Two Stroke supercharger???

[mx250]

Why do you think they have groved the crank flywheel? Increasing the 'windage' to have a supercharger effect?

[Lozza]

A mob in the US do this to lighten unsuspecting peoples wallets.Which it does with alarming regularity.

[mx250]

A mob in the US do this to lighten unsuspecting peoples wallets.Which it does with alarming regularity.

So that's the claim is it? I was wondering. I know the opposite, polishing, is also done to reduce the windage, 'drag', and increase HP.

[tony27]

I'd say some form of plot against 2 strokes as that would drop primary compression due to those chamfers on outside of crank 

[Marc.com]

windage and compressing air have 2 different meanings. If windage from oil drag then possibly as you are breaking up oil film, not sure what meaning that would have on a 2 stroke that runs dry crank. If you are talking about compressing air forget it and even if it did you need an exhaust valve to make it all work.

[Lozza]

Exactly Marc, these is pure snake oil. Show me the dyno print out.

[felix7]

The only benefit in this on a two stroke is lightening the crank.
But - I'm probably way off here - if it's a pressed four-stroke crank the grooves promote spray which cools the underside of the piston.
And, as mentioned before, lightens the wallet.

[Marc.com]

if you really want to super charge a 2 stroke you need one of these

http://library.abb.com/global/scot/scot208.nsf/veritydisplay/7d71e16c42799eddc12575ca0049097c/$File/ABBTC_TPL_B.pdf

[firko]

Years ago I bought a siezed up Maico 250 engine and when I pulled it down I found something similar to the above. Some "genius" had used an angle grinder to grind similar grooves into the flywheels. There was no uniformity on depth or pitch and I often wondered why someone would do such bastardry to a perfectly innocent set of flywheels .

[maicomc490t]

I'm with Lozza - a dyno print out would be interesting and so would the shops profit margin !!! Nice engineering though .........

[montynut]

MarcFX, unless you have a 2 stroke diesel which is totally different to a 2 stroke petrol engine the turbo can not work.

[Lozza]

Sorry to rain on your parade there monty but turbo's on 2T engines are all the rage in the sand drag and snowmobile drag(both summer and winter) worlds 

[KB171]

Something to wake up the Jawa 

[paco]

I love thar jawa.

[montynut]

I stand corrected Lozza although my post was not very clear I was referring to the link in MarkFX's post. Having said that I did not think that a 2 stroke spark ignition engines could be successfully turbocharged - Supercharged yes.

I wonder how they overcome the porting overlap issue and restriction in the exhaust? I would expect that the gains on a spark ignition 2 stroke would not be as easily found as in a 4 stroke.

Anyway that teaches me for opening my big trap

Interesting links on this subject
http://www.physicsforums.com/archive/index.php/t-64413.html
http://www.youtube.com/watch?v=CjFOOG1WYws