Trying to Learn squat....

[Grant 302]

I mean, yeah that would make it squat, but that's not the same as transferring weight to the point of over coming the spring rate, which is what would give you traction.

I don't know. This was at the beginning of the side discussion. Kinda opposite of the diagrams. Squat doesn't occur without weight transfer.

 

[Fabman]

I don't know. This was at the beginning of the side discussion. Kinda opposite of the diagrams. Squat doesn't occur without weight transfer.

And weight transfer is resisted by a combination of the spring rate and anti squat, which is what puts the pressure on the contact patch....which is what I've been trying to say.

 

[TMSBOSS]

Thanks.

I have learned more from reading this string than others on the subject.

 

[Grant 302]

And weight transfer is resisted by a combination of the spring rate and anti squat, which is what puts the pressure on the contact patch....which is what I've been trying to say.

Spring rate doesn't resist the weight transfer. It speeds it up. That's why I used the spring helpers on drag cars in the past. I know you know suspension stuff, but I think we understand it differently and that seems to get in the way. Even when we're mostly agreeing.

The LCA angle seemed to be confusing things. You can still have anti-squat with the LCAs pointing downward.

With relatively stiff springs I think the lower angle and higher ride height are needed to dynamically maintain enough squat to lift the wheels at n/a power levels. Also to give enough travel to take an additional 1,000+ lbs on a 350lb-in spring.

I have learned more from reading this string than others on the subject.

I'm glad somebody thinks so! I'm pretty sure the bulk of reaction is, "there they go again!"

I also forgot to get into why a panhard is probably better for lifting a tire and doing it on left turns...maybe some other thread!

 

[Fabman]

Spring rate doesn't resist the weight transfer. It speeds it up. That's why I used the spring helpers on drag cars in the past. I know you know suspension stuff, but I think we understand it differently and that seems to get in the way. Even when we're mostly agreeing.

The LCA angle seemed to be confusing things. You can still have anti-squat with the LCAs pointing downward.

With relatively stiff springs I think the lower angle and higher ride height are needed to dynamically maintain enough squat to lift the wheels at n/a power levels. Also to give enough travel to take an additional 1,000+ lbs on a 350lb-in spring.



I'm glad somebody thinks so! I'm pretty sure the bulk of reaction is, "there they go again!"

I also forgot to get into why a panhard is probably better for lifting a tire and doing it on left turns...maybe some other thread!

The spring and anti squat is what supports the weight, if not the corner would fall to the ground. So in that aspect, it is resisting the weight transfer. And of course the stiffer and more anti squat the faster the response, but it is still supporting the weight.

 

[Grant 302]

Ironically, breaking up something complex in suspensions is easier understood by analyzing individual parts or groups of parts to look at all related forces and reactions. That's the best way to make sure the reactions are correct.

 

[Fabman]

Ironically, breaking up something complex in suspensions is easier understood by analyzing individual parts or groups of parts to look at all related forces and reactions. That's the best way to make sure the reactions are correct.

What’s actually happening is usually the simplest thing.


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[Grant 302]

The spring and anti squat is what supports the weight, if not the corner would fall to the ground.

Anti-squat does not support ANY weight. The spring supports weight. The ARM(s) can essentially borrow it or momentarily add to or subtract from it during acceleration/decel events. They do none of that in static or set speed instances.

Like I said before, you gotta draw out a fully 'exploded' free body diagram to understand ALL the forces and reactions for yourself.

 

[Fabman]

Anti-squat does not support ANY weight. The spring supports weight. The ARM(s) can essentially borrow it or momentarily add to or subtract from it during acceleration/decel events. They do none of that in static or set speed instances.

Like I said before, you gotta draw out a fully 'exploded' free body diagram to understand ALL the forces and reactions for yourself.

We are getting nowhere here.
"During acceleration" the anti squat is lifting the body through mechanical advantage; ergo supporting the weight (maybe counteracting the weight is a better term)...yes the spring is helping it...I said so.

 

[Mad Hatter]

Yee gads..... I will leave all my university physics behind for now and just try it out.... Phoenix car = Fast..... Phoenix car = Squat...... So Me going to squat and see......

Or too be a little more correct.... a little less then 100% Anti-squat.

 

[Fabman]

From the BMR website:

AND I QUOTE....

"When you lower the car you lower the car's body. But, the rear axle stays put. This has the effect of lowering the front of the LCA. Instead of being horizontal, the LCAs are now lower in the front and higher in the rear. When you accelerate, the LCAs push in a straight line, just as they always do. But now the straight line is angled downwards at the body connection of the LCA. This means that MOST of the force from the wheels is still pointing forward, but a portion of it is actively pushing the body of the car down towards the ground. Newton taught us that every action has an equal an opposite reaction. And it's this reaction that's bad. The reaction to the body being pressed down, is that the rear axle is being pressed UP. This force actively lifts the tires off the pavement....as if you had a big helium balloon tied to your axle. The harder you accelerate, the more your axle gets lifted up...and that costs you traction. A car that is lowered without LCA relocation brackets has LESS traction under acceleration than a stock-height car because of this! The angled LCA also causes a rougher ride.

How can we fix that? LCA relocation brackets let you change the position of the rearmost end of the LCA. By switching them to a lower mounting position, we can restore the OEM horizontal configuration on a lowered car. That means you can have your car lowered, but without suffering the ill effects I just described.

But we can also change things to our advantage. If we lower the rear end of the LCA even more, so now it's lower in the rear than at the front, we get a similar situation to what I described above...but backwards. Now, the force from the rear axle is pushing up on the body. The reaction force pushes DOWN on the axle, planting it to the pavement. In this case the harder you accelerate, the more the tires are pressed onto the road...providing more traction."

 

[Mad Hatter]

Been over all the BMR articles and those diagrams are burned in my brain by now.

Nothing in this setup below goes against the BMR diagram or blurb...

LCA angle is 1.4, probably be 2 degrees by the time I raise the aft. UCA angle is 14 degrees now and hope to get it to 13 degrees...... aim is less then 100% antisquat... by how much will depend on results I guess....

Oh bother..... What would you do if you had a torque arm..... ??? No UCA/LCA intersection point.....

 

[Fabman]

Been over all the BMR articles and those diagrams are burned in my brain by now.

Nothing in this setup below goes against the BMR diagram or blurb...

LCA angle is 1.4, probably be 2 degrees by the time I raise the aft. UCA angle is 14 degrees now and hope to get it to 13 degrees...... aim is less then 100% antisquat... by how much will depend on results I guess....

Oh bother..... What would you do if you had a torque arm..... ??? No UCA/LCA intersection point.....

If you can go to a torque arm...do it. And that's my opinion.

 

[Mad Hatter]

Lol!! But then I would have to ask WHY!!! and we would have start this all over again!

 

[Grant 302]

We are getting nowhere here.
"During acceleration" the anti squat is lifting the body through mechanical advantage; ergo supporting the weight (maybe counteracting the weight is a better term)...yes the spring is helping it...I said so.

At 50% anti squat, the rear doesn't lift. So what's supporting the weight?

Okay this is as simple as I can make it.

View attachment 3365

See, that screwdrive is a lever arm over a fulcrum.
Anti Squat is also a mechanical lever arm.
See what it's doing? It's lifting the body. What is one property of a race car body?
It has mass and mass=weight. Ergo, under acceleration, that lever arm is lifting the weight or counteracting the force of that weight as gravity pulls it to the ground.
Ah but we have a lever arm and it's trying to lift that weight. Whaaaaa.....?
But but but...Grant says that can't happen?

I'm tired of this...

So if I take a light pole and stick it under my car at the track and put it on the tire wall...

Apples and table legs.

From the BMR website:

LOL. That is one of the worst explanations I've seen. "tied balloons to..."

Which angle is the UCA at what is *it* doing? Is that one going to explode because it's pointing down?

LCA pointing down, still has anti-squat:

 

[Grant 302]

Lol!! But then I would have to ask WHY!!! and we would have start this all over again!

Good luck lifting the front wheel then. Well, maybe at the drag strip.

 

[Mad Hatter]

Well, the leg lifting...... would be a nice side benefit of going faster!! but not the be all, end all..... Does any one have any angles for their UCA?? Its not the easiest thing to measure, lucky I have a pit at home!

 

[Grant 302]

If we lower the rear end of the LCA even more, so now it's lower in the rear than at the front, we get a similar situation to what I described above...but backwards. Now, the force from the rear axle is pushing up on the body. The reaction force pushes DOWN on the axle, planting it to the pavement. In this case the harder you accelerate, the more the tires are pressed onto the road...providing more traction."

If this worked exactly like this, drag cars would mount the LCAs at 45º up.

As soon as the 'hit' is done and the suspension is 'set' and rolling, the effect is essentially gone. It stays in a very small form right until the moment that torque is no longer increasing.

All that is very important to drag racers to get out of the hole. Not so important for road racers, last I checked. Would also help when you want to bang gears and powershift too.

 

[Grant 302]

Well, the leg lifting...... would be a nice side benefit of going faster!! but not the be all, end all..... Does any one have any angles for their UCA?? Its not the easiest thing to measure, lucky I have a pit at home!

I don't. I don't have an adjustable front mount so I just have to live with whatever it is. Mine is pretty steep, and I know if I could adjust it I would bring it up and as level as possible.

 

[Mad Hatter]

Nothing personal here fellows! If we all agreed with each other it would be no fun.... Fabman, what are your LCAs angle up at?? (assuming that up is from the axle forward )

If I remember right you are with the Watts and torque arm?