Datsun Roadster Forum-311s.org

Good discussion.
I will take some pictures tomorrow after I get the car back on the ground and drive around a little to settle them.

Add locknuts when you can find them, they are just thinner plain nuts, hold the inner nut, tighten the lock against it The urethane might be harsh, I used urethane on the bushing under the nut, rubber between the shock and mount hole, made it a bit less harsh on expansion joints. Urethane won't compress much, so probably doesn't need too much torque before the rubber bushing bulges.

Phils math makes sense, but my track record on math is not the best. I don't have the book handy, but things like tire height and offset would change the location of the contact patch, and should affect roll center height, while IIRC instant center is strictly the relation between the suspension components. I found this link, understand about a third of it, but it seems to make sense
http://www.google.com/url?sa=t&rct=j&q= ... kw&cad=rja

There's probably a cool CAD type program where you can plot all this stuff and then change variables, or if not, there should be.

fj20spl311 wrote:Will,
You might have a error in your Roll Center Calculation.

The intersection of the lines drawn through the control arm pivot points are the instant centers. The intersection of lines drawn from the contact patches to the instant centers is the roll center. This locates the height of the roll center above the ground, and the location left or right from the center line of the car.

Yep, I forgot about the instant centers. Good catch. Still, it would be great to stick a car on a rack where it would sit level and loaded (on the suspension) and actually plot this out with measurements to document for future posterity.

Will

dbrick wrote:Add locknuts when you can find them, they are just thinner plain nuts, hold the inner nut, tighten the lock against it The urethane might be harsh, I used urethane on the bushing under the nut, rubber between the shock and mount hole, made it a bit less harsh on expansion joints. Urethane won't compress much, so probably doesn't need too much torque before the rubber bushing bulges.

Phils math makes sense, but my track record on math is not the best. I don't have the book handy, but things like tire height and offset would change the location of the contact patch, and should affect roll center height, while IIRC instant center is strictly the relation between the suspension components. I found this link, understand about a third of it, but it seems to make sense
http://www.google.com/url?sa=t&rct=j&q= ... kw&cad=rja

There's probably a cool CAD type program where you can plot all this stuff and then change variables, or if not, there should be.

There is a program somewhere on line that allows you to plug and play the #s, but I can't find it anymore. I had it bookmarked on my old computer. A friend of mine put it to good use on his 914. He went from pretty quick to flirting with TTOD while still running a 4 cyl. He tuned and tweaked the suspension by using the program to find roughly where everything should be and the results are hard to deny. Good link.

Will

SLOroadster wrote: it would be great to stick a car on a rack where it would sit level and loaded (on the suspension) and actually plot this out with measurements to document for future posterity.

Will

I would also Like to do this or have the information.......I have some ideas to make it worse....LOL

fj20spl311 wrote:
I would also Like to do this or have the information.......I have some ideas to make it worse....LOL

Still trying to get those Bias ply tires to grab better? That whole radial tire thing is just a fad, it'll pass.

dbrick wrote:

fj20spl311 wrote:
I would also Like to do this or have the information.......I have some ideas to make it worse....LOL

Still trying to get those Bias ply tires to grab better? That whole radial tire thing is just a fad, it'll pass.

Bias ply tires can be loads of fun. I like running on a good set of Hoosier Street TDs.

Will

Got the springs finished today. Feels so much better. I think the roll center is good, it's not too low at all, and it feels pretty close to stock. I'll post a few pics later.

Urethane shock bushings = WIN.

Now I want STIFFER springs.

I need to find my 'before' pics...

Garm wrote:I need to find my 'before' pics...

Those wheels are awful! You should just send them to me and I'll send some Panasports your way!

J.K. wheels are hot!!!!!!

haha, never! They are my favorite thing about the car, except for driving it!

Garm wrote:I need to find my 'before' pics...

Page 6. Nice fit. road test results please

I really like the raw roll bar.

Rides really good, a little stiffer than stock, but a pleasant, crisp ride. The drop is just right, not too low to make handling suffer. Needs firmer shocks.

Once I get the rest of the suspension done, I'll go autocrossing and really test them.

meanwhile, I love Delrin. I use Delrin shift knobs in my other cars, and discovered that with the insert for an auto trans Yaris, the ones I have in stock ($30 from my online store) fit the Roadster perfectly.

I didn't like that the wooden knob has a rubber insert -- feels too mushy.

Not only that, you get about a 1" reduction in height -- a CHEAP short shifter!

Delrin has an awesome feel, many race teams use this material for shift knobs.
Delrin doesn't get hot in the sun -- no need for a sock or other covering.

I have Type R and Ball in black and white, Type R in black is shown here.
( I would like to see this installed in a better example of a Roadster, lol)

soft top hardware removed. 0.85 pounds
metal speaker box/speaker removed. 2.5 pounds
twisties/posties removed. 0.25 pounds
radio antenna removed. 1.15 pounds

Put a floor plug where the antenna was.



Large Object Inhibitor = mesh