Engine Dyno

This is a Sports Devices engine (inertia/acceleration) Dynamometer.  It operates by way of connecting a chain from the front sprocket to a shaft connected to the drum.  The drum has a sensor which picks up the rate of acceleration which is fed to a processor and then downloaded to the Sports Devices Computer Software where the information is displayed in various formats.

There are several benefits to an "Engine Dyno" over a Rolling Road type Dyno.  From an engine development point of view the engine can be worked on in situ and access to the various parts is un-restricted.  An "Engine Dyno"  also shows up small increases in power output where a "Rolling Road Dyno"might not, as parasitic losses are reduced. The benefits of this are that changes to things like Jet size, reed valves, optimal running temperatures can be detected,  ideal for Minimoto purposes.  The Graph will also reveal at what RPM peak torque occurs and therefore the optimal RPM for clutch engagement. In addition to water and spark plug temperature sensors there is also an Exhaust gas temperature sensor. 

Outright HP figures are fairly meaningless as much depends on the calibration of one Dyno to another, amongst other things.  The important part is the before and after Dyno graph and the shape of the curve produced.

You might ask yourself "what's the point"? Well, the point is that I can test engines in various set ups and get the best from the engine in accordance with what best suits a particular riders use.  With Proddys and 4.2 there are a limited number of things that can be tested, all of which are a bolt on part of one variety or another and some of which only make small differences, however I have seen big differences between the various pipes available.  The other thing is that there is constant speculation as to what is the best set up for a particular engine/pipe/reed/squish clearance set up.  With Dyno set up all element of doubt is removed and you can be sure that the engine is performing to its full potential. 

The dyno graphs can be overlaid so that direct before and after comparisons can be clearly seen.  Often you'll be looking at receiving between 3 and 6 dyno graph printouts which will be a combination of single and overlaid graphs.  I'll probably have made more runs than that but the intention is to show where progress has been made!  I use Society of Automotive Engineering (SAE) as the default correction factor.  Different organisations, ISO, DIN...........use slightly different formulas to calculate Torque which in turn calculates Horsepower. Typically the outputs vary by as much as 5% through the use of the differing formulas but I can Dyno with any of the above options if requested.

The calibration of this Dyno is set by programming into the software the inertia of the drum.  If the inertia isn't correct the Torque and HP readings don't correspond.  HP is just Torque x RPM / 5252.  I don't know what readings another Dyno would give but the readings I get from this seem 'real world' to me.  I'd have been concerned had the readings given outputs any higher than those seen above.  I view many of the claims of power outputs with a degree of suspicion.

Price For Full Testing/Tuning

Supers/Multi Meter Carbs  £80

Proddy or Aircooled/Single Meter Carbs £60