Too much TRACTION!

[TLM4t4]

This may sound silly but I'm having a problem with too much traction. We are very fast at our bull ring tracks. We qualify on the pole and run top 3 at all different tracks. But we have a few tracks around that are very fast momentum tracks with minimal throttle lift during qualifying. Went Saturday and didn't lift for both qualifying laps. The car is bogging very bad on exit, we have tried everything but for every positive we do for exit its a negative for entry and center. We are currently at a 425 LF spring, 325 RF spring, 200 LR, 250 RR, with a 250 5th at 35". The J-bar is 9" on frame and ½" above center of pinion. We have 53.4% L/S and 52.9% rear with 107 pounds of bite. Also when the track starts slicking off and taking rubber it starts picking the LF up and hunkering down on RR. All bars are standard except the left bottom and its one up, this is a 2008 Mastersbilt Smack down. Any and all help will be appreciated!

[Matt49]

This may sound silly but I'm having a problem with too much traction. We are very fast at our bull ring tracks. We qualify on the pole and run top 3 at all different tracks. But we have a few tracks around that are very fast momentum tracks with minimal throttle lift during qualifying. Went Saturday and didn't lift for both qualifying laps. The car is bogging very bad on exit, we have tried everything but for every positive we do for exit its a negative for entry and center. We are currently at a 425 LF spring, 325 RF spring, 200 LR, 250 RR, with a 250 5th at 35". The J-bar is 9" on frame and ½" above center of pinion. We have 53.4% L/S and 52.9% rear with 107 pounds of bite. Also when the track starts slicking off and taking rubber it starts picking the LF up and hunkering down on RR. All bars are standard except the left bottom and its one up, this is a 2008 Mastersbilt Smack down. Any and all help will be appreciated!

Less bite and maybe go up on the top right bar so the car will turn better on the gas.
If you're on the gas entering the corner like you describe, take everything anybody has told you about changing handling on corner entry and scrap it. Think more in terms of making changes that would normally be thought of as corner exit adjustments even for corner entry.
If you're truly on a momentum deal track, see about getting your RF shock rebound pretty stiff to keep it buried (but not bottomed out) all the way around the track. This will also help the car turn while on the gas because it decreases dynamic wedge while on the gas.

[TLM4t4]

Thanks for the Matt49, I really don't need the car to turn anymore I just need to lose traction. I like your suggestion with the RF. I know there's quit a few guys running around here with a 250 spring on RF. Could I soften the RF, add rebound, and take some j-bar angle out? Most people are running center of pinion or 1 below, we are 1 above center with all of our lead down low. I'm really stumped here!

[Matt49]

Thanks for the Matt49, I really don't need the car to turn anymore I just need to lose traction. I like your suggestion with the RF. I know there's quit a few guys running around here with a 250 spring on RF. Could I soften the RF, add rebound, and take some j-bar angle out? Most people are running center of pinion or 1 below, we are 1 above center with all of our lead down low. I'm really stumped here!

Then I guess I'm confused on what you mean by "too much traction". I took that to mean that you had too much LR drive on the throttle (what most people refer to as forward bite) not allowing the car to turn. What is the actual handling condition you're trying to fix?

[7uptruckracer]

How much are you traveling 5th? Could you use the traction you have if you delayed when the traction comes in?

[25drtrkr]

I think ur too soft and or long on 5th coil. I experienced the same thing on blue Rocket. We went from a 300@36" to a 250@38" and picked up WAY too much drive. I would try a 300 in the same hole and then move it back if that wasn't enough.

[Bubstr]

Never too much traction, just not enough horsepower. Gear change for a start. If that don't work, more cubic inches. Why do you think they run them monster 500 inch motors or turn up the RPM at places like Knoxville or Eldora. You can hear them grunt. There can be some disadvantages to overpowering a track, but can anyone see any advantage to under power one? This is why some carry up to 4 different power packages. This is why some stay off so called big motor breaker tracks.

The good thing is your doing a lot of things right.

[grt74]

don't know what engine combo your running but there have been several times that we have run a lot more gear than most just because we were tractioned up so much,im just guessing here but this sounds like a crate car

[TLM4t4]

It is a crate car, my super car is spot on. We have the j bar an inch higher on pinion than super plus different shock combination. I'm gonna agree on the 5th, I'm gonna put a 300 on at 35" which is standard. The 250 at standard works well with the open motor. As of now on the crate I'm getting around 3¼" of travel. What's puzzling me is when it tractions up it stays on the bars but it puts a squaring effect on the car laying it over on the RR and pulling the LF up on exit. Thinking about putting a 275 - 300 on RR to also try and hold that corner up better. But thanks for mentioning the 5th, come to think of it we softened it on the super car to try and stop blowing the tires off of it on exit.

[TLM4t4]

Squating effect sorry!

[john94]

are you saying add gear takes traction away ?

[DEKconsulting]

Not really takin away traction just changing where ur torque and horsepower come in. I have done this before an it does help

[Bubstr]

If you have the traction, use the hey out of it. Drive it in harder, roll the center faster. More speed brings you farther into torque curve. If your flat footing it, higher numerical gear, will get you into torque curve farther. More RPMs = more HP. If you have the traction to use that HP, use it. Changing grooves can improve your corner speed at times and get you farther into the torque curve and have the wheel speed to take advantage of it. High side momentum. If the track is agreeable. Warning the end of straight a way RPM has a live or die number, dictated by you pocket book and how well built your engine is.

[7uptruckracer]

But he said its a Crate Car.......

[7uptruckracer]

You're running a crate with higher then normal bite if its a 604 or 602 on a RUBBERED UP race track which is its own animal. Which CRATE engine are you using 602, 604, 525? with your lack of HP are you sure its not you lugging the engine down instead of too much traction I mean its kind of the same kind of different. You're not over traveling the 5th by any means. Maybe you might want to think if you're running to much upper bar angle on both sides. You could have to much dynamic thrust for your motor and your track conditions. Maybe think about dropping both upper bars a hole.

[TLM4t4]

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.

[TLM4t4]

And its a 604, if I put more gear in it then it hits limiter or falls on its face. I can't drive the car any harder, flat footing it now. Thanks for all the help, we getting a lot closer!

[powerslide]

how much slack in RR chain?

[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.

shorten the lr chain limiter,but it will only take a little say a 1/4 inch,just remember if it gets super slick you need to let it back out,there is also alot of different areas to take away traction so its hard to say,i guess my question would be where does it have to much traction(I'm guessing off the corner and causing a push)you could lengthen the rr or more stagger,if the right side tires are in the track to hard you could go up on your left side%,just need to know where in the corner to help,if the rear tires are in the track to hard you could loose some rear weight,see what I'm saying there are alot of different ways to free up a car,if you have it that close you could try a 1" spacer on the rr as an easy adjustment that way when it slicks off you can take it back off

[25drtrkr]

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.

[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.

[grt74]

If somebody hands you a fish, you eat today.

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

maybe i need to go hungry for awhile(it wouldn't hurt to loose some weight),as always you have great advise

[25drtrkr]

If somebody hands you a fish, you eat today.

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

That is true.......unfortunately, in dirt racing, a lot of the "fish" you catch, don't even qualify as stink bait!

[RacerX10]

I'm chiming in a vote for gear change. What's your high RPM reading ?

[7uptruckracer]

I don't guess anyone reads this is a CRATE car...... and he said hes bogging....

[fastford]

your right 7up, I often wander why they even have a crate section any more, cause no one uses it.

[TeamGRT12x]

Very simple, raise left lower, raise right upper. I don't see why everyone makes this stuff out to be rocket science.

[TLM4t4]

OK we found a solution and it sounds very silly but won 2 weeks ago and been top 3 ever since. Put a 300 on RR spring, dropped down on the pinion to 1 below center, pulled right bottom rod to the top, raised left bottom rod to one up from standard, top rods standard, LF 375, RF 375, and LR 200. We also have about 160 pounds of bite to rotate center with no dummy. I know this sounds silly but I think if you don't have enough j-bar angle to keep RF planted you are using only your rear for traction giving it a squating effect. We went as low on chassis and high on pinion as possible and made it worse, only to mention all our lead is low. Seems like a double edged sword and I'm sure everyone thinks this is crazy but it worked!

[swartzman]

160 pounds on the left rear, I never would have guessed that.. we never go over 30 for any track.. but what works for you go for it.. the main thing is you kept working at it til you found what worked for you and like grt74 and masterbuiltracer try to explain to everybody they can get you headed there but you got to find what you like which is trail and error..

[swartzman]

something not silly is the 300 200 combo on the rear that's money in the bank on a high speed momentum race track.. we use a 275 or 300 depending on the track

[MasterSbilt_Racer]

160 pounds on the left rear, I never would have guessed that.. we never go over 30 for any track.. but what works for you go for it.. the main thing is you kept working at it til you found what worked for you and like grt74 and masterbuiltracer try to explain to everybody they can get you headed there but you got to find what you like which is trail and error..

Swartz cars are the exception, not the rule with that no lr weight stuff.

[Dirtmod13]

Is that for dry slick or rubbered up surface? Seems like the soft left front paired with the heavier rr makes sense for entry but it's not too loose in mid and exit?

[wfo77LR]

you can't have to much traction I was at racewise school put on by rocket chassis and mark bush (look him up if you don't know who he his) someone raised there hand said they have to much traction he just laughed and asked if they would teach the class because you can't have to much traction

[Matt49]

When most people say "too much traction", they mean "the car won't turn when I'm on the gas".
Mark Bush is great at explaining traction "management" and when somebody phrases a question like that, he is usually quick to correct their terminology after figuring out what the problem really is.

[7uptruckracer]

Bingo Terminology is a big deal when you're trying to address a problem correctly

[Matt49]

Exactly, a bit off topic but prime example: For the longest time, my dad and I were having some communication breakdowns on shocks. Like I would tell him I think we need a little less rebound in the RF. He interpreted that to mean that I wanted the RF to rebound less (stiffer) but what I meant was I wanted less rebound control (softer). We've both had to adjust the way we talk about shocks to make sure we're on the same page. We no longer use "less" and "more". Just "stiffer" and "softer".