Avanti Weight Distribution

[jlmccuan]

Does anyone know the weight distribution is on a Stude Avanti? What I'm actually after is the balance point, fore to aft, but I can get close with a front/rear percentage or actual axle weights.

Jim

_________1966 Avanti II RQA 0088______________Rabid Snail Racing

[Gunslinger]

I've seen a couple of different values for that. I guess it depends on how the car is equipped...a/c, blower, none at all, etc. The values I've seen are about 58/42 to 60/40 front to rear weight bias. Avanti II's are a bit better balanced as the GM engine weighs less.

Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

[wagone]

Gunslinger is right on. It is too bad that Studebaker didn't see fit to move the engine back and make it a 2+2. Road and Track said 59/41 on a supercharged car with power steering--this in the October '62 issue. And A/Cs are going to be heavier than (non-air) R2s. So......58/42 for a non-air R1. It would be nice to try a bow-tie model with aluminum heads and no air. Anybody wanta trade?. Someone who writes on this forum (my apologies for not knowing who the gentleman is) occasionally is building a stainless frame Avanti. If I were he I'd design it to move the engine back a foot or so. Since he has SUPERIOR fabrication skills relocating the engine to a more neutral position is no big deal.

wagone and R2 "63 Avanti.

[Gunslinger]

I'd be interested to see how gross weight and front/rear weight bias works out on my '70. When it was rebuilt I had a new GM Performance 350HO crate engine installed. From what I understand, the heads, even though cast iron, weigh somewhat less than the old heads due to improved casting techniques. Also, instead of a cast iron intake manifold, it has fuel injection with an alumninum intake, a lightweight GM a/c compressor, and aluminum serpentine belt setup. The original cast iron case Borg Warner Power Shift transmission was replaced by an aluminum case 700R4 with an aluminum driveshaft. The steel leaf springs were replaced by composite units, taking nearly 100 pounds of unsprung weight off the car. Even the spare tire was replaced by a donut spare.

That car must weigh several hundred pounds less than it originally did. I should have put the car on a scale before and after to find out the difference. I don't know what the front/rear weight bias might be, but it's probably somewhat better than before. The composite leaf springs, taking away weight off the rear of the car, may have made for no change in the bias, though they definitely reduced the weight of the car overall.

If the Magnum 500 wheels on the car weren't in such great shape and I like the looks of them, I'd consider getting a set of aluminum wheels to reduce unsprung weight even more.





Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

[wagone]

Hey Gunslinger, those Magnum 500 wheels look great on the Avanti.....keep em. But you're right....heavy. It always surprised me when the disk-braked Corvette first came out and all the auto writers raved about them and yet none of them (that I read at any rate) mentioned how much those brakes added to unsprung weight--those huge iron 4-piston calipers! So.........where did you find composite springs for the rear? Iron leaf springs are HEAVY--course that is the surprise of the century. Sounds like you have a great car. The only problem with those light weight "modern" (by comparison) cast iron Chevy heads is that some of them can tend to warp. But...they're a lot cheaper than aluminum. Your car may not weight much over 3200 pounds.

wagone

[Gunslinger]

I got the composite springs from Flex-A-Form. They have the specs on file and it only took a week to get them. They weigh about eight pounds each instead of fifty pounds apiece that the steel leaf springs do. They also cost no more than a new set of steel springs from Eaton.

After the car was rebuilt...it was a real mess when I bought it a couple of years ago...it took a while to get used to how it drove...it all too easily smokes the rear tires in three out of four gears. Part of that is due to the crate engine being more powerful than the original, some due to the weight reductions and some due to the front/rear weight bias.

I also have a '69 Corvette 427...that whole generation Corvette has a history of brake issues. Not so much of design...they're an excellent design (for the 1960's), but the problem is of manufacture. They're cast iron and will often corrode, causing problems. They have to be driven regularly to keep that from occurring. Most likely GM never expected the cars to last long enough to make difference, but many owners now don't drive them regularly, leading to problems. Many replace their calipers with replacement with stainless steel sleeves for the pistons, or buy complete newly engineered kits with modern design calipers.

I had to have all four calipers rebuilt a few months ago due to issues like this. Besides the calipers, I replaced every rubber brake hose, whether it needed it or not.

Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

[Alan]

Hot Rod Magazine tested 3 Avantis in their Oct. 1963 mag. 2 R2's and an R3. The R2 with an automatic and air weighed 3590lbs. full of fuel but no one inside. 56% of the weight was on the front wheels (pg. 106)

[wagone]

Fifty-six percent is certainly in line with a lot of contemporary cars. I wonder who is right Hot Rod or Road & Track (56 vs. 59 %)? I wouldn't think that the difference in weight distribution between air and s'charger could possible be three percent. No way.

wagone

[Gunslinger]

I don't see any way the weight difference an a/c compressor and a blower is 3% of the car's weight. That York compressor is heavy, but not that heavy.

I could see the difference if one had a full tank of fuel and the other nearly empty.




Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

[Alan]

One of the things in their tests was that the front seat passengers added 62% of their weight to the rear and the rear seat passengers added 80% of their weight to the rear. The gas in the tank is right over the rear end.