Hard "on the right front". Why?

[timcole421]

Accidentally posted this in the "gossip" section, thought I should repost this here.....

Just curious to the theory of being hard on the right front, in addition to the tons of camber on the RF?

I'm only asking as I am not sure I understand the physics of what is involved and what the goal is. It makes you wonder.....most track records are 10-15 years old, set back before these types of setups, exotic shocks, etc.

Should this theory work the same on a modified or stock car as well?

Thanks in advance!

[mab475]

Most of those records were set when tracks were wet and heavy and used a lot of chemicals that are banned now by the EPA not like todays track prep

[keeks]

Don't mean to hijack, but what kind of chemicals were being used back in the day for track prep?

[mab475]

Some used calcium some used soap and even brine water was used a lot.

[hpmaster]

7 tears ago or so there were tracks that used so much brine the cars would start oxidizing after a weekend show. Yea they were fast, tacky and would hold a ton of torque. Now all that torque is a game killer on an untreated track.

[Matt49]

Accidentally posted this in the "gossip" section, thought I should repost this here.....

Just curious to the theory of being hard on the right front, in addition to the tons of camber on the RF?

I'm only asking as I am not sure I understand the physics of what is involved and what the goal is. It makes you wonder.....most track records are 10-15 years old, set back before these types of setups, exotic shocks, etc.

Should this theory work the same on a modified or stock car as well?

Thanks in advance!

Your post on the gossip section got some pretty good answers from guys that frequent this tech section. I personally have nothing to add on the subject that the others didn't point out other than not ALL cars like the RF pinned down like that. Older front suspension geometry designs don't see as much gain in doing it and start to have some negative affects, not the least of which is bottoming out the frame and/or rack and pinion.
If you want anything technical answered, start in this section. The gossip section is 90% a complete waste of Internet bandwidth and server hard drive space thanks to a handful of people that could really use a good country ass whooping. It used to be a good spot to talk racing from a fan perspective but by the time you weed through all the garbage it just isn't really worth it anymore. But I digress...

[manwplan]

Matt49 and Mastersbilt, What do you guys think about some on the gossip page saying the cars are flatter these days? I disagree, they are hiked more than ever just in a different, calmer, more drive-able way. Flat to me is a 1980's leaf spring car. Those babies were flat.

[MasterSbilt_Racer]

Matt49 and Mastersbilt, What do you guys think about some on the gossip page saying the cars are flatter these days? I disagree, they are hiked more than ever just in a different, calmer, more drive-able way. Flat to me is a 1980's leaf spring car. Those babies were flat.

Some cars are really jacked in the back. Some are not. There are guys running real well without a lot of lr drop.

[mab475]

Its mostly driver preference. Some guys like the feel of being up on the bars and some don't. My driver prefers to be up on the bars. That's his comfort zone.

[Matt49]

10 years ago the entire left side of the car was coming off the ground and guys were carrying the LF 2 feet in the air. Things are different now. Keeping the nose down is where guys have found more speed for many different reasons. I think in most cases the LR is hiking up just as much as it always was but having the nose down is making it look "calmer". Also, look at the difference in the wheel well cutouts now and how some even cover the LR tire at ride height. That is done for several reasons but one is to disguise how much hike they are getting when the LR drops down.
As MBRacer said, some guys are running less than 12 inches of drop and having success. LR drop is all about a compromise between rear steer and LR drive.

[SR444]

10 years ago the entire left side of the car was coming off the ground and guys were carrying the LF 2 feet in the air. Things are different now. Keeping the nose down is where guys have found more speed for many different reasons. I think in most cases the LR is hiking up just as much as it always was but having the nose down is making it look "calmer". Also, look at the difference in the wheel well cutouts now and how some even cover the LR tire at ride height. That is done for several reasons but one is to disguise how much hike they are getting when the LR drops down. As MBRacer said, some guys are running less than 12 inches of drop and having success. LR drop is all about a compromise between rear steer and LR drive.

In what ways are guys today able to keep the left front down and still have drive and rotation? is it in the j-bar or rear angles of the 4-bar

[hpmaster]

Some very fast cars are limiting the right front movement and in doing so are making the cars look flatter. It is just another way of controling how much weight is applied to the right frt wheel. Maybe someone figured out how to turn a tight race car.

[Ltemodel]

Soft springs can give the illusion of weight transfer, but things aren't always as they appear. I believe it is a definite advantage to keeping the left front on the ground. Any air passing under the car creates lift and takes away traction. The less air under the car the more air over the car = more traction, side bite, whatever you are looking for.

The key is getting a good balance in the car. If you picture a perfect race car. It would be: put as much horsepower and traction it it as possible and drive it as smooth as possible to not loose momentum. On dirt this is not possible, so we start backing up from that perfect car and create something that is as close as we can get it. We cut horsepower, lift off the gas entering the corner, use the brakes, etc.; but the same mindset should still apply. How close can we get to that perfect race car and still be drivable enough to win races.

Guys liked picking the left front years ago, when four bars were young, because it felt good. Tons of traction off the corner. Now as guys progress, shocks got better, aero becomes more important; the cars are getting more calmed down and maneuverable. Nowadays drivability seems to be the main focus while getting maximum downforce on the entire car.

[Ghopper]

Center of gravity position and lateral acceleration determine all Left-to-right weight transfer. Nobody disagrees with this.

Front and rear roll stiffness determine how the weight is distributed over the tires. Nobody disagrees with this.

As Ltemodel mentions, soft springs can make this transfer look exotic. Because of ride height rules, the static body position of the car is much different than the dynamic race body position. It has been learned that low INITIAL front roll/ride stiffness will create a desired transition from static body position to race body position. Then bumpstops or staged springs increase the roll/ride stiffness to create desired dynamic wedge rates.

.....and to add to your left front tire on ground discussion. LF is needed for entry/middle, but not really on exit. These are rear drive cars. The more load we can get on the rear tires the better. This is usually related to keeping load on the LR tire. X weight will be transfer anyway because of CG height and Lateral acceleration. You would rather unload the LF and load the LR with what weight is remaining on that side.


Ghopper

[Brian Gray]

you cannot have downforce without air getting under the car. downforce is created by equal amounts of air moving at different speeds . without air under the car all you have is drag

this aero influence does contribute to the setups many teams use and is partly the reason we try to keep the frontend relitive to the race track.

[MasterSbilt_Racer]

you cannot have downforce without air getting under the car. downforce is created by equal amounts of air moving at different speeds . without air under the car all you have is drag

this aero influence does contribute to the setups many teams use and is partly the reason we try to keep the frontend relitive to the race track.

Downforce is a difference of air pressure on opposite sides of a surface. Can be achieved by having different speed airflows on each side or by simply having much less air on one side. The advantage of a vacuum under a race car was demonstrated in the 1960s with the Chaparral 2J.

[Matt49]

Downforce is a difference of air pressure on opposite sides of a surface. Can be achieved by having different speed airflows on each side or by simply having much less air on one side. The advantage of a vacuum under a race car was demonstrated in the 1960s with the Chaparral 2J.

Exactly! There's a lot to be said for keeping air OUT from under the car yet letting it escape out the back. Thereby creating a huge low pressure area. I'd love to get some pressure readings from just under the decking of a late model at speed on the track compared to just above the decking.

Remember a few years ago when some guys were trimming their LF quarter panels almost completely off? With the way the LF QPs are tapered in at the back, it creates a major hindrance for air trying to evacuate out the back (especially when the car is yawed out). I guarantee they weren't doing that because they thought it looked cool. Somebody figured something out and I'm guessing officials put a stop to it.

[Brian Gray]

Take air away from the high speed area of an airplane wing and tell me if it will still stay airborne.

If the air isn't under the car there is nothing to escape out the rear. You can disagree all you like but the physics don't lie.

[Ghopper]

Take air away from the high speed area of an airplane wing and tell me if it will still stay airborne.

If the air isn't under the car there is nothing to escape out the rear. You can disagree all you like but the physics don't lie.

Brian - The high speed side of a plane wing is the top (longest side) to create lift. I think your argument is not going the right way for a late model application. If applied to a latemodel, with equal flow above and below the car would also cause lift, as it is a longer distance over the top than the bottom.

We get much of our downforce from high pressure areas (nose, spoiler). More like angle of attack for airplane wings. In this case you want minimal air under the nose of the car. In cases when you have a splitter (like NASCAR), a small amount of air can be beneficial.



Ghopper

[hucktyson]

As usual Brian Grey is a toss off , wind tunnels don't lie Brian