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> Torsional rigidity of the 914, Differences roof on / roof off / steel roof?
rgalla9146
post Jan 6 2019, 08:47 PM
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QUOTE(73-914 @ Jan 6 2019, 08:41 PM) *

QUOTE(rgalla9146 @ Jan 6 2019, 06:14 PM) *

This is a great topic.
I want a 914 coupe.....with AC

It's called a Cayman


Yeah, one of them too. They're beautiful. Make mine a GT4 please.
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Beebo Kanelle
post Jan 6 2019, 11:06 PM
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This is interesting :
http://youwheel.com/home/2016/06/20/car-bo...rehensive-list/
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VegasRacer
post Jan 7 2019, 12:18 AM
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2013 Cayman Steel.
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Dave_Darling
post Jan 7 2019, 10:05 AM
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QUOTE(Curbandgutter @ Jan 6 2019, 03:13 PM) *

Bottom line is that the stock 914 chassis is very flexible, 3,326’# per degree from my testing.


We know that is the value in at least one case. It would be interesting to see if that is the same on many different 914s.


QUOTE
In testing, I found that one of the longs had a stress crack in it. I don't know if that was just mine, or if most of the 914's out there are running around with cracked longs.


It is pretty common for the inner long to crack at the recess for the handbrake handle on 72+ 914s.

--DD
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mepstein
post Jan 7 2019, 10:33 AM
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QUOTE(Curbandgutter @ Jan 6 2019, 06:13 PM) *

Hello, I did run some numbers on the torsional rigidity of the 914. Here's the link http://www.914world.com/bbs2/index.php?sho...p;#entry2396780

See POST#10

Bottom line is that the stock 914 chassis is very flexible, 3,326’# per degree from my testing. Although I didn't say it at the time, I ran the numbers with and without the doors and found no real difference. From my "door" tests, it's safe to assume that the roof will not be any different. There is too much flex in the hinges, and latches before the roof and doors begin to provide support.

Based on testing, I can say that, other than a full roll cage, that the next best thing is to stiffen the longs. Then, if you wanted more, a welded steel roof like the factory. There is a reason why the factory went with a welded steel roof in the 916.

I'm almost to the point where I can test again with the full roll cage in place. Based on modeling, I'm expecting a 10x stiffer chassis now.

In testing, I found that one of the longs had a stress crack in it. I don't know if that was just mine, or if most of the 914's out there are running around with cracked longs.

Was the crack at or near the e-brake mount?
@Curbandgutter
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sixnotfour
post Jan 7 2019, 11:05 AM
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beefing up the pillar base


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Curbandgutter
post Jan 9 2019, 05:10 PM
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QUOTE(mepstein @ Jan 7 2019, 08:33 AM) *

QUOTE(Curbandgutter @ Jan 6 2019, 06:13 PM) *

Hello, I did run some numbers on the torsional rigidity of the 914. Here's the link http://www.914world.com/bbs2/index.php?sho...p;#entry2396780

See POST#10

Bottom line is that the stock 914 chassis is very flexible, 3,326’# per degree from my testing. Although I didn't say it at the time, I ran the numbers with and without the doors and found no real difference. From my "door" tests, it's safe to assume that the roof will not be any different. There is too much flex in the hinges, and latches before the roof and doors begin to provide support.

Based on testing, I can say that, other than a full roll cage, that the next best thing is to stiffen the longs. Then, if you wanted more, a welded steel roof like the factory. There is a reason why the factory went with a welded steel roof in the 916.

I'm almost to the point where I can test again with the full roll cage in place. Based on modeling, I'm expecting a 10x stiffer chassis now.

In testing, I found that one of the longs had a stress crack in it. I don't know if that was just mine, or if most of the 914's out there are running around with cracked longs.

Was the crack at or near the e-brake mount?
@Curbandgutter


@mepstein it was actually about 12" back from the a pillar. See POST 193 in the link below for a picture of the crack

http://www.914world.com/bbs2/index.php?sho...6845&st=180
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steuspeed
post Jan 9 2019, 06:19 PM
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QUOTE(Beebo Kanelle @ Jan 6 2019, 09:06 PM) *

This is interesting :
http://youwheel.com/home/2016/06/20/car-bo...rehensive-list/



Convertibles consistently about half as rigid as the coupes. My dad raced a Corvair 140 corsa for years. Got his hands on a 180 turbo convertible. Went from first to last in the class. Horrible handling no matter what he did. Turbo lag was no help either.
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mgp4591
post Jan 10 2019, 04:02 AM
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QUOTE(sixnotfour @ Jan 7 2019, 10:05 AM) *

beefing up the pillar base

Jeff, any special treatment when you weld those up besides the usual "take your time and space the weld points accordingly"?
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phillstek
post Jan 10 2019, 05:07 AM
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QUOTE(sixnotfour @ Jan 8 2019, 04:05 AM) *

beefing up the pillar base

Have this done on my car after cracking two windshields. Car was lowered with stiff suspension. Haven't had any issues since. I used Armando's pbase site as my template.
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rick 918-S
post Jan 10 2019, 08:38 AM
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Urethane the windshield to the frame will help also.
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Tdskip
post Jan 10 2019, 08:50 AM
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QUOTE(sixnotfour @ Jan 7 2019, 12:05 PM) *

beefing up the pillar base


Interesting - I have a '74 where the windshield is loose that I may try this on.
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dr914@autoatlanta.com
post Jan 10 2019, 09:14 AM
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There is an amazing difference between a 914 top on and a 916 welded top.

When I picked up the 916 in Jacksonville and drove it back in circa 1991, the very first thing I noticed was when going over rail road tracks I can only describe it as the car would go bump only once where as every other 914 I had ever driven (and I have driven thousands) would go bump bump. The car is much more precise and stable like everything is working together rather than having a front half and a rear half. Quite sensational as the car feels like a 914 with its act together. An absolute pleasure to drive at high speeds and around corners.
That car Brutus, with the 2.9 is CRAZY. Both fast and precise, when driving makes one reminisce about what could have been


QUOTE(Beebo Kanelle @ Jan 5 2019, 07:17 PM) *

Does anybody anywhere know where to find the torsional rigidity of the 914 with the roof off vs. roof on vs. steel roof (916) ?

Thanks in advance.
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sixnotfour
post Jan 10 2019, 01:19 PM
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QUOTE(mgp4591 @ Jan 10 2019, 03:02 AM) *

QUOTE(sixnotfour @ Jan 7 2019, 10:05 AM) *

beefing up the pillar base

Jeff, any special treatment when you weld those up besides the usual "take your time and space the weld points accordingly"?


Ask George AA did it..for Jon Lowe
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914forme
post Jan 10 2019, 01:35 PM
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John had templates and the parts made, Georges crew welded them in for John, not sure if they did the fabrication or not. Lots of parts on John's "GT" clone where done either by locating the original, or by having them fabricated by various entities that had access to GT parts. Moss comes to mind as a chief fabricator of GT parts including the 100L tank.

Man I miss talking to John, and I miss that car, I found a few NOS parts for that one.
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dr914@autoatlanta.com
post Jan 10 2019, 02:37 PM
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we spent hundreds of hours on Jon's car making it identical to the original GT. Probably was close as any clone could have ever been. It was quite a while ago though so hard to remember
Jon really lost it after a nasty divorce with Valentine's sister, sold his GT clone for a song and never looked back


QUOTE(sixnotfour @ Jan 10 2019, 12:19 PM) *

QUOTE(mgp4591 @ Jan 10 2019, 03:02 AM) *

QUOTE(sixnotfour @ Jan 7 2019, 10:05 AM) *

beefing up the pillar base

Jeff, any special treatment when you weld those up besides the usual "take your time and space the weld points accordingly"?


Ask George AA did it..for Jon Lowe
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914_teener
post Jan 10 2019, 03:49 PM
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QUOTE(rgalla9146 @ Jan 6 2019, 03:14 PM) *

This is a great topic.
I want a 914 coupe.....with AC



Buy a Cayman.
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Tdskip
post Jan 10 2019, 04:21 PM
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QUOTE(914_teener @ Jan 10 2019, 04:49 PM) *

QUOTE(rgalla9146 @ Jan 6 2019, 03:14 PM) *

This is a great topic.
I want a 914 coupe.....with AC



Buy a Cayman.



Hmmmm, wonder if anyone actually did that exact thing?
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ChrisFoley
post Jan 10 2019, 04:22 PM
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I add a-pillar reinforcements when I build a hard top
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BeatNavy
post Jan 10 2019, 04:30 PM
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QUOTE(ChrisFoley @ Jan 10 2019, 05:22 PM) *

I add a-pillar reinforcements when I build a hard top

Chris, are these something you sell or would be willing to sell? I like the idea of additional structural integrity here. Some of us can weld somewhat competently but can't fabricate very well (IMG:style_emoticons/default/dry.gif)
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