question about yanking the tires during launch

[rwrows]

what affects yanking the tires? i've seen low 11 second cars with at least 1 tire up, and then i've seen 9 second cars without wheelie bars not yanking at all. i know cars with the HR bar don't yank them. can someone elaborate on this? i want my car to yank them at least a little bit. what's the best set up for that? grumpy's car has the atr bar and his car doesn't even yank them. and that's goin high 9s. he says it just goes. i understand that some guys don't want to yank them. so obviously it has to do with the suspension. shocks? any input? thanks.

[jasjamz]

How a car transfers weight matters. The "Shock" to the car when it launches, and even the stance of the car could have an effect. Power level can be taken into consideration but is not the key to it. I was always told the yanking a tire was bad because the time spent twisting the car to pick that wheel up adds time to heading towards the finish line. Looks cool, though.

[Chuck Leeper]

"Yanking the tires" AKA: pitch rotation, is reaction to the acceleration of the vehicle. Once the ft wheels are off the track, wt transfer is at the max. Stand it up 45*, and it gets no better.
As for the HR bar comment... Not true. That device helps to more evenly plant the tires.
Feel the need for "yanking them"?. Add a loose converter, no ft sway bar, a set of Moroso springs, and loose shocks... That should pretty well do it..[Assuming the engine is not a mutt.]

[87Regal3.8SFI]

I always thought yanking 1 tire was also a partial direct result of the factory triangulated rear suspension set up.

[Audie1]

Originally Posted by Chuck Leeper

"Yanking the tires" AKA: pitch rotation, is reaction to the acceleration of the vehicle. Once the ft wheels are off the track, wt transfer is at the max. Stand it up 45*, and it gets no better.
As for the HR bar comment... Not true. That device helps to more evenly plant the tires.
Feel the need for "yanking them"?. Add a loose converter, no ft sway bar, a set of Moroso springs, and loose shocks... That should pretty well do it..[Assuming the engine is not a mutt.]

What would be considered "Loose Shocks"? Does this apply just to the front shocks?.........Thanks

[rwrows]

audie nice combo. what are you turning at the track?

[it's just a six]

Originally Posted by Chuck Leeper

"Feel the need for "yanking them"?. Add a loose converter, no ft sway bar, a set of Moroso springs, and loose shocks... That should pretty well do it..[Assuming the engine is not a mutt.]

Forgot another item,,,,,a nice transbrake.

[rwrows]

oops

[Chuck Leeper]

Yanking 1 tire usually is the result of the chassis twisting, and the rt rear side of the axle being pulled up into the body by torque reaction on the r&p.[Look @ Nick Micales pic of his T-type!!]
A couple "cures":
A well thot out roll bar/cage.
Antiroll bar, such as HR.
Correct shock settings.

Audie:
I think the loose shock deal could be:
Cheapo shocks.
Worn out shocks.
Good shocks that are adjusted loose.

justa 6.. Yep, the t/b would be another good idea, assuming the rest of the drivetrain would hold up!!

[Nick Micale]

Originally Posted by Chuck Leeper

Yanking 1 tire usually is the result of the chassis twisting, and the rt rear side of the axle being pulled up into the body by torque reaction on the r&p.[Look @ Nick Micales pic of his T-type!!]
A couple "cures":
A well thot out roll bar/cage.
Antiroll bar, such as HR.
Correct shock settings.............

This was "fixed" a few years ago with new stock GN springs, used KYB shocks up front, and the HR bar. I use the HR adjustable uppers and tubular lowers, nothing exotic or complex about getting the factory 4-link set up to work.

The pic below is just after I "added" about 300 HP with my TA alum motor. Big difference going from mid-10's to mid-9's.

It now picks up the front end past the 60' mark with almost no air under the front tires, and can easily run 1.35 60' times.

Video on my web site shows how it leaves now.

Also, Chucks advise on chassis set up has been very valuable over the years on many cars we have done.

[bison]

Originally Posted by rwrows

i know cars with the HR bar don't yank them.

They dont? Have you ever seen TSO or TSM cars launch? I doubt it. Yanking the tires doesnt do **** for acceleration once all the weight is the rear tires any further lifting of the front of the car is wasted power. Hard core heads up racers dont care how high they "yank" the tires. They care about going fast. If you look at the fastest passes the wheels usually just come up a little and the car shoots out like a bullet.

[rwrows]

Originally Posted by bison

They dont? Have you ever seen TSO or TSM cars launch? I doubt it. Yanking the tires doesnt do **** for acceleration once all the weight is the rear tires any further lifting of the front of the car is wasted power. Hard core heads up racers dont care how high they "yank" the tires. They care about going fast. If you look at the fastest passes the wheels usually just come up a little and the car shoots out like a bullet.

excuse me for not seeing a tso or tsm car launch. i'm talking about high 10 low 11 second cars. my car doesn't have a cage so i can't go that fast anyway. i just want a launch pic with my tires in the air. if i cared about going fast i would build a race car. i'm not talking about the fastest passes ever. all i'm saying is that i've seen several 10 second cars with the front tires in the air. and i've seen some 11 second cars with 1 tire off the ground. who cares about going fast anyway when you're bracket racing? or excuse me, you are a hardcore heads up racer. there's always someone faster than you. i'm building a 10 second capable car that i only really want to go 11s with. maybe sneak in a 10 second pass here and there just to get booted for fun

[bison]

Originally Posted by rwrows

excuse me for not seeing a tso or tsm car launch. i'm talking about high 10 low 11 second cars. my car doesn't have a cage so i can't go that fast anyway. i just want a launch pic with my tires in the air. if i cared about going fast i would build a race car. i'm not talking about the fastest passes ever. all i'm saying is that i've seen several 10 second cars with the front tires in the air. and i've seen some 11 second cars with 1 tire off the ground. who cares about going fast anyway when you're bracket racing? or excuse me, you are a hardcore heads up racer. there's always someone faster than you. i'm building a 10 second capable car that i only really want to go 11s with. maybe sneak in a 10 second pass here and there just to get booted for fun

TSM and TSO are examples of cars that are stock type 4 link suspensions and very often run HR bars. Those are just the fastest examples of stock suspension in the Buick world. Most do wheelies to a certaoin degree. There are many low 10 and faster Buicks that carry the wheels to the 60' mark. You cited a Grumpy's daughters car in th first post. Their goals are going fast. Not doing wheelies. Ive seen 12 sec cars lifting the tires on hard launches. You want wheelies then get some tall wide slicks, a trans brake, lighten the front of the car with a glass bumper, skinnies, and put the battery in the trunk. Get some Moroso drag springs, and shocks. Use VHT on your slicks. Do a light burnout. Leave at 15-20psi off the t-brake and you will do wheelies until you break something like and axle or driveshaft..

[rwrows]

Originally Posted by bison

TSM and TSO are examples of cars that are stock type 4 link suspensions and very often run HR bars. Those are just the fastest examples of stock suspension in the Buick world. Most do wheelies to a certaoin degree. There are many low 10 and faster Buicks that carry the wheels to the 60' mark. You cited a Grumpy's daughters car in th first post. Their goals are going fast. Not doing wheelies. Ive seen 12 sec cars lifting the tires on hard launches. You want wheelies then get some tall wide slicks, a trans brake, lighten the front of the car with a glass bumper, skinnies, and put the battery in the trunk. Get some Moroso drag springs, and shocks. Use VHT on your slicks. Do a light burnout. Leave at 15-20psi off the t-brake and you will do wheelies until you break something like and axle or driveshaft..

great! that's what i wanted to hear. i'm doing moser axels and cclip elims before the spring. do i have to go that crazy just to get the tires off? i only want them up an inch or so. don't want a tranny brake either.

[GNDriven]

When you say low 11 mid 10 sec cars, do you mean turbo regals?

I wonder myself about the variation that turbo regals have in there suspension setups and chassis stiffness.
I haven't seen a turbo regals in the low 11s pull a front tire.

I have watch in person my friends 2001 TA pull a front left tire about 5" with 1.62 short time, 11.60 quater time. I know that he does have some suspension mods for tracktion sake.

I doubt those low 11s second turbo regal cars have adjusted there Instant Center point.

[rwrows]

Originally Posted by GNDriven

When you say low 11 mid 10 sec cars, do you mean turbo regals?

good question. i was gonna point that out but was in a rush to post. mainly i'm talking about chevelles. i know they have a different weight transfer and all....my buddy has a 71 grand prix that was running 11.7 - 11.80s and he yanked his left front tire. and a mid to low 10 second 70 chevelle i saw yanked them like 2 feet in the air. and i know a magna member with an '87 gn that went 11.19 and his front left tire is off the ground, not sure about the right. here's a gn from the tb home page. it says 10.6 and it looks like he's got them yanked.

[Audie1]

Originally Posted by Chuck Leeper

Yanking 1 tire usually is the result of the chassis twisting, and the rt rear side of the axle being pulled up into the body by torque reaction on the r&p.[Look @ Nick Micales pic of his T-type!!]
A couple "cures":
A well thot out roll bar/cage.
Antiroll bar, such as HR.
Correct shock settings.

Audie:
I think the loose shock deal could be:
Cheapo shocks.
Worn out shocks.
Good shocks that are adjusted loose.

justa 6.. Yep, the t/b would be another good idea, assuming the rest of the drivetrain would hold up!!

Roger that..........Thanks

[Audie1]

Originally Posted by rwrows

audie nice combo. what are you turning at the track?

Thanks...........actually I don't know what she will run after I put the CPT-66BB,SMC Alky, and a Cotton's fmic on, (just ordered them). They closed down Cooper River Drag Strip, which was close to me. There is one other 1/8 mile strip (Dorchester) (it is pretty getto, I would not want to put a hurting on some crack head).... ....so I don't go there. The last and only time out with this GN I made one pass, blew the tires away and ran a 7.6 at 99mph in the 1/8th at 20 psi with a TE45A, some good gas, and a little Kenne Bell fmic . I have done some work on her to help with the traction........ With 25 psi and a decent launch and the new mods, I'm hoping to run maybe a 6.8 in the 1/8th mile, that is my goal anyways. Guess I'll have to go to the "Crack Strip" and find out what she will do.

[toofastforyou]

Originally Posted by rwrows

here's a gn from the tb home page. it says 10.6 and it looks like he's got them yanked.

Here are two pictures of my car on Labor Day Weekend at Englishtown, NJ....but taken at least 10 years apart!! The first one on the left is with an H&R sway bar and the second pic is with a stock sway bar...

Claude.

[bison]

Originally Posted by rwrows

great! that's what i wanted to hear. i'm doing moser axels and cclip elims before the spring. do i have to go that crazy just to get the tires off? i only want them up an inch or so. don't want a tranny brake either.

Without a t-brake it will be hard to hold the boost. You could get air realy easy with just slicks and a t-brake with a hard boost launch. Foot brake it will be hard. You will need a good converter to spool that 66 quick enough to get air.

[2QUICK2B6]

Originally Posted by rwrows

what affects yanking the tires? i've seen low 11 second cars with at least 1 tire up, and then i've seen 9 second cars without wheelie bars not yanking at all. i know cars with the HR bar don't yank them. can someone elaborate on this? i want my car to yank them at least a little bit. what's the best set up for that? grumpy's car has the atr bar and his car doesn't even yank them. and that's goin high 9s. he says it just goes. i understand that some guys don't want to yank them. so obviously it has to do with the suspension. shocks? any input? thanks.

lake wood 90/10 fronts 50/50 rears shocks moroso Drag springs in the rear air bags with metco upper and lower control arms a loose converter and good brakes with a sticky track and my car will yank the drivers tire up on DR's and its only in the 11's. Like someone said above its all how the car transfers its weight on the launch ... ive seen very slow mustangs jerk both tires up and put them back down.

[it's just a six]

Originally Posted by bison

Without a t-brake it will be hard to hold the boost. You could get air realy easy with just slicks and a t-brake with a hard boost launch. Foot brake it will be hard. You will need a good converter to spool that 66 quick enough to get air.

If you run a hydroboost brake system, brakes should hold.

[Red C5]

I was told that in this vid, my GN picked up the tires a few inches off the ground. I've got a little bit of suspension and a trans brake.

YouTube Video

[bison]

Originally Posted by it's just a six

If you run a hydroboost brake system, brakes should hold.

Probably not unless you used larger rear wheel cylinders (which are a no no on wet pavemen). I think the piston is the same size on the hydroboost and the powermaster

[rwrows]

Originally Posted by bison

Probably not unless you used larger rear wheel cylinders (which are a no no on wet pavemen). I think the piston is the same size on the hydroboost and the powermaster

my car has the factory brakes and i can hold 20 lbs of boost at the line. i put the pedal to the floor and have a stock converter. i use the parking brake. who needs a tranny brake? lol

[Grumpy]

ok ..back home here. here is Melissa's 10.10 @ 132/133 with a 1.47 short time (I think) Foot braking it!! .. car just took off.. after the run she left the track and drove to Dunkin Donuts for her morning coffee We are goin to work on her short time this year (I hope).. Still goin to keep reg street tires on the front.. but we are not goin to do a 2 foot wheelie's

[corsair231]

What I've seen done to some "home brewed" (ie: lowbuck, redneck) racers is that they would install a short length of chain between the a-arms and an upper mounting point. It would basically limit the amount of travel for the wheel to drop. What would happen is that when the rear squatted enough the slack came out of the chain and it would "snatch" the front wheel off of the pavement theoretically giving more weight transfer and better bite to the rear. I've seen it on more than one car but like I said they were racers. I would be very hesitant to trying anything like that, especially on a streeter.

[turbodave231]

The geometry of the rear suspension will ultimately dictate whether the car wants to pick up the front tires.

If you were to project the imaginary lines formed by the rear control arms forward into the car, the point where they intersect is called the Instant Center. The location of the IC changes with the location of the control arm attachment points and ride height.

The "Neutral Line" is an imaginary line drawn from the rear tire contact point thru the Center of Gravity out toward the front of the car. IC's that fall above the Neutral line and near the CG will cause the front to lift.

Knowing where the IC is located will help you tune the suspension for a "bigger hit" or "softer hit" and will control or cause wheelstands to happen.........but it is surely not the only factor involved with big wheelies.

Take a look at the video below..........Huge wheelies. Right? I know exactly where the IC is located. A few small changes, (torque converter and tires) caused my car to do violent wheelstands. Another small change (front suspension travel limiters) calmed the car down with no other changes....and the car now is in the 1.28-1.30 sec 60' range. The car will leave with about 2 feet of air under both tires and great traction.

If you really want to understand what is happening with your car and suspension, buy the Doorslammers book by Dave Morgan and his 4 link calculator software. If you can digest this information, you can then start effectively tuning on your suspension. Tuning your suspension without good information is a waste of time and money, IMO.

Dave

[V6RACER]

Too much launch RPM/Boost, no limiters on front, and aggressive rear suspension.. Learned a lot that year..



Big Wheelie from Need2Speed's Dead Hookers II at B- Video

[bison]

Originally Posted by V6RACER

Too much launch RPM/Boost, no limiters on front, and aggressive rear suspension.. Learned a lot that year..



Big Wheelie from Need2Speed's Dead Hookers II at B- Video

What the hell was that under your car? Looked like the exhaust hanging down.

[XXQUICK6XX]

Here is some of mine.

[XXQUICK6XX]

Another

[V6RACER]

Originally Posted by bison

What the hell was that under your car? Looked like the exhaust hanging down.

The test pipe slipped off the down pipe.. Have V-band clamps now.

[pacecarta]

hey rodger
heres a wheel up pic for you


on an 11.98 pass
stock turbo, stock sway bars , footbraking on a D5 converter

[Sydwyndr]

Originally Posted by turbodave231

The geometry of the rear suspension will ultimately dictate whether the car wants to pick up the front tires.

If you were to project the imaginary lines formed by the rear control arms forward into the car, the point where they intersect is called the Instant Center. The location of the IC changes with the location of the control arm attachment points and ride height.

The "Neutral Line" is an imaginary line drawn from the rear tire contact point thru the Center of Gravity out toward the front of the car. IC's that fall above the Neutral line and near the CG will cause the front to lift.

Knowing where the IC is located will help you tune the suspension for a "bigger hit" or "softer hit" and will control or cause wheelstands to happen.........but it is surely not the only factor involved with big wheelies.

Take a look at the video below..........Huge wheelies. Right? I know exactly where the IC is located. A few small changes, (torque converter and tires) caused my car to do violent wheelstands. Another small change (front suspension travel limiters) calmed the car down with no other changes....and the car now is in the 1.28-1.30 sec 60' range. The car will leave with about 2 feet of air under both tires and great traction.

If you really want to understand what is happening with your car and suspension, buy the Doorslammers book by Dave Morgan and his 4 link calculator software. If you can digest this information, you can then start effectively tuning on your suspension. Tuning your suspension without good information is a waste of time and money, IMO.

Dave

Here is a wheels up shot