The Shop Truck

[folkenheath]

So I can't find any minimum delay setting in the software either. I measured my shifts and it was .58 seconds from the call to shift and .37 seconds to actually make the shift once it starts. However, if you look at the actual gear ratios it takes .18 seconds to from when the ratio starts to change to when it is full changed ratios.

Here is an NA pass with my regal. Except you can see the launch caused my foot to let off the throttle a tad, I learned quick to correct that one.

I may make a youtube video showing people how to do this.

The blue line is the "gear ratio" math channel that calculates the trans ratio. With my trans brake it lets the input shaft turn some on the brake which means the ratio is infinite with the output speed locked, but you can see the ratio come in and then you can see the gear changes happen pretty fast, and if you hover on them you can see them go from 2.48 to 1.48 then to 1. This line will be off in 4th gear as the OD planetary is in front of the turbine shaft, but I don't use 4th at the strip anyway except sometimes at the shutdown area.

The peach colored line is the converter slip math channel. You can see it peaks during the transbrake, then it peaks again during the gear changes and it drops to its lowest point at max RPM right before the gear change.

The rest of the lines are standard Holley channels with a 4L80E. RPM, TPS, gear, input shaft speed, speed, line(trans) temp.

You can also see the TC Clutch output I created so I can lock it immediately whenever I want, on a timer, at a certain speed, etc. I use speed.



Here is a nitrous pass where I lock the converter....it looks like a 4th gear but its not as you can see.



Here are those two math channels. I may make a youtube video on how to do this...



The converter slip is easy, just

((RPM/Input Shaft Speed)*100)-100

The Gear Ratio channel depends on what you have your stuff set at in the Holley software such as Tire diameter and axle gear, it has to match or it will be wrong.

This is the equation I derived...

(Input Shaft Speed x 3.14159 x TireOD)/(Speed x Axle Gear x 1056)

Once you do that you can see if the gear ratio is a quick change like mine on the 1-2 and 2-3, or if its drawn out or not a flat line. I have zero filtering on those lines. If the 1-2 and 2-3 looks crisp. Then look at the converter, IMO it should get to 10% or less at high RPM, mine drops down to under 3% before the 1-2 gear change and about 6% before the 2-3 gear change. You can also see my converter lockup at 135 MPH wasn't holding the full power on that run or it should go to zero slip, even though it was still dropping the slip quite a bit in high gear. The slip is less in lower gears because the converter basically has more leverage so it's easier for it in lower gears.

Hope this helps you diagnose...

 

[r3dd0g]

Thanks @folkenheath, I'll try to set that up, it looks like useful information.
I have sent my datalogs and tunes to GearStar and they're looking at it. Their initial response is to just work around the long shifts by moving the WOT RPM shift points out of the way like you mentioned. I gave them 3 sets of datalogs, one from my last 1/4 mile pass at Firebird where everything worked properly, one with the 1-2-3 shift, and one with the 1-2-3-2-3 shift.
They talked to Yank and if anything they think my torque converter is too tight, not too loose. The tech I talked to was digging into it more and I'm still waiting to hear back from him.
I'm thinking the softer launches could be from me holding the brake harder and not letting off quickly enough. I'll be honest, when I launch it I don't even think about my brake foot, I just let go of the button and it goes. The reason I don't trigger the nitrous and 2 step with the brake pedal is because it takes .3-.4 seconds for the light to go off after I let off the pedal. When I compared my best launch (1.42 60') with my last launch that should have been quicker with the 3200 RPM leave the brake light was on for an extra .03 seconds, so that could have been the issue. I will likely be adding a trans brake to fix this issue.

 

[folkenheath]

Thanks @folkenheath, I'll try to set that up, it looks like useful information.

For what you are dealing with I consider it vital information. It will tell you definitively if your clutches are slipping or your converter is not holding at high RPM.

The great thing about the Dominator is it records everything, so you can go back and add those math channels and then insert them into your trans graph in the data log config and see everything from those passes.

It may be the shift is slow but the clutches are holding good once complete, that can be fixed in the valve body without removing the trans either by eliminating accumulators or enlarging the orifices. I have zero accumulators. Or maybe your trans is fine, you'll know.

I have sent my datalogs and tunes to GearStar and they're looking at it. Their initial response is to just work around the long shifts by moving the WOT RPM shift points out of the way like you mentioned. I gave them 3 sets of datalogs, one from my last 1/4 mile pass at Firebird where everything worked properly, one with the 1-2-3 shift, and one with the 1-2-3-2-3 shift.
They talked to Yank and if anything they think my torque converter is too tight, not too loose. The tech I talked to was digging into it more and I'm still waiting to hear back from him.
I'm thinking the softer launches could be from me holding the brake harder and not letting off quickly enough. I'll be honest, when I launch it I don't even think about my brake foot, I just let go of the button and it goes. The reason I don't trigger the nitrous and 2 step with the brake pedal is because it takes .3-.4 seconds for the light to go off after I let off the pedal. When I compared my best launch (1.42 60') with my last launch that should have been quicker with the 3200 RPM leave the brake light was on for an extra .03 seconds, so that could have been the issue. I will likely be adding a trans brake to fix this issue.

If you continue to launch from the foot brake I would log brake pressure with a sensor, that will tell you. The brake switch shuts off only when the brake pedal is all the way back, whether there is pressure on it or not.

I am a dealer for ATD, "Hipsters Brake". There billet 4L80 brake is full manual and would require a race shifter and shift solenoid.

I used a brake from Jakes Performance that still allows automatic shifting with the ECU, I built the trans myself over 15 years ago before the Hipsters brake existed, I really should give it a refresh.

 

[folkenheath]

I also log trans pressure too, I use a 500 psi sensor in the case. So I can see that too but I hid it because the graph was busy enough for this illustration.