Lightened flywheel, Pro's & Con's
21 July 2008, 08:33 PM
#1
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Lightened flywheel, Pro's & Con's
just want your input, experiences & knolege on this please
Should i invest in a lightened flywheel?
OR
Just stick with standard weight flywheel?
What are the dissadvantages with having one also the advantages
Should i invest in a lightened flywheel?
OR
Just stick with standard weight flywheel?
What are the dissadvantages with having one also the advantages
22 July 2008, 10:24 AM
#3
Less weight to accelerate so quicker pick up, but less weight also equals less rotational momentum so the car won't idle as smoothly and is easier to stall, will shunt a bit in low gear manouevring if you don't positively drive the car the whole time.
I've got a very light weight RCM flywheel, plus lightened RCM cam pulleys, crank, etc,etc - so a very light engine but you do get used to it very quickly
Some details - RCM pulleys - 1.95KG over standard, RCM fly - 5.8kg over standard at 4.7kg, RCM billet wrc crank - 2kg over standard = 9.75kg less than standard weight in total = very keen to rev engine. I was constantly hammering into the rev limiter initially as I just wasn't used to changing gear so fast. Despite 10 kg off rotational mass I've got used to it for 95% of the time. Very occasionally forget during low speed manouevres and stall when reversing etc
I've got a very light weight RCM flywheel, plus lightened RCM cam pulleys, crank, etc,etc - so a very light engine but you do get used to it very quickly
Some details - RCM pulleys - 1.95KG over standard, RCM fly - 5.8kg over standard at 4.7kg, RCM billet wrc crank - 2kg over standard = 9.75kg less than standard weight in total = very keen to rev engine. I was constantly hammering into the rev limiter initially as I just wasn't used to changing gear so fast. Despite 10 kg off rotational mass I've got used to it for 95% of the time. Very occasionally forget during low speed manouevres and stall when reversing etc
Last edited by Fat Boy; 22 July 2008 at 03:45 PM.
22 July 2008, 10:46 AM
#4
Pros:Engine revs more easily.
Cons:
Due to less rotational inertia, you need to use more revs when pulling away so as not to stall. The engine braking effect when you change down a gear will also be reduced.
Cons:
Due to less rotational inertia, you need to use more revs when pulling away so as not to stall. The engine braking effect when you change down a gear will also be reduced.
A very good mod IMO.
22 July 2008, 01:15 PM
#6
There are various weight flywheels available.
Reduced mass = better acceleration
The reason car manufacturers choose a particular weight is that it is suitable for the mass market. When tuning your car for optimum performance, what is important for Mrs Jones to go shopping in is of of little relevance.
A lightweight flywheel might not show any gains on a dyno, but the dyno does not show real world gains in acceleration as it measures max power at constant revs.
For an engine to accelerate a car, it must push the mass of the car and the engine components also need accelerating. This takes up power.
Therefore by using a lightweight flywheel, less power is needed to accelerate the internals, thus freeing up power to accelerate the car.
Reduced mass means the car will accelerate faster. In terms of characteristics, it will make the car accelerate like a lighter car (far more than just the kg saving on the flywheel). The difference is more pronounced in lower gears.
The lower you go in flywheel weight, the bigger the gains. There is a tradeoff of trickier medium speed take offs, easier to stall - if you go very light (4kgs), but if you can get used to this the gains in acceleration are worthwhile.
I run a 4.3kg forged flywheel in my daily driver and wouldn't use anything else.
6kg forged flywheels are the most popular choice with our customers as there is less of a tradeoff and suits more people.
We sell forged flywheels from just £205 delivered. No exchange needed. Also doing some great deals on clutch/flywheel combos
Not to be confused with cast OE ones drilled/machined (aka lightened)which are simply limited to what weight can be offered due to the limitations of material strength. We do sell these also, but they don't make much sense when our forged ones are so cheap.
Reduced mass = better acceleration
The reason car manufacturers choose a particular weight is that it is suitable for the mass market. When tuning your car for optimum performance, what is important for Mrs Jones to go shopping in is of of little relevance.
A lightweight flywheel might not show any gains on a dyno, but the dyno does not show real world gains in acceleration as it measures max power at constant revs.
For an engine to accelerate a car, it must push the mass of the car and the engine components also need accelerating. This takes up power.
Therefore by using a lightweight flywheel, less power is needed to accelerate the internals, thus freeing up power to accelerate the car.
Reduced mass means the car will accelerate faster. In terms of characteristics, it will make the car accelerate like a lighter car (far more than just the kg saving on the flywheel). The difference is more pronounced in lower gears.
The lower you go in flywheel weight, the bigger the gains. There is a tradeoff of trickier medium speed take offs, easier to stall - if you go very light (4kgs), but if you can get used to this the gains in acceleration are worthwhile.
I run a 4.3kg forged flywheel in my daily driver and wouldn't use anything else.
6kg forged flywheels are the most popular choice with our customers as there is less of a tradeoff and suits more people.
We sell forged flywheels from just £205 delivered. No exchange needed. Also doing some great deals on clutch/flywheel combos
Not to be confused with cast OE ones drilled/machined (aka lightened)which are simply limited to what weight can be offered due to the limitations of material strength. We do sell these also, but they don't make much sense when our forged ones are so cheap.
Last edited by Aztec Performance Ltd; 22 July 2008 at 01:43 PM.
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22 July 2008, 03:33 PM
#8
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lightweight flywheel = better for heel and toe, the rest is all just marketing bollocks imo, never made my car faster up the strip, never changed any power outputs.
even with the lightened crank pully to match.......
paid 75quid for mine on an exchange basis and was weighed in at 7kgs
even with the lightened crank pully to match.......
paid 75quid for mine on an exchange basis and was weighed in at 7kgs
22 July 2008, 03:52 PM
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so you are marketing/saying that buying one of "your" special flywheels will make my own car faster???? for 1kg weight saved?? lol, complete codswallop, yes it might make the engine a bit easier to rev up when the clutch is down, that is it in real terms, it means **** all when its dragging 4 wheels around when the clutch is up on the average road car.
22 July 2008, 04:01 PM
#11
It's understandable if you're not happy with your OE lightened flywheel and I've got no interest in defending it.
We offer various weights to suit different applications and are not limited by how much material can be taken off a OE flywheel before it becomes to brittle.
You obviously don't have a grasp of the simple physics.
Which weight do you think competition cars run?
All our customer feedback to date has indicated that our customers are very happy with the results.
I highlighted some time ago that people sometimes don't notice the benefits of lightened OE units as they are not perhaps quite light enough (normally in the region of 7.5kgs to 8.5kgs)
Did you actually weigh yours?
We offer various weights to suit different applications and are not limited by how much material can be taken off a OE flywheel before it becomes to brittle.
You obviously don't have a grasp of the simple physics.
Which weight do you think competition cars run?
All our customer feedback to date has indicated that our customers are very happy with the results.
I highlighted some time ago that people sometimes don't notice the benefits of lightened OE units as they are not perhaps quite light enough (normally in the region of 7.5kgs to 8.5kgs)
Did you actually weigh yours?
Last edited by Aztec Performance Ltd; 25 July 2008 at 03:42 PM.
22 July 2008, 04:11 PM
#12
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no i did not, but alyn from ASP did right in front of my very own eyes 
im not knocking them because they are crap, i am knocking them because the only benefit of them on a road car IMO is heel and toe which not many people actually do anyway.
not sure what bringing rally cars and such into it has to do with anything
rally cars run a lightened steering wheel, if i fit one of them will my car be faster down the drag strip?
you could argue it would be, but the gains in real terms for an average road car equal **** all
remember i fitted the lightened crank pulley as well which most people do not do.
i have a firm grasp of the physics behind it, i put that down to the fact that i did an a level in physics a long time ago lol
im not knocking them because they are crap, i am knocking them because the only benefit of them on a road car IMO is heel and toe which not many people actually do anyway.
not sure what bringing rally cars and such into it has to do with anything
rally cars run a lightened steering wheel, if i fit one of them will my car be faster down the drag strip?
you could argue it would be, but the gains in real terms for an average road car equal **** all
remember i fitted the lightened crank pulley as well which most people do not do.
i have a firm grasp of the physics behind it, i put that down to the fact that i did an a level in physics a long time ago lol
22 July 2008, 04:20 PM
#13
Just for the record, I am a big fan of the 1/4mile and using it as a yardstick for performance measurement.
Not many cars can do the 1/4mile in 11.7secs@119mph with 400-450bhp (including pro drivers), let alone with a 16g Turbo and just 340bhp
Part of the (quite basic) spec is a 4.3kg forged flywheel, which at the time people on here were telling me was a
for the strip. 
The lighter you go the bigger the difference, and yes there is quite a difference between 7kgs and 6kgs, and a massive difference between 6kgs and 4kgs.
Not many cars can do the 1/4mile in 11.7secs@119mph with 400-450bhp (including pro drivers), let alone with a 16g Turbo and just 340bhp
Part of the (quite basic) spec is a 4.3kg forged flywheel, which at the time people on here were telling me was a
for the strip. The lighter you go the bigger the difference, and yes there is quite a difference between 7kgs and 6kgs, and a massive difference between 6kgs and 4kgs.
22 July 2008, 10:10 PM
#16
BOB'5
Ive got a new clutch for my build
Exedy Hyper Compe R twin plate. I havent yet had time to split the assy and weigh them indevidually.
However i have weighed the complete assembly and it was 10.2kg.
I know youre an Exedy supplier so do you know how light my setup is in comparission to that of an OEM or single plate unit?
Cheers
Ive got a new clutch for my build
Exedy Hyper Compe R twin plate. I havent yet had time to split the assy and weigh them indevidually.
However i have weighed the complete assembly and it was 10.2kg.
I know youre an Exedy supplier so do you know how light my setup is in comparission to that of an OEM or single plate unit?
Cheers
23 July 2008, 07:11 AM
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I have a 5.7 kg fly that comes with an Exedy Hyper single plate clutch. My experience with this as follows.
On the plus side:
1. Idle is just as steady as before.
2. Easier to heel and toe.
3. Gearchange quality improved.
4. Subjectively the car feels more lively.
Only one small minus:
5. Need to use a lower gear when in traffic as it needs 2000 rpm to pull smoothly against 1500 with the old heavier fly. Don't really drive it in traffic so don't particularly care.
Frayz, that Exedy comp twin looks tasty.
On the plus side:
1. Idle is just as steady as before.
2. Easier to heel and toe.
3. Gearchange quality improved.
4. Subjectively the car feels more lively.
Only one small minus:
5. Need to use a lower gear when in traffic as it needs 2000 rpm to pull smoothly against 1500 with the old heavier fly. Don't really drive it in traffic so don't particularly care.
Frayz, that Exedy comp twin looks tasty.
Will weigh one up for when I get a chance and let you know
23 July 2008, 01:53 PM
#19
i get judder on pull away with ap ceramic and lightened flywheel..so is it the flywheel that is making the judder would i get less judder with a standard flywheel as not bothered about performance gains would rather be able to pull away smoothly
23 July 2008, 02:29 PM
#21
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If youre lightening the flywheel then Id suggest fitting all lightened pulleys too. Whilst youre changing the pulleys Id look at getting under-driven ones... (and ditching the power steerin gpump altogether in favour of an electric pump, now youll really start to feel the benefit).
24 July 2008, 11:25 PM
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Frayz I have an excedy hyper twin plate to go in mine complete with lightweigh flywheel it weights 14kg all in just need to get the time to fit it do you have any idea on what the oe 6 speed all in weights out of intrest.???
24 July 2008, 11:42 PM
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BOB'5
Ive got a new clutch for my build
Exedy Hyper Compe R twin plate. I havent yet had time to split the assy and weigh them indevidually.
However i have weighed the complete assembly and it was 10.2kg.
I know youre an Exedy supplier so do you know how light my setup is in comparission to that of an OEM or single plate unit?
Cheers
Ive got a new clutch for my build
Exedy Hyper Compe R twin plate. I havent yet had time to split the assy and weigh them indevidually.
However i have weighed the complete assembly and it was 10.2kg.
I know youre an Exedy supplier so do you know how light my setup is in comparission to that of an OEM or single plate unit?
Cheers
25 July 2008, 12:10 AM
#28
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