Suspension 101 questions

[sambo]

Has the Excel spreadsheet on this forum been shared here before? Looks pretty handy.

Ozrodders.com • View topic - Coil spring rate calculator

Direct link here: https://www.box.com/shared/gcuutlsgbd

[justcobra]

Thanks Les for replying and would you kindly advise how the inner pivot is constructed for the front end.
Please advise the angles/dimensions together with the positioning of the inner pivot to the chassis.
I have sent you a email requesting the same.
Rx Stanley.
PS I have already got some pics as sent by yourself but now require the method of construction on the inner pivot and dimensional aspects as the caster is quite critical as to the driveability of the RMC.
You might have to check out your mates RMC in Qld.

[stephen low]

JC

Revisited the old photos and have thrown three up I am sure I originally posted.

To be honest I've no idea where I got to in the end but it worked when the car was on the road.

Hope these photos help.







Cheers

Steve

[justcobra]

Thanks for the three additional photos
It appears that the lower/inner pivot is unique or has to be manufactured and cannot be obtained from any P***y cat front end unless I am corrected.
Perhaps some constructors have opted or went down the path of sectioning a Jaguar front end and grafting it to the RMC chassis rails which eliminates the need of having special jigs to replicate the angles/caster and dimensions of the original jaguar front end.

Rx Stanley Kilmore Vic.

[stephen low]

The G Force and the RMC chassis were built to simply receive the standard Jag donor suspension parts.

If you are building a special you would need to replicate the same using Jag gear or the same using some other donor I guess.

You could use some of those fancy fully adjustable upper and lower arm sets that are coming out of the States but again the mounting locations would need to be carefully considered and located I guess.

One reason why I was happy for a kit that has had this work already done.

Cheers

Steve

[justcobra]

Thanks Les for the information on how the inner lower control arm is constructed using one inch tubing with a inner bolt being welded in place .
As expected this part is unique and has to be manufactured
As advised the rubber bush is then fitted giving the lower wishbone movement.
As to angles and dimensions one has to wait for this information when a hoist or pit is available.
I will extrapolate the information on hand with a Series 3 Jaguar front end already removed and apply it to the RMC.
In the meantime any other CC Forum members who can help it would be greatly appreciated as I want to get this right the first time.
Rx. Stanley.

[Rebel1]

Originally Posted by justcobra

Thanks Les for the information on how the inner lower control arm is constructed using one inch tubing with a inner bolt being welded in place .
As expected this part is unique and has to be manufactured
As advised the rubber bush is then fitted giving the lower wishbone movement.
As to angles and dimensions one has to wait for this information when a hoist or pit is available.
I will extrapolate the information on hand with a Series 3 Jaguar front end already removed and apply it to the RMC.
In the meantime any other CC Forum members who can help it would be greatly appreciated as I want to get this right the first time.
Rx. Stanley.

Stanley, The inner pivot bolt is NOT welded in place. The mount is but not the pivot bolt itself.

My comment regarding the inner pivot bolt not rotating has to do with design of the Jaguar lower arms. When assembled and torqued to spec that pivot bolt compresses the rubber bushes to the extent that any movement of the control arm is by way of flex in the rubber bushes not by the pivot bolt rotating.

Note the page in my gallery showing the series 2 jag lower control arm dimensions. It indicates an inner measurement of 225.3 - 225.81mm (say 225.5mm as nominal.) between the legs of the arm when the pivot bolt is torqued to spec. As advised the inner mount is 210mm long.

That leaves (225.5 - 210mm) = 15.5 mm/2 = 7.75mm to allow for compression of the rubber bush on each side of the mount. Also note that there are two serrated washers between the rubber bushes and the mount which take up some of this distance.

This is why the jaguar service manual manual advises that the lower control arm bolt is not torqued to spec ( 32 - 50lbf.ft) until the weight of the car is fully on the suspension.

[sambo]

I'm taking my Cobra to a proper suspension place after the local Bridgestone misaligned the IRS on the passenger side, causing the coilover to rub through a CV boot - don't get me started on that!

Just after some thoughts on what I'll call "aggressive street" settings, not full blown race as the car will spend 99% of the time on the road. Happy to cop a bit of extra tyre wear as it does so few kms.

After they correct any excessive bump steer, here's what I'm thinking:

Front camber -1.5
Front castor +6 (power rack)
Front toe in 1.5mm (3mm combined)
Rear camber -1.0
Rear toe in 1mm (2mm combined)

Does that sound pretty right for a Harrison?

[sambo]

Just located my snow gear for the frozen drive to the suspension place in the morning. Any thoughts on the settings in my post above?

[d488y2]

I have very similar settings to the above for my road car, HSV GTS, it handles heaps better then the stock settings.