NS F355 Project (Page 63/73)
Bloozberry JAN 19, 06:54 AM
Superb drawings, as always. You should consider making a nice poster for the shop walls some day when it's finished.

The configuration looks like it should work... the nice wide spacing on the inboard control arm mounts will resist toe and apply accel and decel forces to the frame better than stock. You shouldn't get any toe throughout the range of suspension travel other than through bushing compliance under load. When that does happen, you'll want to make sure that the outside tire toes in rather than out otherwise you'll be battling oversteer. With the powertrain configuration you're planning, you'll probably have a greater rear weight distribution than stock and a greater propensity to oversteer too. Anxious to see the analysis.
85-308 JAN 19, 11:19 AM
Nice! I like your toe-defeat solution. Very similar to what I was thinking of (I don't have nice dwgs like that to post..) Obviously you're keeping the 84-87 spindles and the lengths of the 'tie rod' should be perfect.

Question - if you're there yet: How do you plan on connecting the outboard end of this 'tie rod' to the spindle itself; ie right at/near the ball joint? Welding? it is at the pinch nut location.
I was looking at bolting it to the spindle but still playing with that a bit.

Keep it up; great tech article in all respects!
GP
Yarmouth Fiero JAN 19, 11:44 AM
Thanks for asking 85-308. I have designed an albeit, rudimentary bracket that will be bolted at the lower end to the ball joint pinch bolt ( there is a nice flat surface already ) with the upper end being bolted to the spindle stock tie rod location. I'll drill the taper out of that hole first. I'll likely use grade 8 bolts and nuts with locking wire for added safety. I may also add a small gusset to this fabricated bracket for extra strength. I don't advocate welding to the OEM cast spindle unless you know what you are doing.

When I am designing / drawing, I tend to leave the fasteners out of the picture so that I can easily see if I have accidently shifted a part because the holes no longer line up. Its too easy to "bump" a part in the drawing if I haven't locked the layers first and then keep on drawing like everything is ok. Plus its easier to snap to centers of holes when the fasteners are hidden from view. I hope this answered your question.
85-308 JAN 19, 11:55 AM
Ok s you're not using a ball joint there; similar to what some of the kits do, and bolting it solid. The spindle is cast steel, I guess, since it does 'flex' at the pinch bolt, but I agree, in my bit of research on welding different materials I don't think I want to touch it with weld...
Yarmouth Fiero JAN 19, 12:06 PM
No, I am using a ball joint and using the pinch bolt to hold the ball joint and the extended bracket for the bump steer correction. Unfortunately I don't have my updated drawing on my work computer so I can't post more detailed pictures until tonight. I'll capture a few images that show that area in better detail. Sorry about that.
355Fiero JAN 19, 06:13 PM
Yarmouth Fiero;

I went through a bunch of this analysis back when I was building my extended rear suspension. Albeit, my drawings were very crude and not nearly to yours and Blooz's standards..... I came up with an option that does not require a a trailing arm of any sort.

I would be interested in yours and Blooz's opinions on the setup I thought about.... You replace the ball joint at the bottom of the hub with a bolt and nut setup and make a cross bar setup at the bottom. As per my drawing. I always though that this would allow the hub to move up and down and not introduce bump but, again, I did not go through a lot of analysis on this. It was more of a drawing exercise than anything.

In the end, I moved my trailing arm pivots outward from their original locations on the cradle so that they pivoted pretty much over the suspension pivots on the cradle. Through moving the tire and rim through its entire motion, I removed all but about 1/16" or bump at full extension and contraction. By that time, I was already rolling so not so worried about bump by then......

Back to my thought, the picture below shows what my thought was. The top image is what I ended up going with for my wider suspension but the middle image is what I was thinking about after I had built the top one.

Cheers
Don
Yarmouth Fiero JAN 19, 07:50 PM
Thanks Don. That is an interesting concept. So is that showing a custom spindle with two pivots on the bottom end? If so, that would cure the bumpsteer for sure. I guess because I am changing my engine cradle quite a bit, I decided to get away from mounting the inboard end of the tie rod there. I think once I tweek my design and then test the kinematics, it should give results more than acceptable for my project. I don't plan on racing it anyway

Edit to add: To 85-308, here is a shot of my design with the bump steer bracket bolted in place. Hope this helps.

[This message has been edited by Yarmouth Fiero (edited 01-19-2015).]

85-308 JAN 19, 09:25 PM
ahhhh
NOW I get it; good idea. Thx!
GP
zkhennings JAN 20, 05:05 PM
I had the exact same idea even down to using the pinch bolt as the attachment surface! It's floating around here somewhere.

I designed it to not be in single shear however and had a U shaped piece that went over the ball joint so the pinch bolt would go through both sides. I also had some additional reinforcement gusseting at the 90*, but I am sure you will too, excited to see how it turns out!
355Fiero JAN 20, 06:43 PM
Graham;

The setup I drew was very similar to how you are set up except instead of having the training arm going to the inner mount location, I made a square bar that connects to the control arm both sides and then the Fiero hub bolts to the square bar and an arm comes up from the square bar to the trailing arm mount on the hub. The Fiero hub bolts to the square bar and the trailing arm mount.

If you took your drawing and made a square tube that bolts to the Fiero hub where the ball joint currently is, and extended your trailing arm hub mount down to that square tube, you would have my design. The ends of the square tube would connect to the control arm ends through hiem joints or pivot points similar to the inner control arm mounts.

I will see if I can do up a quick side view to show how the Fiero hub mates to the square tube on the control arm.

Cheers
Don