How to Build Traction in a Dirt Late Model

4 link rear suspension is some of most complex geometries in motor sport. This Video explains forces generated by these rear ends. For info on adjusting 4 link suspension see my Detailed Track , Adjustment Guide (32 pages long) for dirt late models and applies to 4 link MODS follow link below. Adjustment guide breaks down adjustments into desired and undesired effects it has on these dirt late models. Included is the guide to scaling and what to check and measure (54 Pages long) I also include all set up info I use on these DLM cars new and old.
Set up guide www.paypal.com/instantcommerc...
Adjustment guide www.paypal.com/instantcommerc...
Tire guide www.paypal.com/instantcommerc...
Tip Jar paypal.me/superdave10

[@doughirsch9930]

Thank you! Learning a lot from your videos, trying to apply this to my own road racing 4 link setup. Any thoughts on setting up a 4 bar for the road course?

[@DirtTrackDave]

Glad they are helping Doug. I have a variety of customers competing in different forms of motorsport like land speed cars, saloon cars, and sprint rally stuff. For road racing two key things compared to DLM geometry,. One: longer and way flatter (less angle) bars for less movement. Two: Liftbar set up less aggressive, don't need all the hike or anti-squat that we require. Always glad to expand potential gains from working with other car types. Feel free to contact me about more 4 link information.

[@austinjones6963]

Great guy, no one else in the dirt world will work with you like this guy does!

[@DirtTrackDave]

I appreciate that Austin!!!

[@KEIFabrication]

Hey Dave. Thanks for the amazing videos and explanations of the science behind chassis dynamics. I was a development engineer for Competition Engineering from 1998-2006. I was using CAD software and testing to design suspension components for drag & oval track racing. I was using cameras and video mounted on vehicles (before Go Pros LOL) to better understand what is happening throughout the race. Nothing fascinates me more than the dynamics on the dirt late model. Thanks for posting all of this! It makes me smile and my brain instantly goes to work trying to develop an understanding of what goes on and how these forces effect traction and other handling charactoristics. My most challenging project was developing traction components for the front wheel drive drag racing platform. Believe it or not, the dirt track technology and suspension design is very similar to FWD drag racing. Your channel is extremely helpful!

[@DirtTrackDave]

If you like to get greater in depth can try my guides until I put out next set of videos. Set up guide www.paypal.com/instantcommerce/checkout/4J87KMZC9D5PU Adjustment guide www.paypal.com/instantcommerce/checkout/9974U9XA5MTYS Tire guide www.paypal.com/instantcommerce/checkout/W6GF2X6VSBNFN

[@nolimitaustin2775]

Dirt track dave to 10k!!!!

[@DirtTrackDave]

Ahhh yeah!

[@jamesparrottjr3396]

Thanks

[@H3110NU]

Just a fan trying to understand how these cars work, slowly getting an understanding

[@DirtTrackDave]

I have items to help you shorten the learning curve I have guides for set up, making adjustments at track and tire work. Along with one on one consulting.

[@classicpanelcompany2461]

Hi Dave, I'm over in the UK and Do a similar type of racing, Except go clockwise around the track, but looking to build a new car again next year, i've not built this type before where the car is front engined RWD, most of my previous car builds has been rear engine RWD, If building from scratch is there certain things that go in certain places give or take an inch? I will only have the wheel base of the original car to start with.

[@DirtTrackDave]

Please email me with some more information on your needs @ [e-mail]

[@jerrellkull5347]

On the subject of roll-steer. I've always worked on the theory, not fixing a problem by taking out bite. With that being said, roll-steer is loose steer, taking out bite to make the car turn, if anytging i like tight-steet, pushing bothe rear tires the same distance. Long bar bottom, short on top.

[@DirtTrackDave]

And you are not wrong. As we all know there is more then one way to skin a cat. Having said that, you can't drive a car as sideways in slick as you can in heavy. If a car has large natural amount of roll steer it will keep wanting to turn car in slick. Taking bite out makes a car less likely to get to max droop as fast feeling like less roll steer but not as great of change as moving plates or changing bar lengths. Just depends on needs of driver to make car work for him or her.

[@fightneagle1255]

Do you have any videos on when you should lengthen or shorten your bars? Any help is appreciated.

[@DirtTrackDave]

Try these two links to my other vids to start with. If still needing help contact me via email or my facebook page: facebook.com/dirtlatemodeltechtips kzbin.info/www/bejne/d2mWn4N5oN2Iiac kzbin.info/www/bejne/sJTQhWZoachoipo

[@ThatBCGuy]

bought my first latemodel a few weeks ago, ive been racing all my life in lower divisions and always helped friends with their LM stuff, so i know an ok amount. But i am having trouble with lift bar fitment, any way you might could point me in the right direction?

[@DirtTrackDave]

Yes check out these items I offer in description below video

[@DirtTrackDave]

If you need to message me you can on my Facebook business page. Link is on my channel page.

[@Chromedome-ss6mg]

I'm trying to set up my late model on world of outlaws playstation 4, lol . There is alot of settings. My dad used to race them in the late 90s.

[@DirtTrackDave]

Well I have found a the relationship between real world and sim adjustments is not the same. The accuracy in sim DLM racing is way off. Similar but off.

[@thomasmiracle7826]

I destroyed my right rear shock and dont know what to buy to replace it took the old one off took it to speedway they said they dont know i love to race but am just learning as i go on the suspension what should i use

[@DirtTrackDave]

Please email me and I sent you info to what you need.

[@russellpatterson7778]

What size chain is good to use for holding the rear end for pre load

[@DirtTrackDave]

For LR chain I use minimum of 1500 pound chain.

[@TJDmotorsports]

I couldn't get the set up and scaling guide to work. Says not found on link,

[@DirtTrackDave]

Set up guide- www.paypal.com/instantcommerce/checkout/4J87KMZC9D5PU Adjustment Guide - www.paypal.com/instantcommerce/checkout/9974U9XA5MTYS Tire guide - www.paypal.com/instantcommerce/checkout/W6GF2X6VSBNFN

[@jasonmorey7467]

Could use your help with an 06 Black Rocket.

[@DirtTrackDave]

Email me if you would or go to my Facebook page www. Facebook.com/dirtlatemodeltechtips

[@ChrisS-oo6fl]

Never let the RR lower go below zero? Total Nonsense -5 is an extremely useful position as long as you comprehend what your doing the effects on drive angle, wheel base, indexing, etc. negative bar angle is still used often.

[@DirtTrackDave]

Only useful for a crutch in my findings. RR lower below 3* at static means in dynamic you go below 0 and likely around -2 up to -4* . This means the bars go from one thrust direction to zero and then a negative thrust direction. This results in forces countering each other instead of working together. I found the 4-link rear end set up works best and more efficient if a bars forces all pushing same direction. Both LR and RR. However in tuning these things we are not taking grip away necessarily but changing it from one side of the rear end to the other. When tracks are heavy you want more right rear drive, more RR angle especially in the right rear upper bar. However this is the opposite when it's slick. I do decrease my angles on the RR but I never go below zero not lower because it creates an imbalance and the timing and how they're working together LR vs RR that is. But when it's slick I decrease that angle to allow it to work much slower and not get on the bars as quick. This makes the LR drive longer before the RR comes in resulting in more straight line traction exit to just on straight away.

[@coldstuffsmallpecker321]

Do you think something like this could be applied to an autocross car? It’s a torque arm setup currently

[@DirtTrackDave]

Yes there is huge mechanical traction to be harnessed from 4-link system. Just have to tune aggression you want in car.

[@charlesprice915]

Mr Dave is this a lsx or LS2 TNT ?

[@DirtTrackDave]

Charles, that was a 2019 TNT with my standard a-arm lengths I start with majority of the time with customers. The spindles STD TNT with tie rods in forward position for smoothness down straight. Caster and camber are set to my baseline specs, I put everyone on to start same as in set up guide. Rear end 4 bar plates removed and my geometry and range of adjustment custom plates was installed. LR shock mounts relocated, and 5th and 6th also relocated to my base position. All ride heights we altered as well just slightly, springs my baseline same also as in guide. Shocks modified as needed to get attitude and desired feel for driver.

[@nickknickerbocker6415]

🔄 Ok ~ How do U Adjust Bump Steer ¿

[@DirtTrackDave]

It is explained in set up and scale guide

[@haroldzuniga2280]

What is the proper bar angle on a three bar set up on the top bar?

[@haroldzuniga2280]

2:48 Sunday June 4

[@DirtTrackDave]

Center link starting 13-18°

[@raymondbrandt7831]

Hey Dave you need to tell Hunt the front how to set up there slow ass cars

[@DirtTrackDave]

Well if they want on my program all they have to do is contact.

[@jamesglass3278]

Are you in East Tennessee?

[@DirtTrackDave]

Not currently, but Knoxville about 3 hours from my house. I do travel and help teams at all levels. If interested can message me on my Facebook page facebook.com/dirtlatemodeltechtips

[@ohbeazley]

hey i see ur setup sheet is free how can i download that

[@DirtTrackDave]

Message me on Facebook at www.Facebook.com/dirtlatemodeltechtips

[@CoGDWW]

There was a significant rotational force left out of this video. Anyone know what it was?

[@curt9i]

Driveshaft rotational direction.

[@DirtTrackDave]

You are right, not considered by most to do anything but it does have an effect usually over looked. And to be honest I really didn't consider it Factor to brought to my attention even though it's crossed my mind but being so narrow and low torque due to its size. But regardless there's still a force being applied.

[@curt9i]

There is 500+ lbs of engine torque being applied to the rear end gear as the rear end converts driveshaft rotation to axle shaft rotation. Drag strip racers run the left rear heavier to accommodate this effect. Circle track racers mistakenly assume that it is only to counter dynamic weight bias from turning left. I thoroughly enjoy your videos and thank you for this conversation. Keep up the great videos please!

[@CoGDWW]

@curt9i Now lets consider what happens to the effort at the lift arm when we change gear reduction. It changes. This will result in dynamic elevation change at all 4 corners of the car as the torque at the moment is changed.

[@chrisstevens8935]

Have some questions I race a 2018 Swartz wanting some good thoughts on my late model I hate when you ask people question and all they say is talk to the chassis builder and lot of times people use other setups if you could help out I’d appreciate it

[@DirtTrackDave]

If you would email me @ [e-mail]

[@mrj197]

You need a new mic

[@jayirving6996]

why dont ya make a video with some swing arm tech instead of all this 4 bar gayness!!!!

[@DirtTrackDave]

Jay the z-link and swing arm have their uses and benefits. They still run in specific dirt motor sports and asphalt. However the swing arm is inferior to the 4 link geometry. The 4 link uses 100% of forward thrust to drive that side of rear. Where swing arm does not it's less then 50% since one bar is inverted. For old school this was on as cars were not as efficient with 4 link as they are now days. So swing arm take a little drive out yet cut down roll steer as well with it's up and down motion. Where as 4 link is down and forward.

[@mikejones-jk3ts]

That don't tell you s***

[@DirtTrackDave]

Well there good information, basic I say and needs to be common knowledge. However more information is available.