The topic of being able to dyno a vehicle with a CVT has been brought up a good many times and I wanted to share the latest info I have on this subject. We have changed the way we dyno at Hunterworks.

First off you CAN dyno a vehicle with a CVT and get a result, that result is not as accurate as it could be with a manual transmission. Typical dyno runs on any vehicle are supposed to be made in the gear that provides a 1:1 ratio. Since the CVT, which stands for constant variable transmission, it is ever changing gears. On the CVT vehicle you have the help of changing gears multiplying torque. I will explain further down.

The fact is, you can put say a Rhino on the Dyno, do a wide open throttle run and get a number that represents the amount of HP to the ground at the rear tires and that number for a stock Rhino is roughly 25HP. Now if you add some type of mod that does in fact raise the HP then when you re-dyno it the number will be higher, quantifying what you did.

This number will not be as useful as having the transmission in one gear because you will not be able to find what RPM you are getting peak power from the engine simply because the CVT is "changing" gears. If the only thing you want to know is, is the mod you made making more HP and that is it then the number you get will let you know it is or is not making HP.

So how do we do a dyno run on a CVT vehicle and get a number that is more useful? We lock out the CVT. Lock it out??? What I did was remove the primary sheave, remove the roller weights and placed a spacer between the two sheave halves and one between the movable sheave and the fixed plate or cam as Yamaha calls it, leaving the roller weights out. I had to figure out what thickness of spacers on each side of the sheave would place the belt in a 1:1 ratio with the secondary sheave. I won't tell the thickness of the spacers, can't help the competition too much. Now once that was done it was kind of like having a 5 speed manual tranny car in fourth gear.

To perform the run you speed the vehicle up to 10 mph and then open the throttle all the way. What this does is isolates the power to the ground to the engine not the CVT changing gears and giving the engine mechanical advantage.

The results are far more accurate this way because the RPM's are not staying basically the same thru the run like when you are using the CVT they change directly proportional to wheel speed. The resulting number will be less since the engine does not have the mechanical advantage of the CVT changing gears.

What can you do with the results this way you can't do with them the other way? One example would be: the RPM at which peak power is. Two would be: Did my mod change the RPM where peak power is, did I get more low end power or more top end RPM power.

The other way you would just get a peak HP number and you would know that the mod did or did not gain HP but you would not know what RPM the mod made or lost the power.

What I learned today is the Rhino 450 in stock form makes its peak Torque at around 3800 RPM and peak HP at 5800 and that number is 13.86hp

All this being said we are changing the way we dyno so we will get some more useful information to help us determine the best mods to make or not to make.

We recently added a Eddy Current Load Control to our dyno at the tune of $9000 and have a torque cell coming for it now for another $2000 for a total of $30,000.00 in our dyno that we really only use for R&D. We don't dyno other peoples vehicles at this point.

http://www.rhinoforums.net/hunterworks/240...t-vehicles.html