Scooterotica

Gents- What flywheels do you use on small block kitted engines ?

I am currently using an AF lightened (1.6kg) and it has been suggested to me that it is the reason I have very little bottom end grunt.

Cheers

Personally I would have said the reverse should be true. A standard F/W is approx 2.8kg, so the engine has to get this spinning before any "power" can be transmitted to the road. A lighter F/W will spool up much quicker and therefore the usable power comes in quicker- in theory!!

Lightened F/W's were / are a popular mod on old Minis and gave good results thru the gearbox with the greatest gain being in 1st gear and diminishing up thru the box till 4th. Against this was a lumpiness on tickover.

No doubt none of the above applies to Lambrettas

Anyone else got any theories?

Chris

Thanks Bristolmod -It was explained to me as "lack of inertia".

My missus says that about me..............

Once a heavy F/W is spinning its harder to slow it down, so as long as you keep the revs well up they should run OK. But, if the revs drop off then it takes more energy to get it back to speed- a lighter one SHOULD get there quicker.............IMO

Are there any Physics teachers out there?

Chris

I'm far from an expert but I'd have thought that a heavier flywheel would make the scoot feel more torquey and smooth at lower revs because of the inertia. It will make the throttle less responsive though.

Angry Bloke wrote:Gents- What flywheels do you use on small block kitted engines ?

I am currently using an AF lightened (1.6kg) and it has been suggested to me that it is the reason I have very little bottom end grunt.

Cheers

That is correct ...........grunt being torque .........you will rev more instantly for quicker power response but the pulling power will be less as you need the mass of the flywheel for backup pull.......

ArmandTanzarian wrote:I'm far from an expert but I'd have thought that a heavier flywheel would make the scoot feel more torquey and smooth at lower revs because of the inertia. It will make the throttle less responsive though.

I'd go with that.
so something less than the standard item, but lighter[oops] heavier than an AF.
I was thinking about one of these from sandy Scooters for my next engine.

If you are going for the 2kg item, MB does one: http://www.lambrettaspares.com/sparepar ... ab034.html#

or with welded boss: http://www.lambrettaspares.com/sparepar ... l0142.html

Thanks for that Gents I think i will try a heavier flywheel and see how i get on.

it is a known fact that the heavy flywheel will keep you going longer,all modern diesel engines run light flywheels ,not like the old perkins that only revved to 2000 rpm.if i could run a boss and no fan i would,look at all the karts ans race bikes when they blip the throttle the engine goes no lag .,the lighter one will be kind on bearings but for two up riding around town the 'boss' flywheel has no inertia to keep the engine rolling,
dont waste money stick with the af one!
regards
joe