Beta Coupe Weight Bias?

[KeppelmanJ]

Anybody know from weighing wheels/corners or reading specs what the Beta weighs front to back? The Fulvia coupe/Zagato weights fully twice at the front wheels what it weighs at the back, about 1250 to 650 pounds.

[Charley]

According to Road and Track Magazine's April 1976 road test of the Beta Coupe the front to rear weight distribution is front-62% rear-38%.The curb weight is 2485 lbs. so with my calculator I came up with front=1540.7 lbs. and rear=944.3 lbs. BUT I AM NO MATH GENIUS.So I could be totally wrong. :confused:Anyone care to verify?

[1,6 HF]

I see John's been following the V-L Fulvia thread. Charley's calcs are correct, and I can't say I'm surprised at the front/rear distribution, which is virtually identical to the Fulvia coupe's. FWD coupes tend to have virtually the same front-end weight as their sedan brethren, but less weight at the rear (less sheet metal, less glass, &c.) and therefore a fairly significant front bias.

[KeppelmanJ]

Thanks, Charlie, for the info. I guess one Betas bias advantage is that the engine is transverse so that it's is not so far forward of the front axle. Having driven both the Beta and Fulvias on the same tracks I've wondered for ages why the Beta handled better when pushed in fast corners, understeers less. I guessed it had to do with more even distribution of weight. Of course the Fulvia I drive is a race car (130 hp/1850 lbs) and has better power to weight ratio, but still the issue in a fast corner if both cars enter the corner at the same speed is if each car can track around the corner without running wide. The Beta is noticeably better at that. The chassis is stiffer with the Beta too and that may be a factor. Ed, I'm not aware of the Fulvia thread you mention. Can't seem to find it either. I haven't figured out how to get back several threads into the Fulvia forum. I'll look again.

[1,6 HF]

John,

Having owned Beta coupes as well as the Fulvia coupe I run now, I'd completely agree with your assessment that the Beta is more stable through sweepers. The Fulvia is more agile, but certainly less neutral through fast turns. It's not, however, due to weight distribution; it's mostly due to the Beta's more sophisticated rear suspension.

BTW, the Fulvia weight / weight distribution discussion in on the Viva Lancia Fulvia Forum, about halfway through the "Spring stiffness" thread. http://www.viva-lancia.com/lancia_fora/list.php?f=10 The standard coupe is about 61/39, while the HF is about 63/37--virtually identical to the Beta coupe.

[KeppelmanJ]

Ed, you may be right that the Beta's rear suspension is a factor. I'll have to think some more about that. I tried everything to improve the Fulvia. Stiffer in the front helped, of course. But nothing helped the back. I tried no anti-roll bar (about the same) and stiffer versions, all of which were more or less treacherous, particularly in the rain. I never had any luck with the controlled throttle lift in tight corners to get the tail around suddenly. I scared the heck out of the guys following me but never really improved my times. As to the weights of the cars I am quite sure about my measurements. Mine is a typically prepped/stripped Fulvia, plexi for glass, fuelcell for the tank, battery into the passenger seatwell, roll bar with stiffening struts going to the front wheel arches. A clone of the factory racers, Sport and coupe for asphalt surfaces. The only thing haven't done is drill lots of holes in the bodywork. Engines are 1.6. I did add a little weight to the front with adjustable heim joints on the lower A-arms (1.5 neg). As it is, in a fast sweeper, you cannot apply full power for rear of running off the road toward the end of the turn. Especially if it's downhill at all.

[1,6 HF]

Johnny, IIRC, the Beta coupe rear suspension links were engineered to toe in slightly under forward weight transfer, specifically to increase cornering stability. The Fulvia, by contrast, is basically a really well tuned ox cart, and I find it much more skittish at the rear (though, admittedly, I'm running skinny, mediocre tires). Perhaps it's because of the tires, and perhaps it's because I'm not pushing it to the limit it on a track, but I find my Fanalone to be fairly neutral, and I have no trouble getting the rear to slide around on tight turns on Mulholland on those very rare occasions that I push it that hard. Out of curiosity, what front toe-out and camber settings are you running on the Fulvia? Does adjusting front/rear tire pressure bias help at all?

[KeppelmanJ]

The front toe is 1/8-3/16 out and the camber 1.5 degree negative. I've experimented with those figures and those are the best. Rear air pressure doesnt seem to matter too much. Too high and and the back gets real squirrely if you have to let up in a tightish corner. Oddly, even after 20-30 minutes on the track the tires don't get hot enough to be within factory (Yokohama) temp range for stickiness so the pyrometer isn't very useful.

[1,6 HF]

The toe-out and camber settings are really about what I'd expect, but the tire pressure and temperature issues are a complete mystery (I could understand the rears not getting up to temperature, but not the fronts). As I said earlier, the Beta rear suspension was specifically designed to counteract the unloading of the rear suspension under braking. Particularly with the lift-off characteristics you describe, transitional weight transfer has to be involved with your Fulvia handling issues, but I have no real explanation for it.

[KeppelmanJ]

I think the deal with the tires not heating up is that the power and weight are not enough to produce 180 degrees (ideal) in an over-sized tire. You have to run something between 180 - 205 cross section because the stability and contact patch are needed to stay on the road, but that's more tire than the stresses involved cah heat up. That's not to say all tires can take it. The Yokos are great. But I used some BFGs and Goodyears that came apart in chunks all around the outside edges in spite of the negative camber. All on the front as you suggest above.