I'm looking to troubleshoot a few problems with our 1380cc A-series racing car and was hopeful that some of you could give some solid advice before I go and blow a load more cash on the car...
As the bodyshell was from my first ever road car, it was paired with some 13x7" superlites that 17 year old me thought were the dog's dangly bits. As we had these wheels already, we've utilised them on the car in its current racing guise with Yoko A048R rubber. We've had a bit of a problem with the tyres rubbing on the Grp6 arch extensions (mainly on the rear) so were looking to raise the position of the arch extensions. However, I'm now wondering if it's worthwhile ditching this idea completely and switching to 10" wheels and not having arch extensions at all (similar to the App. K historics with the chrome finishing strip and nothing else). My question however is, with a Mini, is there such a thing as too much grip? I guess the general rule-of-thumb is that the more grip you have the better (up to a point), so would I be shooting myself in the foot by switching to a smaller/narrower wheel/tyre combo? I know there are benefits with regards to the "feel" of the car and the driveability, but from a sheer speed-of-cornering point-of-view, which wheel diameter/width combination would be best? Are 12" wheels even something to consider? It would also be great to have a wheel size that allows us to have a dedicated wet tyre fitted to it. The other problem we've encountered is that when we try to stiffen the Gaz dampers, the car literally becomes undriveable with the LSD dragging me all over the place and the car hopping/bouncing around corners. Possibly a symptom of having wheels that are too big?
We're currently running with MG Metro Turbo 4-pots but from a previous post from Cooperman (the oracle) he reckons that the 7.5" Cooper S setup is just as good provided you have some decent pads in there. Any other opinions floating about? Obviously if I change to 10" wheels then I'll need to switch the current setup out anyway.
As previously mentioned, we're running with Gaz shocks. Gaz advised that 8 clicks from the softest was a good starting point. We've tried stiffening them up but the car really didn't like it (as mentioned in the Wheels section above). We're now back at 9 all round but I was wondering if there's a train of thought regarding splitting the stiffness and perhaps having softer on the front and harder at the back or vice versa?
As mentioned, we're running a 1380cc with a single Weber 45, Salisbury Plate type LSD, 3.9:1 final drive, 296 scatter cam, ported/polished head with 35.7 inlet valves and 31.0 exhaust valves. It's pushing out 102bhp at the flywheel but I seem to be getting dropped quite considerably on the straights by an MG Midget which their builder tells me is pushing out 135bhp. I absolutely trust that our engine builder knows his stuff as he has about 50 years of experience but he's a specialist in twin-cams and maybe doesn't know the little tricks of the trade to get every last drop out of an A-series. I know that the Midget is using a different cam (possibly a 649) and possibly split 40s but how much of a difference could that make? I read an article by Keith Calver saying that every engine he'd driven with a 296 scatter cam was a "complete dog" so maybe that's where we've gone wrong? Anyway, the only variables where I think the problem could lie is in the cam selection and the final drive as I'm certain that our man will have nailed everything else as far as the engine build goes.
We're literally putting 35psi in all 4 tyres and sending it out so any advice on general rules-of-thumb would be very well received!