Postby Hasbeen » 14 Oct 2021 16:28
If you are going racing, & the tracks are near billiard table smooth, there is not much wrong with the stiff springs approach. However for general road work, on average roads, it is a very poor way to go. A little story about roll bars.
In the late 60s in Oz we had 3 categories of serious open wheeler racing, plus Formula Ford & Formula V as training categories. We stayed with the previous world championship 2.5L for our F1, when Europe went to 3.0L. Superseded cars came cheaper. We had our Formula 2, which was really a rewrite of your Formula Junior, 11cc engines from a homologated road car, with much tuning, & Australian Formula 1,5, basically current world F2 with 1.5L engines, basically the Cosworth 1.5 twin cam.
My F2 in 1967 was the oldest Brabham still in one piece, being FJ 3 62. I bought it without an engine. A mate & I upgraded it to close to 1965 standard, & built an 1100cc Ford Anglia/Cosworth engine for it. It had all the good forged bottom end, with an Anglia block & head bought from a wreckers & developed by us. We made our own manifolds very similar to the Cosworth stuff, & had a locally developed cam.
On the dino I had similar power to the best Cosworth 1100cc engines, with it coming in just a little lower in the rev range. We were more than chuffed by that. In it's first race at Warwick Farm, a premier circuit I broke the 5 year existing lap record in the first race, & the top driver in the category broke it by a little more in the next. We had done a lot of work on the suspension, & it was running softer springs, but stiffer roll bars. A little under 2 years later I had knocked 6 seconds off that record.
But this is a story about Bathurst & roll bars. Bathurst was getting very rough by this time. I was getting cracks in the front fenders of my Morgan +4 from the bolt hole fastening them to the stay from the front subframe each time I raced there. Knowing this for the 66 F1 feature race to which I was lucky enough to be invited, I softened the springs even more, by about 12%, & stiffened the roll bar settings.
The field was about half F1s of varying age plus mostly ANF 1.5s & a 3 of us tiddlers to make up the numbers. People were amazed at my cars performance. I could drive around some of the ageing Brabham Climax on the faster corners. I made the third row of the grid. Even better I finished 3Rd outright.
Amazingly I repeated this the next year 1967, again taking 3Rd outright in my little 1100cc Brabham.
The next year I had won an F1 drive in a Brabham Repco. Repco being the engine builders using specially cast for them, Rover V8 blocks. They won 2 world championships for Jack, & supplied some 2.5L versions for us in Oz. I convinced the owners top soften the spring rates in that car, & won the race. I was a bit lucky. The stiffer spring rates on the car of the driver who probably would have beaten me caused the top of a rear upright to break off just above the axel bearing.
The 4.6L Tr8 had 200Lb springs when we bought it. I changed them to 140Lb springs, not being game to go any softer. My son likes it that way, so I have left it. It does not handle as well as the Tr7, which has the original springs, on our Oz country roads. I had them retempered to full factory rating when I had the 30% stiffer roll bars made, while building the car. It easily out handles the 8, but to be fair, the 8 is a drop head, which probably reduces it's cornering ability as much as the stiffer springs.
Hope you find this useful.
Hasbeen
Last edited by
Hasbeen on 15 Oct 2021 04:07, edited 1 time in total.
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