Front Wheel Drive Race Car Questions

[KevMcNJ]

The dirt track I regularly attend has created new entry level division using FWD 4 cylinder cars. Right now the hot set up seems to be old Saturns.

Since the rules require them to be kept 100% stock they all have very bad understeer.

I wouldnt sit in one of these coffins long enough to even get my picture taken but I am curious to know if tire stagger is as effective on FWD car as it is with RWD cars.

They been running these cars long enough now that I would have assumed someone would have figured how to get some of the push out of them.

But no, they all push bad.

Even the cars that run up front

[RS2]

I have much experience driving FWD cars on racetracks. But road courses only. I don't know what totally stock means in this instance. But it woulod seem to me that if you had stagger it would induce wheelspin to the inside tire making it understeer more due to the power being taken away from the right front to power it to the left. You need more traction on the front than the rear and you need the rear to be way more softly sprung and no anti roll bar on the back if possible. So in your case on dirt I would probably use a M&S or snow tires on the fronts and worn out rubber on the rear. I would aslo inflate the rears to just before they pop.

[KevMcNJ]

So in your case on dirt I would probably use a M&S or snow tires on the fronts and worn out rubber on the rear. I would aslo inflate the rears to just before they pop.

THIS is a great idea.

I sorta know a guy that races one of these death traps. I think Im gonna suggest it. I think the bald tires on back is a great idea

Im no chassis guru but I sorta understand the physics behind it all and this just seems logical

[jandj]

All I can tell you about FWD Mini's is what a friend who was winning in a $2000 Pinto told me when they allowed FWD cars the next year and obsoleted all the RWD cars: "You can beat the hell out of 'em and they still won't spin"....which in plain English means that as long as the front end is anywhere close to pointed in the right direction, the rear is just along for the ride.

[fasteddy]

On a sort of related note, back in the early 80's I owned two VW's, a Scirocco and a Dasher wagon. In snow the Scirooco would understeer so bad it was scarey, and the Dasher would oversteer. I figured it was the tires, Michelins vs. Contis.

[rrrr]

The dirt track I regularly attend has created new entry level division using FWD 4 cylinder cars. Right now the hot set up seems to be old Saturns.

Visit a Saturn owners forum sometime...the engines are apparently prone to rolling over dead with no advance warning and there are six or seven things that can cause it. Remember how Saturn was going to be a game changer?

[drtuba]

The dirt track I regularly attend has created new entry level division using FWD 4 cylinder cars. Right now the hot set up seems to be old Saturns.

I haven't seen many Saturns in MS. Last time I saw the FWD class race a mid-90's Altima won going away. Ironically, I drove to the track in the same model Altima...it was kind of surreal.

I wonder how RS2's idea would go over...I know the idea with that class is that you can't make changes...but if the rule book didn't extend to tires...it'd be interesting to see.

[Motie]

In sporty car racing with FWD, you charge into the corner like a madman, and then trailbrake past the apex to get some weight over the fronts. This is much more difficult than it sounds, because you have to modulate the brake pedal pretty delicately. And you can get oversteer and spin if you brake too hard. In the old days, I used to watch packs of Minis buzz by RWD Triumphs and MGs on the corners. I'm still not sure how that is possible, but they were doing it. It was hilarious.

[Motie]

All I can tell you about FWD Mini's is what a friend who was winning in a $2000 Pinto told me when they allowed FWD cars the next year and obsoleted all the RWD cars: "You can beat the hell out of 'em and they still won't spin"....which in plain English means that as long as the front end is anywhere close to pointed in the right direction, the rear is just along for the ride.

That doesn't sound right to me. A couple of cases:
1) What if you are going straight, and you hit the brakes hard? If you try to turn, you will get big understeer, because most of your front traction is going into braking.
2) What if you are cornering with a RWD car, and you apply too much throttle? If you use up most of the rear traction on acceleration, you don't have much left for cornering, and you oversteer, and maybe the back end comes around. This is why high-powered RWD cars can be very dangerous with novice drivers.
3. What if you are cornering with a FWD or RWD car, and you apply too much brake? Weight transfers to the front, you lose traction at the rear, and you get oversteer, and maybe the back end comes around.

So you can have throttle-induced oversteer in a RWD car, and brake-induced oversteer in a FWD or RWD car. Google traction circle. http://en.wikipedia.org/wiki/Circle_of_forces

Notice that the behavior of the car can change from understeer to oversteer depending on whether you are going straight or cornering.

All of these problems get worse if you punch the gas or brake pedal too fast, especially if you have a relatively soft street car suspension, and the car starts oscillating in the pitch axis.

My guess is that your friend is on the gas past the apex. That feels really good and controllable, and you will never get oversteer, but I don't think it's as fast as accelerating deep into the corner and then trail-braking past the apex. Carroll Smith's books talk about this in detail. This is how I was taught to drive my Honda CRX by a very fast SCCA VW Rabbit driver.

Edit: the traction circle also explains very simply why FWD cars understeer in corners when accelerating. Most of the front tire traction is being used up on acceleration, so there isn't much traction left for cornering. So the front end washes out. It gets worse. When you accelerate with a FWD car, weight transfers to the rear, and front traction gets even worse. This is why it's so hard to make a high-powered FWD car work. If you trail brake through the tightest part of the corner, you are transferring weight to the front, which gives more front traction, and reducing weight on the rear, which makes the car want to rotate. That's what you want.

By the way, you can also get understeer if you turn the steering wheel too much (which novice drivers always seem to do). Beyond the optimum steering input, the cornering force will actually decrease as you turn the wheel more, because the front tires are sliding. And you can't accelerate if you are applying power through sliding front tires, so you are losing a lot of time. When I was instructing, I was constantly yelling "Unwind the wheel!", especially on tight corners. If you are using the gas and brakes correctly, you don't need much steering input.

[KevMcNJ]

Visit a Saturn owners forum sometime...the engines are apparently prone to rolling over dead with no advance warning and there are six or seven things that can cause it. Remember how Saturn was going to be a game changer?

Its a box stock class and it seems most of them last 3 or 4 weeks before puking on the track. It was expected to be a class that had full fields but its rarely above 5 or 6 cars even this far into the season.

I think trying to race stock engines in cars that are no longer road worthy is too tall of an order and it seems that if they crash they are junk.

Not a good combo if youre trying to build up a new class

[rrrr]

All of these problems get worse if you punch the gas or brake pedal too fast...

This is one of the things I find interesting about NASCAR in-car shots on ovals. There are barely perceptible differences between drivers in how they roll in throttle off the corner, yet doing so at the optimum time and with the best rate is what makes the fast guys fast. Sure, this sounds obvious, but the differences are literally tiny fractions of a second. These actions aren't as clear in IndyCar shots, mostly because the ovals are usually flat out and the sound present in the NASCAR TV coverage is just easier to hear.

It's not easy to drive those heavy cars on the edge of losing control. As one of the best, Tony Stewart plays the throttle like a master violinist. Jimmy Johnson is also on the list of great car control drivers.

Oh, and please do me a favor...I don't need anyone posting comments about taxicabs, the most diverse series on Earth, road course skills, traitors, gapped teeth, and all such associated crap.

[Motie]

It's hard to convince people that they should go easy on the gas and brake transitions, because in open-wheel and mid-engine prototypes, they hammer the gas and brakes. The reason is that the suspensions in these cars are extremely stiff and extremely advanced. So you can apply your control inputs much faster than you can in a big, softly sprung car. An Indycar is not likely to start pitching back and forth just because you punched the gas pedal. But in a street car, once those pitch oscillations get started, you are in trouble. Weight is transferring front to back, back to front, and traction at the front and back is varying rapidly with time. If you are cornering near the limit when this happens, you are probably going to lose control.

Driving a race car looks so easy on TV. It drives me crazy. Viewers have no clue how much skill is required just to keep the damn thing on the track, let alone win the race. I agree with rrrr: it's like a concert violinist. The driver has to be so good that the proper actions come instinctively, because there isn't time to analyze what the car is telling you. That comes with a lot of experience, probably including one or two balled-up cars.

[jandj]

What my friend meant was that on an oval that if you're behind a FWD car you can't root him up out of the groove (or even turn him) like you can a RWD car since he's steering with the same wheels he's powering with.
In other words, you can knock him sideways and still not get by because he doesn't lose the traction (and thereby lose speed) like he would in a RWD car. As long as the front is pointed more or less where you want it, the ass end will follow.
They will come to a stop as quickly as a RWD car if you just plain stuff 'em in the wall, but that's kind of obvious and you want it look somewhat like "just racin' "....

[KevMcNJ]

Driving a race car looks so easy on TV. It drives me crazy. Viewers have no clue how much skill is required just to keep the damn thing on the track, let alone win the race. .

The first time you take the green in a real race car in a real race you think youre driving so fast that you must be setting a new track record.

Your bubble is quickly burst when the leaders lap you in less than 5 laps

[Motie]

The first time you take the green in a real race car in a real race you think youre driving so fast that you must be setting a new track record.

Your bubble is quickly burst when the leaders lap you in less than 5 laps

Reminds me of a story a friend told about entering an unsanctioned (illegal) motorcycle race. It was his first real race, and he was in the middle of a bunch of guys with more experience. They took off, first, second, third gear. And then the first turn was coming up, and he was ready to drop down to second...but then everybody else shifted up to FOURTH. It was a very fast trip up the learning curve for him. He says he will never forget it.