How "stable" is your car on the open road???

[NASSTY]

The best arrangement would be to have the trailing arms mounted in line with the inner pivot rod and have both ends rose jointed, effectively turning the lower control arm into a wisbone and no binding issues. From memory Python Cobras do this from what I saw but the trailing arm is mounted behind the diff instead of in front of it.

[Rob. Smith]

I decided to lower the whole drive train,the floor and the seating arrangement. This resulted in a zero degree(horizontally) alignment of the tail shaft. Seats that leave you below the windscreen, seatbelts that stay on your shoulder and no room for trailing arms. I bought a set of Watts Links from Ken Karcevski from Cobra Craft,Peakhurst, Sydney and this set-up is fully adjustable. It is retrofittable but I changed this whilst the car is in bits.
The alignment has yet to be tested at speed, but being spanner adjustable I'm probably in for a bit of fiddling.

[Plums]

I painted up my new arms (thanks Harrmac) and had them ready to install. I pulled off one side (I thought I'd better check them before I go putting it all back together) and they are identical to the arms I already have.



This means that I basically have the maximum amount of Castor available, and that's with the offset arms. If I had to use symmetrical arms I would only have about 1 - 1.5 degrees

I think after rego I'll need to do some front end "re-engineering"....

[Rebel1]

Bobby, are your lower arms series 11.

The series 1 lower ball joint is 1/4" further back than a series 11.

Or......

If series 11 lowers, do you have them on the correct side of the car.

The lower ball joint stub on a series 11 should curl forward....not back.

Cheers

[Plums]

The lower arms seem to be correct, i.e. if you swapped sides I think you'd end up with no castor.

Rob from G-force reckons that 3 degrees of castor is enough, but I want more!!!

[Rebel1]

I know where your coming from Bobby.

I moved my top arms back 10mm and took all the anti dive out of them. (ie. they are now parallel with the lower arms.

cheers

[400TT]

Originally Posted by Rebel1

I moved my top arms back 10mm and took all the anti dive out of them. (ie. they are now parallel with the lower arms.

That's also what I would like to do after getting advice from Rebel1 & OzVenom.

[Rebel1]

Craig, I'm sure Scotty will get that RMC of yours cruising like a limo with perfect manners.

A lot of the info I have came from Jaime Garde who was the employed engineer at RMC.

His job involved improving the RMC chassis by experimentation with their race car.

I believe the then owner of RMC, Mike Moylan, was involved in motor sport and competed in Targa Tasmania a couple times with the cobra.

However, the handling improvements never made it to the production Jigs mainly because the business was put up for sale.

Cheers

[stephen low]

Bobby

Have a look at my alignment figures again. Yes all I have at present is 2.3 - 2.4 degrees castor but look at what he achieved on the left side with the before figure about a degree increase.

I believe he manipulated the upper pivot shims to help increase the castor as I already have the three shims in front of the upper ball joint on my S1 uppers.

So for me it would be reversing the uppers with the shims to the rear of the ball joint to reduce the increasing rearward castor by this swap. However A Mike inadvertantly did this and I think he said he had about 9 degrees and needed superman arms to muscle the wheel at all.

Happy tinkering but do let us know what you do and the result.

Cheers

[Plums]

But if I reverse the uppers and swap the shims to behind the balljoint, I'll end up reducing castor and making my problem worse....

[Rebel1]

There is a way of getting another couple of degrees without surgery.

It does however depend on how your lower arm pivot is fitted.

On the RMC ( and standard on the jag) the lower arm has a surrated washer fitted to the inside on the wishbone. ie. they fit on the inside of the wishbone bushes against the bracket thru which the pivot pin fits. There is one front and back .

If you remove the front one and put it to the back you'll gain about 1/8" movement forward of the lower arm.

The installed distance between the inside of the lower arms is 8.88". However, some kit manufacturers make the pivot bracket length such that you don't use the surrated washers.

I have also seen some instances where the washers were supposed to be used but the builder neglected to use them. This causes the lower wishbone arms to be compressed when the lower pivot pin is tightened to recommended 32 - 50 foot Lbs. Measure the distance between the lower pivot arms when installed and torqued up. If they are less than 8.88" then your lower wishbone is not installed correctly.

The other "trick" is to install your lower pivot bushes off center moving the arm forward.

[Harrymac]

Well done Rebel1, that is thinking outside the square, I like it.
It's amazing what 1/8th of a inch can do, I would never have thought of that.
Harry.

[Rebel1]

Thanks Harry, but it is something I really don't like.

The reason being that it loads up the shocky bushes.