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Old 07-15-2004, 06:55 PM   #3
SeanSmith
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Join Date: May 2004
Location: London
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Re: Flywheel question (technical stuff.....)

Woa now that's one looooooong question.....

Ok, lightening the flywheel will only really show any performance gains if you've modded your engine quite a bit and have already done a fair amount of weight reduction to your car.

A heavier flywheel takes more power from the engine to drive it, but a heavier flywheel carries more momentum. The difference this makes is that a lightened flywheel will rob less power from the engnine and so you'll have a little more power, but the lighter flywheel will have less momentum and so you will lose some torque.

IF you lighten the flywheel and also fit a big-bore freeflow exhaust you'll notice you have more power on the flat but will notice you have to work the engine more when you get to the hills.

I would only lighten the flyweehl as part of bigger mod's. Rebore the block, skim the head to the maximum and then get the head gass-flowed and port matched.

Doing this will give you more power and torque. One thing I learnt is if you are reboring the block always skim the head as well. Reboring the block will give you increased cc capacity but will also reduce your compression ratio. This itself will lose you some torque. But skimming the head will increase your compression ratio again and give you more torque.

A few years ago I took a 1.8litre Opel Astra and rebored the block to the max, skimmed the head max, gasfolwed and portmatched the head, fitted a crank from a 1.6 astra (has a longer throw - piston travel) and that along with exhaust and intake mod's and a Schrick 296 cam nearly doubled the original power.

The only donwside was it would strip a cambelt every 40 000 kilometers and also the engine management had to be remapped to get it all running smoothly.
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