How To run Drag Slicks with over 100% Anti-Squat! Start HERE!

Thanks Kevin your videos are helping me a lot.

Curious what your thoughts are with setting this method up on a ladder bar car is? I was about to make the switch to radials anyhow...

Hey Kevin, forgive me if you have already covered my question in a different video. How much of this video applies to a ladder bar car? And if it doesn't apply, can you please do one like this for a ladder bar car.

Excellent video one question on front slick what psi is in range cheers

Sorry for your loss I also what to thank you for all your videos very helpful getting my suspension right cant wait for more information to come thanks

Hi Kevin,
Awesome videos! How would you set up a ladder bar car on 10” QTP’s running on virgin streets? Heavy G body at 3600 lbs with 1000+hp. Right now I’m at less than 100% anti squat and having a hard time getting it to hook. On virgin streets what would be more important.... weight transfer or anti squat?

How important is IC height when your trying to get around 100% antiisquat? Say the camshaft is 17" off floor is it ok to be towards the 9"s?

Your videos are great and the presentation is clear and concise, thanks for that...
All of the static descriptions are easy to see but understanding how it all work dynamically is where it gets tricky
Perhaps a power point animation could be put together which could show how the IC point varies with ride height and how
the AS line can vary with sidewall compression and how the torque application, weight transfer and varying surface conditions effects all of it. LOL just kidding...
Thanks again for another great video.

Great video 👌.. I will likely need to watch several times to truly understand.. my situation ma be a little bit unique, I have a 75 Cosworth Vega with the fuel overhead cam 2.0L. I'm hoping to do some drag racing with it next year (covid permitting 😅) and wonderuhow much it would benefit me to change the lower control arm angle to provide anti squat.. I'm only making about 150 hp but my torque is around 110lbft😢 so I would be leaving the light around 3500/4500 rpm to keep the motor out of a bog situation, but with 13" tires traction is now the issue.. being a torque arm suspension can I get away with just lowering the control arm at the axle and maybe adjustable shocks to achieve more traction on a street tire or would I just be pissing into the wind.. again..great vid👍

Great video . we are on the same page, i tune a lot of peoples cars and i have been setting their cars up with radial inspired setups with slicks for a long time. i have a Turbo chassis car/Blazer that leaves like a nitrous car and no body out 60 foots me on the street. Belfab Race Cars

Just found your channel recently, awesome source of info and finally getting a solid above average understanding of what’s going on with rear suspension. Towards the end of the video when you were talking tire pressures, is that referencing small or big tire cars? Thanks for what you’re doing man, keep it up!!

I think u can get better 60ft closer to 100 percent squat because if you hook you will waste alot less energy if you dont squat or seperate wheels from body.

Question about cars running big tire slicks on a front wheel drive car. Under acceleration the rear tire and chassis are moving together instead of opposed but as I understand it the anti squat calculation is still the same. Is this correct? Can you still run a high anti squat to minimize the anti lift on the front since the anti lift angle will increase as the back comes up? I can’t see any physics model that would cause the front to squat so this is the only model I see to minimize the front end unloading. Is my thought process sound? And would it still benefit from longer or shorter side view swing arm?

What happens when you unload the tire

Wow when I started racing 40 years ago we didn't have any of this stuff and we have to figure out how to drive those cars great stuff now I do a little stop light to stop light street racing and show but this is good stuff if I get back into it I'll look you up in person thanks again

How do i get in touch with you for help with my car?

Kevin Wilson Im glad I stumbled across your videos. I just started watching yesterday. So you talk about slicks and drag radials. I was wondering how you classify the Hoosier Quick Time Pro tires? Which way would you suggest to set the anti squat for the QTP tires - more towards the slick or radial setting? I run the QTP 27x11.5x15. I noticed the QTP likes around 15-17 lbs air pressure (pressure measured before burn out).

Car is a 70 Cougar 520hp/450tq at flywheel. I have the Calvert stock height split mono leafs and the CalTracs bars and weighs 3110 lbs with me I have always had the bar in the lower hole. Shocks: for 12 years I ran the same set of Lakwood 50/50 rear and 90/10 front. They wore out so my buddy gave me his from his 69 Cougar but have not tested yet due to no time. I now have the Rancho 5 way adjust rears and Calvert 90/10 front. I know the info I gave you is less than what you probably need but im just curious. Again, great info man.
--Matt

Kevin you have taught me a lot on suspension thanks to your information I’m successfully hooking on a radial at the track ( adjustable coilovers, traction bars on leaf springs Sierra 14’ ) now I’m watching your videos so I can be successfully hook at the street with slicks keep up the good content

Hello Kevin...What you say make perfect sense with something I had heard many years ago which was to pull up on the wheel opening and then push down on the fender. Your feet are experiencing the load between the tire and track. To get the best traction you want the tire to wheel arch to separate (pulling up not pushing down). I believe I heard you say, but maybe not in so many words, that for both a radial and a slick you want separations at the rear and not squat. Is that correct? If you have a multi-link rear suspension (modern factory stock) do you also want separation or is squat needed? It seems like most if not all cars with unmodified suspension have squat on the left rear. Is it possible to have separation with a modern factory multi link suspension? Thanks and BE SAFE

Love all the videos thank you so much for all the knowledge! What about 4 link setups on street conditions, where you need squat and weight transfer to keep it hooked up?

Like to chime in. If its pounding the sidewalls just add air pressure. I heard you mention "16psi in radials" well that's where people should start out on slicks when running anti squat. Its gonna drive the rear tires into the ground so make sure you're adding air pressure. Tire shake and tire chatter is mostly low tire pressure. Slicks can act just like a radial you just have to run more air pressure. Keep adding every pass until it finally spins then back them back down some. My general starting points are full loose rear rebound, 5-8 clicks from loose rear compression, and 15-16psi in the tires. Then add to everything throughout the day except rebound unless it has excessive separation.

Can you recommend some books to read to more understand i meN i have a real good idea of what's going on and I will orob watch this a few more times great stuff man

Good stuff Kevin. Thank you for all this information.

Can you please go into more detail about Cal trax systems. I've watched you other video
And I'm real interested in leaf springs and 4 link combo. Thx.
Love your content.

Good videos Kevin. I do feel like I need to add something though. This all applies to people bracket racing, looking for a dead hook on the tire. However, maximum acceleration occurs between 20-35% tire slip on a Drag Slick. This can be proven by looking at a G-Meter. To do this on a well prepped track, you NEED squat to induce tire spin. Ideally, you would use the wheelie bars to do this, and set the 4-link up to stay 100% neutral. Almost every fast Big Tire car (Pro Mod or Outlaw) uses this strategy for a much quicker 60' and ET. You try to manage power to keep the tire spinning at the optimal slip as long as you can, or as long as you have the power to do so. That is the fastest way to get a car down the track, BUT it is not easy. Just figured I would throw this in here because it does apply to the very high HP cars of today.

Talking about "setting" "Bar-Angles" is completely absurd.
The location of the imaginary "Instant-Center" is what counts,
how you achieve that is almost irrelevant.

If you have reasonably long Suspension Travel, (which you should),
the Instant-Center will MOVE from less than 100% to more than 100% as the Car Body rises.
The distance between the Rear-Axle, and the Center of Gravity of the Car,
should be expressed as a PERCENTAGE, not necessarily how many "Inches",
when referring to how "long" the Instant Center is.
A smaller percentage of that distance results in a more violent,
and much shorter in duration, "Hit" to the Tires.
A larger percentage of that distance results in a softer, but much longer,
application of additional, temporary, "Effective-Weight" being applied to the Tires.

Here is what you are trying to achieve in the long run ..........
You are trying to lift the entire car off of the ground by using the
Torque of the Rear-Axle.
This applies MORE-THAN the full weight of the car to the Rear Tires ..........
Until the Suspension "Tops-Out".
The Front Tires need to be off the ground just BEFORE the Rear Suspension "Tops-Out".

Both the Front AND Rear Suspensions should "Top-Out" at "almost" the same time.
The Front Suspension needs to "Top-Out" slightly BEFORE the Rear Suspension.
They must both "Top-Out" smoothly, this comes from the Rebound Settings of the Shocks.
If they don't "Top-Out" smoothly, the entire Car will try to jump off of the ground,
and you will instantly blow-away the Tires..

Preferably, the "effective" Spring-Rates of your front and rear springs,
AND the amount of suspension travel,
will be equal for both the Front AND Rear Suspensions.

Normal Ride Height should provide approximately
25% Compression Travel, and 75% Rebound Travel from "normal" ride height.
On a Drag-Only car, you may want to go even less, to ~20% / ~80%.

Softer Spring-Rates will allow for the "possibility" of a less violent initial "Hit" to the tires,
AND will extend the time and distance created by a softer "Hit".
Higher Spring Rates make everything much more critical, and harder to tune.

More Suspension Travel is almost always better.

The Suspension should NEVER "Bottom-Out" , for any reason,
if it does, increase Compression-Damping until it doesn't.
This will also reduce potential parts breakage.

Shocks are your best friend.
Never-Ever scrimp on Shocks.
Get the very best that you can afford.
The Shocks are what keeps everything under control.

A harder, more violent "Hit" may actually cause
a LOSS of Traction by "Crushing" the Tires too hard and too fast.
An extremely violent "Hit" can put more than 3-TIMES the weight of the Car on to the Rear Tires.

If you "Blow-Away" the Tires BEFORE the Front Tires are off the ground,
you're probably doing something wrong with Suspension Set-up.

If you "Blow-Away" the Tires AFTER the Front Tires are off the Ground,
you must reduce power for Track Conditions, OR, find a way to get more Traction ....
( Tire Compound, Tire Pressure, Tire Size, Rim-Width, Burn-Out procedure, etc. )
( You may also be "Topping-Out" the Rear Shocks )

A Side-View Video of the Car leaving the Line is your most valuable Tuning-Tool,
along with an extensive Data-Acquisition-System.

The Car should rise EVENLY, FRONT AND REAR, for as much Distance / Time as possible.
.
.
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Hi Kevin! Thanks you much for the instructional video. Solid info! But in my case I don’t have a 4 link, but a Torque arm with 2 LCAs, so how do I work with the IC?
Thanks!

Great video, 3 months ago I just wanted a better tire. As of today I have adjustable control arms and adjustable shocks. World of difference

Would you stay with this theory on bad/no prep surfaces? I have the car working somewhat well on drag radials on a marginal track. But I’m moving to Hoosier c07 slicks and worse surfaces.

If you have to much anti squat will it cause tires to spin ? I have a friend who has a fbody I have one as well , we have same shocks up front I set his to mine , I cut 1.5s he cuts 2.1s both stick turbo cars with relative same power ,

Love your channel man! So full of information, thanks for sharing.
Do you have a video on how to determine how much air pressure to start with with slicks? Thanks in advance 👍🏽

This channel should have took off already! Great information

do these principles still apply to a small tire non W slick, Or will you just crush the hell out of it

Running slicks the tire starts driving over it’s self when you get the lower bar angle running up hill too much. You get more bite by running it slightly down hill. With radials it’s a whole different ball game, no matter how much force you put on a radial . It will spin before it tries to drive over it’s self.

I can't tell you how much your content has helped me tune the chassis on my 9sec street/ strip car Think I found the sweet spot on my anti squat 🙏👍

Amazing information!! Thank you

You have the best videos on suspension I have ever seen. Great work!!!!

kevin i have 64 c10 shortbed with stock single trailing arm .is there a caculator that will work with this type of rear suspension to get percentage of rise or squat. thanks marvin

Nicely covered. Is it worth focusing on height of instant center vs axle centerline as much as anti squat line?

Thank you once again for sharing this information. I just started with a fox body and as I got it , it has a lot of separation. I started with loose separation I can see that I need to slow it down . Watching your channel has confirmed my thoughts. Also, I watch a lot of no prep and some of these guys are getting 4 plus inches of separation even on crap surfaces. I think I;ll pick up a tenth on my second outing . Again thank you for detailed information

If the slick does not crush when separation occurs, and holds with little to no wheel speed (spin) does that translate to more front end separation? rotation front to rear? ie trying to wheelie? Thank you Kevin for sharing your information and experience

Just wanted to say set up a new car build 29.5 x10.5 car. nailed it first time with all the information learned from these videos! 1st pass was fastest 60' and it is above anti squat line.

I'm new and just starting out drag racing. This is my 3rd summer having fun up here in Alaska! Love the channel, very well explained for beginners such as myself so THANK YOU BIG TIME!!! We don't have hot days or a rely good prepped track. My question is. Old timers say slicks but Ive started hooking decent on a drag radial. Is it more of a preference, and is there a margin or geometry error more so on a small tire slick than drag radial? I want to buy a new set of tires this year and IM debating a slick or new radial :) Forgot to add Im in a 1980 Malibu 9 sec cararound 1k HP to the ground on the dyno. Th400 Trans brake supercharged small block. Viking double adjustable coil overs. 2800lbs

Hi Kevin, Ive been watching your videos and have a few questions.. I run a Suspended Top Dragster. The car typically runs in the high 4.20s. I run a Mickey Thompson 3197 "Big Bubba" tire. The engine makes about 1350 and the car weighs 1875 with me in it. I have 2 Penski canister style double adjustable shocks built by Eric Davis at Penski. My car seems to be very consistent, and does separate on the hit. It separates about .400 from the hit to the 1/8 mile stripe. Not all at once. The initial hit is about .125 then it slowley increases. My question is with a 250" dragster with no front suspension where would you like to see the IC? My bar angles with me in the car are about 1.5 degrees down on the bottom and about 12.5 down on top. I don't believe that would be below the squat line but it does still separate. Im interested to see what you think about this setup
Thanks,
Mike Sullivan

Still great videos Thank you I really enjoy them and keep watching them to get a better more in-depth understanding how all of this works together

Your videos are killer..thank you my brother....I have a 2002 mustang tube chassis brand new...from a to z I'm going with your advice..I'll make video of results

Good vid mate.

Good info here. I somewhat get it but how do I find out my center of gravity?

Yes you absolutely can run slicks with more than 100% Anti Squat!! Not as crazy as Radials, but I do believe you can put the movement of the proper bar angles to help plant the slicks while moving the car forward. For sure, you can fight the squating nature of less than 100% Anti Squat as well and have traction. My thought is if I have to pick one or the other, I will start with more than 100% Anti Squat as that rear separation is a more productive use of the forces being applied on the hit and the entire run!! Bar angles in relation to the Anti Squat line, coilover spring rates and length, shock installed height, proper compression and rebound valving and settings, and air pressure all come to the party to create a balanced approach to drag racing launch!