Flywheel: light weight vs Standard/Heavy

Technical Area Engine, Transmission, Exhaust etc
2

hey everyone, i would like to know your personal experiences with heavy or light flywheels and how different they feel to each other also your personla pros and cons to having either one.

from physics . Heavy  more energy used up starting off and accelerating throughout the gears. Less energy consumed when traveling at a constatnt speed.

                     Light: quicker acceleration throughout the gears less energy consumed. more energy consumed keeping the car at a constant speed.

 

hope to see your personal experiences and why is either better than the other

3

How do you use your car? Commuting, heavy/light traffic, fast w/e runs, track etc?

4

Can’t say I’ve ever noticed a difference between my 1996 Roadster S-Special, which came from the factory with a lightened flywheel, and a previous car, a 91 Roadster, which had a standard one.

5

couple of relevant threads on nutz.

The general consensus on a mk2 1.6 is that it brings it in line acceleration wise with the 1.8, but it tails off toward the top end.  I plan on having one fitted with a clutch change, its got to be good from a weight reduction point of view, and apparently makes gear changes much nicer as the revs drop more quickly.

if you’ve got 2-300 quid to burn its got to be one of the more effective mods vs ££s spent.

6

its going to be mostly comuting, various traffic conditions( more medium light conjestion), but i do intend to take it out for track days as well… 

7

I had a lightweight flywheel fitted to my Elise and the difference at low rpm was very noticeable, principally of increased response. In stop start traffic however it did take more effort for smooth progression with the revs sometimes dropping to near stall level. Within a few weeks I became quite used to it, but it was less drivable. On the track it came in to its own and was a real pleasure. If this relates to a a MX5 then I’d say, if you’ve got the money to burn whilst having the cliuch changed anyway, the go for it, but it’s not one way traffic.

 

HTH

8

just a quick one , would it be normal for the car to be at around 3000prm doin 100kp/h and around 4000rpm doing 120kph

9

at 100kph (62mph) mine sits at 3000rpm.  at about 4000rpm im doing about 80mph.

10

A lightened flywheel can (not will) lead to rough idle as there is reduced weight evening out the transmission.

If you’re using the car mainly for commuting personally I’d keep the money in the bank.

11

Just to add I have recently had (after an engine rebuild) a lightened flywheel and modified (fast road)cams put on mine and after hours of fiddling by both doctormx5 and myself cant sort rough idle out have got it to an acceptable level (well done Julian) so in my experience yes superb when driving the car very fast acceleration and good gear change but left with a rough idle.