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 |
rgalla9146 |
Jan 31 2021, 02:19 PM
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#2
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Advanced Member Group: Members Posts: 4,555 Joined: 23-November 05 From: Paramus NJ Member No.: 5,176 Region Association: None |
My GT conversion.
Is this lighter and stronger ? If the trailing arm were re-shaped (narrow + taller ) could it accomodate the narrow body wheel / tire requirement ? Attached thumbnail(s) |
horizontally-opposed |
Jan 31 2021, 03:19 PM
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#3
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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 |
My GT conversion. Is this lighter and stronger ? If the trailing arm were re-shaped (narrow + taller ) could it accomodate the narrow body wheel / tire requirement ? Whoa! Never saw these. Very cool, and I'd be curious re: your questions. I have no doubt that Porsche engineered (and overbuilt) the 914's steel trailing arms down to a price. I doubt it did so with a 50- to 100-year service life in mind, but there's no doubt they're long-life parts. I cannot remember hearing of a failure, but they were reinforced for racing by Porsche and others. I do wonder what goes on inside of the boxed sections, as it's "unlikely" they were treated for condensation/rust any better than the 914's longs and center tunnel were. What did yours look like inside when they were sliced up, Rory? Rory also has some suspension console reinforcement that you can see in the pic. Some very nice work indeed on Rory's car. That car keeps impressing me, visually and technically—how has it not been nominated for COTM yet? (IMG:style_emoticons/default/blink.gif) (Makes mental note.) I've been considering the reinforcements below next time my engine comes out. The inner mount reinforcements are from Tangerine Racing, while the outer is from Patrick Racing. Like the idea of reinforcing the outer mount with the long, but wonder what an engineer with relevant experience might say—and don't love having to remove the rocker panel to adjust if that's what would be necessary. The factory did some interesting things with rocker panels on some of its rally cars, including leather straps to allow the back of the rocker to be peeled open for field service. Looks cool on a Monte Carlo works GT, but zero interest in that for a road car. Attached thumbnail(s) Attached image(s) |
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