Heart of Darkness

[Ron&Gill]

Interesting comments about the radiation ratios

That's why you often read on the forums, "Don't use chromed engine tin."

(Is that why you're hotheaded? )

[ZeroAxe]

A nice shiney block behaves like a mirror. Reflecting heat back. BUT, a nicely painted block also acts as a 'shield'(almost like wrapping yourself in cling-film. Your body cant get rid of the heat). So, a 'natural' unpainted block is still the best thing next to sliced bread). Interesting read those stats there, but it aint always just about theory.....



Ron&Gill,

Yeah, that is what I tried to say with the flywheel.... You can pump up the revs real quick, but you dont gain much when torque comes into play(like taking off from the lights). The only reason why you can get away quicker from the lights is because your engine is revving much higher. So in theory(hahaha, didnt I just say that it aint always about theory ) there aint much difference between a Bug with a stock flywheel and a Bug with a lightened flywheel BOTH revving at 3000rpm leaving the lights........

[ZeroAxe]

Interesting comments about the radiation ratios

That's why you often read on the forums, "Don't use chromed engine tin."

(Is that why you're hotheaded? )

[JamesD]

why wrap your oil filter? Its a good spot to get extra oil cooling, plus that shiv will come off in chunks when you remove the filter.

It sits next to the exhaust, so rather wrap it and not pick up the heat from the exhaust. The stuff my uncle found isn't going to disintegrate, it reminds me of a seat belt. Its not just carbon, i think there is nomex or something with it. they say it drops temperature around the exhaust by 200 - 300 degrees. and price wise it was around about R600 for 5 meters or something. Once i buy i'll give more info.

A nice shiney block behaves like a mirror. Reflecting heat back. BUT, a nicely painted block also acts as a 'shield'(almost like wrapping yourself in cling-film. Your body cant get rid of the heat). So, a 'natural' unpainted block is still the best thing next to sliced bread). Interesting read those stats there, but it aint always just about theory.....

Ya, have taken into account but dont have calculations yet, your heat transfer through 2 thin coats of paint should be reasonable. but i'll still confirm that one. Wish i was still in varsity with those nice varsity labs and equipment, would so make a final project out of this, Bullshit the varsity by saying its to improve heat exchangers on petro chem plants

i figured i might as well just have the flywheel lightened, because once the rotating bits are balanced then its not going to come off to be lightened. just do the things while you can...

this afternoons mission is to go find jets for my carbs, thats going to be fun...

[Tony Z]

Actually, a lightened flywheel is good for throttle response when the clutch is in. I.e. you are standing on the line, you can blip the throttle and your revs do what you want really quickly, or you are changing gears, or you are impressing the hobo begging next to you at the traffic light.

But when you let the clutch out, it all returns to normal and the few grams you have taken off the flywheel are negated by the transmission, car, caravan and boat trailer weight that is now attached to the engine through the clutch.

The coolest about a lightened flywheel is the fact that when you turn off the ignition, the engine, like, stops, like, immediately. It doesn't slow down and stop, it just stops.

Ron, I have to disagree with you on this one....
Take it to the extreme.... add 50kg to the flywheel. You will have the slowest acceleration on the planet from a traffic light, but on a plus side, you will never be able to stall the car.
Remember the inertia of an object - mass x radius squared. Lighten the mass and there is less inertia to overcome. Remove the mass further away from the centre and it becomes less still, but removing the mass from the centre of rotation has very little to do in reducing inertia. A flywheel is there to make life easier (it keeps the engine turning and helps prevent stalling). It saps power during acceleration and returns it during freewheeling. T

I once upon a time had my disc brake conversion done - disc brakes put onto all 4 corners and new mags too. Nothing was done to any other part of the car. I remember being surprised at how much quicker the car was on take off... this was all due to me having much less rotational mass.

[JamesD]

it all comes down to unsprung weight yes. Discs have less inertia than drums. Smaller lighter wheels with thin spokes give you less unsprung weight. all equals better acceleration and stopping. Thats why racing cars normally run as light a wheel as possible

[Ron&Gill]

You need to distinguish between clutch in and clutch out. (same as with an AC alternator, either synchronized to the grid or not). Clutch in, I agree with you, the motor resonse will be quick, slight bit on the gas, and the revs will pop right up. How much do they really take off a flywheel, 500grams? 1kg?

OK, now you let the clutch out and press the accelerator down, the engine speeds up just as fast as the car does (unless your clutch is fcuked). Why? because the whole car's weight is now hanging on the flywheel. 1000kg vs 999kg with a lightened flywheel. Sorry, mate, no discernable difference there.

Lightening flywheels is a raceing trick, where you need very rapid responses from the engine with the clutch in, while there is no power going to the wheels. You don't want to sit there free wheeling waiting for your engine speed to catch up with you to select a gear, for example, no, no, no. it needs to be instantaneous, hence the lighter flywheel.

[dubster]

Just a quick one? when a flywheel gets lightend,do they balance it aswell?or is that a whole other thing?personly i took of my balanced and might have been lightend flywheel because the ringgear was vrot and put on my stock flywheel and i cant notice any significant changes,seems to rev just a quick as always...

[Tony Z]

to balance it properly you need to have it attached to the crank. The factory pumps out such large volumes that they balance each item to a tolerance, which is no-where near to what it can be balanced to.

[ZeroAxe]

I agree with Tony. It should be properly attached (and INDEXED) to your crank and then balanced.



However, I think I can put the question a little 'clearer'.... When you look at a stock FW you can see where it is drilled to balance it. Now, when they go to town on your FW, do they 're-balance' your FW be drilling it? Or, while is it spinning on a lathe, the same amount of metal is removed in a 'circumferencial' way, so it doesnt get un-balanced?? Know what I mean?

[Edmond]

I had my flywheel lightened and then balanced with the crank it got drilled in a different location to where the factory drilled it to balance it

[dubster]

Mine also has alot of holes drilled in it...should get another ringgear and put it back on...whats perks of balancing the crank?james you gonna balance yours?how much is it to lighten the flywheel?

[dubster]

sorry meant to say perks of balancing the FLYWHEEL...

[Edmond]

The ring gear is an intergral part of the flywheel so if its stuffed you need another flywheel.

[JamesD]

Mine also has alot of holes drilled in it...should get another ringgear and put it back on...whats perks of balancing the crank?james you gonna balance yours?how much is it to lighten the flywheel?

Balancing the crank/flywheel basically removes some of the vibrations in the system and will prolong bearing life. they say it also frees up some power, but what is 0.005kW going to make a difference...

Mine went for balancing on monday. Not sure of what this is all costing, i told the guy to just do it, we will talk money at a later stage....

Is yours an 8 dowel flywheel and crank? if it is then all is good. If its not then make sure the balanced fly wheel goes back on the same orientation that it came off.