How effective is flywheel skimming?
22 September 2005, 07:02 PM
#1
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How effective is flywheel skimming?
When i get my new clutch fitted i would like to skim my oe flywheel down a bit....
Is there a realistic limit as to how much you can skim? is there a particular situation where you cant use an OE flywheel again? im guessing if theres any teeth damage etc...
any thoughts?
Is there a realistic limit as to how much you can skim? is there a particular situation where you cant use an OE flywheel again? im guessing if theres any teeth damage etc...
any thoughts?
22 September 2005, 07:49 PM
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quite a lot can be removed from the wear areas before they're scrap... but if you're thinking of lighten-ing it that way.. thats not quite how it's done......
22 September 2005, 07:59 PM
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no you drill it out done you? as in lots of holes, while making sur eits still ballances right? dont get me wrong....i wouldnt be doing it myself 
22 September 2005, 08:04 PM
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I got a replacement/exchange flywheel from API as part of a group buy, if you know the clutch is gonna need doing, why not fit a lightened flywheel at the same time, it might not make a huge difference to performance, but it did make it feel different..!!
22 September 2005, 08:40 PM
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that was my initial idea, but the cash just isnt there to do the flywheel at the moment 
hence why i thought skimming a few lbs of the weight of the OE one (assuming its not totally fecked) was the way forward....
hence why i thought skimming a few lbs of the weight of the OE one (assuming its not totally fecked) was the way forward....
22 September 2005, 11:41 PM
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Lightened flywheels don't get consistent reviews on here.
Some seem to think them worthwhile others claim they are a waste of time or worse.
Hmmmmm ?????
Some seem to think them worthwhile others claim they are a waste of time or worse.
Hmmmmm ?????
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22 September 2005, 11:53 PM
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There's a distinct difference between a 'lightened' flywheel, and a billet ultra-light one, go too far with the light weight, and you'll lose out big time, but a lightened one is safe....
23 September 2005, 12:04 AM
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I thought it was yeh, but then going from a clutch that can't take what you're giving it, to one that can easily cope makes a difference too, and clearly both theings were done at the same time, so hard to judge exact effects...
but i'm happy, and thats what matters!! To me!!
but i'm happy, and thats what matters!! To me!!
23 September 2005, 12:29 PM
#11
Originally Posted by RON
There's a distinct difference between a 'lightened' flywheel, and a billet ultra-light one, go too far with the light weight, and you'll lose out big time, but a lightened one is safe....
Neil: I would spend the extra £50-£100 or so and buy a aftermarket fly instead of having the OE one lightened. They don't drill anything AFAIK just skim away some of the material until the fly is around 8kgs. Some places charge £100+ for this.
A normal skim of your OE one will be about £20 from you local machining shop.
Last couple of aftermarket flys have gone for about £150 secondhand.
Bob
23 September 2005, 01:30 PM
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The "lose out" element i believe is that the other end fo the crank is unbalanced....in a perfect world the flywheel would be counter balanced by the crank pulley, thus balanceing the front and the back of the engine....if one is less than the other y a small amount then this is ok, but if by along way then its my understanding that the engine can be harmed when coming down the rev range.....
23 September 2005, 04:29 PM
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its one of those things that "over time" will reduce engine life i guess...not going to kill it in the short term. It jst puts extra strain on the other end of the engine where it used to be balanced.
PS. Bob, love the way youve now dropped the std UK gearbox bit out of your location
PS. Bob, love the way youve now dropped the std UK gearbox bit out of your location
25 September 2005, 08:02 PM
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Originally Posted by BOB'5
No change in spec.
Just hopefully faster this time if the ratios dont hold me back.
Just hopefully faster this time if the ratios dont hold me back.
Standard gears:
Gear-Ratio-Step (%)
1 3.454
2 1.947 43.6
3 1.366 29.8
4 0.972 28.8
5 0.738 24.1
Your new gears are like this Bob:
Gear-Ratio-Step (%)
1 3.180
2 1.910 39.9
3 1.320 30.9
4 0.950 28.0
5 0.738 22.3
Last edited by ZEN Performance; 25 September 2005 at 08:25 PM.
26 September 2005, 05:29 PM
#21
Originally Posted by Zen Performance
Your new gears should be better, they are close in places, although perhaps the longer 4th gear isn't ideal unless you are trap speeds allow good use of 4th gear.
Standard gears:
Gear-Ratio-Step (%)
1 3.454
2 1.947 43.6
3 1.366 29.8
4 0.972 28.8
5 0.738 24.1
Your new gears are like this Bob:
Gear-Ratio-Step (%)
1 3.180
2 1.910 39.9
3 1.320 30.9
4 0.950 28.0
5 0.738 22.3
Standard gears:
Gear-Ratio-Step (%)
1 3.454
2 1.947 43.6
3 1.366 29.8
4 0.972 28.8
5 0.738 24.1
Your new gears are like this Bob:
Gear-Ratio-Step (%)
1 3.180
2 1.910 39.9
3 1.320 30.9
4 0.950 28.0
5 0.738 22.3
I was advised the ratios were:
1st 3.18
2nd 1.87
3rd 1.35
4th .95
The difficulty I found @ Tuner GP was getting to grips with the length of 1st gear (7mph longer).
Will hopefully get to grips with it on the weekend @ Avon.
Bob
27 September 2005, 12:07 AM
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Originally Posted by Neilo
The "lose out" element i believe is that the other end fo the crank is unbalanced....in a perfect world the flywheel would be counter balanced by the crank pulley, thus balanceing the front and the back of the engine....if one is less than the other y a small amount then this is ok, but if by along way then its my understanding that the engine can be harmed when coming down the rev range.....
27 September 2005, 12:20 AM
#24
Originally Posted by unfeasablylargegonads
I know **** all about crankshafts/bottom ends but does a 12KG flywheel not weigh more than the pully the other end of the crank, or is there some other bit that counters this weight?
The idea of lightening the flywheel and the ali pulley is to reduce the weight the engine needs to rotate. Less weight means the engine responds more quickly, it can also mean a lumpy idle.
Gerry
27 September 2005, 12:39 AM
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Originally Posted by Houghton
The flywheel also has the clutch assembly bolted to it so it weighs a fair bit more anyway. 'Balancing' refers to the rotating balance, hence the part drillings around the flywheel perimeter, crank journals, etc. so the crank assembly doesn't vibrate to destruction at 7K+ rpm.
The idea of lightening the flywheel and the ali pulley is to reduce the weight the engine needs to rotate. Less weight means the engine responds more quickly, it can also mean a lumpy idle.
Gerry
The idea of lightening the flywheel and the ali pulley is to reduce the weight the engine needs to rotate. Less weight means the engine responds more quickly, it can also mean a lumpy idle.
Gerry
Cheers
Dan
27 September 2005, 02:57 AM
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this was discussed a few weeks ago and it got in depth to do with rotational whatsits and spinning plates or something. do a search it was covered quite well i think.
27 September 2005, 06:56 PM
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Does a lightened Fly wheel reduce low rev Torque?
I always thought it only helped performance at high revs and was for racers only?????
Hence the different characteristic of pulling away smoothly, reported on here at times.
I always thought it only helped performance at high revs and was for racers only?????
Hence the different characteristic of pulling away smoothly, reported on here at times.
27 September 2005, 07:51 PM
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Yeah,I think a bit of weight is reqd.to keep some "inertia" at low revs, like if trickling along in a traffic hold up, or low revs in 2nd gear pulling away,instead of changing to 1st Gear.
No expert though.
No expert though.
27 September 2005, 08:15 PM
#30
Originally Posted by tath
this was discussed a few weeks ago and it got in depth to do with rotational whatsits and spinning plates or something. do a search it was covered quite well i think.
Tried a search but no good. Any idea where it is?
Gerry