The Vauxhall Nova rally cars had what you suggest done Daved. They were similar to the mk2 / 3 golf style with the open end section at the front.
If Vauxhall/GM did it, I don't want to know. They had to buy Saab to make their cars handle. And, they still don't handle as well as a 1969 Saab 99!
I read somewhere about a touring car axle where they added / took away plates from the front open section of a beam to alter its bending characteristics - see if I can find the article.....
That would be very interesting. Also, consider this. Back in the day a lot of racing Minis switched to a straight beam rear axle. The very successful Audi 80 GTs used a straight axle. As did Saab on the 99s. They all used Panhard Rods and Trailing Links. I think?
That's an interesting point Mike. I've listened to seasoned racers saying why they stand rear wheels vertical to lose grip. Which is right? I suspect it depends on spring rates and body roll. Soft rates and a leaning car will have the rears on the outer edges. Seen it done - crude, but it saves fitting a roll bar.
Driving style and personal preference are bound to be a factor too. I've been encouraged to experiment that way, but I like the car safe and relatively understeery, as I need to drive it home at the end of the trackday
In set up, indeed (ref driving style), but the point I was making was that to reduce grip at the rear end, some racers definitely stand their rear wheels up vertically.. (which counters the point you were making) whilst a lot of camber would appear to do the same if the car doesn't roll and the car never uses the full tyre footprint. I really mentioned that to see what others would say as it's an interesting point (+ confusing to visualise), and surely if it works both ways, it's got to be down to springs?
You sure Dan? I was well into Novas and still have the Gp A Harry Hockley Motorsport build manual but don't remember a fully enclosed beam. I know they had the lower damper mounts sunk into the beam to give more strength and longer stroke on lowered cars - as I had a Gp A beam on my SR.
I was not referring to the works Vauxhalls, merely several competitors that used Novas in clubman rallying, forest and tarmac. The rear beams were prone to flexing / bending and plating them was seen as a good way to help reduce these effects and also improved handling to reduce understeer characteristics as a bonus. (presumably down to the rear being stiffer) The cars were also converted to coilover rear struts instead of the std springs sitting on trailing arm layout as std. I reckon all the pros and cons of this axle triangulation stuff will ultimately be down to trial and error, as well as driver preference in handling characteristics. Most seriously built cars will have full weld in multipoint cages allowing next to zero shell flex, which then means that the suspension is ever more important as there is no compliance in the shell. Know a lad that has two race cars, one full weld in cage and the other bolt in. In the wet all the full weld in cars cannot look at the bolt in one. Identical suspension setups (fully adjustable) on both. The bolt in car must allow a degree of flex and compliance giving more grip than the rigid shelled cars that lose traction sooner. Swings and roundabouts. IMO. And being in the UK means that it will rain for 50% of the meetings in a year.
I was making an assumption that these were stiff-sprung lightweight racers with little body roll (at least in a dry setup) so fair point, Chris, and worth stating my assumption more clearly. Next time I catch up with the people concerned I'll see what more I can find out. It would be interesting to know what Geoff Thomas has to say about it too.
There are many things common to the Nova, especially on Mk1/Mk2s...I must admit I didn't know about bracing the beam...but adding rear negative camber in order to make the rear more mobile was accepted - it turns out I was chatting to Chris Eyre regarding this very subject at Castle Combe back in 1996! Rear negative camber and toe out, I ran. Anything to get the damn understeering chariots to turn in! I did know about that...I never bothered though. Opel Ascona fronts in the rear of my Nova!
Yes the same driver. He has two cars and rents one and drives one. There have been occasions when he has been beat by renting out the wrong car! The various folk that use both cars have been racing for a good while, and they all agree that the bolt in car is better in the wet. Both cars dyno out the same as near oem spec, but with airfilter and exhaust. Same Dunlop wets or slicks depending on conditions, same geometry, suspension and spring rates etc.
the very first line of the tread ''Berg Cup build in the members section''. does anyone have a link for this? I've tried searching and I can't find it. I'm interested in more details, front wishbone (tubular from rear pics) and spacers arches etc. Please and thank you.
http://www.clubgti.com/forum/showthread.php?p=1726624 You just click this after the person's name in the quote ">" - it takes you to whichever thread the quote is from, and you just keep going (provided the quote is post-March 2010 when we had a software upgrade).
Triangulated rear beam and toe/camber effects On the question of rear triangulation etc. I am planning a few tests at the start of next season on my car. I have a triangulated rear beam on my MK1 inc. an Eibach roll bar, Gaz coil overs checked stopped at ride height, polybushed etc. and have played with heavy springs (750lb) and lighter springs (350lb) this season and but as yet come to no conclusions. My car is an ex circuit car and when I first had it it had 3.5 degrees of negative camber and was toed out by about 1.5 degrees at the back. I was assured that whilst twitchy this was the quickest way around a race track. I found it a bit too twitchy in testing (for my driving ability!) so took the toe out of it but left the camber. What I have found is that with the softer springs it's a more drivable in the wet but in the dry doesn't turn in quick enough with the soft springs. I'm in the process of fabricating a rear toe and camber adjusting system like the works MK3 cars so I can play with camber and toe easier than shims. The argument is that with a good front end the need for a loose back end becomes less important as the car will follow the wheels under power but with a std type front set up (i.e. no plated diff or rose joints/tubular wishbones etc. ) then the need to make the back end loose is more important. As far as I can see it's a trade off, on a fast sweeping bend, where you are not hard in to the throttle, than a sticky back end!! is desirable but on twisty/tight corner you want a loose back end to get it round and follow the front wheels. As I said it's my intention to modify my beam to make it adjustable (and sort the front end) so hopefully I can report back early next season and see what is what. I know what I think but other people have different views so it's interesting to actually see what happens. Having said that I hill climb and sprint so my needs are not quite what a circuit racer wants but still it will give an idea what affects what.
Just doing this to my Mk1 polo rear beam. What size rod ends have people used in the past? m10 or m12? Cheers
