Thank you so much for taking the time to help us average guys out. Would love to hear you talk about scaling a race car and talk about what the rear tire weights do at the start of the launch.
I can sum this up is a few words. For 95% of OEM springs and shocks the uncompressed springs length and total shock length is at the same point, minus a very small amount preloading to keep the spring in position. So, IF the total travel of the shock is 5", then you want a spring that compresses 2.5" when loaded so it rides in the middle. So for your "SETUP", you have to calculate your "Sprung weight" (not gross weight) and determine how many pounds per inch you need to push the spring down 2.5". Example: if your car weighs 3800 pounds, and the weight distribution is 60/40 and you estimate the sprung weight on 1 side of the FRONT, at 1 wheel is 900 lbs, then you need a spring that will compress 900 pounds over a 2.5" distance. Since this is LINEAR, then we can calculate 900lbs/2.5 = 360 lbs per inch! which is about a 6.5kg spring
Scott Nettell thanks so much for your comments! I will keep them coming out for sure! Pinion angle, rear end twist, front suspension and alignment, rear steer, rear alignment, and more on the way! I will also vlog me getting the 48 Ford down the track with the Blown SBC 406 on Mechanical Fuel Injection addicted to Meth. That will be fun as the 48 is so front end heavy, and I will vlog it all. Go fast, go straight! Be Safe!
First off thank you for all this knowledge! I have watched all your shock/spring /adjusting videos. And maybe I missed it. But I can't seem to find any of your insight on when and how you like to use the spanner nut to compress the coil sping. Thanks.
LS IT! thanks so much for your comments! Regarding compressing the coil springs for preload, that is mainly dictated by your shock installed height and ensuring you have the right spring rate for your weights. For instance on the 48 Ford with 125 lb rear springs I generally run about .5" of spring preload to get the proper ride height and shock installed height. Hope this helps. Go fast, go straight! Be Safe!!
Syskill thanks so much for your comments and supporting the channel! Will have more videos out this week for sure! Stay tuned! Go fast, go straight! Be Safe!
I want to say thank you for these videos been watching for a while finally got a chance to put some of your knowledge into action on my car and have already gotten my best 60’ and 1/8 et ever and believe I have more left in it. Slowly turning up the power and making adjustments as i go. Thanks, Bryan
Thanks again you're easy to understand it might look complicated in the beginning and you're totally right about having a camera having somebody film that hit and at the Finish Line when you pull the chute that's really big
I drove a car that they said no one could control, it was a big block nitrous car. In order to get the big tires to clear the fender wells they had topped out the rear coilovers. When the car switched into second the nitrous turned on well it hopped back tires off the ground and went straight towards the wall I fixed it by relocating the rear shocks to where they were in the middle of their travel
I'm fifty one years old and a first timer Is building a street rod. It's a 1949 g m c truck. I will be running probably just under a thousand horsepower hopefully. I will be installing a 4 link so I guess I will need to find center to see if I have anti squat suspension or squat. The frame under the truck is from a seventy three g m c truck. I will play at the track but only no-prep. It will be made for the street. Any suggestions on beginner suspension companies. I don't have much money and do not want to waste buying crap. Thanks for the video.
Racing motocross, I know temperature Can change what the shock is doing due to the fluids getting hot. Do temperatures matter in one street race? Not talking about the surface of the road but does the temperature outside effect the shocks gas inside, like Motocross racing just not to the extreme?
I have a 70 Chevelle with the ladder bar setup with strange coilovers on the rear. I'm not racing the car it rides way too stiff I just want the car to ride softer what can I do to achieve this can I just go with the taller softer spring. It's a single adjustable strange coilover should I just turn the knob counterclockwise first time I ever owned coilovers I just want the car to ride softer and similar to stock
Hey Kevin, great videos! I've learned alot from you. I have a 65 Chevy ll gasser, big block, trans brake, car weighs 2860 with my in it, ladder bar set up. My shocks are 14" at ride height. Curious on what spring rate I should go with.. Would love to hear what you recommend! Thanks
Wouldn’t it be more correct to say that the shock can modify what the spring is doing? Once it cannot do that then a spring change would be needed. Thanks for explaining drag suspension. It’s a mystery to most.
Barry C. thanks so much for your comments! Springs need to support the weight of the car. Shocks help control reactions of the chassis to changing conditions due to acceleration, braking, or other movements. Go fast, go straight! Be Safe!!
Kevin , what are your thoughts about having 40% spring compression at ride height ? I have read 30% is ideal but I’m having trouble finding a spring that will do that with the adjusters I have and keep my shocks in the right spot .
Your video was eye opening. So my question on your video is this. On a 12/130 spring. Wouldnt it be more like this? And Im talking installed height. 12/130 and 11/260 10/390 9/520? Just curious if im understanding this?
On a 12" 130 lb spring (which is a linear rate spring, not progressive), for every 130 lbs on top of the spring with it sitting at 90 degrees (not tilted), it will compress 1" for every 130 lbs put on top of it. With no weight, it is 12". Add 130 lbs and it is 11", add 260 lbs (another 130) and it compresses to 10" and so on. If the spring is not at 90 degrees then that changes the rate of compression. Go fast, go straight! Be SAFE! .
Your videos are great for someone who is trying to understand how the suspension works without really having a lot of previous knowledge, I have learned a ton. I have two questions, if your car is low power (under 400 HP) do these coilover compression percentages change? My other question is, if you have a coilover kit that adjust height with spring preload, does that become your springs free height? ( so if my ride height has the spring compressed to 11.75 instead of 12 inches, so I do calculations off of 11.75). Thanks
Thanks, Briah! Coilover compression is a general baseline. For a street car under 400 HP these are good starting points all the way around. With springs, the free height will always be the uninstalled length. Go fast, go straight! Be SAFE!!
Thanks for the explanation. I have a qeustion. Ladder bar set up. 164% anti squat. Unsprung weight is left 557lbs right 525lbs Strange doubles ride height eye to eye 13" leaving roughly 1"3/4..of shock shaft out extends 5.5 i had 110 lbs springs thinking theu are to light.. want to try my 130s .. if the math works i set them to 8.5" compression. And still have around 2" of shock showing.
jason white thanks so much for your info and questions! There is a good bit more info I would need about your car to feel more confident in answering your question. Might be best for your to shoot me an email from my website listed in the description (samsonperformance.com) and give me some more info from the Suspension Tuning PDF file on my site. You said unsprung weight but the springs will be supporting all the sprung weight on the rear, so not sure if I am following you. At a high level, I would encourage you to try the 130 lb springs as that change is terribly difficult in most cases to switch out and test. Go fast, go straight! Be Safe!
@@KevinWilsonSBC thanks for your reply. My weights i was referring to was a rough estimate from my scaled rear weight of 1480, or corber weights of left 773 right 707. -150 per side may i am doing it wrong
I may be overthinking this but I’m not sure. I currently have a car with coilovers up front and I am trying to figure out what length/weight springs I need. You say if you have a 14/140 every 1” compressed is 140lbs. On a coilover you are able to control how compressed that spring is with the spanner wrench before it even goes on the car… so how exactly does that work?
tbucket 14" coil with jack down only compresses 1.5", 175 sp rate 16 " fully extended shock, have 2.5 comp and 2.5 extension. Sps are mounted vertical so as to rake T bucket 2.5 up and 2.5 down. Have not finished install yet. Kevin do you think my ride will be tolerable. Thanks, Tbuck.
Herman Ripps thanks so much for your comments! That is a really stiff spring for a tbucket in my experience. I own a 23 tbucket and 27 tbucket streetrods each with SBC 350 engines. Can you give me more info on wheelbase, engine size, kit frame or custom frame, etc... Go fast, go straight! Be Safe!!
Chuck Vaughn thanks so much for your comments! Not really.... put a stick car may not need as soft a spring as an auto, just from how hard the clutch dump hits the chassis. Go fast, go straight! Be Safe!!
Great video. Admittedly way out of my depth but I picked up a few things. Looking at fortune auto 500 coilovers for my 2012 mustang GT/CS. This car is mainly driven for fun on the street and occasionally commuting. What spring rates would you recommend?
Jimmerz Squared thanks so much for your comments & question! I would need to scale the car to feel comfortable with recommended spring weights, but I would reach out to Team Z Motorsports as they can help from street to full strip on the Mustangs. Also, if you hit the track and run any slicks or radials, that can impact the recommendation. Go fast, go straight! Be Safe!!
Supernaut thanks so much for your question about shock/spring location! Same physics apply with squat and separation of the rear end. Spring rates will be impacted slightly, but each car is unique, so do the same compression measurements and work with a reputable company on your setup and weights for sprung and unsprung weights. The ladder bars will do their part and the shocks will be helping the rear end plant the rear tires. Go fast, go straight! Be Safe!
I have a v12 Cl600 getting coil overs, what spring rate would you recommend? Has 20" wheels and will be daily/track, also car has no anti-roll so something that would counter roll?
GRAND HIT thanks so much for your question! Unfortunately, I would need a bunch more info before I could help you further. Probably best to shoot me an email from my website at samsonperformance.com Go fast, go straight! Be Safe!
so if someone had less than 100% anti and the initial rear end movement would be up into chassis, would you be tuning the shocks with softer compression to let it make that move then tighter extension to let it hold? -then if you were to change to say something above 100 you would want tighter compression softer extension? or would you always be on the tighter compression / softer extension side of tuning to try and keep the tire planted even if the less than 100% wants the body to squat on tire?
godecki motorsports thanks so much for your questions! As a general rule of thumb, when a car has squat on the hit and the tire is being pulled up in the body, then you have to use compression to overcome that movement to help keep the tire planted. That doesn't always mean tighter compression is better in all cases, but compression is usually your first place to start. The opposite know helps control how long it will hold working in balance with other parts of the suspension like springs, wheelie bars, etc. You have to make small changes to see what that car likes along with air pressure, front end rise, rear spring rates, etc... I have a video coming in the next couple of days to cover What If scenarios so that should help keep tying all this together. Go fast, go straight! Be Safe!
Maybe you can help Im about to purchase a set of coil overs for my front 65 GTO. The weight of the car is 3700 lbs the front is 2000lb which makes each side about 1000lbs. KNowing that is there a way to figure which spring or set of QOs I need? I dont have them in the rear. I purchased new springs.Stock. But Im not sure the QOs will fit without moving the exhaust and it is new. Im not going to race it but I am installing a strocker engine
dan roach thanks so much for your question and info! You will be around the 450 lb spring rate for the front. For example, if you went with viking coilovers on the front for the street, you would likely be going with the A225-450T to keep control of the weight and that shock is made for the 65 GTO to ensure good shock travel. My 48 Ford is 2000 lbs on the front and I currently run 450 lb springs on the front. Go fast, go straight! Be Safe!!
Well that all depends for sure. Watch this one: ua-cam.com/video/2xcQ3M5xskM/v-deo.html but there is not a set answer for that question. Go fast, go straight! Be SAFE!!
Victor Mendoza thanks so much for your question! Is that your fbody on your channel? On the coil springs the main job of the spring is to support the weight of the car but not near coil bind to allow for compression of the spring, but with enough spring compressed to allow the shock to control the reaction. Do you know the rear weight of your car? Controlling excessive separation is more the job of the shock and if you can change the instant center. Shoot me back more info around my questions or email me from my site at samsonperformance.com Go fast, go straight! Be Safe!!
Ron Niles thanks so much for your comments! I always start as level as possible. Remember front end caster will move weight around. Go fast, go straight! Be Safe!!
kevinnagle thanks so much for your question! Depends on some factors. Front or rear? Slicks or Radials? If slicks, big tire or small tire? Car 4 corner weights? Prep or no-prep? Go fast, go straight! Be Safe!!
tommy b thanks so much for your question! Spring rates will not change that drastically, but absolutely will have influence. I recommend for drag racing rear, err on the side of soft based on your rear weights. Go fast, go straight! Be Safe!!
Hi Kevin, if you put too much anti-squat in a car, the tire will go down and put more weight on the ground BUT after that, the car won’t tilt back so much and wouldn’t transfer weight to the back. If it squats too much, the tire will go up (will put less weight on the ground) BUT after that the car would tilt more to the back and would transfer weight on the rear tire. If you have a car racing on the street, where you are very traction limited. What do you actually want? Instant hit (anti squat) or less hit in the beginning but transferring more weight to the back ? What would you prefer?
Alexandru Mardare thanks so much for your comments and questions! My main goal of the videos is to get racers understanding the behavior of the suspension on the hit. We have setup many cars with rear separation and they definitely still transfer weight to the rear. Each car is different and the AS value for each car will depend on that car and what it works best with for sure. The front end is critical on weight transfer as you know. From the videos, see how your car reacts, then make changes to see how your car responds based on the info in the videos. Go fast, go straight! Be Safe!!
I enjoyed the vids and am using the advice. 60ft dropped from 1.50 to 1.42 this weekend. Next for me, stiffer spring up front (54% compression), and lighter spring in the back (17% compression, and not centered for installed height). This is 157% Antisquat. Thanks again! ua-cam.com/video/9OF637kl1do/v-deo.html
Fred G thanks so much for your comments and updates! Very nice progress for sure and don't quit tuning!!! Nice video also! Go fast, go straight! Be Safe!
Technology has come so far, it's not even funny. I remember the good ol' days when you slapped a set of 90/10 shocks on the front and a set of 50/50 shocks on the rear and just drove it.
Best drag racing tech tutorial channel i’ve found ...key word ‘tutorial’ You are a great teacher.
Billy Shepherd thanks so much for your comments and kind words! Go fast, go straight! Be Safe!!
Thank you so much for taking the time to help us average guys out. Would love to hear you talk about scaling a race car and talk about what the rear tire weights do at the start of the launch.
David Altman thanks so much for your comments and feedback! I will definitely add that to the series. Go fast, go straight! Be Safe!
I can sum this up is a few words. For 95% of OEM springs and shocks the uncompressed springs length and total shock length is at the same point, minus a very small amount preloading to keep the spring in position. So, IF the total travel of the shock is 5", then you want a spring that compresses 2.5" when loaded so it rides in the middle. So for your "SETUP", you have to calculate your "Sprung weight" (not gross weight) and determine how many pounds per inch you need to push the spring down 2.5". Example: if your car weighs 3800 pounds, and the weight distribution is 60/40 and you estimate the sprung weight on 1 side of the FRONT, at 1 wheel is 900 lbs, then you need a spring that will compress 900 pounds over a 2.5" distance. Since this is LINEAR, then we can calculate 900lbs/2.5 = 360 lbs per inch! which is about a 6.5kg spring
Awesome Kevin. Have watched this video several times. Pick up something I missed each time. Keep them coming
Scott Nettell thanks so much for your comments! I will keep them coming out for sure! Pinion angle, rear end twist, front suspension and alignment, rear steer, rear alignment, and more on the way! I will also vlog me getting the 48 Ford down the track with the Blown SBC 406 on Mechanical Fuel Injection addicted to Meth. That will be fun as the 48 is so front end heavy, and I will vlog it all. Go fast, go straight! Be Safe!
Wow this is my go to video.I am way out of wack.Thank you so much for this educational video.Hate wasting money.Lessons and lessons.
Thanks for the videos. Building an RWYB on 28s outlaw car..hope to get the strange GT/SS struts this week.
First off thank you for all this knowledge! I have watched all your shock/spring /adjusting videos. And maybe I missed it. But I can't seem to find any of your insight on when and how you like to use the spanner nut to compress the coil sping. Thanks.
LS IT! thanks so much for your comments! Regarding compressing the coil springs for preload, that is mainly dictated by your shock installed height and ensuring you have the right spring rate for your weights. For instance on the 48 Ford with 125 lb rear springs I generally run about .5" of spring preload to get the proper ride height and shock installed height. Hope this helps. Go fast, go straight! Be Safe!!
Becoming a big fan of your channel, keep it coming!
Syskill thanks so much for your comments and supporting the channel! Will have more videos out this week for sure! Stay tuned! Go fast, go straight! Be Safe!
I want to say thank you for these videos been watching for a while finally got a chance to put some of your knowledge into action on my car and have already gotten my best 60’ and 1/8 et ever and believe I have more left in it. Slowly turning up the power and making adjustments as i go. Thanks, Bryan
bryan tucker thanks so much for your comments and always good to hear racers like you making progress! Go fast, go straight! Be Safe!!
Looking forward to applying some of these applications. Thank you
You are so welcome! Go fast, go straight! Be SAFE!!
Thanks again you're easy to understand it might look complicated in the beginning and you're totally right about having a camera having somebody film that hit and at the Finish Line when you pull the chute that's really big
Dale Chirstopher thanks so much for your comments! 100% agree!!! Go fast, go straight! Be Safe!!
I drove a car that they said no one could control, it was a big block nitrous car. In order to get the big tires to clear the fender wells they had topped out the rear coilovers. When the car switched into second the nitrous turned on well it hopped back tires off the ground and went straight towards the wall I fixed it by relocating the rear shocks to where they were in the middle of their travel
Cool story! I bet that was a ride!! Go fast, go straight! Be SAFE!
I'm fifty one years old and a first timer Is building a street rod. It's a 1949 g m c truck. I will be running probably just under a thousand horsepower hopefully. I will be installing a 4 link so I guess I will need to find center to see if I have anti squat suspension or squat. The frame under the truck is from a seventy three g m c truck. I will play at the track but only no-prep. It will be made for the street. Any suggestions on beginner suspension companies. I don't have much money and do not want to waste buying crap. Thanks for the video.
Absolutely amazing videos! Being new to drag racing it’s been a great help!
Kyle Montgomery thanks so much for your comments! Go fast, go straight! Be Safe!
Please Kenin, release the subtitles for Brazil, I love your videos but it's very difficult to translate, big hug, thank you for everything!!
This is GREAT info! Love this series.
RecklessRegal thanks so much for your comments! More videos on the way! Go fast, go straight! Be Safe!
Racing motocross, I know temperature Can change what the shock is doing due to the fluids getting hot. Do temperatures matter in one street race? Not talking about the surface of the road but does the temperature outside effect the shocks gas inside, like Motocross racing just not to the extreme?
I have a 70 Chevelle with the ladder bar setup with strange coilovers on the rear. I'm not racing the car it rides way too stiff I just want the car to ride softer what can I do to achieve this can I just go with the taller softer spring. It's a single adjustable strange coilover should I just turn the knob counterclockwise first time I ever owned coilovers I just want the car to ride softer and similar to stock
Hey Kevin, great videos! I've learned alot from you. I have a 65 Chevy ll gasser, big block, trans brake, car weighs 2860 with my in it, ladder bar set up. My shocks are 14" at ride height. Curious on what spring rate I should go with.. Would love to hear what you recommend! Thanks
Unfortunately, I would need a more info on the rear corner weights and unsprung weights on the rear. Go fast, go straight! Be SAFE!
another great informative video !
Andrew Thorpe thanks so much for your comments! Go fast, go straight! Be Safe!!
Thanks I needed that information
Russ Turner thanks so much for your comments! Go fast, go straight! Be Safe!!
Wouldn’t it be more correct to say that the shock can modify what the spring is doing? Once it cannot do that then a spring change would be needed.
Thanks for explaining drag suspension. It’s a mystery to most.
Barry C. thanks so much for your comments! Springs need to support the weight of the car. Shocks help control reactions of the chassis to changing conditions due to acceleration, braking, or other movements. Go fast, go straight! Be Safe!!
Kevin , what are your thoughts about having 40% spring compression at ride height ? I have read 30% is ideal but I’m having trouble finding a spring that will do that with the adjusters I have and keep my shocks in the right spot .
Your video was eye opening. So my question on your video is this. On a 12/130 spring. Wouldnt it be more like this? And Im talking installed height. 12/130 and 11/260 10/390 9/520? Just curious if im understanding this?
On a 12" 130 lb spring (which is a linear rate spring, not progressive), for every 130 lbs on top of the spring with it sitting at 90 degrees (not tilted), it will compress 1" for every 130 lbs put on top of it. With no weight, it is 12". Add 130 lbs and it is 11", add 260 lbs (another 130) and it compresses to 10" and so on. If the spring is not at 90 degrees then that changes the rate of compression. Go fast, go straight! Be SAFE! .
Your videos are great for someone who is trying to understand how the suspension works without really having a lot of previous knowledge, I have learned a ton. I have two questions, if your car is low power (under 400 HP) do these coilover compression percentages change? My other question is, if you have a coilover kit that adjust height with spring preload, does that become your springs free height? ( so if my ride height has the spring compressed to 11.75 instead of 12 inches, so I do calculations off of 11.75). Thanks
Thanks, Briah! Coilover compression is a general baseline. For a street car under 400 HP these are good starting points all the way around. With springs, the free height will always be the uninstalled length. Go fast, go straight! Be SAFE!!
Good information
Thanks for the explanation.
I have a qeustion.
Ladder bar set up.
164% anti squat.
Unsprung weight is left 557lbs right 525lbs
Strange doubles ride height eye to eye 13" leaving roughly 1"3/4..of shock shaft out extends 5.5 i had 110 lbs springs thinking theu are to light.. want to try my 130s .. if the math works i set them to 8.5" compression. And still have around 2" of shock showing.
jason white thanks so much for your info and questions! There is a good bit more info I would need about your car to feel more confident in answering your question. Might be best for your to shoot me an email from my website listed in the description (samsonperformance.com) and give me some more info from the Suspension Tuning PDF file on my site. You said unsprung weight but the springs will be supporting all the sprung weight on the rear, so not sure if I am following you. At a high level, I would encourage you to try the 130 lb springs as that change is terribly difficult in most cases to switch out and test. Go fast, go straight! Be Safe!
@@KevinWilsonSBC thanks for your reply.
My weights i was referring to was a rough estimate from my scaled rear weight of 1480, or corber weights of left 773 right 707. -150 per side may i am doing it wrong
I may be overthinking this but I’m not sure. I currently have a car with coilovers up front and I am trying to figure out what length/weight springs I need. You say if you have a 14/140 every 1” compressed is 140lbs. On a coilover you are able to control how compressed that spring is with the spanner wrench before it even goes on the car… so how exactly does that work?
Joshua Chavarria thanks for commenting. Go to samsonperformance.com and shoot me an email and I will respond. Go fast, go straight!
tbucket 14" coil with jack down only compresses 1.5", 175 sp rate 16 " fully extended shock, have 2.5 comp and 2.5 extension. Sps are mounted vertical so as to rake T bucket 2.5 up and 2.5 down. Have not finished install yet. Kevin do you think my ride will be tolerable. Thanks, Tbuck.
Herman Ripps thanks so much for your comments! That is a really stiff spring for a tbucket in my experience. I own a 23 tbucket and 27 tbucket streetrods each with SBC 350 engines. Can you give me more info on wheelbase, engine size, kit frame or custom frame, etc... Go fast, go straight! Be Safe!!
Yeah, Shawn could definitely use some of you guidance.
Robert Ford thanks so much for your comments! Go fast, go straight! Be Safe!!
Does an auto versus a stick car change how much compression you have since a stick car will be at rest at the tree before you launch?
Chuck Vaughn thanks so much for your comments! Not really.... put a stick car may not need as soft a spring as an auto, just from how hard the clutch dump hits the chassis. Go fast, go straight! Be Safe!!
Great video. Admittedly way out of my depth but I picked up a few things. Looking at fortune auto 500 coilovers for my 2012 mustang GT/CS. This car is mainly driven for fun on the street and occasionally commuting. What spring rates would you recommend?
Jimmerz Squared thanks so much for your comments & question! I would need to scale the car to feel comfortable with recommended spring weights, but I would reach out to Team Z Motorsports as they can help from street to full strip on the Mustangs. Also, if you hit the track and run any slicks or radials, that can impact the recommendation. Go fast, go straight! Be Safe!!
Really enjoyed this video. Does it make a difference on a ladder bar set up if the coil over shocks are mounted in front of the rear end?
Supernaut thanks so much for your question about shock/spring location! Same physics apply with squat and separation of the rear end. Spring rates will be impacted slightly, but each car is unique, so do the same compression measurements and work with a reputable company on your setup and weights for sprung and unsprung weights. The ladder bars will do their part and the shocks will be helping the rear end plant the rear tires. Go fast, go straight! Be Safe!
I have a v12 Cl600 getting coil overs, what spring rate would you recommend? Has 20" wheels and will be daily/track, also car has no anti-roll so something that would counter roll?
GRAND HIT thanks so much for your question! Unfortunately, I would need a bunch more info before I could help you further. Probably best to shoot me an email from my website at samsonperformance.com Go fast, go straight! Be Safe!
so if someone had less than 100% anti and the initial rear end movement would be up into chassis, would you be tuning the shocks with softer compression to let it make that move then tighter extension to let it hold?
-then if you were to change to say something above 100 you would want tighter compression softer extension?
or would you always be on the tighter compression / softer extension side of tuning to try and keep the tire planted even if the less than 100% wants the body to squat on tire?
godecki motorsports thanks so much for your questions! As a general rule of thumb, when a car has squat on the hit and the tire is being pulled up in the body, then you have to use compression to overcome that movement to help keep the tire planted. That doesn't always mean tighter compression is better in all cases, but compression is usually your first place to start. The opposite know helps control how long it will hold working in balance with other parts of the suspension like springs, wheelie bars, etc. You have to make small changes to see what that car likes along with air pressure, front end rise, rear spring rates, etc... I have a video coming in the next couple of days to cover What If scenarios so that should help keep tying all this together. Go fast, go straight! Be Safe!
Maybe you can help Im about to purchase a set of coil overs for my front 65 GTO. The weight of the car is 3700 lbs the front is 2000lb which makes each side about 1000lbs. KNowing that is there a way to figure which spring or set of QOs I need? I dont have them in the rear. I purchased new springs.Stock. But Im not sure the QOs will fit without moving the exhaust and it is new. Im not going to race it but I am installing a strocker engine
dan roach thanks so much for your question and info! You will be around the 450 lb spring rate for the front. For example, if you went with viking coilovers on the front for the street, you would likely be going with the A225-450T to keep control of the weight and that shock is made for the 65 GTO to ensure good shock travel. My 48 Ford is 2000 lbs on the front and I currently run 450 lb springs on the front. Go fast, go straight! Be Safe!!
What is the best length for a rear coil over shock?
Well that all depends for sure. Watch this one: ua-cam.com/video/2xcQ3M5xskM/v-deo.html but there is not a set answer for that question. Go fast, go straight! Be SAFE!!
I have a lot of extension on my car I have 110 14” springs should I go to a 150 or leave in. and also springs back up after the hit
Victor Mendoza thanks so much for your question! Is that your fbody on your channel? On the coil springs the main job of the spring is to support the weight of the car but not near coil bind to allow for compression of the spring, but with enough spring compressed to allow the shock to control the reaction. Do you know the rear weight of your car? Controlling excessive separation is more the job of the shock and if you can change the instant center. Shoot me back more info around my questions or email me from my site at samsonperformance.com
Go fast, go straight! Be Safe!!
How do you scale a drag race car using coilovers. Is it ideal to adjust rear shocks to get left and right to measure close to the same as possible
Ron Niles thanks so much for your comments! I always start as level as possible. Remember front end caster will move weight around. Go fast, go straight! Be Safe!!
Where can we contact you for help?
I am looking for recommendations for a coil over shock combination for a 32 Ford with a single inverted crossover spring. Please advise.
Paul Kessens thanks for commenting. Go to samsonperformance.com and shoot me an email and I will respond. Go fast, go straight!
How do you calculate initial spring length? 12" over a 14"?
kevinnagle thanks so much for your question! Depends on some factors. Front or rear? Slicks or Radials? If slicks, big tire or small tire? Car 4 corner weights? Prep or no-prep? Go fast, go straight! Be Safe!!
How much do you think these theories would change for foot brake vs trans brake/ clutch cars?
tommy b thanks so much for your question! Spring rates will not change that drastically, but absolutely will have influence. I recommend for drag racing rear, err on the side of soft based on your rear weights. Go fast, go straight! Be Safe!!
I have a 70 Chevelle
Hi Kevin,
if you put too much anti-squat in a car, the tire will go down and put more weight on the ground BUT after that, the car won’t tilt back so much and wouldn’t transfer weight to the back.
If it squats too much, the tire will go up (will put less weight on the ground) BUT after that the car would tilt more to the back and would transfer weight on the rear tire.
If you have a car racing on the street, where you are very traction limited. What do you actually want? Instant hit (anti squat) or less hit in the beginning but transferring more weight to the back ?
What would you prefer?
Alexandru Mardare thanks so much for your comments and questions! My main goal of the videos is to get racers understanding the behavior of the suspension on the hit. We have setup many cars with rear separation and they definitely still transfer weight to the rear. Each car is different and the AS value for each car will depend on that car and what it works best with for sure. The front end is critical on weight transfer as you know. From the videos, see how your car reacts, then make changes to see how your car responds based on the info in the videos. Go fast, go straight! Be Safe!!
Need help with our shocks?? Here's a vídeo of what it's doing
I enjoyed the vids and am using the advice. 60ft dropped from 1.50 to 1.42 this weekend. Next for me, stiffer spring up front (54% compression), and lighter spring in the back (17% compression, and not centered for installed height). This is 157% Antisquat. Thanks again!
ua-cam.com/video/9OF637kl1do/v-deo.html
Fred G thanks so much for your comments and updates! Very nice progress for sure and don't quit tuning!!! Nice video also! Go fast, go straight! Be Safe!
Technology has come so far, it's not even funny. I remember the good ol' days when you slapped a set of 90/10 shocks on the front and a set of 50/50 shocks on the rear and just drove it.