Lower Track Control Arms

[black eclat]

So we all know the suspension design on the front of our Elites and Eclats but have you ever thought that the steering feedback and the ability of the car to travel straight over a bumpy road could be a bit vague?

Here in Ireland most of our road tax is spent on everything except road maintenance so the lesser B roads can be far from smooth. Living in a rural area, I always though that this was the case, especially when taking advantage of Mr Plods absence and making some "progress" on the journey.

I fitted uprated poly ARB's but these take a fair hammering and my heavy right foot and tendency to cover a lot of track miles dont help.

 

 

I have replaced all the bush's on both the top and bottom arms and this helped but I always though it could be better.

 

Enter some research and I discovered that Spyder Cars did some modified front wishbones that were triangulated which could be used by welding some brackets onto the existing chassis.

 

 

This encouraged me to have a go at making a modified arm that could be tested but also be fitted with an easy "return to normal" route in case it went south.

 

The design idea was to fit a plate that would join both arb mounts and extend out in line with the lower pivot bolt. From here a new mounting would be welded to the plate in a position so that it was directly in line with the lower pivot bolt. I then used a rear control arm cut and angled so that it bolted into the new mounting and raked rearwards to connect to the lower suspension arm just inside the shock mounting bolt.

 

This created an "A" frame lower arm which I hoped would improve the handling and feedback. The whole set up was checked unladen with no spring to ensure no fouling or tight spots for the range of suspension travel.

 

 

 

I put it all back together and took to the track. There is no better testing ground than a good race track and I am fortunate to live a short 7 miles from Southern Irelands only Intenational ractrack, Mondello Park.

 

So, the outcome?

I would normally get 2 full days of track action from my Wilwood pads but on this occasion, I had worn out 1 set of pads by the end of the day. The car felt stiffer, I could certainly leave my braking later which in turn gave me faster corner entry speeds. I still had to wait for weight transfer before applying power to exit but all this seemed to happen much earlier and much quicker than before. I say "seemed" because it was impossible to anything but concentrate on the next approach and braking points. An 8 lap stint at a time was as much as I could do without getting raggy and losing control.

And the conclusion?

I think its better but I have no automotive qualification or mathematical equations to verify its design. So I open it to the floor, What say you?

[StevenD57]

That sounds like a cool mod. Quite original thinking there.

Any chance of getting some higher resolution photos of this? The small low res photos that are available from this forum are too small to make out details.

Some photos of the whole plate between the antiroll bar mounts and a close up or two of the new control arm mount on the end of that plate would be useful as well.

 

Thanks for sharing this idea.

[Dunc]

It does look clever.

 

As you know, those little bushes on the end of the ARB take an absolute pounding under braking, and whilst light is always good, an extra bit of tube like in your design wouldn't have gone amis.

 

hat well and trully doffed!

[Denis247]

That sounds like a cool mod. Quite original thinking there.

Any chance of getting some higher resolution photos of this? The small low res photos that are available from this forum are too small to make out details.

Some photos of the whole plate between the antiroll bar mounts and a close up or two of the new control arm mount on the end of that plate would be useful as well.

 

Thanks for sharing this idea.

As the op stated, Spyder did this some time ago, and their Donington frame was equipped to take their optional lower control arms from the outset. I don't know if they offered this on their standard chassis, I was only interested in the Donington.

I never bought the optional arms from Spyder and, like the op, fabricated my own.

This was all many years ago, (I've had the car since 1982 ish), and I find my ar bar bushes last much much longer, although I use poly, and I've no complaints about the handlling.

[StevenD57]

Yes, but the original poster did this WITHOUT the special donington frame or any spyder parts so he would have better pictures to share with the rest of us.

[black eclat]

All this was designed on the back of a sweet wrapper, so there are no drawings or blue prints. I have the luxury of a 2 post lift so once the car was elevated and the components removed, I spent a few days with a welder and some material to determine what could be made, while being reversible, that provided some form of triangulated lower suspension arm.

 

It turned out I had 2 spare rear suspension lower link arms that were the correct length and could be modified to become a track control arm.

 

I will take some more detailed pictures over the weekend and post up for you to examine.

 

@Denis247, its interesting to read that you did a similar modification with no reduction in performance and extended ARB life. I too have fitted Poly bush's and now find the steering and suspension very responsive on any surface.

[Denis247]

All this was designed on the back of a sweet wrapper, so there are no drawings or blue prints. I have the luxury of a 2 post lift so once the car was elevated and the components removed, I spent a few days with a welder and some material to determine what could be made, while being reversible, that provided some form of triangulated lower suspension arm.

 

It turned out I had 2 spare rear suspension lower link arms that were the correct length and could be modified to become a track control arm.

 

I will take some more detailed pictures over the weekend and post up for you to examine.

 

@Denis247, its interesting to read that you did a similar modification with no reduction in performance and extended ARB life. I too have fitted Poly bush's and now find the steering and suspension very responsive on any surface.

Yes, Lotus used the ar bar also for lower link location, something the mod addresses, making it just act like an ar bar again.

 

The original design didn't locate the lower link that well anyway, as evidenced by the wear on the bushes, and put extra work on the inner bush of the lower link as well.

 

This mod, im my opinion, is well worth doing, almost as much as the rear suspension top-link mod.

 

Yes, but the original poster did this WITHOUT the special donington frame or any spyder parts so he would have better pictures to share with the rest of us.

It's really not that hard to work out for yourself if you look at it.

Edited December 12, 2014 by Denis247

[black eclat]

 

 

This mod, im my opinion, is well worth doing, almost as much as the rear suspension top-link mod.

 

 

 

Please tell me more.

 

Is this the mod to link the 2 rear inboard lower link pivot points?