I am looking to get a dyno and I've been looking at the DynaPack dynos. http://www.dynapackusa.com/index.htm



As you will notice the dyno runs directly off of the hub of the vehicle.

This eliminats the tire to roller interface on a conventional roller dyno.
The problem I have seen with rollor-dynos is to many variables: Tire temperature, pressure, traction, etc, are all variables that can change - not only from run to run, but during the run as well. I have heard of cases where the ratcheting tie-down straps were loosened by two clicks and the measured power increased by ten horsepower.

But without the wheels you have a large amount of inertia that is not accounted for in the final dyno plot.

But the Dynapack is also very portable. (yeah, track days!!!) So I don;t have to allocate an bay for JUST the dyno and I don't have to dig a hole for an inground or pay for the lift for a above ground.

Thoughts? Suggestions? Input? Has anyone ran their car on one of these? Set-up time? How much was charged?


[Modified by mrlegoman, 8:09 AM 4/4/2002]

 

no one has any thunks on this?

 

I think Steve D'Geralamo is still the US distributor for these. They are nice, and very accurate. Quite repeatable in terms of numbers, so that is bonus.

Once they are familiar with a car's setup, it is very easy to test them out.

Honestly though? It doesn't matter what dyno you use, as long as it's always the same exact dyno. The relative numbers are all that's important.

Warren

 

not sure if you saw it, but this page has excellent info on it
http://www.autospeed.com/A_0930/P_1/article.html

 

something you might want to watch out for
"The car is then set up and ready for dyno'ing - once the correct data is entered into the controlling PC, anyway. The mechanical set up process takes about 30-45 minutes, Lachlan Riddel suggests. And while Dynapack representative Chris Spencer says that setting up any dyno takes about this time, that's not quite the case. While it is true that the dyno'ing of a high powered car on a roller dyno can take a while to organise (what with the tie-downs, wheel chocking and the like), a quick run on a roller chassis dyno can involve a set-up time of less than 5 minutes. There is no way in the world that a car could be placed on the Dynapack in five minutes!"

 

I'll read the article, but 30-45 minutes of set-up time? I assume that this is mechanicle set-up. Taking the wheels off, bolting on the hubs, positioning the dyno. My first thought on this would be to stage the cars to be dyno'd. Have two or three sets of hubs and have the second car already set up as the first car if dynoing.
But even then it seems like it would be hard to get a high throughput of cars (like at a track event).

But the cost of getting a portable roller dyno compaired to the cost of transporting this dyno may justify the lower thoughput of cars.