Spider weight loss plan

Make it go fast! Kick it up a notch. Post tips in here.
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v6spider
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Re: Spider weight loss plan

Postby v6spider » Fri Apr 29, 2016 12:26 pm

beater wrote:I think this is kind of like cyclist that want to have the lightest bike possible but are carrying 20 pounds themselves they don't need LOL :)! Seriously you spend all the money making your Spider lighter and then a buddy jumps in and you are back where you started. Let's face it these are fun cars to drive but short of a power plant swap or gobs of money into the original engine it is what it is.

More power is the best bet I think shedding weight is a tough call in a car that is already pretty lightweight..

Cheers!
Rob

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RRoller123
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Re: Spider weight loss plan

Postby RRoller123 » Fri Apr 29, 2016 12:33 pm

Yes, but I think we are talking about the value of shedding it on the rotating parts. 4 pounds taken off the crank pulley, several more off each of the camshaft pulleys, and ~8 or more pounds off of the Flywheel is far more effective, obviously, than taking those pounds out of luggage.

Pete
'80 FI Spider 2000 (rolling "resto")
'74 X1/9 (many years ago)
'79 X1/9 (fewer years ago)
'86 Jaguar XJ6 (2nd Hobby Car)
2011 Chevy Malibu (daily driver)
2010 Chevy Silverado 2500HD Ext Cab 4WD/SB
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124JOE
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Your car is a: 1978 124 fiat spider sport 1800
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Re: Spider weight loss plan

Postby 124JOE » Fri Apr 29, 2016 5:56 pm

he should look into getting a dino
when you do everything correct people arent sure youve done anything at all (futurama)
ul1joe@yahoo.com 124joe@gmail.com

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v6spider
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Re: Spider weight loss plan

Postby v6spider » Sat Apr 30, 2016 2:15 pm

RRoller123 wrote:Yes, but I think we are talking about the value of shedding it on the rotating parts. 4 pounds taken off the crank pulley, several more off each of the camshaft pulleys, and ~8 or more pounds off of the Flywheel is far more effective, obviously, than taking those pounds out of luggage.

Pete

Doesn't do anything for torque... Not to mention the effect would be minute at best.. However, i do realize increases in torque on the twin cam are tough, but can be done via supercharging and turbocharging..In my opinion, lightening the rotating parts is not going have enough of an effect to warrant the time and expense of doing so.

Cheers!
Rob

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RRoller123
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Re: Spider weight loss plan

Postby RRoller123 » Sat Apr 30, 2016 5:27 pm

Nonsense! :mrgreen: Ask anyone who has installed a lightened flywheel what the performance effect is. Best bang for the buck out there. Like a whole new car.
'80 FI Spider 2000 (rolling "resto")
'74 X1/9 (many years ago)
'79 X1/9 (fewer years ago)
'86 Jaguar XJ6 (2nd Hobby Car)
2011 Chevy Malibu (daily driver)
2010 Chevy Silverado 2500HD Ext Cab 4WD/SB
2015 Keystone Montana High Country 343RL

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v6spider
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Re: Spider weight loss plan

Postby v6spider » Sun May 01, 2016 1:59 pm

RRoller123 wrote:Nonsense! :mrgreen: Ask anyone who has installed a lightened flywheel what the performance effect is. Best bang for the buck out there. Like a whole new car.

Maybe adds 5hp to the rear wheels and low end torque and drive ability suffers. But if you like it that's all that matters.. I have done a lot of reading about this and there is a ton of debate over the gains regarding as lightened flywheel. From what I have read and seen, a lightened flywheel changes the throttle response, and your horse power/ torque curve and puts your peak HP and torque in the higher rpm range.. Great for race applications but less Streetable. I'm more for raising compression, adding a good flowing header, installing a performance cam set, dual carbs.. Any of those items are a bigger gain in HP and torque I think than the lightened flywheel for the money.. Again just my opinion.. :)

Cheers!
Rob

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RRoller123
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Re: Spider weight loss plan

Postby RRoller123 » Mon May 02, 2016 7:54 am

To each his or her own, of course. I can only speak from my personal experience with this. I have installed Mark's lightened flywheel. Low end torque does NOT suffer, in fact it is dramatically improved. Less downshifting on hills, etc. I can go up a moderate hill (maybe 10-15% grade) in 5th gear at 2000 rpm's no problem. Now, this is with an FI 2L engine, so I can't speak to what the effects are on other sized or carb'd engines might be. It is important to note this, as they may not respond as well; so I can't comment on those configurations. Drivability is also very much improved, it is far quicker and responsive at all speeds, although I will qualify this by saying I never go over 5000 rpm with this car.

Acceleration through the entire band is improved, to the point where I thought about maybe just stopping here, the car is now quick enough, even at 8.1/1. (But Nahhhh...... :mrgreen: ) and the reasoning is pretty obvious; the flywheel is a parasitic loss, it has no effect on the generation of power, only the loss (storage actually) of power between the engine and the gear box. It has no effect on the FI system, doesn't require any tuning at all, and it has absolutely no effect on shifting of the power band, because at any steady-state rpm, the engine itself still produces the exact same power it did before, and the flywheel, if not being induced into a change in angular velocity, is only adding air frictional drag, and inertia between power pulses. And the smoothing inertial function between pulses is pretty much irrelevant once the engine is beyond idle speeds.

To grasp all this, we can do a simple thought experiment where we imagine a huge granite flywheel, maybe 6-8 inches thick, hanging off the back of the crank. Assume it to be many Hundreds of pounds. Assuming that we could get a clutch to survive, it would take quite a while to get up to speed, the concept of "acceleration" would be laughable. Same for deceleration. We would need enormous brakes to slow the car down while in gear. But we could probably turn off the engine and still have enough energy to drive it down town and get a bottle of milk and get back before using up the energy stored in that big granite flywheel. The opposite is also true, take the flywheel weight down to zero and the engine would accelerate like a champ, but obviously the power pulses at idle would be very badly leveled out. The idle would likely have quite a shake to it, if it would idle at all.

With the ~8.5 lb flywheel I installed, I have not noticed ANYTHING more than a very minor change in idling smoothness, at about 900-1000 rpm idle (via tach, not verified), where I tend to keep the car. Being that the flywheel supplies rotational kinetic energy between power strokes, I suspect that it is far more influential on a large V8 than on these small 1.X and 2L engines. But that is just speculation on my part.

All the other upgrades you mention are fantastic, and I have put some of them in subsequent to the flywheel, and plan to eventually use all of them, but it is pretty difficult to see how this is not a good bang for the buck, IF you do your own work. That is the kicker. If you pay a garage to pull the transmission and install it, well that is another thing, it gets pretty pricey then. Probably not worth doing on its own. But if one is in there putting in a new clutch (as I was, and paid a garage to do it), there isn't another upgrade for $400 that will give you as much performance bang for the buck, imho.

Pete
'80 FI Spider 2000 (rolling "resto")
'74 X1/9 (many years ago)
'79 X1/9 (fewer years ago)
'86 Jaguar XJ6 (2nd Hobby Car)
2011 Chevy Malibu (daily driver)
2010 Chevy Silverado 2500HD Ext Cab 4WD/SB
2015 Keystone Montana High Country 343RL

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Nanonevol
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Re: Spider weight loss plan

Postby Nanonevol » Mon May 02, 2016 8:02 pm

djape1977 wrote:13" cromodoras are 7-10 pounds each, depending on model. nothing newer doesn't even come close

Why is this, does anyone know? Is the magnesium alloy used hazardous?
1977 Fiat Spider
1967 Triumph Bonneville (hardtail chopper)

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v6spider
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Re: Spider weight loss plan

Postby v6spider » Mon May 02, 2016 9:55 pm

RRoller123 wrote:.....There isn't another upgrade for $400 that will give you as much performance bang for the buck, imho.

Pete


It'd be cool to see some before and after dino results to really see the gains.. If it is a 5hp gain like I've read then there are many other mods that will yield a better gain for the money.. Just recurving your distributor will yield a 5hp gain which I can do myself for peanuts.. But it is a subject of serious debate . maybe Mark Allison can chime in here and share some of his insight here.. At any rate, I am curious.. But in my car it really isn't necessary.

Cheers!
Rob

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124JOE
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Re: Spider weight loss plan

Postby 124JOE » Mon May 02, 2016 10:44 pm

i have driven 1 car with a lightened flywheel.as i seen it yes it climbs the rpm faster
the heavy flywheel is there to help keep it from stalling on take off
i killed it twice then changed the way i featherd it
when you do everything correct people arent sure youve done anything at all (futurama)
ul1joe@yahoo.com 124joe@gmail.com

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RRoller123
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Re: Spider weight loss plan

Postby RRoller123 » Tue May 03, 2016 6:17 am

There are no HP gains or loses, only a perceived gain or loss, due to its effects on the ability of the engine to accelerate and decelerate more or less quickly depending upon how much mass is added or removed. A flywheel is nothing more than a storage device, which changes the rate of delivery of power to the rear wheels, by parasitically storing some of the kinetic energy produced by the engine. It has no effect on fuel, CR, ignition burning, mixture, gas flow, nothing. Purely external, after all power has already been generated. It is just a big hunk of metal that acts as a parasitic loss exterior to the motor. The engine produces exactly the same power as before a change to the flywheel is made (except at extreme low rpm where the power pulse dampening effect is needed) Think of it as a capacitor in a DC electrical circuit; which charges up and stores energy for use later and for dampening of the baseline supply voltage.

The beauty of these things is their simplicity, which is one reason they have been explored as sources of storage in alternative energy systems, such as hydro, solar etc. They don't make too much sense in transportation systems because the system would have to lug around all that mass, but in a stationary system, they can be of some use. The only two significant losses are frictional in the bearing, and frictional in the air it spins through. Plus any losses incurred during the spinning up of the flywheel by the supply system. The air friction can be fairly easily :roll: resolved by containing the storage system in a vacuum/semi vacuum, and the bearings already have plenty of technology already available to draw from to reduce friction there. I have had a very small peripheral input casually discussing these things with a utility commission member out on one of our Pacific Islands, where the desire to get away from oil is desired. A small community with hydro or solar power readily available could use these, when scaled properly, to augment a solar or hydro system to deliver power at night. And they are absolutely quiet, not like a Tesla coil in the neighborhood would be... :wink: The beauty of them is that they are so scalable, and are so easily attached to generators, pumps, the grid, etc. But God help anyone nearby if one let go or broke into pieces, they need to spin at enormous rpms to contain enough energy at reasonable size to be useful. The containment structures have to be extremely strong. :shock:

It's too bad that it hasn't caught on more quickly, but the emphasis and efforts in alternative generation have been dominated by photovoltaics, for better or worse. When I was an Engineering student intern at the D.O.E. Northeast Solar Energy Center in Boston in the late 70's, things were in pretty good balance, we promoted photo, fluid, passive, pretty much everything equally, as it wasn't quite clear yet where the industry was going to go. I remember we used to hold training classes for plumbers, electricians, carpenters, roofers, etc. to try to promote the development of fluid based rooftop systems. I always thought that the problem was that there were just too many trades involved in installing these systems, and the costs would never be low enough for them to make sense. Like doing a bathroom in the house, it takes every single trade and costs more per square foot than any other part of the structure. Everyone who shows up has a basic nut to crack to make any money, and the costs add up very quickly. Turns out to be mostly true, and photovoltaics won out in the end for residential use. Although it is amazing that, 40 years later, they still don't make sense without our tax dollars subsidizing their use.

Anyway, that's enough for me, I've said my piece! :D Back to re-plumbing all the ethanol-damaged fuel lines in the trunk and under the car. Oh joy.

Pete
'80 FI Spider 2000 (rolling "resto")
'74 X1/9 (many years ago)
'79 X1/9 (fewer years ago)
'86 Jaguar XJ6 (2nd Hobby Car)
2011 Chevy Malibu (daily driver)
2010 Chevy Silverado 2500HD Ext Cab 4WD/SB
2015 Keystone Montana High Country 343RL

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v6spider
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Re: Spider weight loss plan

Postby v6spider » Tue May 03, 2016 6:49 pm

This clearly shows there are only minute gains in power by using a lightened flywheel..

Image

Exactly what I thought.. :)

Cheers!
Rob

djape1977
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Re: Spider weight loss plan

Postby djape1977 » Wed May 04, 2016 2:57 am

Nanonevol wrote:
djape1977 wrote:13" cromodoras are 7-10 pounds each, depending on model. nothing newer doesn't even come close

Why is this, does anyone know? Is the magnesium alloy used hazardous?

magnesium alloys are dangerous if set on fire. as far as i know, this is the only reason why they aren't used anymore.
ignition temperature is lower then for aluminium alloy or steel, but still far above anything that might happen in any normal situations. in normal use, they're lighter then aluminium and tougher. when you hit a pothole, they are more likely to crack then bend , but again, atmuch higher impact force then modern alloys. they also corrode more then aluminium alloys, which can easily be seen on now 30+yrs old original cromodoras. ones that were outside all the time are pretty much unusable.
problem of fire arises when vehicle ignites for some reason and fire reaches wheels. once ignited, magnesium is pretty much impossible to extinguish with any kind of commonly used fire extinguishers. only practical way of doing it is to bury the wheel in sand or dirt. burning temperature is so high that sparks will melt steel.
i can imagine few situations where magnesium alloy wheel could be the source of fire , like for example, idiots who flee from police and keep on driving on rims after their tires have been shot out.

decision is yours. there is a certain element of risk, but in regular classic car use it's very low.

PatTroy
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Re: Spider weight loss plan

Postby PatTroy » Mon Jun 13, 2016 4:15 pm

RRoller123 hit it on the head. There's no HP change (steady state) by reducing inertia of rotating components. Transiently though, there is a big difference in how much energy is needed to accelerate the parts (either rotating, or moving the car forward). If energy is constant, then the mass will accelerate faster. Force=mass*acceleration, and in this case, rotating parts are "rotating" mass (inertia). Reducing it means you need less force plain and simple.

In racing circles, it's common to say that a pound of rotating mass is worth 4 pounds of static mass. This is because of the fact that you must move the parts in the direction of the vehicle (each wheel moves forward), but also put energy into turning them (each wheel must be spun up).

This is why reducing rotating weight is important (wheels, cranks, flywheels, axles, etc).

The only risks from reducing your flywheel mass are damage due to transient rotational accelerations to the driveline, transmission or crankshaft. At the compression ratios and power outputs of these motors, I don't suspect a reduction of flywheel mass will have a substantial detrimental effect.

I would agree though, that these cars don't have a lot of low-hanging fruit in the weight department, and a lot of it comes off the rear axle, further worsening the mass distribution which is already a little nose-heavy. I've contemplated a cast aluminum cross-member and a-arms for this reason... Dual manual brake master cylinders are probably also worth another 10 lbs up front (and off the driver's side).

QuebecFiatSpider
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Your car is a: 1980 Fiat Sport Spider 2000i Pininfarina

Re: Spider weight loss plan

Postby QuebecFiatSpider » Mon Aug 28, 2017 7:14 am

Hi everyone, I really like this thread and since I have the same philosophy about performance and handling increase by doing weight reduction, I'll follow and comment that post.

I'll probably follow the same route with my Spider 2000 FI and to plan ahead We'll need to get some real weight figures/numbers.

In the first post, bluespider262 stated something about replacing the battery...What exactly and where do you plan on buying your replacement battery?

What will be the exact weight reduction?

This weekend I took the time to remove my rear bumper and here is exactly the weight of it (not including the shock absorbers) = 31.8 lbs (14.455 kg.)

I'll be waiting for some numbers ;)


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