Are there any downsides to having a lighter flywheel?

i know it affects idle, but can this be sorted with mapping?

also how does this affect torque?

i know it makes the engine rev quicker, and slow down quicker, but other than that are there any detrimental affects?

 

will affect the torque according to Gran Turismo, and make you slower up hills!

 

It gets affected by inclines more too, as you don't have a stored mass of energy that you do in a heavier flywheel, if too light they can grenade!!
I have run very light flywheels on numerous cars and they do affect idle, depending on how light of course, for road use I would say of what I have had 25% - 30% made a big difference without seriously giving any side effects.
Saying that the cossie one is stupidly heavy to start with, and a lot of the ring can be machined off.
tabetha

 

torque is not affected if you maintain the same engine rpm as the same air/fuel is being burnt pushing the same piston down the same stroke acting on the same crank. the difference is that, particularly at low engine speed, any load from trying to pull away will reduce the engine speed more as you don't have the same inertia behind it. it just means that you have to use the throttle more to maintain engine speed which can be difficult to control precisely as the engine is quicker to respond.

ime the positives far outweigh the negatives.

 

cheers for the input, its for a stripped out car that is going to be a toy so going for day to day use isnt an issue, its not a cossy flywheel but nearly the same weight, and its only a 150 bhp standard i reckon could loose half the weight easy as its a dual mass jobby, but dont think i'll got that drastic, just save 2-3kg, think that should make a massive improvement.

 

it's not just about the weight loss, it's also where it's lost from. 2 kg lost from the centre has little effect compared to 2kg lost from the outside

 

it would be the outside, affecting cetrifugal force.

basically there is a huge thick ring round the outside similar to YB, its about an inch thick

 

ironically i couuld loose very little wieght from the middle its thin there, its all on the outside.

 

you would be better buying a decent flywheel in the first place ryan,

 

its only a cheap toy though mark, and for conveinece it has the trigger in it for the crank pickup. so just makes things easier this way

 

Light weight flywheels also make it trickier to set off - I have to use a fiar amount of revs to get moving in my Westfield with a 2.1 Pinto and steel flywheel else it just stalls instantly.

I'm often asked how much can safely be removed from a stock flywheel. My generic answer is none imo. Steel flywheels all the way or nothing at all imo.

 

What's wrong with billet aluminium flywheels then?

 

You know what I meant :-P