Hi Guys,
I found this while surfing and i thought it was interesting....
Enjoy.

Sniper.

 

Interesting read.

 

There's a bit more to it than that. The flywheel is there ensure that the crankshaft continues to rotate after each power stroke. Without a flywheel the engine wouldn't actually run because in a 4 cylinder engine with a flat plane crank the there isn't enough rotational inertia for the crankshaft to continue rotating after each piston reaches the bottom of a stroke.

I actually tried this at uni. We took the flywheel off an engine and tried to run it. When it was connected to a rotating transmission simulator it would run, because it acted as a flywheel, but the engine wouldn't run at all when this was disconnected as once the starter was disengaged the engine literally stopped dead within one stroke.

so in answer to the question in the post 'when is the flywheel too light?' the answer is when the flywheel isn't doesn't store enough momentum for the engine to run at idle.

 

Things to do with a Ducati, would have thought #1 was attach to skip Anyway I can talk from a race 2 stroke POV when it comes to flywheels. We don't use them very often, the major benefit to the bike is when you are running at a long 'power' track like Thruxton and up the hill you tend to lose a bit of momentum. Sometimes there is a benefit from having the inertia there to help the crank maintain rotation. It is less hassle most of the time to take them off and run batteries and a decent ignition system. The 4 strokes I have seen have very small flywheels and idle 2-3K, they are not so much for mass more for pickup. Can't remember what the GSRV was using. Also the bizarre firing orders that some of the teams run would probably reduce the need for mass which at the end of the day everyone aims to keep to a minimum.

When is a flywheel too light, when the engine is not useable in the environment it has to work in? On the road it has to maintain idle at a reasonable rate and the response progressive off the throttle from 900rpm. On the track idle is irrelevant as it will be set where the engine will run and pick up will start at the point with most engines having variable maps, optimized gearing and riders keeping the thing on the boil.

 

Nice responses

 

definitely puts things in perspective.

If you've MASTERED shifting as well as clutch feel/friction zone on the s2k and don't mind micromanaging every idle launch, then you're just OK with a light flyweel for street purposes.

Otherwise, there are other modifications out there...

 

What does a stock flywheel weigh compared to a Fidanza/Toda or whatever.

I loved it when I swapped one into my mx5 ~ 8lbs vs 18lbs.

I'd imagine a lightweight flywheel, wheels and a higher final drive would make for a very sprightly S.

 

So does this effect internia when going up hills, running a lightier flywheel than a stock one?

 

Running a lighter flywheel will not make you go up hills slower if that is what you are getting at

The inertia of the car is far greater than the inertia of the flywheel

 

Ive fitted lightened flywheels to all my Honda's and i can safely say it was one of the best/favourite mods i ever did, and i put over £3k into my engine bays. The pro's far out weigh the cons for me, totally different car to drive IMO, and they lend themselves nicely to Honda's high revving engines and quick gear changes.