Technical PtII-Ratio of Spring weight to unsprung weight unfavorable, what helps?

So what's the tricks when the unsprung weight is too much.
Reduction of un sprung weight is pretty popular but if that's already been done and the only options left are incredibly expensive what helps?

part 2 starts on page 10

 

Wotcha try na do?

It this front or rear axle?


Singlefingerspeedshop.com. Detroit

 

It's really a general question I guess but On my particular situation-

33/34 traditional chassis on buggy springs.
Too much unsprung weight Out back at the rear.
392 hemi upfront.

 

I assume the complaint is poor traction on bumpy surfaces, amybe especially corners?

 

This one isn't on the road yet but I can't see it being anything other than what you've described.


I might have to add 500 lbs to the trunk to fix the front and rear weight bias and sprung vs un sprung ratio. but then id need blower on the engine to make up for the extra weight to keep the power to weight ratio up.

 

Obviously then, put the blower in the trunk!

 

do like I'm doing on my Chevy II....

(oh, that would look funny on your car)

 

Unsprung weight is the weight of the axle, wheels, spring's and everything bolted to them. Sprung weight is everything supported by the spring's. Do you think your going to have an excessively heavy axle/wheel assy or are you concerned that there will be too little weight in rear of car? If the car your building is a traditional buggy spring design shouldn't it work as well as the million's of car's already built that way. Maybe I'm just missing something
Gregg

 

Again, a general question about counteracting the effects of unsprung weight.
But we can wack at the obvious here. Lets get that out of the way.

Correct, that's the difference between sprung and unsprung weight.

Yes I think the car I'm building will be exceptionally light in the rear, thus reducing sprung weight. Also I think it will have an exceptionally heavy rear axle assembly thus increasing the unsprung weight. Not much but more than usual I think.

These cars usually have a horrible sprung: unsprung ratio anyway, probably millions of them. They all have the characteristics of getting knocked into the air by the unsprung weight's (mass) inertia (energy) coming up back to the light ass end after bumps. So what I'm after are things that help counteract this.

The number 1 thing is to reduce the unsprung weight by utilizing light weight components. It's really no secret that this has a large impact on handling. So after the easy and affordable dieting, then comes the ultra expensive items that are lighter. Aluminum rear differential housings, magnesium components, titanium components. Not going there but there must be some other things that help this.

 

Radial rear tire 40#, M/T or Hoosier polyester radial 33#, 9" 194#, 8" 170# but stick with 9" for 392, 15x8 steel wheel 26#, 15x8 torq thrust 16#, iron carrier 20# heavier than aluminum but stick with iron for 392. So not much you can do.

 

Softest springs, longest traveling shocks / coil overs, plenty of room for the diff to travel? Or, perhaps a pricey IRS may be all that remains to consider? Gary

 

-Just enough spring rate to keep you from bottoming out.
-Really good shocks.

Ideally those shocks should be double adjustable. You'll spend some bucks on them and strictly speaking they won't be traditional, but if they're hidden under the back of the car who will know?

You will, every time you drive the car.

 

16x11 ET 5 spokes and 345/55/16 tires is what I have.
Maybe ill fill them things with helium

 

Even though you Dawg me out on my questions, I'll give you my advise since stock car racing is about 40-50% of figuring out unsprung weight and how to make it work to your advantage......I was pretty successful at doing this since I won 3 National Championships and was chassis man on 3 other National Championships....not to brag, but you tried to make me look like a '32 owning fool on my site.......I'll give you one little helper...turning the shocks upside down so the heavy end is hooked to the frame saves weight, but to ad weight to another wheel you can turn it the other way and add the weight to the axle...thus giving more axle weight...figuratively, the weight of the car doesn't change one ounce but every pound of unsprung weight moved makes the car react as though 10 pounds were added or taken off...which ever way you move it............just a tidbit from a an Old Racer/Sign Painter

 

I'm running a ford 8.8 (probably one of the heaviest) , narrowed from an exploder. I thought running the exploder IRS too but just couldn't make myself do it.

I did rake the frame tails up to give me an extra 1-1/2 of available travel distance.

 

Jag IRS would be an aesthetic improvement over the 8.8. The ring gear is about the same size, too.

 

Thanks !
I'm sorry, I should have not responded at all since I didn't own a 32.
I'm pretty good at chasing vibrations out though, and the theory is universal from dump trucks to hot rods and yes even the holy grail 32 ford.

 

Apology accepted....here's another one that can really move the front/rear weight a bunch.....this can be used to move weight forward or backward....drawings were just done quickly as an example for you to see what I'm talking about...when we raced the engine Number 1 spark plug had to line up with the top ball joint...it was hard to get rear weight to balance out the car, but this little trick helped a bunch

 

Another area for weight saving's is brake's Run disc with light weight rotor's and aluminium caliper's. I'm sure you already know but move fuel tank and battery as far back as possible

 

I think some non-gas twin tube shocks might start to pump air if mounted upside down.

 

Man That makes sooooo much sense.
Any idea of how much weight that actually moved off the front and to the rear axle?
I do Not really a stock car background and I knew there were simple tricks.
Every little bit helps too.

Looks like I might revisit my motor mounts.

 

Already have the LW rotors and aluminum calipers.
I could hang the tank off the back behind the rear axle, I have a cardboard mock up of it too. I just feel better about the tank in the bulkhead between truck and cabin. That's about 12" forward of the rear axle.

 

Unless it is a ratio type shock like a 90/10 or something like that , the shock has no idea which way it is mounted...also to soften the shock/spring ratio and slow down the rebound so it doesn't have that "bang back up feel", you can mount them at more of an angle....EXAMPLE: take a quart glass jar..fill it half full, screw the lid on it....turn it upside down and see if it still holds water...I know this sounds stupid, but that's how it was explained to be and that got my train of thought to working so I could come up with some of our little tricks we used racing stock cars...........the twin tube shocks may be different..I have never used them, but gas filled shocks you could set different pressures worked the same it they were 50/50 ratio.

 

Two quick questions:
(1) Is this where a drilled frt I-beam axle would be an advantage???
(2) At the risk of starting a possible flame-war, how about an aluminum frt axle ???

 

You need to borrow a set of scales from someone that races stock cars...you would not believe what a difference of 2 pounds air in one tire makes to the cross weight or front to rear corner weight ratio......using leverage here and their moves weight drastically...think about a 10" Crescent Wrench and the difference a 24" makes...BUT...also remember when using leverage, you have to BEEF UP your parts to handle the extra weight distributed to the mounting points.

 

It dosen't work like you think in the drawing...The only weight that is moved back is the weight of the engine bracket on the frame that is farther back..The engine is still in the same place so its weight center is still in the same place...you could suspend the engine at any point, the only weight that moves is the weight of the mounts and brackets..

 

X2 ^^^

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BUT...we're talking about weight transfer when the car is riding down the road...the car still weighs the same, but with the mounts moved back, leverage comes into effect and the car transfer weight is moved..not actual weight, but the way the car reacts....look at my drawing and tell me where the frame would break if enough weight was put on the mounts to tear them out of the frame.......in the stock location or in the altered location........leveraged weight transfer does nothing to lighten anything up...try picking something up from the floor by using only your elbows to lift...use your whole body to lift it....the weight didn't change..but the leverage weight did....It's all Stock Car related stuff, so it's not always understandable...but IT WORKS..believe me.

 

"Back in the day" they used to sell these bolt on canister looking devices that had some sort of floating weight in them. They were supposed to help handling for lightweight roadsters/coupes. I suppose for the reasons you are asking about.
Does anyone remember these? Did they actually work or just a gimmick?

 

If you didn't actually move the engine, all you did was change the shape of the mount, not the weight bias.