Full Suspension Design/Build/Install

[P_Carfahrer]

Merry Christmas everyone!! I wanted to document my suspension update for anyone interested with the parts I have built and decided to start this thread to separate it from my LCA discussion as there will be a bunch of parts other than the LCAs that are going to be installed that I will also share. For transparency, the parts I will install have all been modeled with detailed drawings by myself, taking reference dimensions from the car, OEM parts, a few aftermarket parts, and machined working with buddies’ in their shops. A few parts are still to be built.

I will note materials used, if anyone is inclined to know about that stuff. All parts have been subjected to FEA through Solidworks simulations to analyze potential functional loads on various load axes/directions. I won’t go into detail as any given part will have many scenarios simulated.

The inner monoballs and outer arms are machined from 7075-T6 with the outer modeled after the OEM 996 adjustable LCA. Bearings are Teflon lined FK COM12T with F1 fit. Bushings are 4340 with metric grade 10 fasteners with the outer bolt upsized to 14mm. Grade 12.9 threaded rod is permanently Loc-tited into the monoball end with M8 jet nuts connecting the inner and outers with 6061 aluminum spacers to increase arm length and also take up threaded rod extension. All aluminum is hard anodized.

Both bearings are interference press fit and utilize bearing retaining compounds and heavy-duty Spiro-loc type internal snap rings.

Here are some shots of the installed arms from various perspectives.








Here is a shot using an adjustable hand reamer to enlarge the upright hole to accommodate the 14mm fastener. I could have bought a 14mm drill with a shank small enough to fit a hand drill but had this and it sufficed fine. The family was not happy having to pick aluminum shavings out of the pizza.



Adjustable hand reamer set.

[jaykay]

Wow outstanding work!!!!

[maytag]

dood.... you always impress.
BEAUTIFUL!!!

[P_Carfahrer]

Some other parts ready to install after anodization.

Pinch style toe arms, tie rods, and toe lockouts. Arms are again 7075-T6 with 17-4 stainless spacers and cone inserts. Toe lockouts are 4340. Rod ends are FK JMX/L 10T with F1 fit. Grade 10/10.9 hardware with ARP 12 point screws for the pinch point.

[P_Carfahrer]

Parts anodized and installed. Thrust arm forks built. Working on the thrust arm center links.

[paulofto]

Wow nice stuff!

[steved0x]

Originally Posted by paulofto

Wow nice stuff!

Yeah! +10000000000

[Muskoka Minute]

Very Nice!!

Are you going to be selling these?

[truegearhead]

I'd be interested in lower control arms that had raised ball joints to allow you to lower the car without effecting the roll center (you'd be able to lower the car more without the control arms pointing up). These are common on older 911s but no one is making them for newer 911s...yet.

[P_Carfahrer]

Originally Posted by truegearhead

I'd be interested in lower control arms that had raised ball joints to allow you to lower the car without effecting the roll center (you'd be able to lower the car more without the control arms pointing up). These are common on older 911s but no one is making them for newer 911s...yet.

Porsche offers tapered studs of varying lengths to accomplish this in their racing parts catalog though I can’t seem to find where I had the document saved.

Once I get everything buttoned up I will play around with making some tapered bushings of different neck lengths and longer bolts to lower the upright attachment point to improve roll center geometry.

[truegearhead]

Originally Posted by P_Carfahrer

Porsche offers tapered studs of varying lengths to accomplish this in their racing parts catalog though I can’t seem to find where I had the document saved.

Once I get everything buttoned up I will play around with making some tapered bushings of different neck lengths and longer bolts to lower the upright attachment point to improve roll center geometry.

Keep us posted I would be interested in a set if they can improve the roll center.

[P_Carfahrer]

Finished some thrust arm center links and am finalizing rear monoball mounts with an adapter plate to facilitate mounting the Ohlins coilovers.

[Muskoka Minute]

Originally Posted by P_Carfahrer

Finished some thrust arm center links and am finalizing rear monoball mounts with an adapter plate to facilitate mounting the Ohlins coilovers.

Very Very Nice!

[truegearhead]

Wow. Just wow

[MaxD]

Fantastic - Haven't had a chance to comment and glad the thread moved up the stack.

Roll center, bump steer adjustments, excellent - Too bad it isn't SPB legal.

Spec 944 allows spherical bearings, why not SPB. Far cheaper and easier than replacing the Porsche stock rubber ones.

[maytag]

Originally Posted by MaxD

Fantastic - Haven't had a chance to comment and glad the thread moved up the stack.



Roll center, bump steer adjustments, excellent - Too bad it isn't SPB legal.



Spec 944 allows spherical bearings, why not SPB. Far cheaper and easier than replacing the Porsche stock rubber ones.

Well maybe if Todd is willing to make them really available, we can petition for an allowance in the rules next year?

Sent from my SM-G970U using Tapatalk

[P_Carfahrer]

Originally Posted by MaxD

Fantastic - Haven't had a chance to comment and glad the thread moved up the stack.

Roll center, bump steer adjustments, excellent - Too bad it isn't SPB legal.

Spec 944 allows spherical bearings, why not SPB. Far cheaper and easier than replacing the Porsche stock rubber ones.

Yeah I have never understood the restrictive rules of SPB concerning power/suspension. There are/were faster 986 S cars than some SPB cars. Looking at you Maytag... your Blue Bullet... RIP...

[P_Carfahrer]

Rear Monoball mounts are now completed with a plate to adapt Ohlins R/T coilovers for installation with the monoball mounts. As seen in the pictures below, the Ohlins set comes with a mold formed rubber insert that fits into the OEM strut mount and locates on the three OEM strut mount stud heads. A machined aluminum part then fits into the bottom side of the rubber insert in the Ohlins kit. The machined part has a lip with an OD that mates with the spring.
The Ohlins rubber piece is so large and has such a radius that making a monoball mount that would still fit properly in the car body and have sufficient wall thickness was not possible so I designed and built a different aluminum insert that would locate on the stud heads, be flush with the bottom plate of the monoball mount, and have the correct lip/OD to mate with the Ohlins springs.





A rubber washer supplied by Ohlins sits between the aluminum lip and the spring. Inside the cup is a FK Com14t F1 fit spherical bearing captured by a cap with 5 M5 screws. Bearing retainer compound will be used for the bearing locating surfaces with Loctite blue on all screws/nuts.

Here you can see the monoball, adapter plate, and spring from the side view.



Here is the assembled monoball and coilover though I need to increase spring pre-load by 5mm. I couldn’t tighten the pre-load spanner nut any more by myself. Aluminum will be anodized blue.



I am done with machining other than building drop link adjustment centers after getting everything installed and measuring what length centers I need to build for front and rears. If all goes ok I hope to get the car on the ground again this week. The only issue with this is I can’t get tires I want and the ones I had are completely done. Stupid Covid shortages of everything…

[maytag]

Holy Good golly my friend!
BEAUTIFUL work!
Incredible.
Truly.

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[P_Carfahrer]

Ready for install...



Setting spring pre-load by myself was a royal pain. I couldn't keep the assembly fixed to turn the nut for the last few millimeters

I kind of wish I had not installed anything yet and put everything out together for a full build picture.