Stuart Page

iTrader: (4)

Hi Peeps,
Mr. Thicky hat on again, whats the benefit of fitting:

1) An oil catch tank
2) A lightened / balanced Flywheel

Pros n Cons appreciated!
many thanks

Mad Scientist

Oil catch tank can help matters when running more boost. More boost = more oil mist blow-by which can be detrimental to the petrol thus causing det. Get the oil mist out of the rocker covers and the crankcase and the problem is reduced. Plus, they look cool!

Lightened flywheel can improve throttle response and give more torque, since the crank is rotating less mass. Very light ones can cause some problems with uneven idling/ stalling though.

Hope this helps.

Pete

Stuart Page

iTrader: (4)

Thanks Pete for explaining.


Whats a preferred flywheel weight these days if light is good but too light is bad??!!

Mad Scientist

Couldn't tell you that. Sorry! Not because I won't, but because I don't know!

Try Graham Goode if you are feeling rich or try Mark at Lateral Performance if you are feeling not so rich!

I believe the Toda ones are about right.

Vinnie Mac

Stuart - I asked the same question of Alyn (ASPerformance) he said they take off about 4.5kg and the lightened flywheel then weighs in about 8kg, he said this gives no problem at idle etc.

StickyMicky

dont u lose torque when u lighten the flywheel?

Stuart Page

iTrader: (4)

Thanks Vinnie! So a standard OEM flywheel is over 12kgs??!1

Brit_in_Japan

stickymicky - Torque is the rotational force the engine develops. The engine develops the same torque irrespective of the flywheel weight, the energy is generated by the combustion process which is unchanged.

By reducing the flywheel mass you are reducing rotational inertia. F = m.a, where F = force, m = mass and a = accleration

The rotational equivalent is Torque = Inertia x angular accel'n
or rearranged, angular accel'n = Torque/Inertia

The less inertia, the faster the acceleration. By reducing the mass you are reducing inertia. This also means that the rotational energy stored in the system at a given speed is less.

This means not only does the engine accelerate more quickly, it can decelerate more quickly (for example is you drop the clutch a bit sharply). That's why lightening the flywheel too much can make it more difficult to drive, not enough rotational energy in the system to compensate for dropping the clutch sharply.

Hope I've helped.

mr smash

good exeleration but engine braking is redused.

johnfelstead

acceleration and engine braking are unafected by a lightened flywheel, as its the mass and drag (both mechanical and aero) of the car you are accelerating and decelerating, the flywheel weight is insignificant compared to these.

The main advantage of a lightened flywheel is the ability to match revs on downshifts, as the engine spins up faster between gears when unloaded.

4kg (8.5Kg final weight) out of the stock flywheel is about right for a good compromise of idle and easy rev pickup.

johnfelstead

P.S Your brakes are used for slowing the car down, not the engine.

BART!

I simply couldn't resist to jump on this topic so registered immediatley ...... about flywheels :

I've fitted a FIDANZA alu flywheel weighing only 4.2 kg instead of standard 11.something kg and this is what it does:

-Idling ...no problem, 'same as it ever was' ...
-1e gear / slow traffic : needs just a bit using to...a bit more throttle to get it rolling but minor difference.
-Running through 1e, second and third ....GREAT ! Especially accelerating out of tight-2e gear-corners is great, outrunning STI's and big turbo guys ....great on track. (In 4th and 5th the effect is lost as engine accelerating is slowing down)
-Braking -in gear- has improved (no need to slow down that lump of steel that's revving at 6k rpm...)
-Shifting up can be done quicker as revs drop quicker in-between shifts (so engine speed and 'next gear'-transmission speed are quicker in line...)


downsides.....
-with airco on, revs drop rapidly in-between shifts and needs to get used to ... quicker upshifting solves the problem...
-see above...engine is more nervous and so will you be
(or should I say...'more lively') so ..fuel consumption a bit up .
-expensive ...needs gearbox and clutch dismount...but when you're in for a new clutch anyway.....

Where did I buy it ? Well sorry guys ....far, far, away ..
in good ol' Waalwijk....Holland.

Greetings,
BART! aka Matthijs Otto

ps http://www.pumaracing.co.uk/flywheel.htm !!

[Edited by BART! - 9/25/2003 1:39:30 AM]

Brit_in_Japan

John, you are right that the mass lost by lightening the flywheel is not great when compared to the overall mass of the vehicle. However where you take the mass out is important. I = mr^2. So reducing the mass of a flywheel by 4.5Kg as you suggest might reduce the inertia by what, 50% ? True, there are other things which are also moving so the flywheel only contributes so much to the overall inertia of the vehicle. But I'm quite prepared to believe that BART can feel his car accelerating faster, especially since the flywheel has been lightened so much (inertia reduced by 80% maybe ?)

Stuart Page

iTrader: (4)

Anyone have a definative list of different flywheel weights (+ cost?) ??

DaveW

Spoke to Mark at Lateral Performance yesterday and he does one that is about 7.5kg and costs just over £300 inc VAT.

I'll be fitting one when my clutch goes, but then I have other reasons as it will mean I'll be able to fit any clutch rather than having to buy a clutch designed for a 22b which are silly money.

DaveW.