OzVMX Forum

Clubroom => Tech Talk => Topic started by: noisy toy on June 02, 2012, 07:04:16 pm

Title: home made dyno
Post by: noisy toy on June 02, 2012, 07:04:16 pm
Has anyone built their own bike dyno? Not looking to do full on horsepower curves, just a bit of loading up for jetting,timing, and measure any differences.Any tips on how to go about building one would be great.
Cheers, Shane  ???
Title: Re: home made dyno
Post by: EML on June 02, 2012, 07:30:25 pm
Just start with a set of rollers and a couple of straps.
Title: Re: home made dyno
Post by: Lozza on June 02, 2012, 11:51:57 pm
There are several kits you can buy, you have to decide if you want engine or chassis dyno. Once you decide that, you have the big ticket item, the drum/flywheel, which has to be machined and balanced expect to pay about $3-5k alone for that. Then there is the exhaust fans and ducting, and finaly a often overlooked area of silencing exhaust noise. Dyno's are useless for jetting. In order to apply a load to the engine you have to have a brake that is either electric or water, water brakes are a PITA. So your back to an inertia, with inertia your at the mercy of the software to find if the results are useful or not. SportDevices and Dynertia. After all that buying a used dyno will seem like great value, one sold recently on ebay for $8k( had wildly inaccurate outputs, but any dyno can have that). A alternative is a Iphone and the dynolicious app that even on 650hp cars is within 3-5hp.
Title: Re: home made dyno
Post by: noisy toy on June 03, 2012, 08:02:04 pm
Thanks for all the advice. May have an old eddy current dyno i can get hold of. More the software now i think. I will look at those two sites, thanks Lozza. More for fun, not a commercial venture. Dont need accurate kw, more a comparison to any changes. 25 dunderklumpens is more than 24!
cheers
Title: Re: home made dyno
Post by: Lozza on June 04, 2012, 12:11:33 am
Beware any 'old' water dynos................unless you like plumbing ;D
Title: Re: home made dyno
Post by: Freakshow on June 04, 2012, 10:52:25 am
Watewr dyno at the kart shop works a treat, they use it to run the motors in under load....
Title: Re: home made dyno
Post by: Lozza on June 04, 2012, 03:01:41 pm
Kart engines have about 15hp and bugger all torque