Has anyone tried lightening the flywheel on a Feroza- not radically, but a bit of weight reduction?
Mine's finally going in for the gearbox rebuild and while it' ripped apart the clutch will be getting done. The flywheel will be removed to clean the face up- so I was pondering a bit of weight reduction at the same time....
Any thoughts?
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Lightening flywheel - Feroza
Moderator: Tiny
Interesting idea, so i did some research
I Dont think i would bother with it. My Feroza revs up quick enough for a clunker 4wd. If anything I would like to get some head work done and some porting on the inlet and exhaust to allow it to rev smoother towards the redline.Drawbacks – it takes effort to get the wheel rotating and stops the engines revs increasing or slowing down quickly. A lighter wheel takes strain off the engine and allows the engine to rev more freely. You’ll notice a race-tuned engine increases and decreases revs a lot more quickly than a standard engine. The big downside to a lighter flywheel is that torque is reduced – most noticeably on a hill. Whereas the momentum in the engine is maintained with a heavy flywheel the momentum is reduced and the hill has a much more direct effect on the engine output. Best used in a race situation where the track is flat with a demand for fast engine speed changes and the engine has been tuned to output power matching the flywheel capacity (high revving)
From what I've found the Applause flywheel is not only possibly lighter but also the clutch surface area is smaller. So possibly not the best option- also finding one for the right price could be interesting. I can get the standard Feroza one machined and balanced.
The drawbacks listed are true - apart from I don't think the measured torque output varies as such? From what I found researching the power output (and torque?) doesn't vary at all if dynoed. It's just that extra spinning weight assists the engine in maintaining a constant speed (revs)- so with a lighter flywheel the engine at constant throttle would be more affected by sudden changes in load (ie hills.) But it will also accelerate quicker with less mass....
Like I said I wouldn't do anything radical. I found some info on BMW's last night and they were talking about going from a 27lb flywheel to 9lb!!! I was thinking more along the lines of reducing the weight by 1/5 to 1/4.
Have people who have converted to the Applause engine used the Feroza flywheel or the Applause one?
BTW if you do a lot of off road work then this possibly isn't a good mod- but I spend 95% or more on road, so the extra acceleration would be useful.
The drawbacks listed are true - apart from I don't think the measured torque output varies as such? From what I found researching the power output (and torque?) doesn't vary at all if dynoed. It's just that extra spinning weight assists the engine in maintaining a constant speed (revs)- so with a lighter flywheel the engine at constant throttle would be more affected by sudden changes in load (ie hills.) But it will also accelerate quicker with less mass....
Like I said I wouldn't do anything radical. I found some info on BMW's last night and they were talking about going from a 27lb flywheel to 9lb!!! I was thinking more along the lines of reducing the weight by 1/5 to 1/4.
Have people who have converted to the Applause engine used the Feroza flywheel or the Applause one?
BTW if you do a lot of off road work then this possibly isn't a good mod- but I spend 95% or more on road, so the extra acceleration would be useful.
David
Not a good idea if its an offroader, the flywheel mass smooths out the bottom end and makes low throttle operations MUCH less prone to stalling.
However if its a city cruiser ( what were you thinking ? ) then a lightened flywheel will make the engine itself more responsive at mid to upper RPM.
However it will be harder to get off the line without stalling.
The other major issue to be considered is that the Feroza is so underpowered, issues of "engine response" are pretty meaningless - its not the flywheel mass that limits the Feroza's performance off the line.
However if its a city cruiser ( what were you thinking ? ) then a lightened flywheel will make the engine itself more responsive at mid to upper RPM.
However it will be harder to get off the line without stalling.
The other major issue to be considered is that the Feroza is so underpowered, issues of "engine response" are pretty meaningless - its not the flywheel mass that limits the Feroza's performance off the line.
( usual disclaimers )
It seemed like a much better idea when I started it than it does now.
It seemed like a much better idea when I started it than it does now.
we already know headers and airfilter upgrades and ditching the power robbing clutch fan are effective.
a slightly lighter flywheel would not be a detriment offroad. i know many of the jeep rockcrawler guys go with heavier flywheels for better inertia and low rpm tractibility.(jeeps have 4.0 srteaight six engines though)
a lighter flywhell will change rpm's easier but i highly doubt this will make the engine "stall"
another side effect will be easier shifts(helpefull off road like hill climbs and decsents)
and less motor stress via lower weight on the crankshaft.
a slightly lighter flywheel would not be a detriment offroad. i know many of the jeep rockcrawler guys go with heavier flywheels for better inertia and low rpm tractibility.(jeeps have 4.0 srteaight six engines though)
a lighter flywhell will change rpm's easier but i highly doubt this will make the engine "stall"
another side effect will be easier shifts(helpefull off road like hill climbs and decsents)
and less motor stress via lower weight on the crankshaft.
Yep - all true, its a matter of to what extent ? A small change in mass will produce small changes in driveability - probably un-noticable whilst normal driving.
To get a noticeable change your going to have to remove serious metal and then the effects both positive and negative will be felt more.
If taken too far it will make the engine inoperable - without the inertia of a flywheel or torque converter the engine will not have sufficient energy to perform the induction/compression stroke. The more cylinders the lesser the problem but 4 isnt a great number - 12 on the other hand....
I started my engine with only the torque converter drive plate ( basically as low as you can go ) and it wouldn't continue to run at low speeds, 2K up no problems , but no idle.
As for lower crankshaft stress, flywheel weight is a very minor factor, the forces applied to the crank during ignition/combustion are the major factors.
And ... its not easy to experiment, its a PITA to keep taking off the flywheel, machining and testing on a dyno.
And ... as I said earlier its not the flywheel mass that limits the engines acceleration potential in a Feroza, sure the engine might rev faster in neutral but it wont make any more power in gear and will make virtually no impact on its normal driving.
Sorry bout the ramble.....
To get a noticeable change your going to have to remove serious metal and then the effects both positive and negative will be felt more.
If taken too far it will make the engine inoperable - without the inertia of a flywheel or torque converter the engine will not have sufficient energy to perform the induction/compression stroke. The more cylinders the lesser the problem but 4 isnt a great number - 12 on the other hand....
I started my engine with only the torque converter drive plate ( basically as low as you can go ) and it wouldn't continue to run at low speeds, 2K up no problems , but no idle.
As for lower crankshaft stress, flywheel weight is a very minor factor, the forces applied to the crank during ignition/combustion are the major factors.
And ... its not easy to experiment, its a PITA to keep taking off the flywheel, machining and testing on a dyno.
And ... as I said earlier its not the flywheel mass that limits the engines acceleration potential in a Feroza, sure the engine might rev faster in neutral but it wont make any more power in gear and will make virtually no impact on its normal driving.
Sorry bout the ramble.....
( usual disclaimers )
It seemed like a much better idea when I started it than it does now.
It seemed like a much better idea when I started it than it does now.
if i just had a spare flywheel i could take it down on the brake lathe at work.
who wants to buy me this one?
http://cgi.ebay.com/ebaymotors/MANUAL-F ... p1638.m118
dont forget the 1.6 is not a long stoke motor so a heavy flywheel is not so crucial. what did that flex plate weight maybe 5 pounds?
i just wonder if the stocker is heavy enough to make it worthwhile.
like this one i got eight pounds of material of it.
before.......
after..
who wants to buy me this one?
http://cgi.ebay.com/ebaymotors/MANUAL-F ... p1638.m118
dont forget the 1.6 is not a long stoke motor so a heavy flywheel is not so crucial. what did that flex plate weight maybe 5 pounds?
i just wonder if the stocker is heavy enough to make it worthwhile.
like this one i got eight pounds of material of it.
before.......
after..
not yet. i did have it off and a electric fan in place on my last rocky ,so i know what you meanmurcod wrote:So, have you got rid of your viscous hub fan? Trust me that makes a huge difference and if you haven't done that already then why start with the internals?
i need to shop around for that fan.
what do you mean why start with internals? the flywheel?
if i have a chance to lighten it i would like say if i do a new clutch.
right now i dont know what one weighs so its just discussion right now.
my 1990 rocky has 230,000 on it and i think the clutch is stock
never weighed it - at the time it didn't seem imporant.
But same question - what do you expect to gain ? Yes it will possible rev a bit more freely in neutral, but wont make any more power or torque
its the power to weight ratio and inertia of the vehicle that's the limiting factor. The engine just can't change speed fast enough in a Feroza to matter.
On a dragster it matters greatly, the rate of change of engine RPM is very great and the energy used to accelerate the flywheel is very significant.
On a Feroza ???
And I have two Feroza flywheels spare - but once again shipping would be an issue.
But same question - what do you expect to gain ? Yes it will possible rev a bit more freely in neutral, but wont make any more power or torque
its the power to weight ratio and inertia of the vehicle that's the limiting factor. The engine just can't change speed fast enough in a Feroza to matter.
On a dragster it matters greatly, the rate of change of engine RPM is very great and the energy used to accelerate the flywheel is very significant.
On a Feroza ???
And I have two Feroza flywheels spare - but once again shipping would be an issue.
( usual disclaimers )
It seemed like a much better idea when I started it than it does now.
It seemed like a much better idea when I started it than it does now.
coupled with the aerodynamics of a brickMightyMouse wrote:
its the power to weight ratio and inertia of the vehicle that's the limiting factor. The engine just can't change speed fast enough in a Feroza to matter..
.. My Feroza is the first car ive own that SLOWS DOWN coasting down a hill and it aint brake drag either 
_________________
1988 LWB ,IFS, LSD, POS, PAJ, 31" M/T's on bling rims, Snorkel, 2" Lift ,new shocks ,XD9000 winch
1988 LWB ,IFS, LSD, POS, PAJ, 31" M/T's on bling rims, Snorkel, 2" Lift ,new shocks ,XD9000 winch
[quote="MightyMouse"]never weighed it - at the time it didn't seem imporant.
But same question - what do you expect to gain ? Yes it will possible rev a bit more freely in neutral, but wont make any more power or torque
quote]
slight horse power gain. less weight on the drivetrain means more horse power. so what if its a "slight" gain??
coupled with some other thing it would add up to a big gain all together.
what do you mean rev more freely in buetral ?? thats not going to be the only benefit. i have had good recuslts with leighting flywheels before,i am not just making debate here.
But same question - what do you expect to gain ? Yes it will possible rev a bit more freely in neutral, but wont make any more power or torque
quote]
slight horse power gain. less weight on the drivetrain means more horse power. so what if its a "slight" gain??
coupled with some other thing it would add up to a big gain all together.
what do you mean rev more freely in buetral ?? thats not going to be the only benefit. i have had good recuslts with leighting flywheels before,i am not just making debate here.
Last edited by stariondriver on Sat Dec 22, 2007 11:49 am, edited 1 time in total.
As I understand it, flywheel lightening can change the available but not the absolute engine power. Power is required to accelerate the rotating masses of the vehicle and the more rapidly the engine changes RPM the greater the power required to do this.
The controlling factors are rate of RPM change and rotational mass.
Decreasing rotational mass shows up as :
1/ an increase in the engines ability to rapidly change engine RPM - i.e. better acceleration
2/ a decrease in the engines tendency to want to continue running at a constant speed - i.e. slows down more quickly when you back off.
Both of these factors make the engine / vehicle more responsive and are highly valued in performance vehicles.
But here's the other side of a low rotational mass - by decreasing the mass the amount of energy "stored" in the rotating components is reduced. This shows up as :
1/ unstable low speed operation as the rotating mass is insufficient to damp the cyclic variations in engine speed that are fundamental to an internal combustion engine.
2/ an increase in the difficulty of smoothly accelerating at lower RPM as there is less stored energy available to be fed to the drivetrain when the "clutch is dropped".
Both of these effects are acceptable in a race car, nobody cares that it idles like a dog ( in fact its sounds good to some of us... ), or that its a pig to get off the line - rev the crap out of it and dump the clutch, its an acceptable compromise for the vehicles purpose.
So I'm not saying that flywheel lightening won't have an effect - just that its a Feroza, a vehicle that can't change engine RPM rapidly whilst in gear as it just doesn't have enough power to do it, and that its a 4WD where smooth low end operation is important.
Also rotational mass has absolutely no effect on the available KW when the engine is operating at constant speed, so the engine power available when driving on the freeway for example will be exactly the same with a heavy or light flywheel.
We are obviously working with significant changes in mass, a few grams ( like when a flywheel is machined ) will have no discernable effect on the cars operation.
So - my point is that whilst its generally a good thing for performance engines under racing conditions - be careful if your going to try it on a very non race Feroza. The slight gain here is accompanied by a slight loss there..... a big gain by a big loss.
IF it wasn't a compromise then engines wouldn't have flywheels
Still everyone is different, you may well be prepared to get a little more transient power at the expense of low speed operation. I do a lot of low speed driving off road, so I have a different set of expectations to you.
The controlling factors are rate of RPM change and rotational mass.
Decreasing rotational mass shows up as :
1/ an increase in the engines ability to rapidly change engine RPM - i.e. better acceleration
2/ a decrease in the engines tendency to want to continue running at a constant speed - i.e. slows down more quickly when you back off.
Both of these factors make the engine / vehicle more responsive and are highly valued in performance vehicles.
But here's the other side of a low rotational mass - by decreasing the mass the amount of energy "stored" in the rotating components is reduced. This shows up as :
1/ unstable low speed operation as the rotating mass is insufficient to damp the cyclic variations in engine speed that are fundamental to an internal combustion engine.
2/ an increase in the difficulty of smoothly accelerating at lower RPM as there is less stored energy available to be fed to the drivetrain when the "clutch is dropped".
Both of these effects are acceptable in a race car, nobody cares that it idles like a dog ( in fact its sounds good to some of us... ), or that its a pig to get off the line - rev the crap out of it and dump the clutch, its an acceptable compromise for the vehicles purpose.
So I'm not saying that flywheel lightening won't have an effect - just that its a Feroza, a vehicle that can't change engine RPM rapidly whilst in gear as it just doesn't have enough power to do it, and that its a 4WD where smooth low end operation is important.
Also rotational mass has absolutely no effect on the available KW when the engine is operating at constant speed, so the engine power available when driving on the freeway for example will be exactly the same with a heavy or light flywheel.
We are obviously working with significant changes in mass, a few grams ( like when a flywheel is machined ) will have no discernable effect on the cars operation.
So - my point is that whilst its generally a good thing for performance engines under racing conditions - be careful if your going to try it on a very non race Feroza. The slight gain here is accompanied by a slight loss there..... a big gain by a big loss.
IF it wasn't a compromise then engines wouldn't have flywheels
Still everyone is different, you may well be prepared to get a little more transient power at the expense of low speed operation. I do a lot of low speed driving off road, so I have a different set of expectations to you.
( usual disclaimers )
It seemed like a much better idea when I started it than it does now.
It seemed like a much better idea when I started it than it does now.
Please explain how this is possible. It's at odds with my understanding of how HP is generated.stariondriver wrote: slight horse power gain. less weight on the drivetrain means more horse power. so what if its a slight gain??
Steve.
[quote="greg"] some say he is a man without happy dreams, or that he sees silver linings on clouds and wonders why they are not platinum... all we know, is he's called the stevie.[/quote]
it more about slight loss of power thought drive train weight.so i stand corrected its not "more power" just less power needed to do x amount of work.Gwagensteve wrote:Please explain how this is possible. It's at odds with my understanding of how HP is generated.stariondriver wrote: slight horse power gain. less weight on the drivetrain means more horse power. so what if its a slight gain??
Steve.
ever put a set of 33/12.50/15 on a stock rocky? was it slower or faster to accerate?
yes that tire doesnt just weight more but also has a larger diameter. effectively the same though
read this
http://en.wikipedia.org/wiki/Horsepower ... _.28whp.29
notice in there that weight is part of the factoring
"This article is about a unit of measurement" the references to weight therefore refer to hp measurement and are quite, true but as far as I can see don't deal with the issue of rotational inertia - but might have missed something.......
Your second post is absolutely spot on - and thats the issue we are exploring. Its really the trade off between the storage of kinetic energy ( a large rotational mass ) and its negative effects on the cars acceleration vs the positive effect of using that stored energy to help with low end operation.
I think we broadly agree on the concepts involved - its more an issue about do the gains outweight the losses for an individual application
Tractors have very large flywheels whereas F! cars have almost none -each works well for their intended application.
My use of a Feroza is more in the tractor category, I'll leave the performance driving to my "Z" car.....
Your second post is absolutely spot on - and thats the issue we are exploring. Its really the trade off between the storage of kinetic energy ( a large rotational mass ) and its negative effects on the cars acceleration vs the positive effect of using that stored energy to help with low end operation.
I think we broadly agree on the concepts involved - its more an issue about do the gains outweight the losses for an individual application
Tractors have very large flywheels whereas F! cars have almost none -each works well for their intended application.
My use of a Feroza is more in the tractor category, I'll leave the performance driving to my "Z" car.....
( usual disclaimers )
It seemed like a much better idea when I started it than it does now.
It seemed like a much better idea when I started it than it does now.
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