1st Gen F Body front suspension weights and its effect on performance

[alnoe]

I have a '67 RS/SS with the stock subframe, stock upper and lower control arms with Del Alum bushings, 1st design Stielow spindles with bearing pack assemblies, and c5 brakes. I am going to keep the stock subframe (The DSE piece is really nice, but my current one is welded in-maybe this will be a 2013 or 2014 upgrade), and I want to keep the existing spindle/brake package.

So, in looking at control arms, I have been looking at basically every manufacturer. My main question is weight. If I can save 5-10 pounds by going with brand "A" vs. Brand "B" will the weight savings be more important than any improvements in the camber gain?


Also, I have been looking at a coil over/shock assembly to replace the current factory style coil springs and Koni Red shocks I run. Same as above, is it worth the $500 to upgrade to a lighter coil over/shock assembly (assume the shock valving is equal, etc.) so that I can save 5-10#?

Once I decide what to run, I am going to weight everything and see how much wegiht it really does save-should be interesting.

Thanks in advance.

Al

[exwestracer]

There are definite gains to be had going down that road, but you've got be prepared to go "all in"... By far the 2 biggest unsprung offenders are wheels and rotor assemblies, and getting weight off there gets expensive. Unless you really commit to it, the weight savings from shocks and control arms aren't worth a lot of extra investment, IMO.

[alnoe]

Thanks Ray. I have read a lot of your posts and you always provide good information. I had a similar question on the rear end. How little wheel back spacing is too little, or when will it put too much side load on the wheel bearings? I have a stock width rear end in my '67. And am thinking of narrowing the housing and using a wheel with less backs pacing. The thought is to take some of the the housing and axle weight off. But can I go too narrow?

[exwestracer]

Well, I've run 15" wide wheels with the bolt face 2" from the inside bead on my super! We run 18' (wide) wheels with 5" offset all the time. But, those are extreme cases, on a very light car.. I'd say 3/4 of the wheel width would be safe on a street car...

[Bryce]

Thanks Ray. I have read a lot of your posts and you always provide good information. I had a similar question on the rear end. How little wheel back spacing is too little, or when will it put too much side load on the wheel bearings? I have a stock width rear end in my '67. And am thinking of narrowing the housing and using a wheel with less backs pacing. The thought is to take some of the the housing and axle weight off. But can I go too narrow?


How much weight will this save?

Lets say you narrow it by 3" on each side. so a total of 6"

housing: 3" diameter and 1/4" wall thickness has a volume of 12.95 in^3 for both sides
Axle: 1.5" diameter solid has a volume of 10.60 in^3

Density of steel is: .284 lbs/in^3
Total weight is: 6.69 pounds

If we assume the rear housing weighs 250 pounds thats a savings of 2.7%

If you are doing the work yourself and not spending money on the narrowed housing go for it. But if you are paying for it I would spend the money on an aluminum center section (~18 pound savings) lighter wheels. If you spent the money on race wheels in the 16 pound range that would be a savings of ~10 pounds a wheel.

If you plan on doing all of these things then there will be a greater benefit to narrowing the housing.

I am very concerned with weight (except for my weight 250lbs) my falcon is now in the low 2600's.

[alnoe]

Thanks Ray and Bryce. Bryce I am in the same boat as you! Maybe my next project will be getting me to drop 20-30 lbs! All of this is kind of tied together. If I buy new, lighter wheels and tires, should I narrow the housing while I am at it. I also like the look of a deep offset wheel. I figure if I am going to do it, I may as well do it all at one time. Right now, the car has American racing torque thrust wheels, so I am sure there will be a lot of weight to save just in the wheels. Bryce-your build is very cool. Lots of neat ideas!

[MyFriendScott]

Racing down the 1/4 mile, it is a general rule of thumb that every 100 lbs saved is a tenth of a second faster ET. How much is a tenth of a second worth to the car's owner? What would 40 lbs of weight savings equate to on a car raced at local SCCA/track events? Is it worth it? Is the competition that close and the driver that consistent to tell the difference?

Some other options on weight savings would be using A/F/X aluminum spindles and hubs, switch to a carbon fiber rotor up front, and run a flexform composite leaf spring in the back instead of the steel leafs. Narrowing the housing to save yourself ~7 lbs just doesn't seem worth the effort.