Anybody looking for a lighter flywheel?
Discussion
Um this is not really a post about any of the hsv/VXR cars per se, more I am posting here because your cars have the LS2 engine...
Is there anybody out there who is getting work done to their engine, and who might have been thinking about getting a lighter flywheel?
See I am getting parts for a custom engine build (stroked LS3 block with LS2 heads) and I wanted a lighter steel flywheel which would work with the standard GM clutch (LS2 and LS7), trouble is that the only people who make the flywheel (SPEC) don't sell many and want an order for 5 before they will sell them...
Would there be anybody interested?
Was just asking on the off chance...
Is there anybody out there who is getting work done to their engine, and who might have been thinking about getting a lighter flywheel?
See I am getting parts for a custom engine build (stroked LS3 block with LS2 heads) and I wanted a lighter steel flywheel which would work with the standard GM clutch (LS2 and LS7), trouble is that the only people who make the flywheel (SPEC) don't sell many and want an order for 5 before they will sell them...
Would there be anybody interested?
Was just asking on the off chance...
ringram said:
Why not an alloy one mate?
Also I take it you mean aftermarket CNC LS2 based (Cathedral port) heads? Or do you mean stock LS2 heads?
Hi Ringram,Also I take it you mean aftermarket CNC LS2 based (Cathedral port) heads? Or do you mean stock LS2 heads?
I have read (not saying its right) that the Aluminium ones would not be as hard wearing/strong as the stock steel one, where as the billet steel one would be as strong or stronger than the stock one while still being a fair bit lighter, ~19lbs for the steel billet one, as opposed to 28lbs for the stock LS2 one (which I already have) and 13lbs for the aluminium ones... It seemed the safer bet.
I am considering an alloy one, but my preference is still for the steel. If you know anybody with an alloy flywheel I really would like to hear their opinion/s.
Actually my heads are the stock LS2 ones, decided I would put my money into the bottom end at this time, at some point the top will end will be swapped for a nice trickflow/etp LS7/AFR type set up with titanium valves etc... but at the moment I can't afford that and really at the moment the best developed top end heads are still aimed 3.9" bore, waiting seems to make logical as well as economical sense (+my hope is the setup will still make nearly 500 hp)
Why bother with a lightened flywheel ?? I really dont see the point. Perhaps in a short geared, mega heavy car, with a 1hp engine, it might be worth it...but on a decent V8, a lightened flywheel really wont make a pick of difference to performance.
I have a steel flywheel here that I bought along with a Spec clutch ages ago. I havent weighed it, but its little different to the standard flywheel.
Just seemed like a good idea at the time to buy it. Had issues with the clutch, so just removed it and fitted a Tex instead.....which uses the standard GM flywheel.
I have a steel flywheel here that I bought along with a Spec clutch ages ago. I havent weighed it, but its little different to the standard flywheel.
Just seemed like a good idea at the time to buy it. Had issues with the clutch, so just removed it and fitted a Tex instead.....which uses the standard GM flywheel.
stevieturbo said:
Why bother with a lightened flywheel ?? I really dont see the point. Perhaps in a short geared, mega heavy car, with a 1hp engine, it might be worth it...but on a decent V8, a lightened flywheel really wont make a pick of difference to performance.
I have a steel flywheel here that I bought along with a Spec clutch ages ago. I havent weighed it, but its little different to the standard flywheel.
Just seemed like a good idea at the time to buy it. Had issues with the clutch, so just removed it and fitted a Tex instead.....which uses the standard GM flywheel.
Not saying I know anything, but isn't the flywheel is a mass which the engine has to accelerate right? So if you have a lighter flywheel the engine will have less resistance to accelerate, thats all minus the car which would in the end be the heaviest thing that the engine has to move.I have a steel flywheel here that I bought along with a Spec clutch ages ago. I havent weighed it, but its little different to the standard flywheel.
Just seemed like a good idea at the time to buy it. Had issues with the clutch, so just removed it and fitted a Tex instead.....which uses the standard GM flywheel.
So a heavy flywheel in a light car would be a hindrance, but a lighter one would not. Why would a light flywheel help a heavy car?
The LS2/7 flywheel is like 28lbs, its heavier than the LS1, and these flywheels are weighted for American manual driving, which is minimal effort to launch the car?
If thats all crap I'd be happy to be told, after all its $300 I wouldn't have to spend.
Agreed with above - have used lightened flywheels in considerably smaller and less powerful engines and not much if any difference.
If you are going to do this then you should do it properly which means that you should have the flywheel, crank and clutch rebalanced as a unit. It's no good just taking a flywheel, making it lighter and refitting.
To make it have any impact you really need to lighten it to such a degree that the idle is compromised.
If you are going to do this then you should do it properly which means that you should have the flywheel, crank and clutch rebalanced as a unit. It's no good just taking a flywheel, making it lighter and refitting.
To make it have any impact you really need to lighten it to such a degree that the idle is compromised.
stevieturbo said:
Flywheel attached to the engine...yes its a mass it has to accelerate. But as I said, you dont have a 1hp french engine here.
IMO, it is a waste of money.
Just use a standard flywheel, unless you really are pushing the limits.
Pushing the limits... unfortunately not... IMO, it is a waste of money.
Just use a standard flywheel, unless you really are pushing the limits.
Well looks like I am sticking with my stock flywheel then...
Edited by eLSerbera on Monday 21st July 21:19
eLSerbera said:
Okay another argument (maybe a small one) - Say you are driving enthusiastically, and you are changing down a gear and the revs don't match, doesn't having a lighter flywheel mean that it would take less energy for the engine to get up to speed if slower, and would give less energy if going faster.
Technically, yes. Throttle response is probably the only argument for a lighter flywheel other than going for every last hp.
However it's easier to either adjust the pedal position to make heel n toe more effective or make the most of the electronic throttle and tweak the mapping of the pedal position to throttle position. It's 90% of what most conventional cars with "sport" button do as it's cheap as chips.
If you really want to get clever and you utilise the microswitch on the clutch pedal so that when the clutch is pressed the throttle mapping is exagerated to make the engine more responsive whilst changing gear but without losing the normal throttle response.
I did experiment with a throttle switch on the gearshift of my old track car. Took some getting used to but under heavy braking for tricky corners it did allow you to concentrate on braking without heel n toeing but to be honest HnT is ultimate a better skill to learn and more rewarding.
The work done by an engine is seen as the weight of the vehicle divided by the final drive ratio.
Any weight removed from the rotating mass is seen by the engine as weight removed from the percieved work done by the car.
eg, the weight of the car = 1600kg , the weight removed from the flywheel, say 5 kg. weight removed from the car + 5kg static. engine does not see itself as moving 1595 kg, but as 5kg taken from the work done, ie the weight of the car / final drive ratio .
...so if car has a final drive of say 3.5, the saving that the engine sees is 5 kg saved from 457.14 kg, or a 1.09 % saving of the work done.
Thus 5kg saved from the flywheel, crank or whatever you like is the equivalent of 35kg removed from the car (assuming the final drive of say 3.5:1 ) the saving the engine sees would be greater still in lower gears.
That is how it works.
The benefits depend on the intended use of the engine.
Any weight removed from the rotating mass is seen by the engine as weight removed from the percieved work done by the car.
eg, the weight of the car = 1600kg , the weight removed from the flywheel, say 5 kg. weight removed from the car + 5kg static. engine does not see itself as moving 1595 kg, but as 5kg taken from the work done, ie the weight of the car / final drive ratio .
...so if car has a final drive of say 3.5, the saving that the engine sees is 5 kg saved from 457.14 kg, or a 1.09 % saving of the work done.
Thus 5kg saved from the flywheel, crank or whatever you like is the equivalent of 35kg removed from the car (assuming the final drive of say 3.5:1 ) the saving the engine sees would be greater still in lower gears.
That is how it works.
The benefits depend on the intended use of the engine.
P15TON said:
The work done by an engine is seen as the weight of the vehicle divided by the final drive ratio.
Any weight removed from the rotating mass is seen by the engine as weight removed from the percieved work done by the car.
eg, the weight of the car = 1600kg , the weight removed from the flywheel, say 5 kg. weight removed from the car + 5kg static. engine does not see itself as moving 1595 kg, but as 5kg taken from the work done, ie the weight of the car / final drive ratio .
...so if car has a final drive of say 3.5, the saving that the engine sees is 5 kg saved from 457.14 kg, or a 1.09 % saving of the work done.
Thus 5kg saved from the flywheel, crank or whatever you like is the equivalent of 35kg removed from the car (assuming the final drive of say 3.5:1 ) the saving the engine sees would be greater still in lower gears.
That is how it works.
The benefits depend on the intended use of the engine.
Didn't we have this conversation when you were doing my big block chevs? When we needed engine braking to help us into the corners? I seem remember you saying that having a lighter flywheel, wouldn't show you any more horse power on the dyno, but it would get there and back quicker. From my basic physiscs, it has to do with Polar Moment of Inertia and Conservation of Angular Momentum. Any weight removed from the rotating mass is seen by the engine as weight removed from the percieved work done by the car.
eg, the weight of the car = 1600kg , the weight removed from the flywheel, say 5 kg. weight removed from the car + 5kg static. engine does not see itself as moving 1595 kg, but as 5kg taken from the work done, ie the weight of the car / final drive ratio .
...so if car has a final drive of say 3.5, the saving that the engine sees is 5 kg saved from 457.14 kg, or a 1.09 % saving of the work done.
Thus 5kg saved from the flywheel, crank or whatever you like is the equivalent of 35kg removed from the car (assuming the final drive of say 3.5:1 ) the saving the engine sees would be greater still in lower gears.
That is how it works.
The benefits depend on the intended use of the engine.
In other words when a skater does a twirl and brings his/her hands in to the body, they speed up because there is then less mass at the periphery. That's also why we ended up going from a 7 1/4" triple plate to a 5 1/2" clutch on the small block. So it does make a difference. Correct me if I'm wrong, but I thought that any weight saved on rotating mass was worth something like 16 times that on the sprung weight. Or that might have been to do with reducing mass away from the polar moment.
In reality a light flywheel will do nothing for power.
In fact, it can hurt acceleration in the real world by making launches almost impossible to nail.
It will make the throttle response considerably faster.
It can make the idle speed rough depending on the map or the ability of the ecu to cope.
It will make it stall easier. Don't even get me started on hill starts.
As before, the flywheel and clutch need to be matched (and balanced with the crank).
I'm not saying it isn't worth doing at all if you are chasing ultimate performance but it should really be thought of as one of the last things to do esp for a road car.
In fact, it can hurt acceleration in the real world by making launches almost impossible to nail.
It will make the throttle response considerably faster.
It can make the idle speed rough depending on the map or the ability of the ecu to cope.
It will make it stall easier. Don't even get me started on hill starts.
As before, the flywheel and clutch need to be matched (and balanced with the crank).
I'm not saying it isn't worth doing at all if you are chasing ultimate performance but it should really be thought of as one of the last things to do esp for a road car.
Thanks Guys,
My aim is to get the engine into a Cerbera, so it would be nice to make the engine as responsive as posssible, there are some other light weight components in the engine as well.
The safe, guaranteed to work, approach will be to use the stock ls7 flywheel with the ls7 clutch which already have, I would be worried about the idle, and the launching issue is something I have considered, I didn't really want an aluminium one for those reasons, but was worried that the stock piece would be quite heavy...
My aim is to get the engine into a Cerbera, so it would be nice to make the engine as responsive as posssible, there are some other light weight components in the engine as well.
The safe, guaranteed to work, approach will be to use the stock ls7 flywheel with the ls7 clutch which already have, I would be worried about the idle, and the launching issue is something I have considered, I didn't really want an aluminium one for those reasons, but was worried that the stock piece would be quite heavy...
Island boy HSV said:
If you wont to make the engine rev freely then have everything that rotates balanced including clutch and flywheel. It makes a whole lot of difference, I have had it done with my engine.
The rotating assembly is going to be balanced by Callies, then brought over here.The engine is going to be put together by Boosted.
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