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Post by turbot on Jun 2, 2010 11:10:30 GMT -6
Hey Russ...., you know, it's free to sign up and register an account under your own name.... ;D
So....you are saying the billet slab core thickness would have to be thicker, increasing costs to keep the front in the stock dimension if I am understanding correctly...?
Still, no sweat with the front, it's the back that bothers me.
Not just the eye bolt setup but the extra hardware.
If I am carrying spares, and the rear camber hole accepted the standard caster block, then in a pinch at an out of town event, I can just pop a stock backup a-arm right on.
As per your design, there is no change to the front to keep me from exchanging with a used backup at a track.
It'd be a big plus if the rear could accept the stock eccentric pin.
T
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Post by Fast Guys on Jun 2, 2010 11:37:56 GMT -6
We are making the price point such that you can carry a spare set of these. ![;)](//storage.proboards.com/forum/images/smiley/wink.png)
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Post by Fast Guys on Jun 2, 2010 22:50:24 GMT -6
Make an account? As who...Faster Guys? I've been meaning to do it, just been a tad sluggish.
Terry, what are you suggesting would normally break on the rear mount? The eccentric pin...the caster block itself? The setup we would be using with the rod end would be a rod end (very standard sizing on all rod ends), a bolt, and a bracket built to be stronger than both. If anything went it'd be the rod end or bolt, both of which should be easy to replace if you have access to a speed shop.
I'm not ruling out your idea of keeping the back stockish, just don't want to throw out the idea of the rod end yet. Putting the rear bolt in double shear and using such an oversized rod end goes a long way in ensuring you won't actually need to replace either part for a long, long time. That rod end in the model is rated 27,000 pounds of force. Actual loading on that rod end wouldn't exceed around 4000 pounds even if you were braking with all of the force on one wheel at the same rate you'd slow down braking with all four wheels planted. Typical force during hard braking would be closer to 1500 pounds on that bolt. I don't have a stress-life diagram for that particular rod end on hand, but that sort of load on a bearing like that constitutes "infinite life."
For what it's worth, I'm leaning towards losing the bearing as you suggest. I get the impression that most 944 guys wouldn't give a second thought to (or need, more importantly) the feature, even if it provides more accurate caster adjustment and the ability to increase caster beyond stock allowances.
~russ
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lane
I just want to go fast!
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Post by lane on Jun 3, 2010 7:57:01 GMT -6
Russ, I'm not married to the stock caster mount and do like the idea of more adjustability in the one's you have. I do have a question though, how do you adjust the caster? I know you screw the eye bolt in or out but will this facilitate you having to remove the a-arm from its mounts to adjust or have you come up with something on the caster mount that won't interfere with moving the bolt?
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Post by turbot on Jun 3, 2010 11:40:17 GMT -6
Lane....just throwing this out there even though technically, the "point" would still be the same position but PCA rules specifically say that all suspension pickup/hinge points should be the same as stock and while this is open for interpretation as far as the placement of the FG a-arms, I think any competitive advantage (i.e. more caster allowance than anybody else) would outside the realm of the spirit of the rule.
Heck....they just started allowing aftermarket a-arms that DO remain exactly the same.
T
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lane
I just want to go fast!
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Posts: 164
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Post by lane on Jun 3, 2010 11:44:44 GMT -6
Hmmm... didn't really think about that. By the a-arm not conforming to PCA rules & regs you certainly cut down on potential sales. I think I like it if castor can be adjusted without removal of a-arm though.
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Post by turbot on Jun 3, 2010 11:46:11 GMT -6
Make an account? As who...Faster Guys? I've been meaning to do it, just been a tad sluggish. Terry, what are you suggesting would normally break on the rear mount? The eccentric pin...the caster block itself? The setup we would be using with the rod end would be a rod end (very standard sizing on all rod ends), a bolt, and a bracket built to be stronger than both. If anything went it'd be the rod end or bolt, both of which should be easy to replace if you have access to a speed shop. I'm not ruling out your idea of keeping the back stockish, just don't want to throw out the idea of the rod end yet. Putting the rear bolt in double shear and using such an oversized rod end goes a long way in ensuring you won't actually need to replace either part for a long, long time. That rod end in the model is rated 27,000 pounds of force. Actual loading on that rod end wouldn't exceed around 4000 pounds even if you were braking with all of the force on one wheel at the same rate you'd slow down braking with all four wheels planted. Typical force during hard braking would be closer to 1500 pounds on that bolt. I don't have a stress-life diagram for that particular rod end on hand, but that sort of load on a bearing like that constitutes "infinite life." For what it's worth, I'm leaning towards losing the bearing as you suggest. I get the impression that most 944 guys wouldn't give a second thought to (or need, more importantly) the feature, even if it provides more accurate caster adjustment and the ability to increase caster beyond stock allowances. ~russRuss, I have no problem believing in the strength as an issue, by that I mean, I am not suggesting that anything would break at the rear. It's the eventual off on rough terrain and the possibility of breaking the a-arm itself and it needing to be replaced with a standby arm at an out of town event. Even on the factory cast ones, which are pretty darned strong by the way, Porsche themselves recommend having the arms x-ray checked for cracks every time a car goes off a street, highway or track at speed. T
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Post by harrisracing on Jun 3, 2010 12:55:36 GMT -6
Please post the PCA rules on the matter.
1) Are roll control adjustments allowed at the ball joint?
2) are offset ball joints allowed (more camber)?
3) What in the rules restricts these if they attached to factory locations?
Patrick
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Post by turbot on Jun 3, 2010 14:42:14 GMT -6
Whew, sorta pressed for time lately but the rules are free to view PDF at PCA dot org.
I have never seen it challenged but probably 50% of the PCA 944s use either the increased diameter ball joint pin version of the aftermarket joint kits or the longer geometry correcting replacement ball joint, probably under the plea of safety and availability scarceness of "new" factory arms more than anything.
It wasn't long ago that rebuild parts were even made available so all you had as options before that was either new (dealer) or used arms.
The spirit of the "original pickup point" locations is really to keep people from showing up with modded twin a-arm suspensions and racing the cars as "stock".
Same as the tub, transmission and engine cases both have to bear a factory original serial number.
Those have to be recorded in the PCA log book and open for inspection.
T
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Post by Fast Guys on Jun 3, 2010 17:15:19 GMT -6
Right now, we are intending to price right around the factory price. We can't say specifics yet, but it will be significantly cheaper than many comparable aftermarket offerings, not to mention, technologically superior. We will be more adjustable, stronger and more reasonably price than anything else on the market.
After we prototype and test the arms, we will most likely offer a significant discount for presales. We will post more information as it becomes available.
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Post by Fast Guys on Jun 22, 2010 9:04:27 GMT -6
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Post by turbot on Jun 22, 2010 10:27:27 GMT -6
[/img][/quote] Don't see how that's gonna work with a stock type rear caster eccentric. T
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Post by Fast Guys on Jun 22, 2010 11:13:08 GMT -6
[/img][/quote] Don't see how that's gonna work with a stock type rear caster eccentric. T[/quote] It will have a heim joint that bolts through the arm with nuts on either side. It will be adjustable while on the car. The factory pickup point on the chassis will be unchanged.
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Post by turbot on Jun 22, 2010 13:10:13 GMT -6
It will have a heim joint that bolts through the arm with nuts on either side. It will be adjustable while on the car. The factory pickup point on the chassis will be unchanged. Uh yeah, I see that Andy....that's why I posted. I think you are running off 75% of the potential market. Make that +1%, because for me personally as well, this = fail. T
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Post by Fast Guys on Jun 22, 2010 14:44:27 GMT -6
It will have a heim joint that bolts through the arm with nuts on either side. It will be adjustable while on the car. The factory pickup point on the chassis will be unchanged. Uh yeah, I see that Andy....that's why I posted. I think you are running off 75% of the potential market. Make that +1%, because for me personally as well, this = fail. T Why does that run off 75% of the market? You guys don't want more adjustability? BTW-answer your phone.
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