Pro Racer - Torque Converter & TC Lockup Schedule

[JoeBoomz]

Pro Racer has a TON of settings that affect the transmission torque converter! Because I couldn't find a lot of information online about this while tuning my Marauder and had to play with it to learn it myself, I wanted to post about it here for everyone's benefit.

Foremost, here's my disclaimer: I am NOT an expert. I've owned Pro Racer since June. I've owned my Marauder for under two years.
However I have an extensive history of safely "tuning" computers (overclocking) and being able to tweak my Marauder in the same fashion is a dream come true for me (I'll post on spark advance in the future).

Anyway, I'll post about my learning experiences, whether I learned correctly or not, and you're welcome to give your feedback and point out if I'm blatantly off. But be cautious if you're doing your own tweaking!



Do you ever notice when you're driving that sometime your car will do a very soft "half shift?" You'll see a drop in engine RPM and a drop in power, even if you didn't move the pedal, even if accelerating at WOT. What you are seeing here is actually your Torque Converter "locking up."

Torque Converters nowadays have a feature called lockup which creates a firm mechanical connection between the engine and the transmission, bypassing fluid-driven transfer of power that normally occurs inside the TC. Lockup is intended to be done at higher RPM's when the TC is no longer multiplying torque (~stall speed) and during steady cruise to avoid wastage and heat buildup due to the fluid-based transfer of power. When the TC is locked up, you can have a ~100% transfer of power between the engine and the rest of the driveline - which means more efficient power when accelerating and more efficient engine braking.

Here's what the SCT Advantage III documentation has to say about TC lockup (I crossed out the unimportant text).


I have tested this and can agree that yes, at WOT, you'll accelerate faster if you lockup the TC early in the 2nd gear. Your primary torque multiplication occurs in 1st. FYI the Marauder only allows lockup in 2-4, not in 1st.

Anyway, in using my Marauder as a Daily Driver, I found that the driveabilty of the car goes down the crapper if your TC is locking up while you're dodging around in traffic. So if you're going to the track, building a TC lockup schedule should be easy. But if you want to drive your car off the track, it becomes a lot more complicated.

Continued in Post 2...

[JoeBoomz]

...continued from Post 1

One very important point. Every Marauder will behave slightly differently. This is especially true if different torque converters are installed. A PI converter has a MUCH faster lockup ability than the stock Marauder converter. This will affect your tuning. My DD has a stock converter and I experience the lockup symptoms described above (with the dip in RPM) every time the converter locks.

All of the below values are taken from a STOCK SCT BMD0 file. They are probably not the values I am using.


To start, I'll go over SOME of the settings I've used in Advantage III. Torque Converter settings are spread out over several of the main categories, below are the categories that the following settings are in:


SCT is very good about documenting what most of the settings in Advanage III do, however it's hard to know exactly what the end result will be without actually testing them. For other settings there is no documentation and you have to guess at what they do (or pony up the cash and set aside the time for proper training???)

First are a set of scalar (non-chart) settings that let you affect the various timings involved with a lockup.


Speed Above to Lock Converter at CT is UNUSED (set to a high value) - CT stands for "closed throttle," so presumably this setting should cause your converter to remain locked at the specified speed even when you take your foot off the gas. I would use this to engine brake at high speeds.

Time to Delay Lk After 12, 21, 23, 32, 32b, 34, 43, 34b - these values are in seconds and allow you to delay a converter lockup after a shift completes. A lockup immediately after a shift can cause engine RPM's to dip too low, depending on your shift schedule, so delaying the lockup will prevent stalling. I have these set to all 0's in my current tune.

Time to Delay Conv Lk After Tip In From CT - if you have the converter unlocked at closed throttle (i.e., you are coasting without engine braking), this is the time to delay a lockup after you put the foot back down on the gas. For example if you have this set to 2 and are coasting on the highway with the foot off the pedal, and then push the gas, after 2 seconds the TC will lock up. I have this setting at 0.

Time to Delay Conv Lk at WOT - this one is pretty self-explanatory. I have mine set to 0.

TP Above to Delay Conv Lk at WOT after Shift - I read this as "throttle position above which to delay converter lock at wide open throttle after shift." So throttle positions above this setting will have a lock delay at WOT directly after you shift.

Some more scalars:


Many of these had good descriptions in Advantage III. I'll point out the ones I've been tweaking that directly affect how the car feels:

Time to Delay Lockup During Tip-in: Tip-in is generally when you go from closed to open throttle, however I have also seen it referenced as the occurring during shifts (don't know for sure). So if you are unlocked at closed throttle and press down on the gas, this is the delay before the converter locks up. Mine is set to 0.

Time to Remain Locked Closed Throttle: This is an important one if you like/dislike engine braking in 2nd and 3rd gear. Coasting with an unlocked converter is much nicer (and better on gas) however it's also nice, if you've closed the throttle for a short time and then apply the gas, not to have to lock the converter again. 0 means the converter unlocks as soon as you take your foot off the gas - which means you'll have to lock it up again when you start to accelerate again.

Time to Remain Locked Closed Throttle 4th: Same as above, but for 4th gear. In my testing I found that I like this setting around 5 seconds, so that I can accelerate quickly again on the highway if I've taken my foot off the gas without having to wait for a lockup, but also so I can coast more slowly to a stop without using the engine brake (it unlocks after 5 seconds).

Time to Remain Unlocked after Brake Input: TC unlocks automatically when you apply brakes. This setting should force it to stay unlocked for the specified time once you take your foot off the brake. I have mine set to 0.

Three of these scalars affect the lockup rates:


Torque Converter Lockup Rate After Tip In, After Upshift, W/high TP, can all be increased to reduce the amount of time that you see "RPM lag" when your converter locks up. I've used values up to 800 for some improvement without adverse affects.

In my testing the stock converter is much slower than a PI converter. The PI converter had an immediate drop in engine RPM and then continued acceleration, almost like an actual shift. The stock converter acted more like it was "bogging" the engine down and the slowdown in RPM was more noticeable.

One more setting to cover:


And SCT's take on it:


With throttle position across the top, this setting allows you to reduce harshness in the connection to the rest of your driveline. The Marauder sock programming actually has 10's up to TP 228 (moderate acceleration), I've set mine all to 0 based on SCT's advice.

Continued on Post 3...

[JoeBoomz]

...continued from Post 2

Advantage III defines the lock/unlock schedule in the same manner as the upshift/downshift schedule, using a chart.



This also allows for graphical representation. Here's the stock BMD0 TC lock/unlock schedule with speed on the vertical axis and throttle position along the horizontal axis.
I posted more details regarding TP's HERE - read for further understanding of TP_ABSOLUTE and TP_RELATIVE. The TC lock schedule uses TP_RELATIVE.




Like the stock shift schedule, it looks like a mess. Makes more sense when you look at it one gear at a time.


Here's the 3rd gear lock/unlock curves:



And 4th gear:



So how do you read these? The TC will lock up above the top line and remain locked until you cross the bottom line, except if you go to closed throttle or hit the brakes.

Also similar to the shift schedule, the lock/unlock lines cannot cross or you will experience rapid locking and unlocking.

Continued on Post 4...

[JoeBoomz]

...continued from Post 3

I have a stock torque converter.

For me, I found TC lockup to be very annoying while driving in traffic. The aforementioned bog in RPM is very noticeable and, if you're running the stock lockup schedule, it is difficult to predict. The RPM bog always seems to happen at the worst time, when you're trying to accelerate around someone and it is very frustrating!

I tried causing a lockup immediately after each shift but there was still a delay and the subsequent RPM bog. In the end I found that the gains with the locked TC were not significant enough to warrant putting up with the bog in RPM's while dodging traffic and decided to turn off converter lock in the lower gears.

So to prevent the TC from locking up, all you have to do is set the lockup values to very high speeds (like 127MPH). To make the TC always unlocked, set the unlock values to the same very high speeds (like 127 MPH).



You're only seeing one line here because the two lines are overlapping. In this example the TC will ALWAYS be unlocked when you are in 3rd.

To keep a locked TC locked and prevent the converter from unlocking, set the unlock values to very low speeds (like 0). Here's what it looks like graphically:



In this example, in 2nd, since you never cross the top line the TC will not lock up. If you shift into 2nd with the TC already locked up, it will not unlock because you will not cross the bottom line (closing throttle or pressing the break will cause it to unlock).

The TC can remain locked during shifts, so it is possible to have it remain locked during a 4-2 kickdown - so disabling an unlock like this in 2nd might actually apply in some circumstances.

My current tune uses the second example for 2nd and 3rd gears - the TC will only be locked in those gears if I downshift from 4th into them with the TC already locked.

Now, as the 4th (overdrive) gear is used on the highway, there is still benefit to using TC lockup. Actually, it is in the 4th gear that you can most easily feel the affect a locked converter has on your acceleration. The Marauder has a LOT more pull in 4th above 3,000 RPM when the TC is locked compared to when it is unlocked!!!

My favorite configuration for my DD Marauder is to have the TC lockup in 4th above 60 MPH at all times, and to have it NEVER unlock in 4th (unless you close the throttle or hit the brake). 4th gear looks like this:



So, while accelerating, I cross the top (lockup) line at 60MPH, the TC locks up. As I never cross the bottom (unlock) line, the TC is never scheduled to unlock and will only unlock if I hit the brakes or close the throttle. Actually I have the Time To Remain Locked Closed Throttle 4th scalar set to 5 seconds, so I can engine brake for 5 seconds before the converter unlocks and the car starts to coast. If I tip in on the throttle (give it gas) before the 5 seconds is up, I have instant power and very strong acceleration without the RPM bog associated with another lockup.

Here's an important point I did not demonstrate here: you can define lockups at different Throttle Positions, and this might help with lockup RPM bog. For example, if you are WOT, you might skip locking up the converter in 3rd, however if you're at a much lower TP and aren't asking for much power, you might opt to lock up the converter because the RPM bog won't be as noticeable. I posted more details regarding TP's HERE.


Interestingly, here is what Mr. Lidio of Alternative Audio has on his website about the Marauder TC lockup:



Sound familiar?

If you have an upgraded torque converter (i.e., from Precision Industries), you might not suffer from a bad RPM bog like my stock converter does and I would recommend trying the converter lock during acceleration in lower gears.

Continued on Post 5...

[JoeBoomz]

...continued from Post 4

Keeping this in mind:


...let's get the TC locking up when we're doing WOT pulls, but NOT for regular driving where the invasive RPM bog would piss us off. We will use the TP position in the chart in addition to speed to define the TC lockup schedule instead of just speeds.

So what speed are we at when we shift from 1st to 2nd at WOT? Let's look at the shift schedule:


This is the stock shift schedule, it has us going into 2nd at 46MPH at WOT.

So let's lockup the TC in 2nd at 900+ TP and at 46 MPH, and at lower TP values we'll set the lockup at 127 MPH to prevent it from happening when we're not at WOT.
NOTE - your car may not actually reach a TP of 900 and you may need a lower value, like 500. I posted more details regarding TP's HERE.
We'll set it to unlock at 0 MPH so it doesn't unlock.



Notice there are two TP entries for 900. This creates a vertical line in the lockup graph.



If you don't, you get this:





This configuration will lock up the TC at lower TP's than you want - for example you will cross the lockup line at TP 755 and 79 MPH. So make sure you have two entries in the TP column to build a vertical line!

The next step is to set the rest of your TC unlocks to 0 MPH so the TC doesn't unlock when you get into 3rd and 4th, and finally, remember to set Time to Delay Lk After 12 to 0. Here's a look at 3rd and 4th together (remember I have lockup in 4th at 60MPH).



So now we can make a WOT pull and have the TC lockup immediately when we enter 2nd, and you can accelerate with the converter locked through 3rd and 4th. However as soon as the pull is complete and you close the throttle the TC will unlock, and it won't lock up again until over 60 MPH in 4th or WOT in 2nd.

Peak HP increased by 1 rwhp and tq went up by 4 from 4200-5000 RPMS with it locked early, thats the only advantage, the disadvantage was that just above 5K RPMs the hp and tq both drop off by almost 10 with the convertor locked. This is where having it unlocked at a higher MPH will help you more on the top end and your ET.

Let's try to build a schedule in an attempt at leveraging Blackened300a's findings. We'll assume a dyno pull in 3rd, and we want TC lockup from 3000-5000RPM and TC unlock above 5000RPM. First, we need to find out what speeds we are at at those RPM's in 3rd - we can use the shift schedules to see this.

This is the 32 shift schedule, so the middle RPM column is in 3rd and the rightmost is in 2nd. I played with the MPH values to hunt for the RPM's in 3rd that we are looking for.



So at WOT we want TC lockup at 69 MPH, but unlock at 115 MPH. This is how I would attempt this:



Here's how the two schedules look; it gets visually confusing but look carefully at the line colors and you can tell the horizontal portions apart.



Imagine how this will work - your TP stays at 900-1020 during WOT, and you accelerate up to 69MPH and cross the lockup line, causing the TC to lockup. As you continue to accelerate, the TP does NOT change, but the speed increases to 115MPH at which point you'll cross the unlock line and the converter will unlock.

I have not tested this configuration and I do not think it will work. Generally the unlock lines appear UNDER the lockup lines and this actually reverses this. I will give it a go and will update this post here to tell you if it works. If it does not work, the converter might actually rapidly try to lock and unlock like SCT warns about if you cross the schedule lines. However it may be that vertical lines don't count because they have an infinite slope and the Computer will actually work with the data on either side of the vertical portion of the graph.

[Dobs]

Hey Joe, I got the Advantage III last month and begun to mess with the trans setting first. Thats pretty nice to share your experience with us most try to keep that kind of information secret to make $$$.

I will read carefully.

[ctrlraven]

Nice write up!

I know exactly what you are talking about with the bog.
http://www.youtube.com/watch?v=Sp-thPZ3wzA


Not trying to hijack your thread, I've had this 1-2 shift bog for the longest time. I will be keeping an eye on your thread now to maybe get some ideas. I have a PI 3500 converter.

[Blackened300a]

... If you have an upgraded torque converter (i.e., from Precision Industries), you might not suffer from a bad RPM bog like my stock converter does and I would recommend trying the converter lock during acceleration in lower gears.

I have a dyno sheet that Ill scan tonight that will show you exactly what you are talking about and show you the advantage and disadvantage of locking it up earlier.
On my dyno sheet, you'll see back to back runs with the convertor locked early and unlocked for the entire run. The lockup shows up as a loop on the dyno sheet and made a audible bog that also made the engine change tone on the dyno. I may even have video of this.
Peak HP increased by 1 rwhp and tq went up by 4 from 4200-5000 RPMS with it locked early, thats the only advantage, the disadvantage was that just above 5K RPMs the hp and tq both drop off by almost 10 with the convertor locked. This is where having it unlocked at a higher MPH will help you more on the top end and your ET.

[Loco1234]

Thanx for the write up... I also have the Pro Racer package & will have to look into that a lil further...

[JoeBoomz]

Hey Joe, I got the Advantage III last month and begun to mess with the trans setting first. Thats pretty nice to share your experience with us most try to keep that kind of information secret to make $$$.

I will read carefully.

Pro Racer is a great software for anyone that wants to "do it yourself" and my goal is to provide some starting information for anyone who has decided to take the plunge. It can be very daunting the first time you open the thing up and see the millions of settings that you can change!!!

Pro Racer is not a replacement for trained professionals who pay a lot more than we did for training, licensing and dealer fees, and it is certainly not my intent to undermine anyone who does this all day every day to pay the bills and put food on their table. Remember that in the end you will always get the best results by talking to an expert and paying for a dyno tune!

That said, having the freedom to customize your car in this manner is priceless and I am very happy that SCT developed the Pro Racer package for amateurs like myself.

[JoeBoomz]

Not trying to hijack your thread, I've had this 1-2 shift bog for the longest time. I will be keeping an eye on your thread now to maybe get some ideas. I have a PI 3500 converter.

Before I finally identified it as TC lockup, RPM bog seriously had me wondering if I had an electrical issue, problems with COP, AF problems, or some other scary thing to think about.

Now that I know what I'm looking for, I can identify TC lockup in any automatic that I drive and it's reassuring to see it everywhere. It's also interesting to compare what different automakers do with it.

It looks like your TC is locking up shortly after entering 2nd gear. If you haven't already tried it, you can increase your Torque Converter Lockup Rate After Upshift to 800 (especially with the PI converter), and reduce Time to Delay Conv Lk 12 to 0.

[LANDY]

I have a dyno sheet that Ill scan tonight that will show you exactly what you are talking about and show you the advantage and disadvantage of locking it up earlier.
On my dyno sheet, you'll see back to back runs with the convertor locked early and unlocked for the entire run. The lockup shows up as a loop on the dyno sheet and made a audible bog that also made the engine change tone on the dyno. I may even have video of this.
Peak HP increased by 1 rwhp and tq went up by 4 from 4200-5000 RPMS with it locked early, thats the only advantage, the disadvantage was that just above 5K RPMs the hp and tq both drop off by almost 10 with the convertor locked. This is where having it unlocked at a higher MPH will help you moreon the top end and your ET.

good info, I had better et with the TC unlocked wot

[JoeBoomz]

Peak HP increased by 1 rwhp and tq went up by 4 from 4200-5000 RPMS with it locked early, thats the only advantage, the disadvantage was that just above 5K RPMs the hp and tq both drop off by almost 10 with the convertor locked. This is where having it unlocked at a higher MPH will help you more on the top end and your ET.

It would be great to see that data! This seems counter-intuitive because as the converter approaches and passes the stall speed, its efficiency and torque multiplication falls off. That's why they built the lockup for use past the stall speed.

It might be possible to define a lockup schedule that locks up the converter between 3000-5000 and then unlocks above 5000. I'll play with it further and post it up here. Every car behaves differently but if this is the data you have for yours, you will be able to tune your lockup schedule to accommodate it.

[ctrlraven]

Before I finally identified it as TC lockup, RPM bog seriously had me wondering if I had an electrical issue, problems with COP, AF problems, or some other scary thing to think about.

Now that I know what I'm looking for, I can identify TC lockup in any automatic that I drive and it's reassuring to see it everywhere. It's also interesting to compare what different automakers do with it.

It looks like your TC is locking up shortly after entering 2nd gear. If you haven't already tried it, you can increase your Torque Converter Lockup Rate After Upshift to 800 (especially with the PI converter), and reduce Time to Delay Conv Lk 12 to 0.

I wish I had the tuning software to take care of it but I don't. Saving up money to have a local Lightning/Mustang tuner do a full driveablitly and dyno tune on it.

[Dobs]

Actually I have the Time To Remain Locked Closed Throttle 4th scalar set to 5 seconds, so I can engine brake for 5 seconds before the converter unlocks and the car starts to coast. If I tip in on the throttle (give it gas) before the 5 seconds is up, I have instant power and very strong acceleration without the RPM bog associated with another lockup.

Im trying to figure this command in the option?