racerfoo

Who has done this and how well does it help on launching the car?

jspecracer7

Never heard of it for the front, only the rear. If you remove the front sway bar though, you'll find very quickly that you have to take turns slowly...unless you LIKE to dive into turns.

PVerdieck

That is the stupidest thing I have heard in a long time.

Megaspeed7

No its not. That is a very common drag racing trick. Do a little research.

7racer

didn't you or someone else post this before??

7racer

ahhh here is the post...

https://www.rx7club.com/showthread.p...front+sway+bar

7racer

and the link to the drag article....
http://www.hotrod.com/techarticles/69818/

duboisr

Will this help for the low cost drag racer ? Put on a set of old worn out front shocks , so the front will lift and transfer the weight to the rear . Just a thought .

maxcooper

Does anyone raise their ride height when they go to the strip? That will increase your weight transfer to the rear, since it is basically a function of wheel base (shorter = more transfer) and CG height (higher = more transfer). I am not a drag racer, and haven't tried this, but it seems like it might help. It would be interesting for someone to try it and compare their 60ft times after raising the car up an inch.

-Max

jimlab

Ask Garfinkle.

93BlackFD

yes, ask your mechanic, he should know, he knows everything except how to use a computer...in the year 2004...

jspecracer7

With the car at full rest, nailing the throttle results in a number of simultaneous vehicle reactions. First, the body tends to pitch upward in the front, moving weight from the front to the rear of the car. That is referred to as weight transfer and improves traction by increasing load to the rear tires. At the same time, most street cars also rotate slightly side to side, moving weight from the left (driver’s) side of the car to the right side. That can be seen by watching a car leave the starting line of the dragstrip from dead astern.

While the body rotates from left to right (clockwise as viewed from the rear), the rear axlehousing rotates in exactly the opposite direction. That counterclockwise rear-axle torque reaction shoves the left rear tire into the pavement while lifting the right rear tire, which explains why nonpositraction-equipped cars always spin the right rear tire. Since unloading the right rear tire can only hurt traction and acceleration, most rear-suspension modifications are aimed at limiting or preventing the rear axle from rotating in this counterclockwise fashion.

There are a couple of tricks you can use to make all this twistin’ and shoutin’ work toward better traction. First, try unbolting the front sway bar from the two lower front control arms. The front sway bar’s job is to transfer weight from the left front to the right front. By disconnecting the sway bar (or better yet, remove it to also eliminate weight), the front end is now able to transfer more weight to the rear tires.


From the article.

I would NOT do this to a daily driven car, which is the main reason I haven't done it to mine(plus I thought it was the rear).

Another really good trick is what duboisr stated. The HKS Hyper-D Drag suspension uses REALLY soft springs. I have heard dozens of people tell me that when I launch, it almost looks like my muffler will touch the ground...

tmiked

This effect is NOT present in cars with IRS like the RX-7. However, getting rid of any weight that far forward has to be good. Also, the Front Swaybar may restrict the suspension travel at full rebound.

DamonB

It doesn't, but if it did it would still be a good thing as the front would leave the ground earlier.

The key to a good launch would be to get as much weight transfer as possible (raising the car) as early as possible (boatloads of front rebound) and use a soft enough spring in the rear to better let the tires absorb the shock of the launch.

jspecracer7

ok

racerfoo

Im probably not the best person to test this out for proof to see if it works, but I'm going to today.

My best 60 to date is a 2.1, we'll see if this helps. Before you laugh at my 2.1, I'm non-seq and run crappy tires. Ok...now you can laugh

NewbernD

iTrader: (1)

Or there's the trick that we used to use with drag bugs.. (probably used a lot with drag-only setups)

You outfit a line lock to the front brakes and wire it (a) with a console switch to activate the system and (b) a switch at the clutch pedal so that when you release the clutch it deactivates the lock.

It takes a bit of work to get the clutch switch in the right spot but the idea is that when you stage you activate the lock, rev it up and release the clutch *a little*.. just enough to preload the whole rear suspension. (We used to load it up enough to let it rest on the suspension bumpers.) When you leave, you release the clutch the rest of the way, nail the gas and the car doesn't have to squat, it just goes.

kyle@insight

It has every bit of effect on the RX-7. People do it with their vettes and cobras, all equipped with an IRS. And Yes, it does drop 60' times.

I seriously don't understand why people have such trouble accepting some old domestic tricks simply because they own a 'much more advanced' japanese sports car. The trick may seem primitive, but it's definatly effective.

tmiked

Kyle,
I was saying the 'lifting the right rear wheel effect' is not present in cars with IRS (see the quote from jspecracer7). Because the diff is tied to that car, the rear wheels do not twist longitudinally at the start.
Other effects would be the same for the 7.

Too many people jump in these threads just to blabber. BTW Kyle, what happened to your beautiful sig's ?

the_glass_man

iTrader: (2)

What about adjusting you coils from hard to soft?
Hmm sounds, like ice cream.

particleeffect

while i can't fathom how removing the front sway bar in an application where it does not restrict the lowest possible point in the front suspension, having any affect here.

if you are lifting the front on a stock rear end and axles, aren't you just begging to blow something out?


-DING got it. unbolting the front sway bar isn't to help the front come up, but to help the car lean, which puts more leaning load onto the rear. (without the front bar in place)

KevinK2

Hot Rod comments, for solid axle rears, miss the real effect. Tes, if you have sbar pivot bushings too tight (mine are not), then it could delay weight transfer to rear. But more significantly, a stiff front bar would keep car flatter, reducing the 'driver lifting' body roll that increases right rear spring compression, which offsets the right rear unloading due to d-shaft torque to the rear axle. ( I did some finite element modeling for a friend with an 89 stang, and designed a single traction bar bar, located about mid span of right axle housing, that eliminated the body roll and the right rear unload effect ).

For IRS, issue is general frame twist. For a given twist at launch, stiff front bar would increase body roll at rear, and decrease opposite roll in front, tending to unload the right rear (but not near as much as for a solid rear axle). Likely best to have no sway bars, and soft roll stiffness.

RTS3GEN

Max,
I have done that, however, I never measured the height by which I raised the rear suspension. With previous setup and 4.33 gears at slammed street height(about 2.5" below stock) and Tokico's on 2, with ET Streets at 18psi. my 60 fts were 1.88, 1.84, 1.79. I ran 12.32, 12.26, and 12.21 respectively. The next trip to the strip everything else the same(power, boost, gears etc) my 60 foot time was 1.72 and I ran an 11.77. I had elevated the rear suspension(ground control coil overs) up about 3 ".(The car looked like and old Camaro jacked way up!) I attempted one backup pass but blew my output shaft in my tranny so I didn't get to try again.

Art

racerfoo

I tried it today, an with stock air pressure in my street tires, it caused tons of wheel hop and crappy 60ft times. I lowered the pressure quite a bit and improved 2 tenths and pulled of a 2.1, which is still crappy, but an improvement over 2.3.

I think good tires makes the biggest difference, but this definately helps transfer weight. Just down try to take corners fast, not fun

AnthonyNYC

iTrader: (3)

Here is a pic of a street driven FD with the front sway bars removed to help launching. I took that pic but was not sure if I caught the car on the way up. A number of people stated it was higher than that in the front...



Anthony