Fidanza Flywheel

[elbon50]

What are the weights please of :

1/ A Fidanza fllywheel

2/ A stock flywheel

Peter

[LimeyMk1]

Stock one's about 12kg from what I remember, not sure about the Fidanza, LOTs less.

Edit: 4.09kg according to Fensprout website.

[elbon50]

Stock one's about 12kg from what I remember, not sure about the Fidanza, LOTs less.

Edit: 4.09kg according to Fensprout website.

Is it possible to go lighter than 4 Kg ?

Peter

[kherseth]

Anything is possible, from memory the F1 cars have no "flywheel", instead it relies on the weight of the crankshaft/rods/pistons and clutch. Result is of course that you need very high idle to keep the engine from stalling.
Also, in order to get going, delicate clutch handling and even higher revs would be needed.

Pure guesswork, but when the flywheel is down to 4kg, would it not be just as useful to upgrade to lighter crank/rods? I guess the cost would be comparable to having a lighter flywheel custom made.

[AdamP]

Anything is possible, from memory the F1 cars have no "flywheel", instead it relies on the weight of the crankshaft/rods/pistons and clutch. Result is of course that you need very high idle to keep the engine from stalling.
Also, in order to get going, delicate clutch handling and even higher revs would be needed.

Pure guesswork, but when the flywheel is down to 4kg, would it not be just as useful to upgrade to lighter crank/rods? I guess the cost would be comparable to having a lighter flywheel custom made.

Motorbikes don't have flywheels either, but they have a very different clutch arrangement.

The problem is that all the torque is transferred through the flywheel. You aren't just reducing the mass, but also the strength. One thing you dont want happening is a flywheel disintegrating...

[LimeyMk1]

Stock one's about 12kg from what I remember, not sure about the Fidanza, LOTs less.

Edit: 4.09kg according to Fensprout website.

Is it possible to go lighter than 4 Kg ?

Peter

You can get lighter flywheels for the MK1, down to 2 or 3 kg from what I recall but they cost a fair bit more.

[elbon50]

Stock one's about 12kg from what I remember, not sure about the Fidanza, LOTs less.

Edit: 4.09kg according to Fensprout website.

Is it possible to go lighter than 4 Kg ?

Peter

You can get lighter flywheels for the MK1, down to 2 or 3 kg from what I recall but they cost a fair bit more.

Thanks Limey

Lots of extra cost for very little gain perhaps ?

Very light F/W would also mean rough tickover I should think ?

Peter

[LimeyMk1]

Thanks Limey

Lots of extra cost for very little gain perhaps ?

Very light F/W would also mean rough tickover I should think ?

Peter

Compared to a Fidanza yes. I had a fidanza on my Mk1 and they're a great mod, makes the engine rev easier and makes the whole driving experience more 'lively'. I have one on my V6 as well.

Vashy has a flywheel that's lighter than a Fidanza and it didn't have any effect on idle from what I recall.

[stenky]

isn't heat dissipation with lightweight flywheels a problem?

[LimeyMk1]

isn't heat dissipation with lightweight flywheels a problem?

Shouldn't be with the Fidanza as it's a solid flywheel. Only difference is it's mostly ali.

The Chromoly steel ones are usually holey so not a lot of material for heat dissipation, so maybe.

[cartledge_uk]

isn't heat dissipation with lightweight flywheels a problem?

Shouldn't be with the Fidanza as it's a solid flywheel. Only difference is it's mostly ali.

The Chromoly steel ones are usually holey so not a lot of material for heat dissipation, so maybe.

I havent had any noticeble issues with mine, but then I do use a paddle clutch. But you can see the heat marks on the flywheel here.

[stenky]

well, i reckon that fidanza has calculated it well and the heatmarks do not alter flywheel's durability (although any heat treating does change material properties of metal, no doubt about that). what does trouble me is fact that, the excess heat a stock flywheel has to absorb and lightweight might not, could transfer way further to the crankshaft, degrading oil faster, or in the worst case, burning it up and damaging shell bearings-crank badly.

any opinions on that? i am really keen on getting fidanza

also, i believe that paddle clutch produces less heat than organic one, so the picture above is probably the least that could happen to the flywheel.

[cartledge_uk]

well, i reckon that fidanza has calculated it well and the heatmarks do not alter flywheel's durability (although any heat treating does change material properties of metal, no doubt about that). what does trouble me is fact that, the excess heat a stock flywheel has to absorb and lightweight might not, could transfer way further to the crankshaft, degrading oil faster, or in the worst case, burning it up and damaging shell bearings-crank badly.

any opinions on that? i am really keen on getting fidanza

also, i believe that paddle clutch produces less heat than organic one, so the picture above is probably the least that could happen to the flywheel.

The photo above is a trd steel one and is fine, no issues whatso-ever.

The fidanza flywheels wouldnt be sold in thousands if there are issues.

[Fab4MR2]

Here are some real life weight measurements for the 4agze components from when I recently rebuilt my MKI SC.

Oem MKI SC 4agze flywheel: 5930 gm;
Fidanza MKI SC 4agze flywheel: 4505 gm;

[cartledge_uk]

Here are some real life weight measurements for the 4agze components from when I recently rebuilt my MKI SC.

Oem MKI SC 4agze flywheel: 5930 gm;
Fidanza MKI SC 4agze flywheel: 4505 gm;

nice

The 4agze flywheel is noticebly lighter than the 4age (N/A) one, i'll try and weigh my spare when I get to my car.

[greglebon]

Re: heat.....

Its worth considering that aluminium is very good at getting rid of heat, compared to steel....

If you put the same amount of heat into a steel and an alu flywheel, the steel one will take longer to both heat up and to cool down after the heat is removed.

This means that the steel one will heat up over time (say, on track) and will retain this heat...not a good thing!

An aluminium one will radiate the heat energy much more efficiently, which may have adverse effects on the clutch assembly itself, but will reduce the amount of conducted heat absorbed by the crankshaft, etc.....

As the above is true whether you have a stock steel flywheel or a drilled-out lighter steel one, I would suggest that the drilled one will get much hotter over time than a stock one...?

I dunno what the practical effect of this is on a mk1, but it surely must be detrimental in some respect, compared to the stock one....

[Fab4MR2]

Don't think that it was mentioned, but the Fidanza flywheels all have a removeable steel clutch surface on them that can be replaced if need be. I have also seen numerous posts from people who were concerned with the different heat absorption rates of the two metals, but it apparently it is not a real concern in this application or you would have heard a lot about it by now considering how many of the Fidanzas have been sold over the years.

[Basirk]

I did have a slight issue with mine.
After the engine had warmed up, when I pulled up at some lights and put the clutch in then the engine would sometimes stall. There could have been an issue elsewhere of course.

[cartledge_uk]

I did have a slight issue with mine.
After the engine had warmed up, when I pulled up at some lights and put the clutch in then the engine would sometimes stall. There could have been an issue elsewhere of course.

Thats probably an issue with the idle and possibly waxstat. The lightweight flywheel amplifies some issues, the first time I had one on an N/a mine did the same until I change the TB and retuned it.

[kaiowas]

Just thought I'd add my recent findings here:

A few years ago I bought a flywheel from a member here, it was a standard mk1b n/a part which had been lightened.

After over 3 seasons of sprinting and somewhere in the region of 200 full on race style launches from 6k rpm or so whilst attached to a supercharger engine we broke it a couple of weeks ago. Judging by how it's failed I'm certain that the failure is a direct result of the way it was lightened, if the corner where the failure occured had been filleted rather that a straight cut it probably would have lasted fine.

As our kitchen scales only go up to 3kg I've just been out playing with levers to get some rough figures from them:

Standard mk1b flywheel ~7.2kg
Our lightened flywheel ~5.3kg

Standard flywheel vs Lightened part:


Failure:


Close up of failure location: