Modern trailing arms for the 914?, 986 carriers/calipers/e-brake, more adjustability, more tire? |
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Modern trailing arms for the 914?, 986 carriers/calipers/e-brake, more adjustability, more tire? |
horizontally-opposed |
Jan 26 2021, 12:21 PM
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#1
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Advanced Member Group: Members Posts: 3,432 Joined: 12-May 04 From: San Francisco Member No.: 2,058 Region Association: None |
I've been reviewing past discussions on these (links below) off and on, having test fit a 215/60R15 Pirelli P6000 on a 911R wheel into both rear fenders of my narrow-body 914. It seems doable, but it's going to take some massaging on the outer fender, custom spacers, and—maybe—narrowed trailing arms. Which got me to thinking about the current state of the 914 trailing arm, which is the same it's been since 1970.
Basically, those heavy, non-adjustable steel trailing arms are one of the very few things on the 914 that hasn't been addressed or evolved by the aftermarket. I'm running PMB-rebuilt trailing arms with PMB-rebuilt calipers, and can redo them again with reinforcements and/or some reshaping, but I wonder how hard would it be to do blade-type trailing arms of similar strength with less weight and/or more adjustment. Could a 911 spring plate, or a triangulated or otherwise reinforced version of it, be adapted? Looking at the basic design of the 914 arm, it doesn't look all that complicated, but I'm no engineer. EDIT: Possible use of a machined 986 wheel carrier, an aluminum casting by Brembo that incorporates the 986 e-brake and 986 four-piston caliper mounts, comes up later—a very interesting idea from @Chris914n6, particularly as the castings are available for $100-200ea used or new from Porsche. Bolting that carrier to a new steel trailing arm with a lower damper mount seems viable to me, but here to learn. The custom work to narrow factory 914 trailing arms looks extensive, but has been done by both @914timo and @sixnotfour as well as, it looks like, Rich Johnson. I could see doing it in the process of moving to 911 e-brakes and 986 2.5 brakes, maybe, but I wonder if a group buy might attract a 914 vendor we all want to support? Relevant threads: http://www.914world.com/bbs2/index.php?sho...p;#entry1247827 http://www.914world.com/bbs2/index.php?sho...ailing&st=0 http://www.914world.com/bbs2/index.php?sho...238144&st=0 http://www.914world.com/bbs2/index.php?sho...234391&st=0 |
ClayPerrine |
Jan 29 2021, 10:38 AM
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#2
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Life's been good to me so far..... Group: Admin Posts: 15,520 Joined: 11-September 03 From: Hurst, TX. Member No.: 1,143 Region Association: NineFourteenerVille |
The factory trailing arms were designed with narrow tires and limited grip as the parameters. With 50 years of tire evolution, you can put enough sticky tires on a 914 that will make it exceed 1G lateral loads. The trailing arms were never designed for that kind of load, and are going to start failing from a combination of metal fatigue and age.
An aluminum trailing arm, similar to the 911 one, would be a great investment. If I were doing it, I would incorporate a mounting pad for a monoblock (Boxster) caliper, all the required provisions for the park brake (stop block, bellcrank, altered cable mount, etc..) and new fairly hard durometer rubber bushings. But it is beyond a hobbyists ability to build a upgraded trailing arm like this. Someone with some deep pockets would have to build and sell it. |
Superhawk996 |
Jan 29 2021, 11:18 AM
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#3
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914 Guru Group: Members Posts: 5,903 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
The factory trailing arms were designed with narrow tires and limited grip as the parameters. With 50 years of tire evolution, you can put enough sticky tires on a 914 that will make it exceed 1G lateral loads. The trailing arms were never designed for that kind of load, and are going to start failing from a combination of metal fatigue and age. An aluminum trailing arm, similar to the 911 one, would be a great investment. If I were doing it, I would incorporate a mounting pad for a monoblock (Boxster) caliper, all the required provisions for the park brake (stop block, bellcrank, altered cable mount, etc..) and new fairly hard durometer rubber bushings. But it is beyond a hobbyists ability to build a upgraded trailing arm like this. Someone with some deep pockets would have to build and sell it. Well said! Doesn't exactly look profitable given a upper bound of ~100,000 vehicles and mabye 22,000 rabid fans (or whatever latest membership is here). Now consider the number of those that would be willing to spend $$$ to make the "upgrade". For me a good chunk of the 914 appeal is that it is what it is. Faster, more reliable, great handling cars are all around us in this day and age. Agree a 914 stands tall given its age but again, it is what it is. |
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