The time had come to return to the GD Mothership and have the ant-roll bar fitted and the suspension tweaked. It was dark and 2 degrees C when I left at 7am! 120 miles later it was time for a coffee and some fried slices of pig in a bun to warm up:
The journey was reasonably uneventful ending up at GD in the warm winter sunshine:
After a bit of a chat with Andy we set to work fitting the anti-roll bar:
It is a bit of a Chinese Puzzle fitting the anti-roll bar with the body on and necessitated removing the alternator to get it in. My advice would be to fit it before the body goes on. I originally didn't think I would need one - but once you get used to the levels of grip available you can't help but corner that bit faster and you'll soon find yourself needing one. And here's the man himself Andy Burrows hard at it:
You can see the anti-roll bar in the following photo - it's the black bar running just aft of the chassis top brace:
It is held in place by two clamp blocks - one each side - which allow the bar to rotate but hold it in position as shown below - this also shows the retaining ring which butts against the inside of each block to fix the bar transversely:
The anti-roll bar is connected to the lower shock mount by a rose jointed drop link:
I knew I should have painted the track rod ends!! The lower end of the drop link is connected to the lower shock mounting bolt by a threaded extension:
The extension piece is of a much larger diameter to provide a large bearing area onto the shock mounting bracket to accommodate the leverage forces. At the top the drop link is bolted directly to the arm of the anti-roll bar:
At the moment the outer hole is being used. If the inner hole is used then this will increase the effective stiffness of the anti-roll bar by around 15%. You will need to grind away the return on the inner wing to provide clearance for the connecting bolt - you can just make this out in the photo.
After everything was put back together it was time for a test drive. After some rudimentary checks of wheel cambers Andy set the dampers to mid range and off we went. It was quite strange sitting on the "wrong" side of my car whilst someone else drove it.
What happened next can only really be described as astonishing. Andy drove the car much faster than I ever had (and probably ever will) although it never felt out of control. After a brief stop to twiddle with the dampers following slight front o/s lock up we continued at an increased pace. I am ashamed to admit that on more than one occasion I felt my right leg twitching for the "ghost" brake pedal on my side of the car!!
It certainly was an eye opener to see how fast a skilled driver could drive the car relying on the feedback he gained from the car. It was also comforting to be shown what the limits of your car are as it then gives you a yardstick to measure how close you are to (or far away from!!) them with your own driving.
The verdict upon our return was that it was now probably "95% there". Having had a quick blast myself I had noticed an improvement, particularly with respect to roll. Andy did say that I probably wouldn't notice a marked improvement as it wasn't "a million miles out" to start with.
Andy left me with a small list of things to do when I got back:
- Increase tyre pressures to 23 psi front and 22 psi rear - I had reduced the tyre pressures as a result of having overdamped the car - the overdamping was due to trying to control roll by damping as I did not have an anti-roll bar fitted.
- Check the bumpsteer as there was slight effect noticeable - You will remember from previous posts that I could not eliminate all the bumpsteer as I had run out of adjustment on the steering rack mounts.
- Reduce the Castor angle - this will reduce steering effort and will drop the height of the front of the steering arm - this should bring the steering rack back into the range of adjustment to eliminate all the bump steer. I had deliberately set a high castor angle to ensure self centering at SVA which can be a problem with new (stiff) steering components.
- Slightly increase the negative camber of the rear wheels to improve corner entry - a bit of a faff to do this one but Andy reckoned it wasn't desperate and would make a nice "winter job". I had set the rear cambers as per the build manual - but the final setting depends upon actual ride height/damping plus the feedback Andy got from driving the car.
All in all a good day and a fantastic experience having the man behind the car actually drive the one you've built. I was also quite pleased to hear that I had "screwed it together properly".
The drive back highlighted a car with a different character - It felt more compliant than before. It is interesting to note how drastically I had overdamped it. Originally I had the rear dampers on 9 clicks - they were now on 8 and I had the front dampers on 7 they were now on 4!! The car felt much more planted and less skittish - as you might expect from reducing the front damping. I also noticed the slight bumpsteer effect which I hadn't really noticed before - probably as I had artificially limited the front suspension travel by running too much damping.
So a few jobs to do. They will have to wait to next week as I'm away this weekend.
Oh...... and my new rocker cover gaskets did the job!
