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

No, that most certainly would move the point load rearward and more weight to the rear axle. The roll CG would probably stay the same though because the mass hasn't changed or its location. Just where the load is being carried.
How much ? I don't know but ill give that an easy experiment tomorrow

Ever play with an engine leveler, run it back and you need to push down on the Trans mount to hold it level. Run it forward and you lift up on the Trans to level it. The weight didn't change but the engine hoist will see a different load depending on if you are pushing or pulling wont it?

 

the frame and mount are one piece. Where the mount attaches to the frame does not affect where the load is applied. It's still applied at the mount.

I never set up stock cars, I just understand physics.

 

NOW THEN!!!!................YOU'VE GOT IT!!!!.....YOU UNDERSTAND THE THEORY NOW OF WEIGHT LEVERAGE TRANSFER..........Your example of the engine leveler was good..............I'm so proud of you........an Old Stock Car racing Sign Painter has taught a young kid an old trick that still works today.

 

It works IF the parts are not welded together. The engine leveler is not welded together. The mount is welded to the frame. There's a difference.

 

Fixed Jib crane example a vs b weight is the same.
Where's the load ?
What where's the stress highest on these two
Which needs to be thicker material. Why ?

The top mount sag rod has the load above the weight, opposite for the low mount gusset.
The top mount sag rod post will fail at the boom/post - low mount will fail at the gusset/post.

Low mount gusset needs to be much thicker than the sag rod. The top mount sag rod post should be thicker because the weight is over a longer span.

 

Try this thought experiment then.
Stand 6" away from the wall.
Hold a hammer out in front of you touching the wall while standing on a scale. Where's the load? mostly at your shoulders, straight down your spine to your heals + scale reads your weight plus hammer.

Now back the scale up 30" from the wall.
Same thing. The load is mostly on your low back, and you'll have more load on your toes than your heals + scale reads your weight plus hammer.

 

No offense but seems more like a structural discussion than relating to fore aft weight bias. If the weight is still residing in the same center but attached at different points along the length of the frame you are only affecting how it effects the way the frame is loaded mechanically.

 

But the weight is being moved.

 

I out ran people with your thinking every week.....physics has nothing to do with why a bumble bee can fly either....science says it shouldn't be able to fly...........BUT IT DOES.....some say it is a controlled crash each time it flies, but still, it flies...everything doesn't have to be a science proven thing................like I said before...put enough weight on the mounts till it breaks and THAT is where the load is.....period.

 

That's what I'm thinking. Didn't Chevy go from front mounts to side mounts in the late '50s?

 

Like I said I'll Monkey around with it tomorrow.
Scales and everything. Seems quite logical that it will move the point load and moving the point load moves the weight and moving the weight moves the bias.

 

No the weight stay put at the wall,
The mount (you) moved

 

Back to rear unsprung weight, I have the same issue with my Bantam. Was driving it today, rear end shoots the whole truck in the air over bumps. Also already have lightweight rotors, aluminum calipers and rims. What got me was the ring and pinion, heavy buggers. The 4:10 ring gear is extra thick to avoid spacers, must weigh 30 lbs. Thought about lightening it, somehow. Maybe I'm wrong but the light vs. heavy end of the shocks doesn't seem like much in comparison. I do have adjustable coil overs and have been gradually lightening them up, does help.

 

My little 31 Vicky guy has became sooooo smart since he finally saw the light of weight leverage............your HAMB mother and father are so proud of you......I know you'd probably says "Thanks Mom", if you won an Academy Award for this, but that's ok

 

And the scale? It's like saying I didn't punch Bobby, he hit my hand with his face.

 

Viki,

What makes you think it will be a problem, you have not driven the car yet. My 32 Ford 3 w cpe with blown 354 Hemi, Tremec 5sp, Winter 10 " QC. is heavy at the rear even with blown motor. LF703 lbs RF744, LR741 RR744. Front total 1460 lbs, rear 1485 lbs. total 2945. The 34 has a longer wheelbase so it should be better. Rear springs should be as soft as you can stand with good shocks. My nephew 32 Ford full fendered 8.8 modern Ford rear end BBC 454 in front copper radiator,Tremec 5sp. Drives and rides real nice.


Ago

 

Well I don't know it will be a problem on this car.
I need to make up some of those load cells Andy did the tech on and get some hard numbers.

But this was posed as a general question.
1, because I'd like to know and 2 because I think it might be problematic. 3 seems all these cars have a bad sprung vs unsprung ratio and almost everyone can benefit from the discussion. It Doesn't really matter if its about my cars or not but I don't mind sharing and giving an example to focus on.

 

Haha, reminds me a question I posed once.

Honey ?, what would you do if Halley Berry fell on my dick?

 

31 Viki,

Most of these early cars are over sprung. If you go by what is recommended in the Speedway catalog for coil overs you will not like it. My 1st 32, (on the 3rd one now), TCI recommended 250 lb rear coil overs. Ended up with 190s. Also if you use progressive frame bump stops it makes a difference. C- ing the rear frame rails is a must. If you could increase rear suspension travel would be a benefit. Now you have aprox.3". The ideal rear setup would be to Z the rear frame rails and get about 5" of travel. I switched shocks and springs on these cars and was able to tune the ride and handling better. IMHO a rear anti roll bar is a must. I talked to a guy that had a 34 Ford sedan and he said he was going to sell it because he had a neck operation, and the ride jarred him too much. I told him his springs were probably too stiff. I took him for a ride in my car over railroad tracks and such. He was really suprised, He was going to order softer springs and said he could keep the 34.


Ago

 

The best example of weight leverage I can think of is the rear suspension pickup points on a dirt midget, on our car we had aluminum plates that bolted to the chassis and the rear suspension bolted to the plates. The advantage of this was that we could change the initial point of lift on the chassis but the push pull action of the rear suspension on the plates is where the leverage came into play. On a very slick track we would run a long set of plates and short suspension parts four link on one side wishbone on the other most of the time but the longer plates made the suspension react faster and with the added length of the plates gave more leverage on the chassis to keep the nose up and rear tires planted when everything was right I would not lift off the throttle just a good hard jab of the brakes to set the car. What does this have to do with engine mounts? Everything, think of the torque that is applied to the mount the push and pull of the torque now think of where the pick up point is then factor in some chassis attitude under acceleration big difference. Still don't think so then why are so many different motor plates made for dirt cars, drag cars and asphalt cars? That is the really long way around to say that you can change the rear suspension pickup points to help counter act some of the unsprung weight just look at how it will load and unload if the chassis has more leverage than the rear axle the unload ( wide open to just total shut down) will be smooth and predictable but this usually affects forward bite.

Pat

 

Picture 2 guys carrying a beam with a large box mounted on a chunk of 4x4 in the middle. Inside the box is a stack of weights at the front end. The front guy gets the load, it is not evenly spread because the mount is in the middle. Besides weight there is something called moments, like torque.
Wheelbase @ 8’, 400# engine @ 2’, mount @ 4’, take moment about rear axle not knowing location or weight of engine but knowing properties of mount. ( 4’x 400# + moment of 400# x 2&#8217/8’ = 300# at front so 100# rear. If 400# motor with regular mount at 2’ and taking moments about rear axle, 400x6’/8’ = 300# at front so 100# rear. No difference.

 

Can you expound on this a bit more .

I find it interesting that some say there is a difference and some say there isn't.
My background is heavy in construction and fabrication, and there is a big difference in point loads when a cantilever type situation is involved.

 

My chassis is set and its using a transverse spring, 40 ford front spring in the rear. I do have 5" available travel in the rear frame, however the tires and wheel well limit is 3-1/2" & there's many factors as to why but that's where it is.
As it sits now, I need about 1" more height in the spring. Now I figured I could get there plenty of ways depending on how the spring works. A longer main leaf with more arch would get there, more leafs, a spacer, less leaves and even more arch. So I have quite a few options on the spring rate. Just can't nail that down yet but I'm not limited, so that's good.

 

Trust me. I'm an old civil engineer.

 

Never said that I didn't trust you, what I mean is that I don't understand what you are saying and that I would like to.

 

Since you have background in heavy, assume you have a 4' long torque wrench plugged into the center of that 8' beam. You swing your 200# at the end of it. The front gets 200#, the rear 0. Now call that torque wrench a motor mount and replace your 200# with a 200# engine. Same result. We do everything based on centers of gravity. We don't care how convoluted a mount may be.

 

31 vicky,
Get the car on the road and let the suspension settle in, then make your decision to change things if you have to.


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First thing to look out for...I'M AN OLD CIVIL ENGINEER.....That means you were spending someone elses money
Second thing.....you said Trust Me.......first sign that we shouldn't

All if Fun......don't take this reply serious...................

 

This question has gotten way off topic since it was asked.......as we all know some things work that we can't explain...it's like Faith in God....we know He's their but can't prove it to some people.....I think where we get all messed up is, everything doesn't have to have an explanation as to why it is what it is......BUT IT IS WHAT IT IS..........and that's what makes us always have to get into science and physics.............

 

Lighter wheels, lighter tires, aluminum brake drums, aluminum shocks, drill holes in backing plates, drill everything....those definitely work.

Lever shocks put most of their unsprung weight on the chassis side, so some Armstrongs from the rear of an MG might help.

If you're using an 8.8 axle now, a DeDion setup would probably shift over 100lbs to the chassis side.