The front end geometry that Jaguar spent lots money developing is fine for a Jaguar but is it ideal for a Cobra?

Don't forget the old XJ6 weighs nearly two tons and has a lot more weight over the front end than our Cobras (especially Dark Side powered ones :p ). It also has a lot longer wheel base. Narrowing the front cross member however may correct the ackerman angles with the shorter wheel base.

The XJ6 also has a lot of anti dive engineered into it's front suspension geometry. You can see this by the angles the upper arms are on. This may not be ideal for a light weight Cobra with a near 50/50 weight bias.

Factory Geometry may be fine for a Jaguar but a Cobra is a different animal and needs a different set of angles.

Cheers

Those Jag Bits...
 

I think that the Jag componentry has had its day.

It was very advanced when released and that it carried around so much weight should give us some confidence when it comes to to charging into a corner, but nowdays its getting a bit dated.

Its very fussy and I think there are definately better solutions out there.

Having said that I still like the look of it and since my car came with the bits then that decision is made.

(BTW - anyone know how to align one on a RMC???)

LoBelly

LB, RMC recommend the following:

Rear camber: 1/4 to 3/4 degrees positive
Rear toe: 0 degrees

Front camber: 1/4 to 3/4 degrees positive
front Caster: 3 degrees
Toe: 1/8"

However, as has been discussed elsewhere the Jag suspension in use under under the cobra needs some attention.

Some time back, when Mike Moyland still owned RMC, his chief engineer ( Jaime) advised me the following is a much better start point. ( with the series 11 RMC, twin vertical side rails) and tune from the following for personal preferance.

Rear Camber: 0 -1/4 degrees negative
Rear toe: 1/16 - 1/8"

Front ( this lot may not apply except to the series 11)

Toe: 1/8"
Camber: 3 degrees negative
Caster: 5 - 7 degrees

With the series 11, Jaime recommended the front top arms be relocated to remove all anti-dive by flattening them to horizontal. To do this the front mount bolt was moved to be horizontal with the rear bolt and both bolts moved towards the back of the car by 1/2".

This meant that an extension has to be welded to the top mounting plate and the rear section of this plate re-inforced by adding a backing plate.

In short, the top a-arms end up horizontal to the road and are 1/2 further back.

This does many things not limited to the following:

Allows more caster, makes the steering a bit heavier in car parks but improves straight line tracking on the highway.

Causes the steering to self center better, and allows the driver more feel of what the front is doing.

Allows for negative camber adjustment to the front suspension. Much better handling.

Removed some of the anti-dive which allows more weight transfer during braking.

Slightly moved both top arms inwards removing some of the bump steer.

The above, when used together with a spacer between the steering rack and
its mount( lowering the steering rack) will allow almost all bump steer to be removed.

With regard to the back end. Scotty (Ozvenom) makes a mod to the rear lower arm to allow easy toe adjustment.

Hope all that helps.

Cheers

Having said all the above...Further discussion with Scotty would be advised as he has done heaps of work on RMC's.

Scotty is an ex owner of an RMC and it handled very well I'm told.

Cheers

Struth

thanks Les :)

LoBelly

I'll have to certainly back Les on talking to OzVenom.

The Harrison my brother compaigns was bought from OzVenom(Harrison dealer), his expertise, fabrication work and enthusiasm enabled us to build a fantastic vehicle. For people here that do not know, it would currently be the most successful Cobra on the track in our club.

Just looking at National events - 1st Overall Nationals 2004, 2nd Overall Nationals 2005, 1st Overall Shelby Fest 2006. Scott is also responsible for fitting the hair dryer at the start of this year. And as usual, it will be driven to and from the Nationals - 2300km round trip. Now that's well engineered. And it would also be one of the cheapest builds in the club. I know my brother doesn't care whether he gets any trophies, it's all about the racing and enjoying the huge amount of fun that comes with it.