1. What do the numbers of your dynos mean? They are horsepower numbers of the motor inside the unit. The 2VS has a 2 horsepower motor, the 3VS has a three hp motor and so on. The VS stands for variable speed. 2. What if I buy a 2VS and I change racing series and now need more power? Our 2VS, 3VS and 5VS are all upgradable. Simply send back your 2VS, we replace the motor, inverter, crossbar and load cell. You pay the difference from the 2VS to the 3VS or to the 5VS and we ship your unit back to you. This way you keep your original investment. 3. What are the power requirements? The crank type dynos are built for their requested power by using a properly suited inverter. They can be either 220VAC or 380-440VAC. Except the 2VS which is only 220VAC, single phase. 220VAC 220VAC 380VAC 440VAC PHASE: SINGLE THREE THREE THREE DYNO: 2VS 7 amps na na na 3VS 6 10 3 3 5VS 17 10 6 5 10VS 34 20 11 10 20VS na na 23 20 30VS na na 45 39 4. What are the columns made of and is there other options? Steel with a Nickel coating. You can custom order lengths for the columns. Each side is actually two pieces screwed together and then clamped. The user could easily remove them and replace them with different length columns for another test requirement. 5. What is the thread pitch of the clevises? 5/8-18 threads. 6. How many data points do tests/graphs produce and is this adjustable? Standard set-up leaving Roehrig is for 2000 hz per channel / second. This is user adjustable in the Hardware section of the software. 7. What if I only have 208VAC? We have seen anything from 196 to 338 VAC work, 220 VAC is just a median. If lower or higher than this range, the inverter will either not come on or it will flash an error message. 8. What is the Peak Force? Our crank type dynos are built and numbered according to their horsepower. The 2VS has a 2 hp motor, the 3VS has a 3 hp motor and so on. The peak force they can make depends on the force curve of the damper and the velocity and stroke of the machine. Like the engine in a car, the dyno is geared to produce a usable test range of force and velocity. If you test a linear shock, the dyno will be able to go faster and produce more force than a comparable digressive curve. We can adjust gearing or point you to the right unit for a given testing need. 9. What does CVP stand for? Constant Velocity Plot. This method collects data through the entire sine wave. 10. What does PVP stand for? Peak Velocity Plot. This method collects data only at the peak velocity or a small window (user definable) around the peak velocity. As a side, we can also collect at mid stroke. 11. Which is better CVP or PVP test? Depends on what you want to do. Some manufacturers require a given test. 12. What is a good starting temperature and why? Common sense says to test at an ambient temperature slightly higher than you will encounter. If your shop is at 75 degrees and you test at 80 deg F, then you go to the track and the ambient is 95, you can not cool back down to 80, so, in this example, do all your testing at 100 deg F. 13. Why would you remove the Gas Test from a run? Because you do not want to compare the static affects of the gas force shock to shock. By measuring it and removing it, you can compare different dampers regardless of the gas pressure. Handy when your front dampers have a different gas pressure than the rears. 14. Can you run a Shock with spring on the dyno? Yes, as long as it is within the capabilities. It may be fun to look at, but eventually you will separate the two items so that you can work on one at a time. 15. Is there any “free fall” of the crank during a run? A very small amount, but it only occurs when the force is very high in the compression direction, like when you run a spring and shock combination. 16. What is the accuracy of the load cell and is there an option to get more accurate? Load cell manufacture states +-0.05% of full range. The easy thing to do is run a test with no damper and see what the load cell reads during the test. The readings are effectively the digital gitter and gives a better reading of what you can see. You can use different ranges of load cells to get better fit for your range of testing needs. The software lets you quickly go back and forth between configurations to allow this change. 17. Does Roehrig do any consulting with companies, teams and manufactures? Not at this time. We are open to the suggestion. 18. Can I load Roehrig Software on other computers? Yes, as many as you want. It is free on our website or load it from the disk that came with the machine. You can look at data, print, export, add math channels, etc…, the only thing you can not do is collect data without having the key / dongle. 19. Can I run the crank dyno on a laptop? Yes. 20. What mechanical parts on the crank dyno need to have regular service? The yolk and the cam follower should be checked from time to time. We use an exclusive, loaded square bearing to remove all slop in the mechanism. Clean the grease when you see it is getting old. Like any electronic equipment, keep it clean. 21. How often do I need to calibrate my crank dyno? User defined. If you need an NIST traceable report, then have it done on a scheduled basis. Roehrig Engineering is able to this for you at a fee. Otherwise, there is no real reason to do it other than peace of mind. We check and calibrate most of our NASCAR teams once a year. During this time, we load the latest version of software, check for any problems, check the calibration, fix any settings that may have gone astray from multiple users, etc.. 22. How do I update my software for the crank dyno off the internet? Ususally, you can download the zip file, extract and install. It is helpful to back up your reg files just incase there is a disaster. 23. Is there a searchable data base on Roehrig Software? Not at this time. It has been requested by several users and we plan on putting it into the next major release of software. 24. Why does my shock have -400 lbs at zero velocity? Because there is a pressure differential across the piston based on the interaction of bleed and shim stack during the transition from rebound to compression. It has to do with the amount of bleed in the damper and how easily it can equalize before going in the opposite direction. This is another long answer best handled in training or over the phone.