk brakes on the rear? A lot lighter than drums and better brakes. I did mine on the cheap with chevy rotors and calipers and speedway brackets cut and welded to the flange on the rearend.
 
CorneliusRox said:
Consistence I am thinking.
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Correct, I like the consistency and freedom it gives to steer and control traction rather than focus on those early quick shift points, although each time I have to take it apart to modify the shift points, i'm tempted to spend the $250 on a shifter and $130 on a TFOD-3 kit and make it a full manual.

gwhammy said:
Have you thought of going to disk brakes on the rear? A lot lighter than drums and better brakes. I did mine on the cheap with chevy rotors and calipers and speedway brackets cut and welded to the flange on the rearend.
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I seem to have great rear brake power with the drums and upgraded GM cylinders. No problem holding 20 psi boost launches now, it's just more a factor of getting the rear to hook with such a brutal launch!

24vriviera said:
Drums hold better on the line by a good bit.
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Although I haven't tried disks, my research leads me to believe that this is correct. The real advantage of disks shows up on long hill descents or stopping big loads in that they have much better head dissipation and therefore less brake fade.
 
Love my full manual valve body. It took a little to get use to but now it's second nature I shift by feel and sound, just about perfect for each circumstance. Although a shift light for that perfect rpm would help sometimes.
 
Little Update:

As difficult as it is to post updates about failures or lack of forward progress, I feel it's important to be transparent about the ups and downs of racing with a low budget diesel truck and to show that sometimes things that look good on paper might not always be the best performance move.

The new DPC V-10 stall quad disk spools up excellent, no problem spinning the slicks in a dry burnout box at the track (they don't put water in the box on street legal night).

While performing modifications to the governor, I also added a much stiffer pressure regulator spring to the valvebody to increase line pressure in the transmission. What I found out is if I command too much pressure at idle, it robs the lube/release circuit and the torque converter will lock-up and stall the motor when shifted into reverse or any forward gear.

As a quick fix to get it to not stall, I had to remove all pre-load from the TV lever. This in turn made the tranny shift really, really, early like 1200 rpm shifts but dropped the idle pressure low enough to prevent the converter from locking up and stalling the truck.

So for my first pass, I tried to manually shift the truck knowing full well I wouldn't achieve torque converter lock-up till 3rd gear. Well it spun off the line, I then pushed the shifter too far and went to neutral, then clicked it back into drive only to have forgotten to turn-off the factory PCM controlled overdrive so it immediately grabbed overdrive and lock-up which spun some more and finally pulled through to the end of the track at a blistering 14.28 @ 110 MPH with a slow 76mph 1/8th mile trap speed.

The second pass I was lined up next to a Nissan GTR. I really wanted to beat a GTR since I've never beaten one. Well I bumped into the lights too deep (fully staged) and left myself no time to spool. The lights activated quickly and I had maybe 2 psi boost.

This resulted in a poor 2.35 60' time, 8.38@95mph 1/8th and a 12.53 @ 116.4 MPH. The GTR ran 11.65 @ 119.82 and beat me by several car lengths.

[ame="http://www.youtube.com/watch?v=v24Gu76O4jU"]http://www.youtube.com/watch?v=v24Gu76O4jU[/ame]

On the third pass, I decided to leave the shifter in Drive, with the lock-up switch turned on and see what it would do. It bogged the motor down and snuffed out the chargers in 3rd gear, then when it re-lit, it spun. The result was a 2.0 60' time, 7.96@94mph 1/8th and 12.1@117.77 MPH 1/4mile.

[ame="http://www.youtube.com/watch?v=8hLgHtpAB3U"]http://www.youtube.com/watch?v=8hLgHtpAB3U[/ame]

I haven't sorted out why it is so down on power, but I will figure it out. Despite the tranny acting up, it still gets good full pulls on the topend and it's only picking up 23.38 MPH on the second half of the track. In Bakersfield it was picking up 24.6-25.2 MPH on the second half of the track. There is a noticeable power drop around 3000 rpm. I loosened up the wastegate for the final pass, however, the truck developed a new small oil leak and I was unable to make a 4th pass. It's too early to tell if the lost power is from the HX40 turbine wheel, dirty fuel filters from old fuel aging all summer (potential algae problem), boost leak, etc.

Speaking of boost, peak boost was only hitting 80 psi and the HT4B was only pushing 40 psi into the coldpipe whereas before in Bakerfield, it was pushing 65 psi between stages. This could be a result of the bigger HX40 turbine wheel driving the He351's compressor harder, or it could be a lack of fueling, boost leak, etc.

I'll get it sorted out and making good passes again!
 
If you tossed that new head on, it could just be less restrictive. You know, moving the same air at less pressure.
 
I've ran a manual and an auto valvebody and although I prefer a manual VB it is definitely a learning curve. I put a shift light in mine which helped drastically. When you think about it in something fast you've shifted 1-2 and locked the converter by the time you pass the tree. Sh!t happens fast. After I put a shift light in mine consistency improved quite a bit. Along with learning the truck. In my setup I don't have lockup until 2nd. So I lock the converter before I launch. One less thing to do and I went faster doing it this way. I was a little concerned that it would be too big of a gap and potentially bog but at least for me it was the exact opposite. It loaded up and pulled harder. Just my $.02 every setup is different though.

Also I'm still running drums in my Dana 80 and they flat hold! LOL I made a rookie mistake and for the first time on my life forgot to put it in 4wd. My drums held a 30psi spool-up and me bumping into the lights in 2wd. And at 30psi in 4wd I cut 1.5 60fts. So she was definitely loaded up :bang
 
Well, the factory original 160 pump has been removed and is getting a much needed cam upgrade by Seth at Farrell Diesel Service. Seth has agreed to go above and beyond to help out the Junker Drag Truck cause for information sharing. The plan is to bench flow the pump as it sits to develop flow rates at a couple of different RPM levels to get a general sense of the pump's fuel curve. Then the new injection pump camshaft and springs that were sponsored by Hamilton Cams will be swapped-in and the pump flowed again at the same RPM points to develop some bench test flow comparisons.

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Dude I need to get on here more often. Cage looks good! Next year is going to be a blast!
 
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