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 Post subject: Re: Suspension Dynamics.
 Post Posted: Tue Apr 07, 2009 6:21 pm 
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Beretta wrote:
Ok will do =;



You taking notes John???


I'm just now following it, I started to read the comments, but my brain burst into flames when I got to the 2nd page, so I called 911 =;

I know we all have different opinions, and yes, I do agree that we all need to be on the same component name page for sure to all understand the whole conversation in this thread.

I like Ron, ran my heavy combo to 8000rpm's and I had a 1.90 1st gear with a 4.88 ratio now do the math on that SLR!!!! I was way over on the ratio's so when I blew my trans, I used some friends parts that now had a 1.76 1st gear, an 8" vs a 9" conv. and 200 more stall on that 8" conv. and I actually went faster than I had ever been with my stuff. Since then, I have new 1.80 straight cut gears, new case, and ran the same gear and still got no better than a 1.40 60ft. wadding the rear tires up due to the wrong tire for my weight, but it was consistant. I found out by watching my videos, and going to Morgan's class, and doing more reading, here, and other places, and found out my lift point was just about under my a$$ and it should have been farther out to pick up the chassis more in the front, I had gobbs of front end travel, and even tailered it to find more info on what the car wanted, and it wanted more, so I gave it more, but Barry, your car is a whole different can of worms, but we are in the same dirt. You need some video of your car, and much footage so you can see it at home in slow motion from both sides, and from a front angle and see what the car is doing, and I think this will help out a bunch. Does anyone else have a chassis car at your track???? heck, make friends and ask for some help from a PRO team if they show up, or at least get some phone numbers to a chassis shop to give you a hand, couldn't hurt, except if you never ask ;-) I'm at the point, that I will just about take my Elky to the most expensive guy here in Detroit named Pastalney(spelling)? who does AA/SS Hemi cars and he is considered to be the best with these and other chassis's. I don't expect you to make the trip here, but you are in Jersey, and I know there are top teams in your turf that can help out, even if they just watch the car at the track, but you need the chassis guy, not the clutch guy or the engine guy, you can make what you have work, you just need that sweet spot we all look for, then once we find it we leave it alone and win then \:D/ \:D/

I see al lot of knowledge here lately on suspensions, and what I think the average racer wants is help, not a class on suspensions, but someone to show them how to do something on the car and tape the results to watch, but you need that chassis guy again, and only him. Let me do some leg work on some people in Jersey for ya and se if I can get you hooked up with someone to meet you at your track, send me the name of the track your at the most and I can go from there, and your phone number too in a (PM). I am happy to help you out Barry and get you happy too.


John ;-)

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Tue Apr 07, 2009 8:53 pm 
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Beretta wrote:
Gettin back to the rear springs.......I measured the spring length, the 110lb spring is compressed to 10 inches from it's free length of 14 inches

I then put the 125lb springs on and it is compressed only 12 inches from it's 14 inch free length.......

So will it take more pressure to compress the 110 lb spring a 1/2 inch or the 125 lb spring???????

The rear seems to be softer in the rear with the 125lb spring :-k


Ok, The 110 spring said it had 440 lbs on it = 110 X 4 inches= 440lbs,
The 125 spring said it had 250 lbs on it = 125 X 2 inches = 250lbs
Now which one is doing what it is rated to do? Is one old and worn out? Is one rated lower than spring rate? That is why they make spring rate checkers. You can bet one or both springs are telling fibs.

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Tue Apr 07, 2009 9:12 pm 
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Everyone that races needs to know hows and whys of the chassis even if they pay someone to do it. Then when you become an old Fart you can tell all your speed secrets.

If you are having trouble understanding something Ask. There are no dumb questions. There are dumb mistakes. I have asked the questions, everyone has.

I think it's good there are more cooks with different opinions. Everyone will have to sort out what he believes and will have options if something don't work. More than one time, I have come out of a bench racing session with a different attitude. It's good to have an open discussion. Some may learn nothing. Some may learn something and some will learn a lot. It is so hard to explain things with out the questions. Everyone that has something to say should say it. If the views are in conflict, oh well we are big boys. No harm intended.

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Tue Apr 07, 2009 10:06 pm 
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Beretta, I may be wrong but I think shrinker wants to know how far it is from the center of the axle to the center of the hole in the bracket on the chasis and from the center of the axle to the center of the bolt on the axle housing. My brackets on my housing are a couple of inches in front of the center of the axle. Having said that, this was my take on his question.

Scott, I think you have given too good of advice in the past to drop out now!

Coy

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Tue Apr 07, 2009 10:20 pm 
 
Beretta wrote:
ron owens wrote:
I'm lost on all this stuff i run a 5.14 gear with 33.5 tires go thru the traps in the 1/4 mile at 7800




Your car also weighs 2000lbs more than mine does O:) O:) O:) O:)

Ya i know i wish i had yours .
I have went through this stuff with so many guy's telling me what i need to do on my car it drove me crazy so i just stopped .
I put everything back to neutral reset my four link and went racing.
Now I'm 100% sure it is no were near right or at least according to all the books and chassis guy's and lord knows i would love to have the car set up to were it just picked the ;left front up about four inches and shot straight out like a bullet.
And i think that's what you are looking for also one day i think i will get it the way i want it but it sure will drive you nuts i just keep fooling with when i can and i race it the way it is at the time.

I keep watching this thread and reading from everyone's post very interesting i must say and i have enjoyed the post from everyone who knows i maybe looking right at the right set up and just don't know it.

Barry I'm sure you will get your car set up the way you want it you have the determination and drive to make it right and I'm sure you will.


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 Post subject: Re: Suspension Dynamics.
 Post Posted: Tue Apr 07, 2009 10:32 pm 
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Bubstr wrote:
I think it's good there are more cooks with different opinions. Everyone will have to sort out what he believes and will have options if something don't work. More than one time, I have come out of a bench racing session with a different attitude. It's good to have an open discussion. Some may learn nothing. Some may learn something and some will learn a lot. It is so hard to explain things with out the questions. Everyone that has something to say should say it. If the views are in conflict, oh well we are big boys. No harm intended.


Very well put. I agree completely. If everybody agrees then nobody learns anything, we'd all follow the same paths forever. I like difference of opinion.

Oh, by the way I agree with Bubstr about the spring(s) lying to you. You didn't change the 4-link at the same time you changed springs did you? Did the springs get mixed up?

Rick


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 Post subject: Re: Suspension Dynamics.
 Post Posted: Wed Apr 08, 2009 1:50 am 
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Beretta; I think some of your measurements are incorrect. Please check the Height above the ground for the axle end lower bar and the upper bar.

The reason why I do all the measurements from the ground and from the axle centerline is the axle is the thing that pushes the car forwards and applies a torque reaction that has to be resisted by the four link. The centerline of the axle is where everything starts from. There are 2 places on the car that the physics start from, one is the axle centerline and the other is the crankshaft.
I dont mean to upset anyone but I argue that the concept of working out thrust lines or antisquat etc from the tyre contact patch is not correct. The tyre thrust occurs at the axle, thats where the forces come into play, not at the tread.
I always find it useful to exaggerate the design or shape of things in order to better understand them So consider this, you take the rear wheels off your drag car and install monster truck wheels. You also install lower gears in the diff so that the final torque applied to the tread is the same as you have now. Then you alter the fourlink so that its still got the same IC. Now who recons that car will launch the same and have the lift etc?


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 Post subject: Re: Suspension Dynamics.
 Post Posted: Wed Apr 08, 2009 6:37 am 
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Bubstr wrote:
Beretta wrote:
Gettin back to the rear springs.......I measured the spring length, the 110lb spring is compressed to 10 inches from it's free length of 14 inches

I then put the 125lb springs on and it is compressed only 12 inches from it's 14 inch free length.......

So will it take more pressure to compress the 110 lb spring a 1/2 inch or the 125 lb spring???????

The rear seems to be softer in the rear with the 125lb spring :-k


Ok, The 110 spring said it had 440 lbs on it = 110 X 4 inches= 440lbs,
The 125 spring said it had 250 lbs on it = 125 X 2 inches = 250lbs
Now which one is doing what it is rated to do? Is one old and worn out? Is one rated lower than spring rate? That is why they make spring rate checkers. You can bet one or both springs are telling fibs.



Dennis both spring sets are new but they are the "Hyper coil" springs that Strange makes.......They may be wound different......

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Wed Apr 08, 2009 9:52 am 
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Beretta wrote:
Dennis both spring sets are new but they are the "Hyper coil" springs that Strange makes.......They may be wound different......


Barry I have no experience with hyper coils. Are they a progressive rate spring? A progressive rate spring starts as a lighter spring and as it is compressed it gains rate. Unlike regular springs that gain the lbs of their rate for every inch compressed. If I get a new spring, I check it then run it and check it again and every so often there after. They can go away, especially the lighter rated springs. I told this story before but I had a 90lb leaf flatten out on a trip to Fla. for speed weeks and it did it in the trailer. Since then I block chassis for even short trips. It was big money time and a sagging left rear. Had to re-arch spring in a press and beat the hey out of it with sledge hammer to normalize it. It didn't work great but worked. It was a one off spring for that car. I usually carry 2 springs, but this was an experiment we was working on the fall before and got good results from. The next closest spring I had wasn't arched to give the same rear steer. You guys would shake your heads if you seen that suspension in the 70s. leaf and slider with coil over helper in LR and 4 bar in the right. Under acceleration the LR would move to the rear as it de-arched, steering the car some. Under brake it moved back and helped get into the corner. Funny I see someone came close to it 30 years later and call it the Fast Boys set up for Mods. Everything old is new again lol

Like I say check rates and for any binding.

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Wed Apr 08, 2009 10:00 am 
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Beretta wrote:
Dennis both spring sets are new but they are the "Hyper coil" springs that Strange makes.......They may be wound different......


Barry I have no experience with hyper coils. Are they a progressive rate spring? A progressive rate spring starts as a lighter spring and as it is compressed it gains rate. Unlike regular springs that gain the lbs of their rate for every inch compressed. If I get a new spring, I check it then run it and check it again and every so often there after. They can go away, especially the lighter rated springs. I told this story before but I had a 90lb leaf flatten out on a trip to Fla. for speed weeks and it did it in the trailer. Since then I block chassis for even short trips. It was big money time and a sagging left rear. Had to re-arch spring in a press and beat the hey out of it with sledge hammer to normalize it. It didn't work great but worked. It was a one off spring for that car. I usually carry 2 springs, but this was an experiment we was working on the fall before and got good results from. The next closest spring I had wasn't arched to give the same rear steer. You guys would shake your heads if you seen that suspension in the 70s. leaf and slider with coil over helper in LR and 4 bar in the right. Under acceleration the LR would move to the rear as it de-arched, steering the car some. Under brake it moved back and helped get into the corner. Funny I see someone came close to it 30 years later and call it the Fast Boys set up for Mods. Everything old is new again lol

Like I say check rates and for any binding.

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Wed Apr 08, 2009 10:42 am 
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shrinker wrote:
Beretta; I think some of your measurements are incorrect. Please check the Height above the ground for the axle end lower bar and the upper bar.

The reason why I do all the measurements from the ground and from the axle centerline is the axle is the thing that pushes the car forwards and applies a torque reaction that has to be resisted by the four link. The centerline of the axle is where everything starts from. There are 2 places on the car that the physics start from, one is the axle centerline and the other is the crankshaft.
I dont mean to upset anyone but I argue that the concept of working out thrust lines or antisquat etc from the tyre contact patch is not correct. The tyre thrust occurs at the axle, thats where the forces come into play, not at the tread.
I always find it useful to exaggerate the design or shape of things in order to better understand them So consider this, you take the rear wheels off your drag car and install monster truck wheels. You also install lower gears in the diff so that the final torque applied to the tread is the same as you have now. Then you alter the fourlink so that its still got the same IC. Now who recons that car will launch the same and have the lift etc?


Ok if we have the same gear ratio including compensation for tire roll out and diameter and the same instant center, and the same COG and the same Traction and power, yes they should be as close as the efforts to make everything the same. I disagree a little on where force starts.not upset or wanting to upset anyone. The Action that creates force is at the tire contact patch. This is where we overcome the law of motion. Things at rest tend to stay at rest and things in motion tend to stay in motion. The car is exerting force straight forward at the tire contact patch, overcoming a car at rest. Sure the force is routed threw the Axle, control links, if it has them or spring in a leaf car or chassis in a solid car. Think of the toy monkey that rides the bicycle on a string with counter weight curved around and under string to maintain balance. Although the force is routed around a curve it still comes from the same place and it's line of force is the same as it started, keeping the monkeys balance. The downward force, ( straight down) due to gravity, never changes. If you bend the wire to the monkey, it may change the center of gravity and the monkey will be tilted on his side some still on the string. It's weight acting on the center of gravity and never moves to the wire or monkey, just acts on them. The line of force never moves, it's gravity to string, straight line. Maybe this toy is too old for some.

If you had trouble following this yell. I have a little science experiment that should clear it up.

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Wed Apr 08, 2009 11:39 am 
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Here's another question =; .....The 4 link brackets on the rear...There are 2 holes for the upper bar and three holes for the lower bar...By looking at the 4 link program and moving them I can almost get the same IC as I have now but the upper and lower bar will be closer to the CL of the axle.....So by moving them closer to the CL of the axle what does this do???????? :-k ....

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Wed Apr 08, 2009 5:22 pm 
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nlmsc33 wrote:
I'd say closer to the centerline =less leverage=softer hit on the tires.


Did I win anything?? 8-[


That's funny =; =; =D> You've just won the Daisy BB gun from Daisy gun company, plus, 100 BB's, Congradulations \:D/ \:D/

Ok, so maybe I was wrong with my comment, maybe we all need a class on suspensions, front & rear, what the heck, might as well do the whole car then :- :-

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Wed Apr 08, 2009 5:37 pm 
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Ok Barry, obviously, you may think you have a problem with your springs, now, you have two sets of springs, and my question is what springs came on your chassis when you picked it up from the chassis shop???? were they these progressive springs?, or a regular style spring? If, they were the reg. style spring, ask the shop(unless you already know) what the rates were when you got the chassis, I would think this would put you back into the game with a new set, but, if you have these progressive springs, hmmmm, we still will need some help on these questions you have.

Can you call or visit on a web site of a spring company and find someone who can send you a graph of what an extremely well setup chassis graph should look like and then mention what you have and are getting for a plot on your graph and get some insight from a tech guy? I just don't know enough about this whole suspension system yet, but, I am on a mission to figure it all out and if I have to I will pay for the help to understand it all even better. I am a (SEE) person, and if I see it, and then do it, I can usually figure it out from there, but many variables come into play with suspensions and power and C/G to get the results we would like to get. Maybe your just at the max of what your car can produce with your power for your best or lowest 60foot time Barry????!!!
I am not sure, myself, but a 1.20 60foot time is one hell of a fast start to me when we compare to MY 1.40 hits!!!! Next :-$

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 Post subject: Re: Suspension Dynamics.
 Post Posted: Wed Apr 08, 2009 6:54 pm 
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Giday Bubster, I agree with you the force that overcomes the inertia of the car is at the tyre contact patch. But what im saying is this, The force that is applied to the ground is at the tyre contact patch but its reaction is at the axle bearing. The axle bearing is the point where there is a forward force applied to the components of the car. The ground receives a force pushing away from the start line if you like, and the axle bearing receives a force pushing it towards the start line.
The force at the axle bearing is equal to the ground force. The connecting linkage design that mounts the axle bearing housing to the chassis of the car receives the forward force of the axle bearing housing. If the linkages are angled other that horizontal to the ground the force within the linkage rod is amplified The resultant force and direction (actually called a force vector)is transmitted to the chassis which reacts to this force in a predictable manner.
Perhaps I also didn't make it clear about the monster truck wheels, Ill use another example. Place go kart wheels or roller skate wheels on your drag car and change the diff gears so it goes the same speed and adjust the springs so that the chassis is sitting at the same ride height etc. Now adjust the four link so that the IC is the same as before. If your imagining this silly car correctly you will see that the four link rods are now all pointing at different angles than before. So the forces in each rod are different amounts and in different directions than the original and the reaction of the chassis is going to be different. We still have the same wheel center contact point and the same forward force at the ground and the same IC. We still have the same anti squat line etc. All the things that have been taught to racers for all these years are still there and arent different. SO why will the car react different? its because the way its been taught to racers for years is wrong.
What I'm saying is clear your head of the way you have been taught, and look at what happens in another way, break it all down into individual forces and directions. Its only then that you can see what is right and what is wrong.

Im not saying this stuff because I think I know more than other people, I'm saying this stuff because I think people need to understand correctly why things happen in order to make the best use of something. Its fine to think of the reactions of the car the way racers have been taught with IC locations and anti squat lines etc but these things don't explain why some people cant get a result that they want. There are limitation to the accuracy of this approach, in order for an explanation to be accurate it must hold up to all scenarios and observations must match the theory. I observed differently to the theory so I went searching for a better explanation.

When I started to get into this subject I couldn't hold it all in my head, I worked at it for decades frustrated, and I tried many methods to evaluate and learn. But then Microsoft Excel came along and I learned how to do a spread sheet and how to do circular referencing. I could then break it all down and get the computer to hold it in its head and that was the solution. I have spent my entire life (53) since I was 4 in the shed on race cars. I have always pondered the physics and always questioned people and tried to learn more. Its good fun. I have never ever written anything like what I'm doing now. But it frustrates me to see what I think are incorrect explanations being used for adjustments.


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