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-   -   Rear Lower Stress Bar Feeler (http://986forum.com/forums/showthread.php?t=73554)

mgfranz 10-20-2018 04:53 PM

Rear Lower Stress Bar Feeler
 
After doing a lot of digging, I found the "Pedro" bar, the Ranntech bar and the "Bristol" bar, but all of them have certain deficiencies that I wanted to avoid in tackling this item. Specifically the issues I found were price, effort of engineering and quality of materials. All of which I believe I have alleviated in the development of this piece.

I present, the new and improved 986/987 lower stress bar.

The kit;

http://i68.tinypic.com/2py49px.jpg

Components;

http://i66.tinypic.com/2s76no1.jpg

And installed;

http://i67.tinypic.com/2cqn34i.jpg

The main differences in this kit is that the attaching bolts are all hardened with hardened bushings that can handle the loads of the stress that can be placed on them and the hardened Heim joints with a thicker end wall which has been tested to over 90,000 lbs of load before failure. Plus since the bar is adjustable you can actually pre-load your rear toe and/or camber slightly, (more is available if you modify your aluminum plate). The bar itself is made out of 1" aluminum and is IMCA appproved. The Heim joints are Carbon Steel and zinc coated to prevent rust, I found that the bearing joint is not necessary and actually added another possible point of failure, therefore the solid Heim.

Initial impressions are a tighter rear feel with less oversteer and firmer ride, but a definite improvement over stock.

These kits are available for $97.50 + shipping. PM me if interested.

rfuerst911sc 10-21-2018 04:43 AM

Where are you installing the flat washer ? Under the bolt head or between the flat of the heim joint and the suspension ear ? I assume you are " pre adjusting " towards the outside then installing the aluminum plate ? A little more detail please . Thanks

mgfranz 10-21-2018 06:16 AM

Quote:

Originally Posted by rfuerst911sc (Post 581347)
Where are you installing the flat washer ? Under the bolt head or between the flat of the heim joint and the suspension ear ? I assume you are " pre adjusting " towards the outside then installing the aluminum plate ? A little more detail please . Thanks

The washer goes under the bolt head to prevent galling of the bushing and the heim joint. As far as pre-loading, I initially installed it nuetral, but I will be playing with it once I get to the track. I want to get over to the alignment shop and see what the best setting would be.

edc 10-21-2018 07:44 AM

I have a version of the Pedro one made of hexagonal Alu. As much as I like the thought and look of your bar have you not overthought this? Mines been on for 4 years or so and doesn't appear to have had any issues.

mgfranz 10-21-2018 08:15 AM

Quote:

Originally Posted by edc (Post 581355)
I have a version of the Pedro one made of hexagonal Alu. As much as I like the thought and look of your bar have you not overthought this? Mines been on for 4 years or so and doesn't appear to have had any issues.

"Overthought"? Maybe, I tend to do a lot of over-engineering. In my past I worked at a fabrication shop building everything from headers, to rollbars, to entire tube chassis, so yeah, I will build something to perform beyond it's means. Besides, it's for a Porsche, has anyone in Germany ever told Porsche "you're overthinking..." ;-)

I looked at the Pedro bar, and quickly thought, "for the price I can do better". The Pedro bar is fine if you just want to stiffen the stress points, but I wanted something better with some minute adjust-ability. What I saw first with the Pedro bar was there was no room for error between the attaching points, I read that some users had problems lining up the bolt holes...

rfuerst911sc 10-21-2018 09:46 AM

Any thoughts of installing " flats " on either end of the tube to allow a wrench to turn/adjust vs. the knurled section you currently have ? I picture the car being on an alignment rack with the holes in the aluminum plate being slotted . Loosen the nuts/bolts on the aluminum plate and now adjust with your cross bar to whatever alignment spec's can be achieved . Tighten down the secondary nuts on your bar and then tighten down the aluminum plate hardware . Is that the general idea ? I'm thinking turning the bar with a wrench vs. your finger tips on the knurled section would be easier . Just thinking out loud .

mgfranz 10-21-2018 01:41 PM

Quote:

Originally Posted by rfuerst911sc (Post 581363)
Any thoughts of installing " flats " on either end of the tube to allow a wrench to turn/adjust vs. the knurled section you currently have ? I picture the car being on an alignment rack with the holes in the aluminum plate being slotted . Loosen the nuts/bolts on the aluminum plate and now adjust with your cross bar to whatever alignment spec's can be achieved . Tighten down the secondary nuts on your bar and then tighten down the aluminum plate hardware . Is that the general idea ? I'm thinking turning the bar with a wrench vs. your finger tips on the knurled section would be easier . Just thinking out loud .

Not a bad idea, however the wall thickness of the link tube would probably be greatly compromised if there were "flats" put into it. I suppose an alternate could be to weld a pair of nuts on the ends of the tube. I used jackstands when I installed mine and had no problem turning the tube by hand.

hockenheim 10-21-2018 02:40 PM

I don't understand how this bar or at the Pedro bar improves stiffness. Aren't the two sides already prevented from moving through the aluminum undertray?

mgfranz 10-21-2018 02:55 PM

Quote:

Originally Posted by hockenheim (Post 581377)
I don't understand how this bar or at the Pedro bar improves stiffness. Aren't the two sides already prevented from moving through the aluminum undertray?

While the aluminum undertray is there to do just that, it has a tendency to flex under strong loads, even bend. This bar alleviates that possibility.

hockenheim 10-21-2018 07:08 PM

Thanks for the explanation. I'd be surprised if a 2.5l can generate enough stress on the suspension to cause the tray to bend. Maybe a good solution for S cars.

maytag 10-21-2018 07:40 PM

Quote:

Originally Posted by hockenheim (Post 581400)
Thanks for the explanation. I'd be surprised if a 2.5l can generate enough stress on the suspension to cause the tray to bend. Maybe a good solution for S cars.

The particular stresses are not related to hp, but are rather a function of cornering loads.

Sent from my SM-G930T using Tapatalk

mgfranz 10-21-2018 07:40 PM

Quote:

Originally Posted by hockenheim (Post 581400)
Thanks for the explanation. I'd be surprised if a 2.5l can generate enough stress on the suspension to cause the tray to bend. Maybe a good solution for S cars.

I dunno, never owned or drove a 2.5, but I would imagine that if you drove it hard enough you could cause some damage.

mgfranz 10-21-2018 08:08 PM

Quote:

Originally Posted by maytag (Post 581403)
The particular stresses are not related to hp, but are rather a function of cornering loads.

Sent from my SM-G930T using Tapatalk

Exactly! It's about how well do you drive your car.

rfuerst911sc 10-22-2018 04:46 AM

Please post your results/thoughts after you hit the alignment shop do you think you'll be doing that soon ? I am interested in your product . Not sure how many others are interested but a " group buy " might get the ball rolling :D

mgfranz 10-22-2018 05:09 AM

Quote:

Originally Posted by rfuerst911sc (Post 581421)
Please post your results/thoughts after you hit the alignment shop do you think you'll be doing that soon ? I am interested in your product . Not sure how many others are interested but a " group buy " might get the ball rolling :D

Possibly this weekend.
And yes, a group buy would get the ball rolling, even save some $.

maytag 10-22-2018 05:16 AM

Quote:

Originally Posted by mgfranz (Post 581423)
And yes, a group buy would get the ball rolling, even save some $.

I'm interested, but also very interested in what the alignment shop visit produces.


Sent from my SM-G930T using Tapatalk

Newsguy 10-22-2018 11:17 AM

Capitalism is a great concept, but all these parts can be obtained from Rod End Supply for about half that.

maytag 10-22-2018 11:31 AM

Quote:

Originally Posted by Newsguy (Post 581440)
Capitalism is a great concept, but all these parts can be obtained from Rod End Supply for about half that.

Well aren't YOU just everyone's best friend? hahaha.

Personally, I don't mind paying somebody to do the research for me on what size, length, etc for the rod ends, plus the tie-rod, plus provide the hardware. then assemble it all into a kit for me, so that I can simply ORDER it, and then INSTALL it.... without worrying if I ordered the wrong one, waiting to see if it'll arrive correctly, hoping that the bolts I sourced are correct, etc etc etc.

And I know that personally, if I were offering a service / product on a forum and you hijacked my thread to tell everyone how to get my service / product without me, I'd probably wish you had started your OWN thread about it.

but that's just me, and my sense of decency.

Robert986 10-22-2018 11:37 AM

Quote:

Originally Posted by mgfranz (Post 581380)
While the aluminum undertray is there to do just that, it has a tendency to flex under strong loads, even bend. This bar alleviates that possibility.

Is this "confirmed"? Do we know that it flexes and do we know that there is a real gain by using the stress bar? Comparing with a front strut brace which I believe is considered redundant..

EDIT: Not trying to sound negative, I want to believe... ;-)

Starter986 10-22-2018 01:13 PM

Quote:

Originally Posted by maytag (Post 581441)
Well aren't YOU just everyone's best friend? hahaha.

Personally, I don't mind paying somebody to do the research for me on what size, length, etc for the rod ends, plus the tie-rod, plus provide the hardware. then assemble it all into a kit for me, so that I can simply ORDER it, and then INSTALL it.... without worrying if I ordered the wrong one, waiting to see if it'll arrive correctly, hoping that the bolts I sourced are correct, etc etc etc.

And I know that personally, if I were offering a service / product on a forum and you hijacked my thread to tell everyone how to get my service / product without me, I'd probably wish you had started your OWN thread about it.

but that's just me, and my sense of decency.

I agree with you. Certainly you have a backend investment of time associated with the development particulars for the part. I recognize the value ($$ - time being money) in that effort. Personally, I commend you.

Further, anyone could source parts to fabricate half-the stuff "sold" upon these forums. That's the easy part.

Keep up the good work. Thank you.


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