| Racepak V300 - Racepak Datalogging in Action
Turbo: What are some key issues you have discovered about tuning a four-link with a Racepak unit?
Paralax: The biggest thing the Racepak has to offer is its G meter. The chassis tuner has the ability to make adjustments to the suspension and the G meter ensures changes can be made for different parts of the run. Let's say your 60-foot times are fairly close, the G meter would read different. It would show you the G reading as the car is going down the track. Looking at the gear changes as you leave the line allows you to make an adjustment, which might not show up at 60 feet, but it might show up at the second or third change further down the strip. That's something you can't always notice with the naked eye.
Turbo: What is something you found with the Racepak that you were never able to find setting up a car the conventional way?
Paralax: When you look at the information downloaded and you compare driveshaft rpm, engine rpm and G reading. You can calculate torque converter slippage on an automatic or clutch slippage on a manual. With the torque converter, you can calculate how much you're losing at the big end. Viewing the screen, you know how fast the engine is turning and if you know your wheel size so you can calculate the mph you should be hitting in the traps. If the calculation doesn't match up in the computer, then you know you're getting slippage somewhere.
Turbo: What would some-body look at to improve 60-foot times?
Paralax: At the start when you leave the line you can see wheelspin on the computer. You would get a spike in the graph when it should be a clean transition. Moving the cursor key over you can physically count the revolutions to see exactly how much tire spin you are getting. The graph will start out with a six and as the tire is rotating, it will keep reading 6. If there is wheel spin, the graph can jump up to 12. 20, or even 100, if you have a lot of tire spin. You can see wheelspin with the naked eye, but when you have a small amount of tire spin you can't see it-but the computer can. In some cases, like fragile drivelines and/or the use of big tires, a little wheelspin takes stress off the driveline and would be beneficial.
Turbo: How big of a change is there in tuning the suspension when horsepower is increased?
Paralax: The other great thing about the Racepak is if you look at engine rpm you can see how much power the car is making. So if you get more driveline rpm and you compare it to engine rpm you can tell how much power you are making and the effect the power has on traction.
Turbo: Besides the G meter and driveline rpm, what would you say are the key sensors one would need to tune the suspension?
Paralax: The shock travel sensor would be critical for cars running stick shifts like a Liberty, G-Force or Lenco. You can adjust the shock by watching the travel, because with the added gear changes you would shock the tire harder compared to an automatic.
Turbo: Would you say the Racepak holds more or better information than what the driver can tell you?
Paralax: Well if you have a good driver, they can tell exactly what the computer tells you. If you have an inexperienced driver that can't tell you anything then your only source is the Racepak. If that is the case, then I would suggest installing the throttle position sensor option to tell if the driver actually lifted his foot off the pedal and then got back on it. It's necessary to have consistent runs to go off of in order to make the proper chassis adjustments.
Another good thing about this unit is no matter what happens throughout the run, it will always download the information. I've worked with some systems that don't download every time and my personal car is a Nitro car and they vibrate really badly and use two 44 amp mags (the cars ignition system which pumps out a lot of volts and amps) that creates a huge interference factor. With the Racepak, you're guaranteed to get a downloaded pass every time.
Turbo: How much time can a person save from tuning using data logging features vs. the conventional way of reading the tire patch and watching the lift?
Paralax: Without the Racepak, I think it would have taken me another three test sessions to tune the chassis on the Venom truck. It gets expensive, because you have to rent the track for a couple of days, get the crew out to the track on top of rooms, race gas and a bunch of other stuff. With the Racepak, you could do everything in one day if you know what you're doing.
Turbo: How user friendly is the software for a beginner?
Paralax: I have very little computer skills and I can run through this thing with ease.