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Setting up suspension starting points etc.

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Old 01-03-2017, 10:11 PM
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Default Setting up suspension starting points etc.

So its winter here in Chicago and doing some upgrades to my car and wondering if anybody has any links to pages i can read up on and get a bunch of info in my head of setting up torque arm suspension. My car is all new front to back so i didnt have any baseline and went in with very basic knowledge on it all, lol. I have a few buddys help me but over the phone and text it got pretty hard explaining what the car is doing.

For rear suspension i have dbl adj. Viking coilovers with 150 lb springs, MWC fab9, MWC ARB, LCA are at the bottom most hole and front torque arm is at the lowest hole also, pinion angle is at -1.5* and LCA angle is around 3* uphill. Front suspension is dbl adj. Viking shocks as well along with travel limiters.

With that being said i see a lot of "instant center", "LCA angle", "ride height" all get thrown around a lot and it makes me wonder how and at what point do all those things come into play. My best 60' so far is mid 1.4 on a radial leaving around 10 lbs of boost which is **** with all my suspension parts. So since i have a lot of couch time to read, does anybody have any good links i can read up on etc on all this stuff?

Heres the last pass of my car (same pass but 2 different views) and my time slip for notes....




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Old 01-03-2017, 10:22 PM
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I'd say the front compression and extension both need to be tightened. Compression, more so but I'm still learning as well.
Old 01-03-2017, 10:35 PM
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Yea I believe it's as tight as it can go both ways, but also looking more for "why" do I tighten or loosen. Kinda like my old teachers told me "well if I do it for you, how you going to learn"....maybe they were on to something back then, lol.
Old 01-04-2017, 01:11 AM
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I just noticed you have your LCA's on the bottom hole. My car hooks and then spins if I have mine set that way any I'm not making anywhere near your power. I'd try moving it up a hole.
Old 01-04-2017, 06:37 AM
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Eric (Midwest Chassis) is only 2 hours or so from you, I'd give him a call up and see if he can help out. I know they have track days during the year, something else to look out for.

There's also no separation of the rear.
Radials aren't slicks, you can't hit them the same.

What shocks are on the back? Settings on the shocks?
What's on the front? Settings on them?
Weight bias front to rear and L to R?

How is power being managed?
Old 01-04-2017, 10:43 AM
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Yea I have to get with him on his track days, just bad timing with me when he has them. What is this separation you speak of and why does one tire need it and one doesn't?

My car has dbl adj coilovers on all 4 corners, fronts were set on slowest rebound to try and keep front end down and stiffest compression to try and keep it from diving. Rears were about half way on both compression and rebound. Power is running off 2-step and wastegate spring and manual boost controller.
Old 01-04-2017, 02:18 PM
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I am trying to learn the same stuff but my car is much slower than yours. See the sticky above on launching a drag car. Here are some other google search finds that I am reading....

http://www.how-to-build-hotrods.com/...f-gravity.html
http://www.baselinesuspensions.com/i...A_Drag_Car.htm
http://www.racingjunk.com/news/2014/...ension-tuning/
http://www.dragracingonline.com/tech...hocking-2.html
Old 01-04-2017, 04:44 PM
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Are you sure the front rebound is set all the way clockwise? What are the rear shocks set at?
Old 01-04-2017, 06:06 PM
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rears look to stiff imo.. rebound looked to fast. I'm just learning as well tho
Old 01-04-2017, 09:05 PM
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Its coming down to quick and unloading the rears. loosen that extension. The rears planted nicely i thought.
Old 01-04-2017, 09:14 PM
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I'd also try backing off compression up front. But whatever you do, make sure you do one thing at a time and test it while recording the results in a logbook. You've got a lot of power, so I'd log everything so you can make changes for different tracks and conditions.
Old 01-05-2017, 04:05 AM
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Here are a couple good reads to help you understand the principles and to get you close.
Attached Files
File Type: pdf
chassis tuning.pdf (980.7 KB, 625 views)
File Type: pdf
899-031-214.pdf (600.4 KB, 176 views)
Old 01-05-2017, 05:52 AM
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Watch the back of the car, see how it separates from the tire. That's Anti-squat. What its doing is pushing the tire to the track. I don't have the shock data in front of me to share unfortunately.

Skip to 14:34 for my reference

Also 8:32 if you want to see another instance, but also what happens when you leave the CO2 off...
Old 01-05-2017, 06:42 AM
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Get some control arm angle into the car. Couple fat radial car I know arenrunning about -6 degrees of lca.

Once you have that done, start tightening the extension up on the front, andtivhten compression on the rear.

Careful it doesn't want to stand up.
Old 01-05-2017, 07:51 AM
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If it wheelies off the hit, tighten the front travel limiters, if it wheelies down track (power wheelie) put weight on the nose.
Old 01-05-2017, 09:01 AM
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Give us a call when you get some time Jerry we will get you straightened out.
Old 01-05-2017, 04:32 PM
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Originally Posted by a05c
Watch the back of the car, see how it separates from the tire. That's Anti-squat. What its doing is pushing the tire to the track. I don't have the shock data in front of me to share unfortunately.

Skip to 14:34 for my reference

Also 8:32 if you want to see another instance, but also what happens when you leave the CO2 off...
https://youtu.be/cN9KW9bQUTk?t=14m34s
Yea that helped out a lot and to actually visualize it made it easier to understand. Now to get that antisquat is that all shock adj. Or with torque arm and lca adj?

Originally Posted by MidwestChassis
Give us a call when you get some time Jerry we will get you straightened out.
I will Eric, I just feel like a dipshit rookie and don't want to waste your time with this **** so I hit the forums up to learn as much as I can before I call so I know what your talking about, lol.
Old 01-06-2017, 05:57 AM
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Originally Posted by Taubr Unit
Yea that helped out a lot and to actually visualize it made it easier to understand. Now to get that antisquat is that all shock adj. Or with torque arm and lca adj?



I will Eric, I just feel like a dipshit rookie and don't want to waste your time with this **** so I hit the forums up to learn as much as I can before I call so I know what your talking about, lol.
Eric can explain it alot better over the phone than I can.
Old 01-06-2017, 12:31 PM
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Anti squat you get with lca adjustment.

Tq arm adjustments will change instant center which will change the way tire is hit. This is why the madman arm has adjustments up and down on the front and back.

You want the tire driven into the ground (radial) and held, with little to no nose lift at all. Travel limiters are generally how most do it but extremely good shocks can do it as well, but the limiters are a way more cost effective way.

I am a big believer in lowering the car a lot as well, as this helps keep it from wanting to pitch-rotate and stand up. Having put my car on the bumper more than once I learned what having the ride height too high will do. Lower car, no more 12 o clock action.



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