Too much TRACTION!

[grt74]

I stiffened the 5th to a 300, also put a 300 on RR along with a super high rebound RF. Helped the car tremendously! Now I still have a tick too much traction. Car has a hopping effect on exit but I'm kind of leaning to putting a dummy on LR.

so i have read this again and you have said that you want to take traction out and the adjustments you have made above adds traction to the car,so let me explain why,the 5th coil you went from a 250 to a 300(this will load the rear tires quicker and harder)I'm guessing it was at the same measurement,next you went from a 250 rr to a 300 rr,what did that do???well it put the rr in the track more(simple physics),yes it frees it up on exit(because of the added traction)but it also tightens it up on entry(again because of added traction)so with all of this said,you have added traction to the car!!!and didn't take it away like you have said you wanted to do(not being a wise guy just trying to explain a little) but what I've said before on the last post if its hopping on the gas coming off the corner and down the straightaway look at the lr chain limiter,just trying to help,

[25drtrkr]

so i have read this again and you have said that you want to take traction out and the adjustments you have made above adds traction to the car,so let me explain why,the 5th coil you went from a 250 to a 300(this will load the rear tires quicker and harder)I'm guessing it was at the same measurement,next you went from a 250 rr to a 300 rr,what did that do???well it put the rr in the track more(simple physics),yes it frees it up on exit(because of the added traction)but it also tightens it up on entry(again because of added traction)so with all of this said,you have added traction to the car!!!and didn't take it away like you have said you wanted to do(not being a wise guy just trying to explain a little) but what I've said before on the last post if its hopping on the gas coming off the corner and down the straightaway look at the lr chain limiter,just trying to help,

With a stiffer fifth coil, you have taken less weight transfer off of the front tires. The more wrap up you get, to a point, the more weight is transferred.

Now, I do agree with you on the RR change. He added traction to that corner, off of the gas, but that's a small adj and he felt it helped him more off the corner.

[grt74]

With a stiffer fifth coil, you have taken less weight transfer off of the front tires. The more wrap up you get, to a point, the more weight is transferred.

Now, I do agree with you on the RR change. He added traction to that corner, off of the gas, but that's a small adj and he felt it helped him more off the corner.

if you compress the springs 2 1/2 inches each(250x2.5=625,300x2.5=700)which one is loaded more,now i do agree you can go to far on the 5th coil because there are other factors there that are needed (track conditions and or traction available,because if you were on ice you would go very soft because of the track conditions),so with all of that said, if you use above,you would have 75 lbs more of lifting force on the 5th arm bar,which in theory should load the tires harder(which is added traction)

there are a lot of factors for the 5th coil area,it has to be a combination of traction available,spring rate,wrap up,where the top of the 5th arm is mounted,and how far out it is mounted on the bottom from the rear end housing,but if all he did is change his spring to a 300 from a 250,he added quicker traction,ill leave it alone now,and I'm not trying to be a wise guy,just trying to explain a little,good luck to all

on the rr he added traction to the entire corner(it helped turn the car on the gas because of the added traction)

[grt74]

but yes some will think that you have added traction to a car by softing a 5th coil spring and in some cases you do,but its because the softer spring doesn't shock the tires as hard and in most cases you have limited traction, if one doesn't believe me just do your own little test,start at 250 and work your way up to say a 450 in 50lb increments,if the traction is consistent the car will get faster and faster but there will come a point that it will start to pick up the front end off the ground(now theres some traction)or the traction will be limited(because of track conditions) and it will start to buzz the tires,its all a compromise

[let-r-eat]

Agree with GRT74. Compromise.

[25drtrkr]

if you compress the springs 2 1/2 inches each(250x2.5=625,300x2.5=700)which one is loaded more,now i do agree you can go to far on the 5th coil because there are other factors there that are needed (track conditions and or traction available,because if you were on ice you would go very soft because of the track conditions),so with all of that said, if you use above,you would have 75 lbs more of lifting force on the 5th arm bar,which in theory should load the tires harder(which is added traction)

there are a lot of factors for the 5th coil area,it has to be a combination of traction available,spring rate,wrap up,where the top of the 5th arm is mounted,and how far out it is mounted on the bottom from the rear end housing,but if all he did is change his spring to a 300 from a 250,he added quicker traction,ill leave it alone now,and I'm not trying to be a wise guy,just trying to explain a little,good luck to all

on the rr he added traction to the entire corner(it helped turn the car on the gas because of the added traction)

It doesn't work like that. That would be the same as softening the rf to gain more forward traction.Instead, when you soften the rf, all you have done is increase weight transfer to the rr. Not only is that is what I felt from experience, but also the Rocket camp has confirmed that with me during many conversations.

[grt74]

It doesn't work like that. That would be the same as softening the rf to gain more forward traction.Instead, when you soften the rf, all you have done is increase weight transfer to the rr. Not only is that is what I felt from experience, but also the Rocket camp has confirmed that with me during many conversations.

any time you add spring rate anywhere on a car, your adding traction,but just like anything on a race car you can over do it and it will cause crazy effects,yes i agree with your above statement,a softer spring on the rf takes traction away(it looses forward traction),and if your speaking on the 5th coil area,just try the test,good luck,I'm probably to technical at times for my own good

[25drtrkr]

any time you add spring rate anywhere on a car, your adding traction,but just like anything on a race car you can over do it and it will cause crazy effects,yes i agree with your above statement,a softer spring on the rf takes traction away(it looses forward traction),and if your speaking on the 5th coil area,just try the test,good luck,I'm probably to technical at times for my own good

So if your car wont turn on entry, you put more rf spring. That doesn't work on the tracks I race at. I'm certainly not bragging, but I've been doing this for 25 plus years. I've tested just about everything on 5th coil setups and longer/softer 5th coils gave more forward bite.Fifth coils are torque absorbers so you don't shear the tires contact patch. Maybe its just the sandy clays we race on, but Josh Richards told me he does the same adj.

[grt74]

So if your car wont turn on entry, you put more rf spring. That doesn't work on the tracks I race at. I'm certainly not bragging, but I've been doing this for 25 plus years. I've tested just about everything on 5th coil setups and longer/softer 5th coils gave more forward bite.Fifth coils are torque absorbers so you don't shear the tires contact patch. Maybe its just the sandy clays we race on, but Josh Richards told me he does the same adj.

i give up,good luck it sounds like you have it figured out,there are 4 corners to the car,you have to figure out which adjustment works for you,

and if a softer 5th coil gave your car more forward bite,back up your explanation on why,i think you will find my post to be true,hey by all means I've been wrong before and ill be wrong again and I'm not perfect,and like I've have said i agree with some of your statements,as far as how it made the car handle,but my question to you is why did it make or help the handling of the car better,I'm speaking mostly from a physics stand point and testing(and i do some crazy things testing 99% of the time i don't find anything but every now and then you find a ton)

good luck to all and i hope I've helped some,i really don't give the whole answers away,i try to tell someone how and why on there race cars and let them make there decisions,so they learn also

[25drtrkr]

SMH.....I wish I had it figured out! But that's what keeps me coming back after all these years. As you know, you can know the theories of racing dynamics, but it doesn't always apply to dirt racing. Most of those are based on a hard, non-compliant surface, but we race on a more softer, uneven moisture content, and last but not least, the effect od soil shearing on the tires contact patch.Then if that's not enough, you throw in the different types of tire compounds, we have to run.In the end, its the 10% that seperates us from the rest of the racers.By that I mean, its making changes that works for us and our driver.....Good luck to ya!

[7uptruckracer]

You said the car was hopping on the bars.....that in my experience is to much bar angle on uppers to much jbar rake or to short of jbar. I would still drop both uppers 1 hole. Or like someone else said move your chain maybe on LR or maybe even LR and RR same amount since that would also be limiting dynamic bar angle gain. What does everyone else think being he did say its POGOing

[MasterSbilt_Racer]

So if your car wont turn on entry, you put more rf spring. That doesn't work on the tracks I race at. I'm certainly not bragging, but I've been doing this for 25 plus years. I've tested just about everything on 5th coil setups and longer/softer 5th coils gave more forward bite.Fifth coils are torque absorbers so you don't shear the tires contact patch. Maybe its just the sandy clays we race on, but Josh Richards told me he does the same adj.

My testing has often given opposite results. It all comes down to giving the tires the load as fast as they can handle it.

[fastford]

not wanting to change the subject here, but the talk above about wheel hoping and a limiter chain made me think of a car I noticed a while back. it was a over rail car and had a 6th coil set up like you run on the lift bar on the left rear for a limiter, it made since to me, has any one else saw something like this?

[MasterSbilt_Racer]

not wanting to change the subject here, but the talk above about wheel hoping and a limiter chain made me think of a car I noticed a while back. it was a over rail car and had a 6th coil set up like you run on the lift bar on the left rear for a limiter, it made since to me, has any one else saw something like this?

I tried one in 2005. Car wheel hopped terribly.

[25drtrkr]

I guess there is one important, if not MOST important, things we have not included in this discussion..TIRES! Whether you race on soft or hard ones and all the different track conditions we each race on. I read one engineers thoughts, and he said "the hardest thing in dirt racing is deciding why a particular tire is sliding....too much load or not enough"!

[stock car driver]

25drtkt, your posts are confusing at best.

Seems as though your a crew guy?

It makes it hard to give merit to anything you post when you appear to just be regurgitating information from others, not first hand knowledge.

On the Smack cars I worked on, we would start with a 300 in the second hole forward.When the track slicked off, we would put a 325 in the first hole.This is what the house car was doing at the time along with several other adj to tighten it up.As a crew chief, I never worked so hard between heats and feature, trying to get the car tight enough.There was a lot of time consuming adjustments.

but also the Rocket camp has confirmed that with me during many conversations.

but Josh Richards told me he does the same adj.

[25drtrkr]

I see I didn't explain that very well. My point was that with the older setups (MB Smack cars), we always went shorter and stiffer to gain forward traction. Now, with the newer setups, longer and softer gives more traction. When you've consulted drivers such as EPJ and Josh, and you try what they recommended, and it works, why argue with the reasons why?

[MasterSbilt_Racer]

I see I didn't explain that very well. My point was that with the older setups (MB Smack cars), we always went shorter and stiffer to gain forward traction. Now, with the newer setups, longer and softer gives more traction. When you've consulted drivers such as EPJ and Josh, and you try what they recommended, and it works, why argue with the reasons why?

If somebody hands you a fish, you eat today.

If you know how to get the fish, you never go hungry.

[Bubstr]

It is important to understand why, so you don't trip on the same stumbling block again. Chassis change, engines change and drivers change. The only thing that stays constant is the laws of physics. If you understand them, there is always a reason these cars do what they do. It's applied forces and resistance values.

Did you ever wonder, why guys like Moyer, Bloomquist and Berkkoffer can change cars and still have great results? They may lack in a automotive engineering degree, but we would have to give them a A+ in shade tree engineering.

Take Wheel hop. Hop would suggest some kind of oscillation. Loading and unloading of the tire contact patch. From there, there are many possible reasons that align with the Physics. Physics is law and some of these laws have been law for a Millennium and still prove true. It's how we apply these laws, where it goes astray. Looking at a problem in a single plane, when it's a multiple plane problem. Take the tire contact patch as a example. It is a point vector for several forces. Think of the other planes that effect this simple point vector. Angle of force, amount of force, the multiple directions of force, is the force constant, do the force vectors change, are the forces constant due to material, a bump, a big bump, side wall rigidity, rim size, air pressure, tire elasticity, tread, the track surface it's self just to name a few. These variables are the reason Physical law seems skewed, when it is not. I'll grant you, it may be close to impossible to find numbers for all these, but they are things that help you detect the problem. When you do find it, it makes Physical law make sense. Your job is detective, more than mechanic, most of the time. These laws are tools to depend on, because they don't change. Most all here know more Physical law, than they think they know. Don't let it scare you. Things in motion, tend to stay in motion and things at rest, tend to stay at rest by Izack Newton, descries shock valving and corner transition and weight transfer basics along with forward drive and picking a gear.

[25drtrkr]

25drtkt, your posts are confusing at best.

Seems as though your a crew guy?

It makes it hard to give merit to anything you post when you appear to just be regurgitating information from others, not first hand knowledge.

Not first hand knowledge??? Do you not read your own quotes? All of my posts on here are things I have personally tried or tested. When I used the term,we, I was referring to it as a team, which always means I was the crew chief. Im not one to offer advice if I haven't personally tried it before.