Hi there, we've created a shift point calculator in support of the TrackCoach ProShift series of shiftlights. What's really cool is that we're giving it away for free to anyone who wants it!

• This calculator has several transmission configurations available from a drop down list.
• There is a custom field for cars other than Minis!
• The calculator will automatically create and display the thrust curve for your car.
• This is the only shift point calculator that I've found that takes into account the effective mass of the car (due to rotational effects from the drivetrain, flywheel, engine internals and all driven accessories).

Anyway, it's available for free from the FES Auto publications page. It's a Windows program. Any Mac programmers want to port it for us? If so, drop me a line here via PM or send an e-mail to mattr@fes-auto.com

Feel free to post any comments or questions.

Matt

 

 

Hey Matt,
I got the shift light on my list for later this year. Thanks for the info on the ODBII connector too.

Mr. Jim

 

Thanks for letting us know of this resource.
When I downloaded the program, I did not find a valid digital signature. Is it working on other's computers with no problems?

 

= check to microsoft!

Matt

 

So far I've done this modeling in Excel.

What is "effective mass" and what effect does it have on the calculation?

I'm a Mac programmer, but I don't usually do applications, I've been meaning to work out how to use the crazy new system in OS X. Maybe I could try porting this as a learning exercise. How about an iPhone version, that's the other thing I've been meaning to try.

 

If you think about a car as a perfect engine that just generates torque, the driveline (and anything that spins) that has mass, and the car (that just goes zoom but doesn't go round and round), the engine does work to accelerate everything. Some of this work goes into spinning all the rotational parts, and what's left (after friction) goes into accelerating the car. If you don't take the rotational effects into account, you get an acceleration that is too high. Now if you think about the transmission, the parts before the transmission spin at different speeds relative to the car depending on what gear your in. So the amount of work that it takes to spin these parts compared to accelerating the car and the rest of the rotational parts depends on the gear that you're in. This effect is much larger than many think because it goes as the square of the relative velocity. So you put 16 times more energy into spinning all the pre-transmission rotating assemblies in first gear than you do in 6th.

While it's very hard to find these numbers for cars, one example that I did find was that an early 60 flacon v8 had an effective mass of 2.2 times the car weight in first gear. Now materials have gotten much better, and the little FWD transaxle is very compact, but my 02 MCS had a 30 lb flywheel in it!

The net effect on shift points is that taking the effective mass into account tends to lower the shift point for maximum thrust.

This is also why lighter flywheels and the like (pulley sets, wheels and tires) can all help a car accelerate faster than just the decrease in raw weight would indicate.

Matt

 

Its not running for me, does it need anything to be installed? I'm running Xp (SP2).

When I run it it says it "failed to initialize (0xc0000135)".

 

I have the program up and running but it wont allow me to import data from an Excel or Notepad generated spreadsheet.

I copy my data fields from Excel, but only the first box fills with data--both the RPM and Torque number.

Even if I manually create the table within the program I get an error message that no RPM or Torque data was imported.

What am I doing wrong?

Here is my data taken from my Dyno run at Helix:

2236 155
2476 161
2716 164
2956 172
3197 186
3437 187
3677 185
3917 184
4158 185
4397 183
4638 182
4877 180
5118 179
5357 174
5599 172
5837 171
6079 171
6317 167
6560 161
6797 149
7040 140

 

when it all goes into one sell, the text cursor shows there. You want to paste in when the sell is grey only, no text cursor. I'll make some screen shots to show you and post it shortly.

But when I ran your data, it also showed that the math needs a bit more work. It's only using the data points as possible shift points, not the spaces in between. With the data points spaced like yours (every 240 RPM), it's missing the proper shift points and returning the next highest data point.

I'll post more later.

Matt

 

any chance of a theoretical 0-60 or 1/4 mi time for giggles?

Keep up the good work!

-Jonathan

 

but the times would be off a bit because so much happens at the launch when things are really non-linear.... But the deltas between shifting at red-line and optimal should be pretty close, we'll start thinking about it...

The next changes will account for aero losses and give top speeds.

Matt