Why DON'T We Want the Rear to Squat?
05-17-2006 | 08:07 PM
#21
Think about it this way...
You jump down from a tree, and just land on the ground. Yeah, you're hitting pretty hard.
Now jump down and try to jump back up just as your feet touch the ground. Sounds like broken legs to me.
All the force that's lifting the rear of the car is just a byproduct (the equal and opposite if you hang out with Newton) of the force that's driving the tires into the pavement.
You jump down from a tree, and just land on the ground. Yeah, you're hitting pretty hard.
Now jump down and try to jump back up just as your feet touch the ground. Sounds like broken legs to me.
All the force that's lifting the rear of the car is just a byproduct (the equal and opposite if you hang out with Newton) of the force that's driving the tires into the pavement.
05-18-2006 | 09:23 AM
#22
Stock rear shocks are 50/50 I believe.
Up here I've run my rears at 4/4, so a little softer than stock, in attempt to hook with so-so track condition.
I remember at NPR once, for a Thunder race, I did 4/4 and then came back and did 8/8. You want the rears to be as stiff as you can, at least that's what the big dogs told me.
Also, I once ran 1995 V6 springs in back. My car squatted when it was H/C and went 1.55 with no drag shocks. Later I added drag shocks, a 422ci, and my car would squat so bad I would cut 1.61-1.65's totally hooking. The car would squat like four inches.
Back in the day, GeorgeC's car was a great example of not squatting and cutting 1.3's on motor.
Sometimes our tracks up here are so junk that I was cutting 1.35 and still spinning.
Up here I've run my rears at 4/4, so a little softer than stock, in attempt to hook with so-so track condition.
I remember at NPR once, for a Thunder race, I did 4/4 and then came back and did 8/8. You want the rears to be as stiff as you can, at least that's what the big dogs told me.
Also, I once ran 1995 V6 springs in back. My car squatted when it was H/C and went 1.55 with no drag shocks. Later I added drag shocks, a 422ci, and my car would squat so bad I would cut 1.61-1.65's totally hooking. The car would squat like four inches.
Back in the day, GeorgeC's car was a great example of not squatting and cutting 1.3's on motor.
Sometimes our tracks up here are so junk that I was cutting 1.35 and still spinning.
05-18-2006 | 11:17 AM
#24
Originally Posted by Pro Stock John
Stock rear shocks are 50/50 I believe.
Up here I've run my rears at 4/4, so a little softer than stock, in attempt to hook with so-so track condition.
I remember at NPR once, for a Thunder race, I did 4/4 and then came back and did 8/8. You want the rears to be as stiff as you can, at least that's what the big dogs told me.
Also, I once ran 1995 V6 springs in back. My car squatted when it was H/C and went 1.55 with no drag shocks. Later I added drag shocks, a 422ci, and my car would squat so bad I would cut 1.61-1.65's totally hooking. The car would squat like four inches.
Back in the day, GeorgeC's car was a great example of not squatting and cutting 1.3's on motor.
Sometimes our tracks up here are so junk that I was cutting 1.35 and still spinning.
Up here I've run my rears at 4/4, so a little softer than stock, in attempt to hook with so-so track condition.
I remember at NPR once, for a Thunder race, I did 4/4 and then came back and did 8/8. You want the rears to be as stiff as you can, at least that's what the big dogs told me.
Also, I once ran 1995 V6 springs in back. My car squatted when it was H/C and went 1.55 with no drag shocks. Later I added drag shocks, a 422ci, and my car would squat so bad I would cut 1.61-1.65's totally hooking. The car would squat like four inches.
Back in the day, GeorgeC's car was a great example of not squatting and cutting 1.3's on motor.
Sometimes our tracks up here are so junk that I was cutting 1.35 and still spinning.
05-18-2006 | 05:40 PM
#25
Originally Posted by 12secSS
What many people think is that as the body rolls over to the passenger's side it is applying force down on the tire, due to the engine torqueing as well. Actually what is happening is that the front end is coming up and tilting on the axis created by the front pass tire and the rear driver's side tire, what then happens is all the weight is placed on the rear passenger tires coil and shock setup. If this setup (RR) is not stiff enough to support the extra load, it will compress absorbing the load ... much like an overloaded 1/2 ton truck with a tired and old suspension. This is not making for traction. What you want is the axle (rear suspension) to react to the initial hit from the torque being applied to it, which causes the axle to literally pound the pavement hard.
See example:
Video
http://www.jenibellaracing.com/Videos/SCS2005-02.wmv
This effect causes the tires to really bite hard into the pavement, which can result in wheelstands, but also better 60's. The other way, squating causes only on tire to really bite hard while the other is unloaded and pulled up into the body, causing a loss of traction. You want the body to lift up off of the axle at launch, to help stick the tire down.
See example:
Video
http://www.jenibellaracing.com/Videos/SCS2005-02.wmv
This effect causes the tires to really bite hard into the pavement, which can result in wheelstands, but also better 60's. The other way, squating causes only on tire to really bite hard while the other is unloaded and pulled up into the body, causing a loss of traction. You want the body to lift up off of the axle at launch, to help stick the tire down.
What ACTUALLY is happening is the pinion is trying to climb the ring gear, rotating the rear end counterclockwise from the rear, picking the right rear tire up(closing the gap between the tire and fender) and pushing the left rear down(opening the gap between the tire and fender) this makes the left front tire come up first this action is accompanied by engine torque..drag race ant-roll bars correct this action. squatting or planting is an action or re-action fromt the length and or settings on the torque arm...shocks/springs and a right rear airbag can manage the situation...squatting as long as the tire is hooked will only effect car reaction time(or the time it takes the car to move out of the beams) excessive squat can only slow this......but if the tire is planted the car will move forward after this takes place..slowing reaction time....I dont see how it would effect 60ft a whole lot.
just my .02
David
05-18-2006 | 08:46 PM
#26
9 Second Club
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I run all the cars that I work on very very stiff. I always have enough tire under the car to handle it so I run my hals on 10 and I tighten the front to about 6-7 so that it doesn't stand on the bumper everytime.
on the street I loosen the rear up about half of what I use at the track. It does alot better on the street that way or if you have drag radials also.
At any given time you can't push down on the back of my car at all. If you do all you are seeing is the tires deflate. You want all the weight of the car on the tire and not on the suspension. No squating and no big nasty wheelies either. It just looses energy that can be used to make you go forward.
on the street I loosen the rear up about half of what I use at the track. It does alot better on the street that way or if you have drag radials also.
At any given time you can't push down on the back of my car at all. If you do all you are seeing is the tires deflate. You want all the weight of the car on the tire and not on the suspension. No squating and no big nasty wheelies either. It just looses energy that can be used to make you go forward.
05-19-2006 | 08:26 AM
#29
Older V6 springs are a good cheap solution if you don't do drag shocks, especially if you are on drag radials.
But I'd suggest doing drag shocks up front, like the QA1 R shocks, with stock front and rear springs if you want the car to work best (on a budget).
But I'd suggest doing drag shocks up front, like the QA1 R shocks, with stock front and rear springs if you want the car to work best (on a budget).
05-19-2006 | 08:57 AM
#30
Originally Posted by Pro Stock John
I remember at NPR once, for a Thunder race, I did 4/4 and then came back and did 8/8.
My car squatted when it was H/C and went 1.55 with no drag shocks. Later I added drag shocks, a 422ci, and my car would squat so bad I would cut 1.61-1.65's totally hooking.
I didn't know dynos measured 60' times. Is there some new software we need to get. .
05-19-2006 | 10:31 AM
#31
Originally Posted by Mike TexaSS
Soften the compression setting on the shock if you're spinning past the 60'.
Good advice, I will try that if I continue to see this happen after I move. Thanks.
Charlie
05-19-2006 | 11:37 AM
#32
Oooh yes Paul, I did try to make passes that one year, but the reluctor ring on my crank was bad.
Thanks bringing that up.
I miss seeing you oil down a track, those were the days.
Thanks bringing that up.
I miss seeing you oil down a track, those were the days.
05-19-2006 | 01:56 PM
#36
Originally Posted by Pro Stock John
Older V6 springs are a good cheap solution if you don't do drag shocks, especially if you are on drag radials.
But I'd suggest doing drag shocks up front, like the QA1 R shocks, with stock front and rear springs if you want the car to work best (on a budget).
But I'd suggest doing drag shocks up front, like the QA1 R shocks, with stock front and rear springs if you want the car to work best (on a budget).
05-19-2006 | 02:28 PM
#37
I thought you couldn't run the stock springs up front with QA1 "R"s "confused:
I have Comp Eng drag shocks set at 50/50 in back with an airbag in the right rear spring. I haven't had my car to the track this year, but I was cutting low 1.5s with just LCAs, the 50/50 rear shocks, and airbag making 360hp cam only.
I have Comp Eng drag shocks set at 50/50 in back with an airbag in the right rear spring. I haven't had my car to the track this year, but I was cutting low 1.5s with just LCAs, the 50/50 rear shocks, and airbag making 360hp cam only.
05-19-2006 | 03:02 PM
#38
Vett's squat like no tomorrow. And I've seen H/C Z06's with T1 Sway bars and solid end links, stock shocks and leafe springs, LOWERD, pull 1.42 60's all day on 16" M/T ET Sreets.
I think it depends on your suspention setup and the car you'r in.
I think it depends on your suspention setup and the car you'r in.
05-19-2006 | 03:03 PM
#39
Originally Posted by 4thGenCamaro
I thought you couldn't run the stock springs up front with QA1 "R"s "confused:
Yes you can. I have stock springs on the older QA1'a up front, but they shocks has the same body as the "R" shock. All you need is the adapter plate that either Thunder Racing or BMR sells.
