Did my lightened flywheel improve performance?

[Aerial_stu]

Hi Folks, after trawling this forum when trying to figure out the benefits of the lightened flywheel, I came across lots of varied answers, but no hard numbers.

I wanted to be able to measure the benefits (as much as an amateur mechanic can), so I set about trying to measure performance.

The only real variable I can measure is 0-60 time, as responsiveness, engine braking etc is hard to put a number on.

So, did I improve my 0-60 time?

[700newtons]

Thanks for that - interesting.

There is a lot of energy stored in a heavy spinning thing.

Simon

[Beagler]

Interesting but for me its not worth the benefit for road use unless your removing the engine for another reason.

[Aerial_stu]

One thing I forgot mention, and it's a big thing for me, was the improved smoothness of gear changes.  

[paul richards]

I find a lightweight flywheel improves the driving experience. I like to use the gearbox and engine braking when on a winding road. Nothing better. You feel much more connected to the car. Well worth it for half a days work. 

[Scotland North AR]

I'd second that Paul, vastly more responsive engine when changing gear. Particularly good on Scottish roads up here, never in the same gear for very long. Makes the current five speed feel more like my old six speed car. Well worth it indeed.

[GulfSeven]

Caterham doesn't list different 0-60 times between S and R models does it?

[Aerial_stu]

I don't know, but physics would suggest an engine will spin up faster with less mass.

perhaps they could use my data? 

[Simon420R]

I love a lightweight flywheel but in London traffic I never allow the engine to do my braking. The deacceleration is phenomenal but I tend to dip the clutch and use the brakes instead (LEDs all round, including a pair of lights mounted on my roll bar). It avoids rear-end shunts from tailgaters who aren't paying attention. Out on the twisties the engine braking is fantastic though. 

[oilyhands]

As well as accelerating the car, the engine has to also accelerate its own mass, the lower the inertia of the engine the faster it will accelerate itself, this improves the acceleration of the vehicle as a whole, especially in the lower gears where the mass of the engine is a greater proportion of the overall mass. The rotating moment of the flywheel is quite high so removing mass, especially at the outer reaches of the flywheel has a profound affect.

oily

[Roger King]

When I worked for Bill Blydenstein at DTV, he used to say that 0-60 figures were a nonsense because of the variables of driver skill, road surface, tyre performance, etc.

Instead (and I agree with him), he preferred 30-70 times to eliminate all the above, but he also wanted to see two figures - once through the gears and once in top gear (I know many moderns won't pull 30mph in top). This gives you the vehicles outright performance, but also shows how flexible the engine is for road us.

[Wrightpayne]

I have one in my K series and wouldnt go back now. Also had one in my tuned mini in the 80s with an EN40B lightened back plate - great fun!