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Title: Suspension tuning for 1981 Beta Coupe US model Post by: Radical Racing on April 19, 2011, 04:46:27 PM I need some advice for setting the suspension on my 1981 US Beta coupe. First the particulars:
Lowered using custom coil over shock absorbers on all four corners 15 x 7 Rota (minilite style wheels) Toyo Proxes RRA1 tires 205/50ZR15 1" spacer used to widen rear track Beta Boyz orange urethane bushings all around. I have never set up a car to road race before. Don't even know where to start in terms of toe in/toe out, caster, camber etc. Any advice would be greatly appreciated. Todd Title: Re: Suspension tuning for 1981 Beta Coupe US model Post by: MattNoVAT on April 19, 2011, 07:01:55 PM When setting up from scratch I would go for setting the toe & camber as a standard car and then modify based on handling/feel. And of course what results for looking for, i.e. more stability/grip on fast cornering. (This is what I did with my first kit car)
Others will certainly be able to pitch in more.... Title: Re: Suspension tuning for 1981 Beta Coupe US model Post by: 75coupe on May 16, 2011, 10:05:34 AM Todd
I have done circuit work and hillclimbs and so far have done: 2 degree neg camber front 2-3mm toe out front Caster I have left STD (about 1.5 degrees) but want to try about 3-5 degrees to see if improves grip in tight turns. I am using Toyo R888 205/50 x 15 semi slicks. Regards Ian Title: Re: Suspension tuning for 1981 Beta Coupe US model Post by: Radical Racing on May 17, 2011, 12:36:24 AM Ian: Thanks for the information on the front set up. I'll definitely start there.
What about the rear setup? I noticed lanciamad, fabricated some adjustable links for the rear suspension of his car. So it seems important to him. It appears that US spec Betas have semi adjustable links at the rear. I might replace these with a custom made rose jointed links. Have you or have you thought about adding the adjustable plates to the top of the front end strut towers? Lots of X19 racers do that here in the States. Todd Title: Re: Suspension tuning for 1981 Beta Coupe US model Post by: 75coupe on May 17, 2011, 12:49:18 PM Todd,
Sorry forgot about rear setup. All is standard at present, std specs are toe in 2-5 mm, 1 degree negative camber. My transverse links are adjustable tubular early type (my car is 1975 model), later models used different pressed type non adjustable links, with offset bottom bolt to adjust toe. My car uses betaboyz lowered springs, poly bushes and spax adjustable shocks all round, and have no complaints about shocks, although springs need to be stiffer for circuits, good for hillclimbs with slower turns and more bumps. Even at 125 mph shocks still good !!! Coilover setup needed for adjustability and to lower the car more. I am planning using some camber plates/adjustable top mounts in the future, as I want to get rid of the rubber top mount on the strut. I believe Ford Escort and Mazda RX-7 gen2 ones can be made to fit easily - see other posts in this section "adjustable top mounts" I have found traction out of corners can be a problem - inside wheel spins, I am planning an LSD in the future. Can you post some pics of your coilover setup? Would be very interested in what components are used. Regards Ian |