Sport Evo Flywheel v.s Stock Flywheel


Flywheel tech....

sport evo flywheel

Lets start of with some Kg's
Stock flywheel weighs 10.5kg
Evo2 / Sport evo weighs 5.4 kg
Now we know that a Evo2 and Sport evo flywheel (they are the same) have less weight than a stock one.

OEM Flywheel
You can clearly see where they reduced the weight of the flywheel.
Both flywheels are made out of 1 piece design.
I have read that there are some stock flywheels where the starter ring is pressed on.
Weight is clearly reduced on the front side (left) at the outer parts.
And the back (right) the concave part, also on the outside.

Evo2 / Sport Evo Flywheel

But what are some of the up's and down's of that weight loss?

Lighter flywheel:
- Faster acceleration
- Better throttle response
- Less stable idle

Heavy flywheel:
- Stable idle
- Strong engine braking
- Anti stalling on the engine when driving of

Horsepower won't increase with a lightend flywheel, but you will get faster acceleration.
There is less weight to rotate, so also quicker throttle response.
5kg's of weight loss is enormus, but 10.5 kg's to begin with isn't that much compared to newer cars.
Newer cars , for instance, the e36 M3, has a dual mass flywheel, this also weighs dual as much.
Our S14 engine's have single mass flywheels, therefore are light to begin with.

Example of a dual mass flywheel

How to lose weight?
First you can get your stock flywheel to a machine shop and let it lose 5 kg's.
This part is easy, but the flywheel also has to be weight balanced.
If you don't balance it, you will get vibrations through your engine and crank and it could snap your cranckshaft.
This part won't be done by any machine shop, this has to be done by someone knowing what they are doing.
Seccond, where to shave the weight.
How less weight on the outside, the better the results will be.
This has to do with the moment of enertia.
There are enough articles on internet to learn about enertia, so I am not going in to that to deep.
So it's not about how much weight you can shave of, it is also about where you shave of this weight.
As we look on a very light flywheel, we can see that only the starter ring is the weight on the outside.
JB for instance makes these extreme light flywheels.

Third, you can use different materials.
The original ones are made out of iron, so changing to alloy or carbon will reduce the weight also.

For installation you require also smaller bolts (22mm).
They reduced weight also of the inner part where the bolts sit, so oem bolts (28mm) are to long and will hit and won't fit.

Installed Sport Evo Flywheel

p/n OEM Flywheel : 11 22 1 311 862
p/n OEM Flywheel bolts (M12x1,5x28mm) : 11 22 1 717 840 (8x)
p/n Evo2 / sport evo flywheel: 11 22 1 312 519
p/n Evo2 / sport evo bolts (M12x1,5x22mm): 11 22 0 616 143 (8x)