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> Pedal Mounted Helper Spring for Heavy Clutch, Prototype ready for testing.
ChrisFoley
post Feb 25 2013, 02:15 PM
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A customer recently asked if we could alter his clutch so it would take less effort to hold it in.
After looking at how the omega spring functions on a 915 trans, I think I could come up with a compact arrangement for the 901/914 that would be a simple bolt in solution.
Instead of attaching to the clutch fork I would attach an omega spring to the pedal in the cockpit.
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mrbubblehead
post Feb 25 2013, 09:24 PM
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yeahmag
post Feb 25 2013, 09:27 PM
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This would replace the existing spring I assume?
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ChrisFoley
post Feb 26 2013, 12:00 AM
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QUOTE(yeahmag @ Feb 25 2013, 10:27 PM) *

This would replace the existing spring I assume?

No.
The purpose of the omega spring is to make the pedal feel soft when fully depressed, so a very stiff pressure plate can be tolerated without tiring one's leg.
Some pressure plates have this feature built in to their spring design.
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euro911
post Feb 26 2013, 12:06 AM
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Any benefit if one is running a hydraulic set up, Chris?
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mrbubblehead
post Feb 26 2013, 12:08 AM
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your right, ive noticed some kennedy pressure plates feel like a compound bow. where the get harder and harder then get real easy toward the end of its travel. my sachs pressure plate is hard all the way thru.
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ScoopLV
post Feb 26 2013, 12:17 AM
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QUOTE(mrbubblehead @ Feb 25 2013, 10:08 PM) *

your right, ive noticed some kennedy pressure plates feel like a compound bow. where the get harder and harder then get real easy toward the end of its travel. my sachs pressure plate is hard all the way thru.


I think that would feel "weird" to me -- like there was something wrong with the clutch. Maybe I could get used to it. Who knows? Maybe I'd even prefer it.

I think I'd want to drive one a few miles to see.
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ChrisFoley
post Feb 26 2013, 10:03 AM
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QUOTE(mrbubblehead @ Feb 26 2013, 01:08 AM) *

your right, ive noticed some kennedy pressure plates feel like a compound bow.

That's a perfect analogy!
We've serviced some cars with engine upgrades that had clutch pedals so stiff that my leg would start shaking in 30 sec. or less.
With a 915 trans its fairly easy to offset this with the omega spring installation.
However, an LS6 powered car with a 930 trans can't use the standard omega spring setup, and there's no way to adapt the omega spring onto the 914 clutch fork.
My idea is to mount an omega spring on the pedal cluster and have the same overall effect on the pedal force as if it was mounted at the clutch arm on the trans.

This would work equally well with a cable or a hydraulic clutch setup.
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messix
post Feb 26 2013, 11:06 AM
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Wouldnt that load the throwout bearing and lead to premature wear and failure
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ChrisFoley
post Feb 26 2013, 11:29 AM
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QUOTE(messix @ Feb 26 2013, 12:06 PM) *

Wouldnt that load the throwout bearing and lead to premature wear and failure

How do you figure that?
914 throwout bearings are in constant contact with the pressure plate fingers as it is.
The forces at the pressure plate would be unchanged as far as I can tell, so
I don't think it would have any different effect on the TO bearing whatsoever.
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messix
post Feb 26 2013, 07:49 PM
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QUOTE(Racer Chris @ Feb 26 2013, 09:29 AM) *

QUOTE(messix @ Feb 26 2013, 12:06 PM) *

Wouldnt that load the throwout bearing and lead to premature wear and failure

How do you figure that?
914 throwout bearings are in constant contact with the pressure plate fingers as it is.
The forces at the pressure plate would be unchanged as far as I can tell, so
I don't think it would have any different effect on the TO bearing whatsoever.

it's prolly 'cause i dont know what the hell a "omega spring" is..... (IMG:style_emoticons/default/slap.gif)
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Mark Henry
post Feb 26 2013, 08:29 PM
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QUOTE(messix @ Feb 26 2013, 08:49 PM) *

QUOTE(Racer Chris @ Feb 26 2013, 09:29 AM) *

QUOTE(messix @ Feb 26 2013, 12:06 PM) *

Wouldnt that load the throwout bearing and lead to premature wear and failure

How do you figure that?
914 throwout bearings are in constant contact with the pressure plate fingers as it is.
The forces at the pressure plate would be unchanged as far as I can tell, so
I don't think it would have any different effect on the TO bearing whatsoever.

it's prolly 'cause i dont know what the hell a "omega spring" is..... (IMG:style_emoticons/default/slap.gif)

(IMG:http://www.914world.com/bbs2/uploads_offsite/forums.pelicanparts.com-26-1361932179.1.jpg)
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bigkensteele
post Feb 26 2013, 08:32 PM
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I would probably be interested. Can you even ballpark the price yet?
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ChrisFoley
post Feb 26 2013, 08:43 PM
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Its a spring shaped like the letter omega.
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ChrisFoley
post Feb 26 2013, 08:54 PM
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QUOTE(bigkensteele @ Feb 26 2013, 09:32 PM) *

I would probably be interested. Can you even ballpark the price yet?

Very roughly at this point.
$200, spring not included.
The pedal cluster will need to be removed from the car, but installation of the kit will be relatively simple.
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mrbubblehead
post Feb 26 2013, 09:01 PM
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how much do the springs run?
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ChrisFoley
post Feb 26 2013, 09:27 PM
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Pelican has them for about $75.
Dealer price is over $100.
Used are probably available.
I checked at dC Automotive but they didn't have any.
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Cap'n Krusty
post Feb 26 2013, 10:58 PM
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Perhaps they don't have them because they break. I've sold a number of them over the years.

The Cap'n
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Woody
post Feb 27 2013, 07:23 AM
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QUOTE(Cap'n Krusty @ Feb 26 2013, 10:58 PM) *

Perhaps they don't have them because they break. I've sold a number of them over the years.

The Cap'n



Yeah they eventually break but it is a good system when they're working correctly. I say go for it Chris.
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ChrisFoley
post Mar 15 2013, 09:31 AM
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Here are pics of the first prototype.
I'm still working on an adjustability feature for fine tuning of pedal position and amount of assistance provided.
I also have to decide whether modifying a stock pedal arm or machining a new arm is the better approach.

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