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How To - Tips => Steering / Suspension => Topic started by: MufasaCAT on May 26, 2015, 04:28:17 AM

Title: C4 Spindle Model
Post by: MufasaCAT on May 26, 2015, 04:28:17 AM

Hi guys
Still building my car - its a loooong time project.
I'm looking for a C4 spindle Cad Model or drawing so I can check my suspension.
Cheers
Peter

Title: Re: C4 Spindle Model
Post by: plans4sale on May 26, 2015, 08:51:12 PM

 The upper A-arms should never be in this reversed position when in a neutral position (car not moving or loaded). Instead, they must be either horizontal or slightly raised from the wheel side.

Title: Re: C4 Spindle Model
Post by: MufasaCAT on May 28, 2015, 05:08:02 AM

Thanks guys

Title: Re: C4 Spindle Model
Post by: 76mx on May 28, 2015, 10:19:07 PM

P4S is right, those upper a-arms slope the wrong direction. I thought I knew a little about chassis design, and I will quickly concede that GM knows more about it than me, but that diagram seems to go against everything. Follow the arcs of the two ball joints and it is easy to see that it is gaining positive camber at the exact time that it should be gaining negative. What am I missing here? What is wrong with this picture?

Title: Re: C4 Spindle Model
Post by: MufasaCAT on May 30, 2015, 03:03:38 AM

Hi Jim
I don't have a real problem as such but I'm ready to do my steering rack and a c4 CAD model would be useful to check bump steer. Rules in New Zealand are pretty tough in that you have to prove everything.

Just realised I need C5 model not C4 (Too many late nights) sorry guys

Title: Re: C4 Spindle Model
Post by: Graeme Stebbing on May 30, 2015, 05:34:28 AM

Hi Mufasacat, What car are you building, is it a Diablo, I used to have some pics from many years ago of a Diablo build here in NZ the frame was in a workshop with lots of equipment painted blue is this your car, I am up in Northland,  I can help with the suspension I have the Diablo manual and have modeled it in Suspension analyzer, Its great to find another Kiwi on here.

Title: Re: C4 Spindle Model
Post by: MufasaCAT on May 30, 2015, 06:25:00 AM

Thats me!
It has been a really long project. Had to stop building the car due to financial problems brought on by no fault of myself. Almost lost my house.
Times are good now so back into it with fall steam.
You say you have done the testings with the steering rack? I would be very interested with the results. What sizes of steering rack and position.
Thanks

Title: Re: C4 Spindle Model
Post by: Robert on May 30, 2015, 07:12:12 PM

http://lamboclone.com/index.php?topic=2236.0 (http://lamboclone.com/index.php?topic=2236.0)
Here is a link to my chassis, it has c4 front control arms.

Title: Re: C4 Spindle Model
Post by: 76mx on May 31, 2015, 01:11:08 PM

MufasaCAT,
   Follow the drawing for the rack and pinion and your bump steer will be dead on. Notice how the inner pivot point of the bottom a-arm is directly below and in line with the R&P joint. Notice how the R&P tierod and that a-arm are parallel with each other. Notice how a line through the outer two ball joints projected to the ground plane and a line projected perpindicular down to the ground plane from the steering knuckle both hit the ground plane at the same point. The bump steer on this model is well done, it is that top a-arm that has me baffled.

Title: Re: C4 Spindle Model
Post by: plans4sale on May 31, 2015, 02:50:48 PM

 The suspension geometry at that drawing is completely wrong. Any car roll will result in a dangerous contact of the tyre patch with the road surface. Check it with this suspension simulator:
http://vsusp.com/#0.8%26project_name%3Adefault%20values%26trim{body_roll_angle%3A0 (http://vsusp.com/#0.8%26project_name%3Adefault%20values%26trim{body_roll_angle%3A0)|front.left_bump%3A0|rear.left_bump%3A0|front.right_bump%3A0|rear.right_bump%3A0}%26front{frame.susp_type%3A0|frame.bottom_y%3A9200|frame.center_to_upper_mount_x%3A28500|frame.bottom_to_upper_mount_y%3A24000|frame.center_to_lower_mount_x%3A17000|frame.bottom_to_lower_mount_y%3A2400|control_arms.upper_length%3A24800|control_arms.lower_length%3A37500|knuckles.hub_to_upper_x%3A15000|knuckles.hub_to_lower_x%3A13000|knuckles.hub_to_lower_y%3A13000|knuckles.hub_to_upper_y%3A13000|knuckles.hub_to_strut_axis%3A14000|knuckles.strut_incl%3A8000|wheels.offset%3A4000|wheels.diameter%3A1500|wheels.diameter_expl%3A35000|tires.size_convention%3A0|tires.section_width%3A19500|tires.aspect_ratio%3A4500|tires.diameter_expl%3A50000|tires.width_expl%3A7620|tires.compression%3A0}%26rear{frame.susp_type%3A0|frame.bottom_y%3A9200|frame.center_to_upper_mount_x%3A28500|frame.bottom_to_upper_mount_y%3A24000|frame.center_to_lower_mount_x%3A17000|frame.bottom_to_lower_mount_y%3A2400|control_arms.upper_length%3A24800|control_arms.lower_length%3A37500|knuckles.hub_to_upper_x%3A15000|knuckles.hub_to_lower_x%3A13000|knuckles.hub_to_lower_y%3A13000|knuckles.hub_to_upper_y%3A13000|knuckles.hub_to_strut_axis%3A14000|knuckles.strut_incl%3A8000|wheels.offset%3A4000|wheels.diameter%3A1500|wheels.diameter_expl%3A35000|tires.size_convention%3A0|tires.section_width%3A19500|tires.aspect_ratio%3A4500|tires.diameter_expl%3A50000|tires.width_expl%3A7620|tires.compression%3A0}%26pref{diag1.px_per_mm%3A200|diag1.front_or_rear%3Afront|tab.active%3A0|units%3A0|show.f%3A1|show.ca%3A1|show.k%3A1|show.w%3A1|show.t%3A1|show.rc%3A1|show.ic%3A1|show.fvsa%3A0|show.tl%3A0|show.kpil%3A0|redraw_during_drag%3A1|chart.x_axis_center%3A0|chart.x_axis_window%3A10|chart.x_axis_num_steps%3A21|chart.x_axis_field%3Atrim.body_roll_angle|chart.y_axis_fields%3A[FR].general.roll_center.y}

Title: Re: C4 Spindle Model
Post by: Robert on June 01, 2015, 12:54:55 AM

Your very good plans!

Title: Re: C4 Spindle Model
Post by: 01Lambiero on June 03, 2015, 12:01:17 PM

Like 76mx said, tie rod parallel to lower A-arm.