Lotus Elan

light flywheels

PostPost by: twincamracing » Mon Apr 11, 2005 7:38 pm

Looks like a lot of metal has been removed and I wouldn't like to say
how much more to go before it lightens itself considerably... Guess
there is probably a bit left to go at.


Probably not really a good idea to 'suck it and see'

should be able to shave it down to 14lbs from 22lbs - Has anyone
got experience of this, or any problems
> that may result from shaving all that
> metal off?


if considering one already lightened look to the edges of the machining
operation, are there nice radius blends or are there sharp (stress
rising) corners?

if having one done, have the machinist blend the edges of the cuts to
avoid stress risers, if he gives you a questioning look he hasn't a
clue and you should go elsewhere.

a 14 lb flywheel in an elan isn't like a 14 lb flywheel in, say, a
camaro. you shouldn't have any drivability issues.

scott



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PostPost by: M100 » Mon Apr 11, 2005 8:34 pm

On Mon, 11 Apr 2005 12:38:54 -0700 (PDT), scott potter
<***@***.***> wrote:

if having one done, have the machinist blend the edges of the cuts to
avoid stress risers, if he gives you a questioning look he hasn't a
clue and you should go elsewhere.

Good advice but isn't the standard flywheel cast iron (steel?) There
is some potential for lightening but no matter how much care you take
in machining its always going to have compromised integrity especially
at high revs. Miss a downchange and the damage they can cause is
scary hence the introduction of scatter shields in a lot of racing
formulas. It's quite a few years since I had a flywheel lightened but
from what I recall its never been a particularly cheap exercise. I'd
figure on an hour for someone who has done it before at around GBP 25,
or two for a newbie.

If you then need a new ring gear (GBP50), then add in the lightening
and possible refacing costs then you wonder if its worthwhile when you
can get a NEW, close to bulletproof steel lightweight flywheel for
around GBP 130 from QED


Martin

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PostPost by: mikecauser » Mon Apr 11, 2005 8:59 pm

On Mon, 11 Apr 2005 21:34:07 +0100 Martin Evans <***@***.***> wrote:

Good advice but isn't the standard flywheel cast iron (steel?)

Low speed (<300rpm) engines might use cast iron flywheels, but above
that you're pretty much in steel for production engines. (Cast iron
does not like tension, but it's great in compression.) Aluminium or
titanium is OK for racing, or possibly some beryllium composite if you
have F1 money to spend.


There is some potential for lightening but no matter how much care you
take in machining its always going to have compromised integrity
especially at high revs.

The compromise is that you are modifying a mass-production part that was
intended for half the revs you want. If you can start from scratch
with a blank of decent steel (and understand stress analysis...) there
is no danger. If you have to start with a production flywheel there is
no subsitute for experience, so I'd go to a reputable engine builder for
advice.



If you then need a new ring gear (GBP50), then add in the lightening
and possible refacing costs then you wonder if its worthwhile when you
can get a NEW, close to bulletproof steel lightweight flywheel for
around GBP 130 from QED

Ah, I think we're violently agreeing with each other.....



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PostPost by: s2lola » Mon Apr 11, 2005 9:39 pm

Hi Guys,

We cut production Kent flywheels down on formula ford engines all the time
(I think the legal weight is 20 lbs including clutch, but can't be too
sure). It is easy, as there is a large thick ring cast on the backside,
just inside of the ringgear, that can come off at exactly the right place.
In my view, the abosolute weight of the flywheel is not really important,
nor should it be the goal - its how close to the outer edge that the weight
can be taken off that brings the performance gains. In Vizard's "How to
Modify Your Mini", I remember he did an interesting calculation on a
lightened flywheel that indicated the "machined wheel" gave a performance
gain equal to lightening the car by about 200 pounds!!!!! The analysis
always made me wonder why someone hasn't done the same calculation for road
wheels/tires, ie they really are 4 quite heavy flywheels, aren't they?????

I haven't seen a FF flywheel shatter, despite years of hard shifts at 6700
rpm, bad downshifts , and banged ringgear (on the ground, as it is exposed
there). I ran one for a couple of seasons at 16lbs with no issues.

Having said all of that, its not a fair comparison to the Elan application
for the following reasons:
- FF weighs 1100lbs with me in it vs the Elan (considerably heavier)
- A FF flywheel could break and the scatter wouldn't hurt you - the Elan
bits could come up through the floor (although they'd have to get through
the bellhousing first).
- 14 lbs is getting pretty darn lite

BTW, on the FFs we do see Ford bolts sheared off quite a few times a year
(better hardware required in this application, clearly). On my BDA, it's a
very lite steel wheel, as it sees up to 9600rpm.

As an aside, has anyone experince using a 4-bolt aluminum flywheel (with
steel clutch facing insert) on a street Elan? I have secured one, and am
intersted in using it in the street car. Your thoughts?

Cheers,
Bill Tebbutt


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PostPost by: c.beijersbergen » Mon Apr 11, 2005 9:57 pm

In David Vizard's "Tuning twin cam Fords" he give a drawing of a flywheel
with the metal indicated that can (should?) be taken off.
I could scan this drawing for those interested. Just let me know.

Cor Beijersbergen van Henegouwen
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PostPost by: lotuselan2 » Tue Apr 12, 2005 12:56 am

Bill

Now you are talking!



I have two experiences with Ali flywheels.



In my early days I put a Pegasus (US) Ali flywheel on by 1500 non-crossflow
Lotus Super 7 (weight similar to a FF). I had about 135 HP in the full-race
motor. It rev'd freely but the big difference was on braking, much less
inertia.



My current +2 has a 190 HP BDR with similar Ali flywheel. Similar effect
and no reliability issues.

Ken



_____

From: Bill Tebbutt [mailto:***@***.***
Sent: Monday, April 11, 2005 5:39 PM
To: '***@***.***'
Subject: RE: [LotusElan.net] light flywheels



Hi Guys,

We cut production Kent flywheels down on formula ford engines all the time
(I think the legal weight is 20 lbs including clutch, but can't be too
sure). It is easy, as there is a large thick ring cast on the backside,
just inside of the ringgear, that can come off at exactly the right place.
In my view, the abosolute weight of the flywheel is not really important,
nor should it be the goal - its how close to the outer edge that the weight
can be taken off that brings the performance gains. In Vizard's "How to
Modify Your Mini", I remember he did an interesting calculation on a
lightened flywheel that indicated the "machined wheel" gave a performance
gain equal to lightening the car by about 200 pounds!!!!! The analysis
always made me wonder why someone hasn't done the same calculation for road
wheels/tires, ie they really are 4 quite heavy flywheels, aren't they?????

I haven't seen a FF flywheel shatter, despite years of hard shifts at 6700
rpm, bad downshifts , and banged ringgear (on the ground, as it is exposed
there). I ran one for a couple of seasons at 16lbs with no issues.

Having said all of that, its not a fair comparison to the Elan application
for the following reasons:
- FF weighs 1100lbs with me in it vs the Elan (considerably heavier)
- A FF flywheel could break and the scatter wouldn't hurt you - the Elan
bits could come up through the floor (although they'd have to get through
the bellhousing first).
- 14 lbs is getting pretty darn lite

BTW, on the FFs we do see Ford bolts sheared off quite a few times a year
(better hardware required in this application, clearly). On my BDA, it's a
very lite steel wheel, as it sees up to 9600rpm.

As an aside, has anyone experince using a 4-bolt aluminum flywheel (with
steel clutch facing insert) on a street Elan? I have secured one, and am
intersted in using it in the street car. Your thoughts?

Cheers,
Bill Tebbutt


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PostPost by: foggy » Tue Apr 12, 2005 1:36 am

per weight taken off stock flywheel...
I could scan this drawing for those interested. Just let me know.


Yes please, I'd like to see the drawing.

Cast iron flywheels are strong. and heavy. 8 lbs is nice and light
and a good weight; would better be steel or aluminum. I have both on
my racing alfas, and they're plenty, remember you're adding the
pressure plate.

the stock pressure plate assy weighs how much?
Are there aluminum ones available?

I would suggest adding pins for locating the flywheel on the crank with
a 4 bolt fastening when running a hot motor. Our alfa motors went from
8 ~10mm bolts to 6 12mm(?) bolts and pretty much we must/should add 3
pins (3/8" or .5") if we run a racing clutch and high revs.

I've a cut down iron flywheel on a street alfa. the greater inertial
moment is out at the perimeter: the alfas have a heavy ring there that
the pressure plate mounts to. Mine is castellated, and it sorta scared
me, but with careful radiuses wherever possible, the strength is ok. I
ran some numbers and found that at 7500-8000ropm, the stresses were
within iron's strength. that would be un-cracked iron, or course. Be
very careful, and design carefully. Or spend a few hundred dollars and
keep your legs attached.

Hope this helps.

Steve
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PostPost by: "John Palmer" » Tue Apr 12, 2005 3:07 am

always made me wonder why someone hasn't done the same
calculation for road wheels/tires, ie they really are 4 quite heavy
fywheels, aren't they?????


Very true, but your road wheels don't experience anything like the angular
acceleration or peak revs of the crank/flywheel... But then again, there
are four of 'em to offset that somewhat... Factor this in along with the
bonus of a reduction in unsprung weight and you can't lose!

Regards,
-John
"John Palmer"
 

PostPost by: Arno Church » Tue Apr 12, 2005 7:18 am

I'll add my bit...
On my x-flowed Seven I went through most of the permutations
Standard ,
Lightened standard- 6 Kgs
Steel - 5 Kgs
Lightened steel 3.5 Kgs ( this was the same wheel as above but we machined holes around the perimeter beween ring gear and clutch plate- i.e we took the weight of where it mattered most , around the perimeter
Ali with steel friction pate insert- 2.7kgs
For racing , the last option was by far the best
For a lightweight road car (Elan) I would prefer EN8 steel- not lighter than 5kgs
Too light it is a bit nervy for road use

Also I do not subscribe to the common "Max Power" theory that you "loose" torque if your flywheel is too light
Arno

Bill

Now you are talking!



I have two experiences with Ali flywheels.
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PostPost by: twincamracing » Wed Apr 13, 2005 4:16 pm

The analysis always made me wonder why someone hasn't done the same
calculation for road wheels/tires, ie they really are 4 quite heavy
flywheels, aren't they?????

indeed, but who wants to kill the aftermarket for wheels that some
think look good, practical experience will bear witness the lightest
wheel/tire combo you can run makes a world of difference in handling.

forged centers and spun rims are pricey even in a 13 x 5 ;)
same thing though, removing mass from the perimeter of the wheel.

my copy of Tuning twin Cam Fords doesn't have the flywheel sectional
view, probably because it was printed in '71, but does give part
numbers for heasvy duty and race clutch covers.

i raced vw and porsche cars back then, an american maker (Schieffer, I
belive) offered a diaphram type aluminum clutch cover where the inside
plate was alloy with a thin steel coating for the friction surface.

light flywheels do not make any extra power nor do they lose any
torque. it simply lightens the reciprocating assembly allowing for
quicker rates of rpm change. lighter or heavier wheels/tires won't
chnage the engine's output but will make a difference in acceleration.

scott



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PostPost by: roadterror » Wed Apr 13, 2005 4:47 pm

Count me in. Will be assembling the motor soon and this would be a good
chance to get the flywheel lightened. Thanks in advance!

----- Original Message -----
From: "C. Beijersbergen" <***@***.***>
To: <***@***.***>
Sent: Tuesday, April 12, 2005 5:57 AM
Subject: Re: [LotusElan.net] light flywheels



In David Vizard's "Tuning twin cam Fords" he give a drawing of a flywheel
with the metal indicated that can (should?) be taken off.
I could scan this drawing for those interested. Just let me know.

Cor Beijersbergen van Henegouwen








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PostPost by: s2lola » Wed Apr 13, 2005 5:40 pm

Lightweight wheels/tires can dramatically improve braking....which is where
modern mag wheels really fall down. Look good, but are heavier flywheels
than the OEM wheels the "tuners" replaced. Ya gotta love them application
of simple science!

Cheers,
Bill Tebbutt


-----Original Message-----
From: scott potter [mailto:***@***.***
Sent: 2005/04/13 12:16
To: ***@***.***
Subject: RE: [LotusElan.net] light flywheels



The analysis always made me wonder why someone hasn't done the same
calculation for road wheels/tires, ie they really are 4 quite heavy
flywheels, aren't they?????

indeed, but who wants to kill the aftermarket for wheels that some think
look good, practical experience will bear witness the lightest wheel/tire
combo you can run makes a world of difference in handling.

forged centers and spun rims are pricey even in a 13 x 5 ;) same thing
though, removing mass from the perimeter of the wheel.

my copy of Tuning twin Cam Fords doesn't have the flywheel sectional view,
probably because it was printed in '71, but does give part numbers for
heasvy duty and race clutch covers.

i raced vw and porsche cars back then, an american maker (Schieffer, I
belive) offered a diaphram type aluminum clutch cover where the inside plate
was alloy with a thin steel coating for the friction surface.

light flywheels do not make any extra power nor do they lose any torque. it
simply lightens the reciprocating assembly allowing for quicker rates of rpm
change. lighter or heavier wheels/tires won't chnage the engine's output but
will make a difference in acceleration.

scott



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Due to the security risks involved in sending information over the Internet, National Bank Financial and NBCN can not be held
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PostPost by: mackmotorsport at aol.com » Wed Apr 13, 2005 9:03 pm

For formula cars and sports racers,lightening wheels,cvjoints and brake rotors is something that sucessful prep shops pay a lot of attention to.I raced a lola 598 years ago and my good set of wheels was worth about 1/2 sec. per lap or more.
Bill Mack

-----Original Message-----
From: John Palmer <***@***.***>
To: ***@***.***
Sent: Mon, 11 Apr 2005 20:07:03 -0700
Subject: Re: [LotusElan.net] light flywheels



always made me wonder why someone hasn't done the same
calculation for road wheels/tires, ie they really are 4 quite heavy
fywheels, aren't they?????


Very true, but your road wheels don't experience anything like the angular
acceleration or peak revs of the crank/flywheel... But then again, there
are four of 'em to offset that somewhat... Factor this in along with the
bonus of a reduction in unsprung weight and you can't lose!

Regards,
-John







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PostPost by: lotuselan2 » Thu Apr 14, 2005 2:35 am

Look on ebay there is an Ali Flywheel for a TC, 6 -bolt. Bid is only $41,
surely will go up.



_____

From: ***@***.***lto:***@***.***
Sent: Wednesday, April 13, 2005 5:03 PM
To: ***@***.***
Subject: Re: [LotusElan.net] light flywheels



For formula cars and sports racers,lightening wheels,cvjoints and brake
rotors is something that sucessful prep shops pay a lot of attention to.I
raced a lola 598 years ago and my good set of wheels was worth about 1/2
sec. per lap or more.
Bill Mack

-----Original Message-----
From: John Palmer <***@***.***>
To: ***@***.***
Sent: Mon, 11 Apr 2005 20:07:03 -0700
Subject: Re: [LotusElan.net] light flywheels



always made me wonder why someone hasn't done the same
calculation for road wheels/tires, ie they really are 4 quite heavy
fywheels, aren't they?????


Very true, but your road wheels don't experience anything like the angular
acceleration or peak revs of the crank/flywheel... But then again, there
are four of 'em to offset that somewhat... Factor this in along with the
bonus of a reduction in unsprung weight and you can't lose!

Regards,
-John







To search the mailing list archives:
http://www.escribe.com/automotive/europ ... index.html

CopyrightC LotusElan.net and the author:
http://www.lotuselan.net/publish/legal_stuff.shtml
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