Just a little more . . . . .

[BC847]

Nice. Where are you referencing case pressure on the IP?

Thanks.

I modified the top of the IP to have room for a pressure tap (originally an HVAC 1/4" Shreader-valve fitting). Just swapped the fitting for the sensor.





The back-pressure (AKA: Drive-Pressure) sensor is protected via a 3-cu/in HVAC filter/drier.





Using pressure reference lines from the two primaries, ties into the one Primary pressure sensor.





The secondary pressure sensor is from the typical reference port.





There's a "Boost" pressure sensor on the engine's intake-log.





There's an incoming charge-air temperature sensor on the intake-log feed-horn.





Got the transmission line-pressure sensor on the accumulator reference-port.





In addition to those sensors above, there's also Transmission fluid temperature, fuel-pressure, Boost, EGT, tachometer, and speedometer. All these have gauges on the dash/steering column.

[79Powerwagon]

Very nice build. Inspiring to watch it all happen.

You are still running a non lockup 518 correct?

Do you feel the truck would benefit from a lockup trans or is the 518 built well enough where the difference would be marginal?

[BC847]

Very nice build. Inspiring to watch it all happen.

You are still running a non lockup 518 correct?

Do you feel the truck would benefit from a lockup trans or is the 518 built well enough where the difference would be marginal?

Thanks.

Yes.

The current "Guts" of my trans are 48RE based with all billet/alloy shaft, steel-carrier/6-pinion planets, increased clutch/steel counts, etc. I've a somewhat unique torque-converter in that, it started life as one of the off-the-shelf A518 non lock-up converter, with the billet back-plate as offered by Suncoast. Ran it for short while and broke something in the trans. Sent the converter back to Suncoast to have them open it, clean it, and tighten it a little. OK fine. Ran it a short while and broke something in the trans. Sent the converter back to Suncoast and had them open it, clean it, and tighten it more. That's apparently when it got "different" in that they swapped out the stator (?) with a billet article with some other tweaks. Turns out, the converter is now one of only two (The lead converter design/tech guy at Suncoast runs the other). IT is pretty tight under load at speed, compared to the stock/OEM set-up.

Then this past weekend, my Son and I did a poor man's flush with five gallons of the John Deere Hy-Gard fluid. Then added some stuff to that. (I had been running a generic tractor fluid for a while). The new blend is thickerer. Raised the line-pressure a little while we were in there.

Over all, there's now a better connection between the engine and trans. I find that getting on top of the turbo(s) now takes a little more effort (all inclusive). Got to adjust my launch procedure to compensate.

We'll see come Thursday.

[BC847]

Well, . . . took the heap to the track and made a baseline. Overall slow both in ET and trap-speed compared to the best the former twins could do. Keep in mind, there's been a lot change: (1) Almost double the air, (2) Tire change, and (3) Transmission dynamics. While only three things, it's a different truck at the track.

Ran two almost identical passes of 8.4 @ 79mph. It's slower out of the hole with a 1.78 60' (.8ish sec slow) and so on.

- The tires are hands down a HUGE improvement. NO perceptible shudder or any crap compared to the former All Terrain Radials.
- A notable increase in delay getting up on top of the turbos while standing on the brakes. It labored to get up to 25psig. But once it got past 20, I had to back off a little cause it wanted to go to the moon.
- It initially seems as though I need to wind-up a little higher before shifting gears. Not sure on that. Gotta look at all the numbers.

Got A LOT of info from the data-logger. Seems to reveal a LOT of stuff.

It's a LOT of info to digest, then act on.



- To the far left is where I'm sitting at 25psig boost, waiting for the lights to come down. Where thing pop-up, that's the green light.

White: Truck speed
Bottom Orange: Engine RPM
Bottom Purple : IP Case Pressure
Darker Blue: Transmission Line Pressure
Lighter Blue: Back Pressure (Drive Pressure)
Yellow: Primaries
Top Orange: Secondary
Top Purple: Boost @ Intake-log

The Blue line running top to bottom is just before I let off the fuel. The numbers in the lower boxes is what was happening there.



My head is spinning.

Still, not bad for no real tuning thus far. Gotta lot to do.

We'll see.

[JQmile]

Just as an FYI, you can calculate converter slip percentage based on speed and rpm. Normally it's on a dyno but I'm sure your fancy computer thingie can do the same thing .....in reality, you need a 14mm pump man. If you're willing to cough up a few bucks I can see if I can get you one.

[oldestof11]

Just as an FYI, you can calculate converter slip percentage based on speed and rpm. Normally it's on a dyno but I'm sure your fancy computer thingie can do the same thing .....in reality, you need a 14mm pump man. If you're willing to cough up a few bucks I can see if I can get you one.

If I am assuming correctly, that vertical line in the graph indicates at that point all of the inputs at the bottom. Slip would be RPM compared to speed. If so, here is some info.

33" tire
.75 OD ratio
3.55 gear

He SHOULD be at 129 MPH locked. He is ONLY 86 MPH. That is a 33% slip. Probably closer to 30% due to the numbers based off of 3500 RPM, which he is not at on the graph.

[BC847]

I'm sticking with the 12mm. But, thanks for the offer Jason.


In the 8th, I don't use OD, Jon.

85.9mph
3420rpm
3.55
33"

I get a LOT less slip. http://www.wallaceracing.com/converter-slip.php = -0.1 %

[Remps]

That's next to no converter slip at all at 3400+ rpm, but I bet you'd see more slip a second after an upshift pulling at lower rpm. I'm most interested to know the lows and highs of your case pressure throughout the run. Which has probably never been gauged, let alone graphed and recorded, on a ve pump somewhere other than a pump shop. Just my opinion, but I'd dual feed the 12 before going to a 14. Case is tapped, just need a tee, a check valve, and a pump.

[BC847]

Looking at the numbers to arrive at slip through the gears is interesting. To make it simple for me, I noted stuff around 10mph increments.

Keep in mind, the race starts with me revved-up to 2200ish rpm to get to 25psig boost sitting at the line (100% slip).
at 10mph/2515rpm = 54% slip
20mph/2697rpm = 16%
30mph/2994rpm = 13%
2nd gear/3063rpm, 37mph = 36%
40mph/2850rpm = 58%
50mph/3236rpm = 74%
3rd gear, 56mph/2800rpm = 0.1%
60mph/2879rpm = 0.1%
70mph2968rpm = 0.1%
80mph3263rpm = 0.1%

Shit apparently gets weird around the shift-points. Not sure if the data increments I used to come to slip, is too close to shift points.


Speed = White
Engine rpm = Orange




The case-pressure data clearly illustrates what happens with big injectors on a VE IP. You can clearly see where I'm sitting at the line, revved-up. The case-pressure droops as soon as I stab the pedal. It pretty-much follows engine rpm as speed goes up.

And right there where I get off the pedal, the engine's still wound up (so is the IP vane-pump), and the case-pressure jumps up appreciably. Remember, our injection event timing widget works off case-pressure. Through the gears, the case-pressure droops a lot thus retarding the injection event timing. In my mess, that's missing power. Gotta fix that.


Speed = White
Engine rpm = Orange
Case-pressure = Purple




I think this data-logging stuff is gonna be a great tuning tool.

[PToombs]

That is freaking cool Dave! With just a few things split out it's easy to see what's happening.

[oldestof11]

Right after the 3rd gear change, it looks as if the pump is cavitating or is losing fuel pressure. Or the pressure relief valve is opening which makes sense since it seems to be dropping pressure at the same mark every time. The lower valley's after it pops open would mean it was getting to a point the relief valve was nearing 100% open.

Also, what happened at the 79 second time mark for the speed?

[BC847]

Right after the 3rd gear change, it looks as if the pump is cavitating or is losing fuel pressure. Or the pressure relief valve is opening which makes sense since it seems to be dropping pressure at the same mark every time. The lower valley's after it pops open would mean it was getting to a point the relief valve was nearing 100% open.

Also, what happened at the 79 second time mark for the speed?

The injectors are outrunning the vane-pump, Jon. Dunno what the deal is with the dip in speed. A glitch in the data-logger mess. ?

Tweaked the injection event timing and adjusted the idle-speed accordingly, then made a couple of passes this past Thursday night. Took a full tenth of a second off the 1/8m ET.
From 8.48, and 8.45 last week to 8.34, and 8.37.

Still working on it.

GOTTA do something about the dip in case-pressure while at WOT.

[Remps]

Do you know what actual psi case pressure is dropping to? It'd be nice if it stayed as high as it gets to at the end of the run when off the throttle.

[oldestof11]

Right after the 3rd gear change, it looks as if the pump is cavitating or is losing fuel pressure. Or the pressure relief valve is opening which makes sense since it seems to be dropping pressure at the same mark every time. The lower valley's after it pops open would mean it was getting to a point the relief valve was nearing 100% open.

Also, what happened at the 79 second time mark for the speed?

The injectors are outrunning the vane-pump, Jon. Dunno what the deal is with the dip in speed. A glitch in the data-logger mess. ?

Tweaked the injection event timing and adjusted the idle-speed accordingly, then made a couple of passes this past Thursday night. Took a full tenth of a second off the 1/8m ET.
From 8.48, and 8.45 last week to 8.34, and 8.37.

Still working on it.

GOTTA do something about the dip in case-pressure while at WOT.

Purple is your case pressure, right?

Not saying I am trying to be the smartest here but I do not see what you are seeing. I see a pressure drop with an RPM drop, even then the case pressure seem to have the same delta in relation to rpm. The would be the vane pump's RPM too. The max pressure never goes higher than a certain point. Even when staging. It also seems you are hitting close to the defuel point on sthi, which would be the gov pulling back on the injectors and case pressure rises because the sudden decrease in fuel flow out.

Vane pump maybe the culprit but I do not think it is the ultimate culprit. I think the vane pump is working as designed and the lose in RPM results in the pump having decreased output.

So how do we fix that?

What is the case pressure you are looking for?

[BC847]

Look at the numbers as I'm fully-staged sitting at the line (from a similar run):
2100 engine RPM.
955* EGT (holding brakes at 25psig boost)
132psig case-pressure.

At the end of the race, just lifted foot:
3150 engine RPM (dropping from 3400ish).
1090* EGT (dropping from 1400ish)
174psig case-pressure.

That 42psig difference equates to some degrees of retarding the injection-event timing over the course of 2100rpm to 3150 @ WOT.

THAT's the issue I'm working to correct. The retarding of the timing results in a drop in power. I've seen it repeatedly on dyno-runs. The power ticks up notably as I let off the fuel. I've actually thought of turning down the main fuel-screw, just enough to have the case-pressure NOT drop with the application of WOT. If the dyno's not lieing, I should see an increase in power in the upper engine RPM. It's counter intuitive.
Or, I can reinforce the fuel supply to the case, and not have the case-pressure drop @ WOT under load and not see the timing retard with high RPM @ WOT under load.

Make sense?