Bucket Dyno

[CookMySock]

To get repeatable results with a road dyno you need to reuse the same piece of road and same rider weight, fuel weight, etc, or you get false "improvements".

I think the dyno could be built into a bike trailer. Ie, the trailer gets used to transport bikes, but has a dyno in it.

Next problem is the 300KG inertia mass weight / rotating drum. This can be resolved by gearing up the drum to a lighter but faster rotating drum. Three times the RPM for the same weight drum is three times the inertia.

DB

[TygerTung]

Somone down here just built an inertia dyno using a 700kg drum.

[CookMySock]

Somone down here just built an inertia dyno using a 700kg drum.

Itsa good idea. Except it weighs 700kg. Just for the drum. Gear it up I reckon.

DB

[koba]

From what Ive been reading on that you can only make it go so fast before the forces cause the thing tio come apart
Dunno how close you would get gearing it up but there would obviously be sa limit that you would want to keep a fair magin away from!

[koba]

The Road Software Dyno is so simple, you just attach a recording device to the bike. Go for a blat. Download the recorded data to a PC. Analyze data. Fiddle with bike. Go for another blat. Check the recorded changes. Real simple. More blats, more changes more power.

This is a really good looking cheep dyno kit about 75 pounds for the kit. http://www.roadtune.co.uk/index.shtml

This is a really good description of how the in vehicle software Dyno is setup and works.
http://www.microsmith.co.uk/rd/dyno.htm

This URL does not work but it is where I got my software from last year.
http://www.charm.net/~mchaney/homedyno/dynokit.htm

Some general racing info and free software
http://racingdownloads.com/

Another dynokit
jgarman@earthlink.net

Still catching up on all this reading!

Altho the ropad thing may not be perfectly accurate it seemms to be good for the price/complexity of it, certainly must be better that an arse dyno!

[koba]

I think "Autocar" use a real fancy accelerometer (vbox or Xbox or somthing?) for their acceleration tests and I think that is supposed to be super accurate.

[CookMySock]

From what Ive been reading on that you can only make it go so fast before the forces cause the thing tio come apart
Dunno how close you would get gearing it up but there would obviously be sa limit that you would want to keep a fair magin away from!

If the geared-up inertia drum bit is much smaller, it will fit in someones balancing machine quite nicely. It would be cool if it could use bike chain-drive stuff for the gear-up bits - cheap and strong. An overrun clutch would be good for safety, as the bike and wheel drum could shutdown real quick and leave the inertia drum to amble down at its' leisure.

Altho the ropad thing may not be perfectly accurate it seemms to be good for the price/complexity of it, certainly must be better that an arse dyno!

Agreed, but to be really useful, the dyno needs to be able to tell you "YES! that mod gave you the extra midrange you thought it would" or else its just an expensive ornament.

An eddy current brake is a simple and effective way of slowing everything down after the run, without heating hell out of the bikes' brakes. http://en.wikipedia.org/wiki/Eddy_current_brake

DB

[TygerTung]

Advantage of a dyno where the bike doesn't move is A: Safety, B: you can hook up gas analysers etc and you can hear the engine and other assorted bonus's

[quallman1234]

http://www.dsm.org/tools/calchp.htm

This obviously wouldn't be anywhere near accurate enough due to human error in getting off the line etc.

However i still tried it using Koba's times from the clif hanger spirnts and his RG150 worked out to be 21hp (170kg total weight at a estimate! 110 for RG 60 for Him what probabaly is quite off)
But 21hp probabaly isn't too shy of the true value.

[koba]

http://www.dsm.org/tools/calchp.htm

This obviously wouldn't be anywhere near accurate enough due to human error in getting off the line etc.

However i still tried it using Koba's times from the clif hanger spirnts and his RG150 worked out to be 21hp (170kg total weight at a estimate! 110 for RG 60 for Him what probabaly is quite off)
But 21hp probabaly isn't too shy of the true value.

Again roughly by that the VFR should have had around 51 at the wheel.
That does sound about right BUT it is still a guess as they say...