We all hear about DynoJet dynos. I got an email from a place not too far from me that uses a different dyno and states that your hp and tq numbers will be about 12-17 percent less than the DynoJet or other inertia-type dynos.
They also can dyno scooters, cruisers, HDs, dirt bikes with knobbies, sprint cars, quads and drag bikes.
I do not know these people or have visisted the store.
If interested go here:
http://www.xtrememachines.us/miscpage_009.asp

 

Is there a question involved with this post?

 

Does there have to be a question? <-There's the question, lol
There was talk of how different evironments can effect the output of dyno runs. Just thought I'ld share some info.

 

No, I just wasn't sure what it all was in reference to. Here is more if you want to know more about the Dyno in the website you posted and how it compares to a Dynojet. www.factorypro.com

 

As with any machine, differences in tolerence is expected...

 

Tolerence, Yes
Math, No

 

You said it best dude, cheers!

 

You can take this for what's it worth from someone that does this for a living 5-7 days a week the last 10 years.

The Eddy current will most likely be more accurate at steady state and much easier to tune an EFI bike then an Inertia style. The website claims from the link above are pretty honest.

The 12-17% I don't buy though. Worst case...YES! Average no. The problem with inertia dynes is a sloppy operator. You can really fudge the HP numbers if you know how to to manipulate (or by lack of training) when to remove the load and/or thorttle. Many aftermarket companies that sell performance parts for ANYTHING with an engine love doing that trick. Many times you can buy an item, install it, have it dyno testing by a good operator and find out you made no more or EVEN LESS power. Dynotech Newsletter used to do that and wass always being sued by parts companies (for telling the truth).

If I was to buy one for use of tuning bikes for people, I would get the Eddy current. It would be great to set the bike up at a customer's complaint speed & load and record data then play it back and make changes. Sweeps are good for peak power, no good for tuning cal tables.

 

Ron, thanks for that expert opinion.

We all appreciate it...

 

I am not disagreeing with what has been said here but rather adding to.

Not all Eddy Current Dyno's are created equal. The way in which the load is applied and measured varies. A load that is applied as a percentage on a high inertia dyno, verses a load that is applied to a low inertia dyno to maintain constant rate of acceleration, is harder to use for EFI tuning.

The 12-17% number may be a little closer than you thing. In fact the dyno used (EC997) has a 1.15 difference vs a Dynojet. IMO, the actual number is not important. The dyno should be considered a tool and used as such. If I minipulate the numbers so the dyno reads that my bike makes 40tq and then tune the bike to achieve max power. Say I get 47tq but the tune is good. The bike is still going to perform as it should. Now I take that same bike and minipulate the dyno so it now reads 100tq and retune it, and it hits 107tq again with a good tune. The final outcome on the bike is going to be the same result regardless of what the number is.