Toymods Car Club
www.toymods.org.au
F.A.Q. F.A.Q.    Register Register    Login Login    Home Home
Members Members    Search Search
Toymods » Tech & Conversions » Lightened fly wheels?? what your thoughts

Show: Today's Posts  :: Show Polls 
Email to friend 
Switch to threaded view of this topic Create a new topic Submit Reply
AuthorTopic
Blaze
Regular


Location:
Brisbane
Registered:
December 2002
Lightened fly wheels?? what your thoughts Fri, 28 February 2003 02:41 Go to next message
I am going to be doing a 18r t0 18rgeu conversion soon, just thinking about all options before it goes in. IS there much benefit in getting a lightened flywheel. And if so can you do this to the standard one/ how is this done. Or do you have to get a specially made one.

your thoughts

  Send a private message to this user    
gianttomato
Forums Junkie


I supported Toymods

Location:
I renounced punctuation
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 02:46 Go to previous messageGo to next message
You can lighten a cast iron flywheel, but you do so at your peril. They can fragment, sending shrapnel thru the transmission tunnel and into you.
Get one specifically made out of chrome moly or 6 series aluminium. It costs a bit more, but what price your legs?
  Send a private message to this user    
Blaze
Regular


Location:
Brisbane
Registered:
December 2002
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 03:14 Go to previous messageGo to next message
Is it worth doing to a standard 18rgeu. or is in just over kill. What price are we talking about, and who can I get one from in Brisbane??
  Send a private message to this user    
gianttomato
Forums Junkie


I supported Toymods

Location:
I renounced punctuation
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 03:27 Go to previous messageGo to next message
For a std motor, probably little benefit.
Could get something like this for 370, and to get the cutaways done (to make it exactly as pictured) add another 100-150.
http://www.toymods.org.au/msgboard/index.php?t=getfile&id=795&rid=21&S=ee9eeb46b92c9cdf1aea4ee78c736e8c
I believe the aluminium ones are about $5-600. They use a disc of friction material for the contact surfaces, usually screwed in place.
  Send a private message to this user    
manipulate
Forums Junkie


Location:
Sydney
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 06:03 Go to previous messageGo to next message
If im not mistaken....lightening the flywheel makes u lose torque down low ???

Ta
Mani
  Send a private message to this user    
Blaze
Regular


Location:
Brisbane
Registered:
December 2002
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 06:36 Go to previous messageGo to next message
Tell me if I'm wrong. (It's usually the case) But if the fly whell is lighter, the engine doesn't need to work as hard to rotate the flywheel, so I thought it would give a better performance starting off.

I can see where once a heavier fly wheel is at a certain speed, it would remain at that speed for a lot longer the a light one. which would help the engine not having to work as hard. but for torque i thought it was the engines ability strenght to turn the fly wheel. so to give it more down low you give it less work to do.

not sure if all that makes sense. I might have it back to front and be talking about HP.

[Updated on: Fri, 28 February 2003 06:38]

  Send a private message to this user    
RWDboy
Forums Junkie


Location:
South Australia
Registered:
July 2002
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 06:37 Go to previous messageGo to next message
Lightening the flywheel can cause you to lose a few more revs between gears because your engine no longer has the same rotational intertia. Also, beware that you can't lighten it too much, otherwise when you rev the crap out of it when you are out of gear you can actually slip the cam timing belts and if you don't have a free running engine then you are screwed (or even a chain believe it or not if you have a chain). Just imagine valves hitting pistons Smile

So just be careful that you don't go overboard, cause it won't really increase your HP that much. I personally wouldn't bother unless I was shoving in a dog box or something like that, something that shifts really quick.
  Send a private message to this user    
Blaze
Regular


Location:
Brisbane
Registered:
December 2002
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 06:43 Go to previous messageGo to next message
From what I have gathered there is not much pint in doing this to an everyday drive car. Maybe some benefit for a racer but besides that i think I will leave it alone. Confused
  Send a private message to this user    
Norbie
Forums Junkie


Location:
Brisbane
Registered:
May 2002
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 08:44 Go to previous messageGo to next message
A slightly lightened flywheel can be a good thing on a street-driven car, especially an RA23 which seems to come with a tractor flywheel from the factory. However, since you intend to use your Celica for a bit of towing, it may be wise to leave the heavy bastard in there; a light flywheel is definitely not an asset when you're trying to tow things.
  Send a private message to this user    
Blaze
Regular


Location:
Brisbane
Registered:
December 2002
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 10:46 Go to previous messageGo to next message
Thanks Norbie. I'm sure when I got to put the new engine in I will be needing some help.

thanks
  Send a private message to this user    
manipulate
Forums Junkie


Location:
Sydney
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 10:48 Go to previous messageGo to next message
Blaze wrote on Fri, 28 February 2003 17:36

Tell me if I'm wrong. (It's usually the case) But if the fly whell is lighter, the engine doesn't need to work as hard to rotate the flywheel, so I thought it would give a better performance starting off.

I can see where once a heavier fly wheel is at a certain speed, it would remain at that speed for a lot longer the a light one. which would help the engine not having to work as hard. but for torque i thought it was the engines ability strenght to turn the fly wheel. so to give it more down low you give it less work to do.

not sure if all that makes sense. I might have it back to front and be talking about HP.





That actually makes sense

Can anyone comfirm whos right ???

Ta
Mani
  Send a private message to this user    
kingmick
Forums Junkie


Banned by his request

Location:
moved to tamworth
Registered:
July 2002
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 11:17 Go to previous messageGo to next message
a lighter flywheel helps an engine rev quicker and reduces drag on the engine{hp loss}! the inertia that a heavier flywheel produces, gives more torque to the engine at very low revs. haha a very light flywheel is a pain in big car parks at 20 km\h or in bumper traffic and makes the need to bring the launch revs up alot high to add a bit of tyre slip so the engine dosnt bog down off the start.
  Send a private message to this user    
Norbie
Forums Junkie


Location:
Brisbane
Registered:
May 2002
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 11:57 Go to previous messageGo to next message
A flywheel has absolutely no effect on an engine's torque output. The only time it does anything useful is when the car is stationary and you're slipping the clutch to get the car moving; in this situation the stored energy in the flywheel helps shove the car along. Once the clutch is fully engaged, the flywheel is just along for the ride.

After this point though, the engine has to accelerate the mass of the flywheel as well as the mass of the car, and in lower gears this can have a significant (negative) impact on acceleration. So a lightened flywheel is a tradeoff; better acceleration, but the car becomes more difficult to drive.
  Send a private message to this user    
manipulate
Forums Junkie


Location:
Sydney
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 23:11 Go to previous messageGo to next message
Norbie wrote on Fri, 28 February 2003 22:57

The only time it does anything useful is when the car is stationary and you're slipping the clutch to get the car moving;



But isnt that EXACTLY what we're saying ?

Helps car move when stationary = torque down low

Am i mistaken ?

Ta
Mani
  Send a private message to this user    
kingmick
Forums Junkie


Banned by his request

Location:
moved to tamworth
Registered:
July 2002
Re: Lightened fly wheels?? what your thoughts Fri, 28 February 2003 23:28 Go to previous messageGo to next message
norbie are you saying im wrong? remmeber torque is twisting force. the help it gives{heavy flywheel} with clutch take-up is adding twist to the crank, hence torque ! read what i said in my first post again and it will make sense.
mick
  Send a private message to this user    
Norbie
Forums Junkie


Location:
Brisbane
Registered:
May 2002
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 00:40 Go to previous messageGo to next message
Slight difference in semantics here. A heavy flywheel can briefly increase available torque at the wheels, but it does not increase or decrease the engine's torque.
  Send a private message to this user    
manipulate
Forums Junkie


Location:
Sydney
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 02:29 Go to previous messageGo to next message
Well its torque at the wheels that counts isnt it ???

Ta
Mani
  Send a private message to this user    
gmsta27
Regular


Location:
Fl
Registered:
February 2003
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 03:03 Go to previous messageGo to next message
I have a ta27 with a 2tg the motor has stock 9.8 pistons 304 intake 288 exhaust header and 44mm mikunis with out the large venturis I have een running a lightened fly wheel with a centerforce clutch the car will start from stop with out slipping the clutch and accelerates very quickly above 3000 rpm the biggest difference is that you can't pull hole shots in the car other than that i have noticed no drawbacks.
  Send a private message to this user    
gianttomato
Forums Junkie


I supported Toymods

Location:
I renounced punctuation
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 03:06 Go to previous messageGo to next message
If you want to get down to tin tacs, a flywheel actually alters momentum, not torque. Torque is generated by the engine. Some of this rotational energy is stored in the flywheel. This is known as momentum. A heavier flywheel has more angular momentum, but this doesn't mean the engine has more torque. If you were to put an engine on an engine dyno with the 2 different flywheel, the torque curve would be identical.
On the road, the extra angular momentum from a heavier flywheel translates to easier standing starts, less rpm drop between gear changes, and anecdotally, better towing and uphill performance. If that is what people perceive to be torque, fine, but it's actually 'stored' torque, more correctly termed momentum.
  Send a private message to this user    
manipulate
Forums Junkie


Location:
Sydney
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 03:45 Go to previous messageGo to next message
Thanx for that Tomato
  Send a private message to this user    
kingmick
Forums Junkie


Banned by his request

Location:
moved to tamworth
Registered:
July 2002
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 08:08 Go to previous messageGo to next message
my god! get it together guys! do you want to hear the fact from someone that is at the top end of the race car game or DIY mechanics? if you back of an engine on an engine dyno and put the power back on with 2 diffrent weight flywheels it will have a diffrent curve down very low as i keep saying. i know have seen it on many a race engine on the engine dyno!
if anyone has a question that would like answered just ask but god i get sick of dipsticks that have half an idea of what is fact and want to toss on about it. we dont even run flywheels on some of our race cars and yes they are manual.
mick
  Send a private message to this user    
gianttomato
Forums Junkie


I supported Toymods

Location:
I renounced punctuation
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 22:40 Go to previous messageGo to next message
Um, OK. I'm just wondering how a lump of metal makes torque? I understand how it might store and releaseenergy, but not how it might make it. I can also understand how a smaller lump of metal might store and release less energy, but not how it might affect engine thermodynamics such that the said engine produces less torque.
  Send a private message to this user    
kingmick
Forums Junkie


Banned by his request

Location:
moved to tamworth
Registered:
July 2002
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 22:56 Go to previous messageGo to next message
that store and release is what ive been talking about the whole time. if you look at my post again i said give more torque at very low rev's, not make more torque!
i hope this has cleared it up!
mick
  Send a private message to this user    
kingmick
Forums Junkie


Banned by his request

Location:
moved to tamworth
Registered:
July 2002
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 23:09 Go to previous messageGo to next message
just to make it a bit clearer! we mount the alternator on the diff{turned by tailshaft} on most of the race cars were possable to reduce power loss at the engine which gives us maybe 2-3hp at the wheels more than if mounted on the motor. this isnt a hp gain as such but a reduction in hp loss caused by friction. your not making more power your reducing the power loss! the power is there its just not being used to turn the wheels because its turning the alternator etc.
hope this helps
mick!
  Send a private message to this user    
Sam
Forums Junkie


Location:
Sydney, Australia
Registered:
May 2002
   
Re: Lightened fly wheels?? what your thoughts Sat, 01 March 2003 23:50 Go to previous messageGo to next message
gainttomato is spot on. you wont see any differences on the dyno.

From my observation, taking off with a lightened flywheel is slightly more difficult - as you ease the clutch out, it gets to the point where you think it's just going to take off, and if you're not careful the thing just dies on you. It's even more noticable on hills. Since I've had an alloy one in my sprinter since I put the 4AGE in, I can't really comment on the differences with/without after that, but I don't really notice it on hills or anything.

sam
  Send a private message to this user    
Jason
Forums Junkie


Location:
Canberra
Registered:
December 2002
   
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 00:06 Go to previous messageGo to next message
Isnt it really just inertia that your looking at and a rotating mass:
Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force.
So wouldnt this mean that a standard fly wheel with a larger mass (not weight) than a lightened one would be easier to drive on the street because of the low down effects.
  Send a private message to this user    
kingmick
Forums Junkie


Banned by his request

Location:
moved to tamworth
Registered:
July 2002
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 00:14 Go to previous messageGo to next message
exactly jason
  Send a private message to this user    
Jayem
Forums Junkie


Location:
Finland
Registered:
November 2002
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 00:58 Go to previous messageGo to next message
Lightening flywheel -> it's a matter of taste...
...said dog while licking ass! Laughing

I believe that there is some extra mass in the flywheel. Car makers have to make bit heavy side flywheels. There are many kinda car owners and some might get into towing situations and there are definitely some peoples that cant use clutch (like my mom Laughing ). Not every car owner is keen on performance. Some are more happy with driveability. I would be more thrilled about light flywheel in my car. Im NOT gona tow anything. Its super flat out here, no hills, no mountains and im willing to sacrifice some driveability. So Im gona get my flywheel slightly lightened.

[Updated on: Sun, 02 March 2003 01:05]

  Send a private message to this user    
gianttomato
Forums Junkie


I supported Toymods

Location:
I renounced punctuation
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 02:18 Go to previous messageGo to next message
Sounds like we are basically saying the same thing, just that there are some basic definition issues.
A heavier flywheel has more stored energy, so when you take off from a standing start, this stored energy is released making take off easier. A lighter flywheel has less stored energy, so there is a slightly greater propensity to stall the car. The engine doesn't magically make more or less torque depending on flywheel weight.
EDIT: I should add that this release of stored energy occurs with any sudden change in load. It just so happens that this for most people is seen most strikingly on take off, so people believe it improves low end performance. In fact it will occur at any rev range. An example might be a short upwards incline. A car with a heavy flywheel might make it up the hill in fourth gear (due to the release of potential energy in flywheel), but the same car with a light flywheel may need to change down a gear half way up. The point I want to make is that this effect will be seen with any sudden change of load.

I'm all for lightweight flywheels, but they have to be done correctly. People generally rapidly adapt their driving style to suit and it becomes a non issue.
I never intended for a slanging match. Smile

Cheers Dave.

[Updated on: Sun, 02 March 2003 02:29]

  Send a private message to this user    
Jason
Forums Junkie


Location:
Canberra
Registered:
December 2002
   
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 02:22 Go to previous messageGo to next message
gianttomato wrote on Sun, 02 March 2003 13:18


I never intended for a slanging match. Smile



Look at it this way we all understand what we are all talking about now and we are that much wiser. Isn't that what these forums are for?
  Send a private message to this user    
gianttomato
Forums Junkie


I supported Toymods

Location:
I renounced punctuation
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 02:30 Go to previous messageGo to next message
Hehehe..right on.
  Send a private message to this user    
kingmick
Forums Junkie


Banned by his request

Location:
moved to tamworth
Registered:
July 2002
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 03:55 Go to previous messageGo to next message
haha so we all know what were saying! good to hear!Smile
mick

[Updated on: Sun, 02 March 2003 03:57]

  Send a private message to this user    
gianttomato
Forums Junkie


I supported Toymods

Location:
I renounced punctuation
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 04:19 Go to previous messageGo to next message
http://forums.off-topic.net/images/smilies/grouphug.gif
Group hug.....er maybe not! Very Happy
  Send a private message to this user    
humble
Regular


I supported Toymods

Location:
Brisbane, QLD
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 06:29 Go to previous messageGo to next message
I don't know if this was mentioned or not (okay, being the slack bastard I am, didn't really read the whole post too well...). Anyways, here goes...

As the flywheel (by definition) is a device that is designed to store energy in the form of angular momentum, it's purpose is to act in a similar fashion to a capacitor in an electrical circuit.
I think the effects of this on real and apparent torque was addressed in detail above. What I would like to point out here is that the flywheel is also used to make the engine appear to run "smooth". An engine doesn't generate constant power. It generates power in pulses during the power strokes of individual pistons. The flywheel mass helps to "smooth out" these pulses of power and the resultant harmonics such that the actual power delivery of the engine appears to be much smoother. In engines where you have very favourable harmonics/degrees of freedom (such as inline 6s or V12s), lightening the flywheel would have the minimum impact as far as this apparent smoothness goes in comparison to other engine configurations with less favourable harmonics/degrees of freedom. This might be another factor you might want to take into consideration. After all, you don't want a car that shakes like a tank.

Cheers

  Send a private message to this user    
kingmick
Forums Junkie


Banned by his request

Location:
moved to tamworth
Registered:
July 2002
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 08:01 Go to previous messageGo to next message
just to correct you V12s have shocking harmonics, like joining two V6's. you will never see a large capacity V12 that revs because they have very bad harmonics. F1 could rev them hard as they only lasted an hour or so and where small capacity. hence why im not bringing any toyota V12's over here. because there power would be limited espically as they are all alloy. it would be one big floppy mess at any decent power level.
mick
haha a little of topic!
  Send a private message to this user    
justcallmefrank
Forums Junkie


I supported Toymods

Location:
Perth
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 09:13 Go to previous messageGo to next message
I don't think you are entirely correct about large V12's not revving mick. Check out some specs on a McLaren F1 or a Lamborghini Murcielago, both of those feed on revs.
  Send a private message to this user    
Norbie
Forums Junkie


Location:
Brisbane
Registered:
May 2002
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 13:18 Go to previous messageGo to next message
Yes, V12's are quite well balanced... they're more like two inline six's joined together, rather than two V6's. There are plenty of high-revving high-performance V12's around.

  Send a private message to this user    
gianttomato
Forums Junkie


I supported Toymods

Location:
I renounced punctuation
Registered:
May 2002
 
Re: Lightened fly wheels?? what your thoughts Sun, 02 March 2003 23:07 Go to previous message
What Mick says is valid. However, choosing the correct angle between the banks of cylinders is incredibly important in minimising these harmonics. For a V6 or V12, the ideal angle is 60, 120 or 180 degrees. For a V8 it is 90 or 180 degrees. For a V10, it's around 112 degrees. Of course, a 180 degree Vx engine is otherwise known as a boxer (Ferrari boxer 12, Porsche flat 6).
Things like the Commodore V6 or the old Capri V6 were 90 degree engines and as a consequence were/are rough as guts, and may necessitate the use of some auxillary harmonic dampener (eg balance rod in Commodore 6).
Sometimes these 'rules' are bent for some other important issues. In F1, the V10s have bizarre, unnatural bank angles because of space considerations.
  Send a private message to this user    
  Switch to threaded view of this topic Create a new topic Submit Reply
Previous Topic:Brake upgrade for ae82
Next Topic:xA-22 head onto RA-23
Goto Forum:
-=] Back to Top [=-

Current Time: Wed Jul 23 16:19:22 UTC 2025

Total time taken to generate the page: 0.0074460506439209 seconds

Bandwidth utilization bar

.:: Contact :: Home ::.

Powered by: FUDforum 2.3.8
Copyright ©2001-2003 Advanced Internet Designs Inc.