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Discussion Starter · #1 ·
As you may have read I recently had a 40% lightened flywheel fitted along with LSD and a rebuilt gear box.

I've already said how the car seems more lively, eager to respond etc.

Now the science I guess is that it takes power (fuel) to turn the flywheel, so if the flywheel is lighter it will take less power (fuel) to turn it. Also when coasting the lighter flywheel slows the engine less - wasting less of the energy(fuel) that got you up to speed........

If we lost a few kg in weight it would take less energy to run about - I guess, but I hadn't really considered the consequences of this.

My work is in East London, travelling about a lot and the area is massively congested and my average speed accross all my driving is 18mph, now I already had great economy of approx 30 mpg, but now, with the lightened flywheel, I'm getting 33mpg, a 10% gain :eek:

I bet on a long run the difference wouldnt be so striking, but in the constant stop start of heavy traffic its pretty amazing............

So - my message - go tune your cars and save the planet :p
 

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Discussion Starter · #4 ·
stipud said:
Didn't you change some other things in the same job as well? It could also be due to your previously faulty CPS causing the car to run poorly.
Do you think the previous 30mpg around town averaging 18mph is poor then :confused:

The CPS fixed a missfire that occured at WOT at about 4750-5000 rpm, but maybe you have a point :confused:
 

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Discussion Starter · #5 ·
Kermit said:
Cheers Chris, pour more petrol on my misery. :cry: SID is showing 13.9mpg at the moment! :eek:
Sorry pal ;oops: ;oops:

Just think of all those welfare benefits and health care costs you alone are covering with the taxes :roll:
 

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Kermit said:
Cheers Chris, pour more petrol on my misery. :cry: SID is showing 13.9mpg at the moment! :eek:
I've been getting 12-14mpg on the SID lately also. I have been driving in boston lately but this worries me. Is there something I should look into?
 

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I found I used more fuel with the lighter flywheel, it needed more gas to overcome the propensity to stall at low speed - that was with a V6, this issue will be worse on a turbo car.
 

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Discussion Starter · #9 ·
ragtopcav said:
I found I used more fuel with the lighter flywheel, it needed more gas to overcome the propensity to stall at low speed - that was with a V6, this issue will be worse on a turbo car.
Not on mine :confused:

Low speed / idle in fact any speed just as smooth as ever...........

How much material had been removed from yours?
 

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blinktude said:
I've been getting 12-14mpg on the SID lately also. I have been driving in boston lately but this worries me. Is there something I should look into?
Well, you're comparing apples and pears, aren't you? Different gallons...:cheesy:

Best regards,

KK
 

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West said:
And what does the lightened flywheel do to your performance?
Mainly, the car will pick up revs quicker and feel more reponsive at lower speeds. Also, a well balanced flywheel will naturally be beneficial also at higher revs.

Best regards,

KK
 

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Ok thx for the quick info!
But is it worth the £299 :eek: that it costs at Abbot?


I read that he just drilled out the origional but I have no idea how or where to do this here in my little country.
 

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Chris 9-5 said:
How much material had been removed from yours?
I had the iron thrown away and I fitted a 5kg billet steel item, the factory iron flywheel was 15kgs.
 

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Discussion Starter · #15 ·
ragtopcav said:
I had the iron thrown away and I fitted a 5kg billet steel item, the factory iron flywheel was 15kgs.
Wow thats a huge drop in weight some 66% lighter.

The guys who machined mine discussed with me the usage of the car and advised me on the weight reduction. they had different suggestions for usage, from fast road to track and about five flavors in between!

They mentioned potential idle problems if too light, I just went with their experience and settled at 40% off which is actualy slightly more than Abbott do.

Abbott Racing said:
The O/E flywheel weighs a staggering 10.25kg, (22.6lbs) and is designed to promote a smooth tickover comparable to a 6 cylinder unit.

The downside results in reduced engine speed up, and engine revs "hanging up" on gear changing...The lightweight billet flywheel is 32% lighter

giving the engine more freedom to accelerate and decelerate for greater driving pleasure.
 

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Hmm have to find a company to do this for me, I guess my Abbot dealer rather sells me a new one.
But I think drilling this one is much cheaper.
 

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Discussion Starter · #17 ·
West said:
Hmm have to find a company to do this for me, I guess my Abbot dealer rather sells me a new one.
But I think drilling this one is much cheaper.
Maybe its a language thing but the flywheel needs to be lightened and balanced, they skim out the material and then only drill to fine balance it.

You can see the drilling on the edge:



Here is the side with most removed - normally this is a solid / flat surface:

 
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