lightweight flywheel for Esprit transmssion

[esprithk]

I have seen many racing clutch for Esprit

but anyone makes a lightweight flywheel of it, too??

I heard the lightweight flywheel helps alot in the performance, please confirm

(but then again, with the speed of the Esprit, I assume that Esprit may already have a very good and lightweight flywheel built-in??)

[lotus4s]

You didn't say what year your car is but Fidanza has aluminum flywheels for some Esprits. http://www.fidanza.com/

The stock flywheel is pretty heavy and could be lightened a bit with proper machining.

JAE sells a lightened version of the stock one which I have in my S4s and am happy with. It's also quite a bit cheaper than the Lotus one. http://www.jaeparts.com/

Some say a lightweight aluminum flywheel will adversely affect street driveability on a small displacement engine like the Lotus 910 but then others say it won't. Maybe you should try it and let us know...

Cheers,

[Artie]

You didn't say what year your car is but Fidanza has aluminum flywheels for some Esprits. http://www.fidanza.com/

The stock flywheel is pretty heavy and could be lightened a bit with proper machining.

JAE sells a lightened version of the stock one which I have in my S4s and am happy with. It's also quite a bit cheaper than the Lotus one.  http://www.jaeparts.com/

Some say a lightweight aluminum flywheel will adversely affect street driveability on a small displacement engine like the Lotus 910 but then others say it won't. Maybe you should try it and let us know...

Cheers,

<{POST_SNAPBACK}>

I'd like to add my perspective to this discussion for posterity! J/K, no seriously, a lightweight flywheel would be a welcome addition to this engine I'm sure. I fought that exact battle within my head for many years with my RX7. I retained the stock 21lb flywheel thru 7 years of modification for fear of losing street driveability. Last year I broke down when installing my 5th transmission and decided to try a lightweight flywheel(remember my displacement in the 7 is 1.3L not 2.2). I put a 9.5lb flywheel in and WOW! The engine revs effortlessly and there was absolutely NO loss of driveability any where, actually, now if I happen to bog off the line at a light I can just stab the throttle and she revs right up! When I install an upgraded clutch (surely will be needed in the next year) I will definitely put the lightened flywheel on! Again, just my perspective but I truly think it would be only a positive modification!

Art

[Paul93Lotus]

I lightened my flywheel on a project car I have....an 87 Mitsubishi Starion. The flywheel on those was extremely heavy....somewhere in the tune of 28 lbs....I had it lightened to 20lb and no adverse side effects at all. Revs a little quicker, no bad side effects.

Now another friend with the same car put a Fidanza lightened flywheel in that wighed only 10 lbs.....there were some bad side effects....while it revved very easily, it also dropped just as fast. Made it a royal pain in traffic conditions. Also the smoothness of the drivetrain was affected. The extra centrifugal energy helps with smoothness.

Key is to find a machine shop you can trust, that will maintain the flywheels strength and not remove metal where it could cause the flywheel to stress crack. Better safe than sorry.

Explain how expensive they are and that it has to be done right the first time.

If you put a super heavy duty clutch on I would be a little careful on how much you take off though, as the flywheel takes the abuse from a stronger pressure plate.

Edited April 14, 2006 by Paul93Lotus

[f1karting]

Hey Guys..

Fidanza can produce FW for the 907 but wont make one for the 910 or later.. Ive tried.

However, I found a race engineering outfit in FL that I have comissioned to build one for me. It will be 9.5lb with drillings for the S300 clutch. It will use the 907 ring gear.

Its the clutch and PP I have had a tough time getting weight reductions on. The disc splines are unique and no one makes anything compatible. I had orignally thought a BMW PP or even a multi disc "road" clutch from Tilton may work .. but no disc match was possible without changing the GB input shaft spline pattern. No win. So the S300 is the choice. I may re-work the PP housing to reduce some of its mass.. but we'll see.

UL flywheels are great.. the reduction in moment of inertia make the engine think the car is lighter, so vehicle acceleration is improved. The effective weight ratios thru the gears 1-5 are something like 36:1 / 25:1 / 16:1 / 9:1 / 3:1. So taking 1# off the FW is like reducing the vehicle mass by 36# when in 1st gear.. etc..

The downside is that it is easy to stall an engine when engaging from a stop because of the reduce MOI. You adapt to that tho'

I have produced a cad drawing of a 910 FW if anyone needs it.

Jan

[Artie]

Hey Guys..

Fidanza can produce FW for the 907 but wont make one for the 910 or later.. Ive tried.

However, I found a race engineering outfit in FL that I have comissioned to build one for me.  It will be 9.5lb with drillings for the S300 clutch. It will use the 907 ring gear.

Its the clutch and PP I have had a tough time getting weight reductions on.  The disc splines are unique and no one makes anything compatible.  I had orignally thought a BMW PP or even a multi disc "road" clutch from Tilton may work .. but no disc match was possible without changing the GB input shaft spline pattern. No win. So the S300 is the choice. I may re-work the PP housing to reduce some of its mass.. but we'll see.

UL flywheels are great.. the reduction in moment of inertia make the engine think the car is lighter, so vehicle acceleration is improved.  The effective weight ratios thru the gears 1-5 are something like 36:1 / 25:1 / 16:1 / 9:1 / 3:1.  So taking 1# off the FW is like reducing the vehicle mass by 36# when in 1st gear.. etc..

The downside is that it is easy to stall an engine when engaging from a stop because of the reduce MOI. You adapt to that tho'

I have produced a cad drawing of a 910 FW if anyone needs it.

Jan

<{POST_SNAPBACK}>

Jan,

What is the projected timeline, I'd love to see the final product and pricing.

Art

[f1karting]

Jan,

What is the projected timeline, I'd love to see the final product and pricing.

Art

<{POST_SNAPBACK}>

Hi Art.. I am in no rush ATM.. I need to send them the 907 RG and S300 PP to test fit and they have asked for an OE FW to double check agains the drawings. I am pretty confident in the drawings, but to be 100% a FW to measure against would be best.. Only problem is I dont have mine available to send them as my engine is still in the car.

My guess is later this year.

These guys in FL do driveline work for BMW touring cars raced in the US series and came highly recommended. So I am willing to let them do it. The owner is very keen to help out.. not like Fidanza where they only care if you want to order 100 off.

We are planning to produce the FW in 6061-t6 with a steel friction insert. The RG would be indexed into the FW with set srews or whatever they normally do.

I anticipate a one-off FW to cost me anywhere from 600 to 900USD (not incl RG, PP and development cost)

J

Edited April 14, 2006 by f1karting

[lotus4s]

FWIW, if any of you guys with electronic ignition take your flyweel to a machine shop to be lightened, make sure they are very careful with what they do.

The flywheel has notches cut in the outer edge which are used by the crank sensor to detect engine timing. A fellow S4s owner took his FW to a respected high performance machine shop for machining to lighten it. They did a great job of lightening the lump and took quite a bit of material off the FW including the notches. He put everything back together and then had a heck of a time figuring out why the engine wouldn't start. A royal PITA!

Cheers,

Jim

Edited April 15, 2006 by lotus4s

[Artie]

FWIW, if any of you guys with electronic ignition take your flyweel to a machine shop to be lightened, make sure they are very careful with what they do.

The flywheel has notches cut in the outer edge which are used by the crank sensor to detect engine timing. A fellow S4s owner took his FW to a respected high performance machine shop for machining to lighten it. They did a great job of lightening the lump and took quite a bit of material off the FW including the notches.    He put everything back together and then had a heck of a time figuring out why the engine wouldn't start. A royal PITA!

Cheers,

Jim

<{POST_SNAPBACK}>

Very good point Jim, if and when I add a lightened flywheel, it will be a replacement FW. I'd rather go the full monty with a light weight fw as opposed to a "lightened stock" flywheel.

art

[esprithk]

thx for the great info and comments.

I have visited the SJ Sportscars UK..and they have a lighten flywheel part for sale (weight 4.3KG)

anyway, have to email them to find out more about it

Edited April 15, 2006 by esprithk

[lotus4s]

Very good point Jim, if and when I add a lightened flywheel, it will be a replacement FW.  I'd rather go the full monty with a light weight fw as opposed to a "lightened stock" flywheel.

art

Agreed....

Oh, and I loved "The Full Monty", great movie...

[f1karting]

Jim.. do you know what the notch pattern is? I am converting my carb/dist arrangement to a full EMS and FI and was wondering what might be the best crank position sensing method. I had considered placing mag triggers in the FW, but maybe notches would be easier to do.

esprithk.. any more in on the SJ kit would be nice to have.. what clutch, RG, price etc.. any chance of finding out?

J

[Vulcan Grey]

Jim.. do you know what the notch pattern is? I am converting my carb/dist arrangement to a full EMS and FI and was wondering what might be the best crank position sensing method.  I had considered placing mag triggers in the FW, but maybe notches would be easier to do.

esprithk.. any more in on the SJ kit would be nice to have.. what clutch, RG, price etc.. any chance of finding out?

J

This is one way to lighten the flywheel.

http://www.lotuscolorado.com/vulcangrey/ga...on/lew_flywheel

Removing material from the largest diameter will have greater results (reduces rotational inertia)

Just don't cut into the outside edge where the timing marks are.

[Jonathan]

I was considering getting this done when the engine is out so thinking about parts.

I was always under the impression a lightened flywheel increased the pickup of the engine but conversly reduces it's torque resulting in the need to increase throttle for things like hills - the idea then is to keep the revs high.

I'm in 2 minds really, if I were in flat country then without a doubt I would have a lightened version but it's not exactly Texas here

[lotus4s]

Jim.. do you know what the notch pattern is? I am converting my carb/dist arrangement to a full EMS and FI and was wondering what might be the best crank position sensing method.  I had considered placing mag triggers in the FW, but maybe notches would be easier to do.

J

<{POST_SNAPBACK}>

Jan,

No I don't know what the pattern is but I may have an extra flywheel around somewhere. It would be an S4s fw which has some differences from the SE.

Maybe Travis knows the difference. He's probably got his laying on a bench somewhere as we speak..

Cheers,

Jim

[Vulcan Grey]

Jan,

No I don't know what the pattern is but I may have an extra flywheel around somewhere. It would be an S4s fw which has some differences from the SE.

Maybe Travis knows the difference. He's probably got his laying on a bench somewhere as we speak..

Cheers,

Jim

It is just lying about. I'm trying to think how to get accurate measurements...

Where's that protractor...

[esprithk]

I am asking SJ sportscars about its ultra-lightweight flywheel now (4.3kg only)

anyway, HK has many mountain road..

so I must find out the info about the torque first..before I can decide to do anything with my car's flywheel...

I must drive uphill and downhill everyday

[Jonathan]

4.3KG !!! Bloody heck.

Yeah it's one of those parts which could really change the feel of the car for better or worse and you don't quite know until you try it. It's not as if you can change it back in a few minutes either.

[karluk29]

ok stoopid question time!!

i was thinking about this on sunday, as i stood next to a lambo one side and 360 the other,,,and they rev like mad, and the lotus GT3 sounds like a snail.

am i right in thinking, if you have a light flywheel its will rev like a loon and in turn reduce gt3's massie turbo lag?

and to go off subject anyone used a anti lag kit on a esprit yet

[esprithk]

answered by SJ Sportscars.

the 4.3kgs flywheel is not for Esprit. sorry!

[Jonathan]

am i right in thinking, if you have a light flywheel its will rev like a loon and in turn reduce gt3's massie turbo lag?

anyone used a anti lag kit on a esprit yet

<{POST_SNAPBACK}>

I reakon so, I hate the very low end performance on the GT3 but I refuse to chip it.

Trying to solve it by other means but the flywheel should allow the engine to rev quicker...which should open the up turbo quicker, it'll be goverend by mechanical acceleration however which might mean you don't see a huge improvement for the loss of torque....it's a gamble.

Whats an anti lag kit ?

[russellbosier]

I beleive its an 'over' fueling strategy that was developed on rally cars when lifting off meaning unburnt fuel exploads in the exhausts - hence the popping and banging they make, and this helps the turbos spool. Sounds like a good way blowing money - literally.

Russell.

[Simon350S]

I was always under the impression a lightened flywheel increased the pickup of the engine but conversly reduces it's torque resulting in the need to increase throttle for things like hills - the idea then is to keep the revs high.

<{POST_SNAPBACK}>

Why are you expecting a loss of torque Jon??

Torque is produced by the porce of the pistons being forced downwards through the cylinders, the flywheel will do nothing to effect this. You will get increased pick up and the revs will drop much quicker when at idle due to the decrased rotational mass. Torque will be unefected as the flywheel is there to simply smooth the charactaristics/drivability of the engine, for example making it less likely to stall when pulling off due to incorrect throttle/clutch useage as the extra mass helps to stop the engine from bogging down, and giving you a smoother idle.

Go as light as you can, just be careful you dont make a tit of yourself and stall it all the time!!!

[f1karting]

Whats an anti lag kit ?

<{POST_SNAPBACK}>

Basically it is an ECU controlled function that when the throttle is lifted rapidly, like when shifting, the ECU retards the timing so that the charge is ignited so late that it creates its pressure pulse in the exhaust port, maintaining turbine speed.. hence the pop in the exhaust J

Edited April 22, 2006 by f1karting

[Jonathan]

Why are you expecting a loss of torque Jon??

<{POST_SNAPBACK}>

Not engine torque but wheel torque. Flat roads no, but hills yes. Fly wheels store energy that can be used to maitain engine speed on hill climbing etc. If you're doing 5000 rpm and hit a 1:3 gradient and lett of the throttle, the car with the heavier fly wheel will get up the hill further than the lightened one becuase of the stored energy.

Some extremes might requie you to downshift the gears to enable you to climb up hills. You can see this on the rolling road when the guy lifts off the throttle and lets the revs run down on run down mine was actually powering the rollers at 46HP.

I'd like to lighten it but worried about the side effects and drivability - to which is totally unique to everyone of us, something someone might find good is not necessarily good for another.