Tom Deutsch

On the trip home after picking up my new (to me) 85 GS, I took a curve onto the highway on-ramp fairly hot. Instead of understeering, which I'm used to in front drivers, and which I might expect from a relatively low-torque front-engine car with cheapo all-season tires, the rear broke loose. It was actually kind of fun because it came back under control pretty easily with a little countersteer.
So, is this the solid rear axle "at work"? Should I expect my stock FB to be tail-happy even though the 12a is nowhere near a torque monster? Has anyone tried wider/stickier tires just on the rear?

mar3

iTrader: (8)

With a LSD rear, it gets even more fun. The lack of torque is somewhat compensated for by the deep gearing in the rear....there's just no weight back there, so it's easy to induce oversteeer around just about any corner. Bigger tires help along with a little more air pressure in the tires...a counter-intuitive thought, I know.

205/50/15 up front @ 35 psi, cold.....225/50/15 rear @ 38 psi, poly bushings on rear bar only for now, with stock sway bars, but Racing Beat rear springs, fronts stock cut down = near-neutral handling at very high speeds on clover-leafs on 'deserted' highway test-and-tunes.

mikewoodkozar

I agree that the first gens are oversteer happy, but i would rather have that then plowing through a corner with the wheels turned, but going straight, lol

82transam

iTrader: (18)

Oversteer is a common FB trait, once you get used to it it'll be your best friend

justint5387

iTrader: (1)

Do you have the rear sway bar on? If the oversteer came out all of a sudden, then you should try removing it.

Kentetsu

Check your tire pressures. That will make the most dramatic difference in handling (having one tire a few pounds over/under inflated compared to the rest of them).

There are several parts of the suspension that can cause this effect as well. For a short term correction, you may want to consider removing or disconnecting one end of the rear swaybar. For long term, your basically going to want to replace every bushing, tie rod end, ball joint, idler arm, rear control arm bushings, shocks/struts if needed, etc.

Once you get done replacing every "wear" part on your 25 year old beast, you'll have a great handling car.

Of course, if you have to replace something, it usually costs only a slight bit more to upgrade to a performance part. This is something you'll want to consider if you have any desire to use the car in competition events (such as autocross, which is a blast).

The two best web sites:

Stock replacement parts = www.rockauto.com
Performance mazda parts = www.re-speed.com

Hope this helps...

REVHED

The first and most important thing you need to do is get some decent tyres!

FBsliderseven

iTrader: (2)

yup oversteer happy.

85 FB

These cars are very tail happy. I've had mine come out on me at least 3 times.

Skidtron

iTrader: (1)

Sounds like a typical throttle lift oversteer to me. It did what you made it do. You go into the corner fast decide to slow down you take your foot off the gas the rear tries to pass the front of the car. This is a common mistake that causes a lot of accidents. Not saying you almost crashed or are an idiot just telling you why it happened. also you adding a bit of brake will help maintain the rear sliding if you wanted to drift a bit. Since the rear end will really be trying to pass the front as you lift throttle and add brake. Then it's back on the throttle with a bit of countersteer and your drifting.

FB does this very well. I don't use the brakes much at autocrossing for this reason.

mpk490p

i dont have anywhere near that kinda pressure in my tyres (225/45/16 rears and 215/45/16 front toyo proxies) i have 32 all round, what sort of pressure should i have?

thanks
Mark

mar3

iTrader: (8)

There is no 'right', just what is recommended...the handling of the car and the wear pattern on the tire will tell you if you got it right...just remember to change one parameter at a time (front tires pressure change, adding poly bushings, changing front sway bar, disconnecting a bar, rear tires pressure change, one side at a time change, etc....) or you'll never be able to know for sure what the sweet range is...it took a month of daily driving to get my numbers. That result is specific for my car but it's a good place to start if you have the same suspension and aspect ratio on the tires like I have. Just read the sidewall on your tire to make sure the max is something in the neighborhood of 44 psi and you'll be OK playing in the 33 -39 psi range.

MosesX605

All this talk of oversteer just makes me miss my 7 more.

Stupid f&^$ing winter, anyhow.

85 FB

That is some good advice I've read yet. Also, considering that it happens because the weight shifts to the front end when you lift off the throttle. No weight on the rear, going to the front, means it's lighter and easier to come out. I always maintain even acceleration while going into a curve to keep the weight shifted to the rear and maintain stability. That's the best course of action when going into a turn.

Skidtron

iTrader: (1)

What you've said here^ plus remeber you can use left foot braking while maintaining the throttle to slow the car without the rear sliding out. It takes some practice though since your left foot is used to only making abrupt inputs to the clutch pedal. It's hard at first to get your left foot to gently squeeze the brakes especially in a sticky situation. Practice makes perfect. If you watched my feet during an autocross they look like I'm doing some crazy Irish dancing or something. Both feet operate the brake and each foot has it's own pedal as well. Sometimes I'm lazy and don't do it though but it hurts your times quite a bit. Left foot brakjing is a very usefuol tool in my opinion. Some people never use it and say that it doesn't work for one reason or another. You just have to be gentle and every input should be smooth anyways for racing.

85 FB

I used to left foot brake but read how a top instructor at the Bourant Driving School (IIRC) stated that, while he knows about the technique, he doesn't do it but can still make a car go fast, whether it'd be RWD, FWD, or AWD. Left foot braking is more beneficial to FWD cars because of their understeering problems. I used to do it with my little pickup but stop after reading that article. And, I soon found weight shifting and throttle manipulation to be an easier key for going faster. This was noticeable when taking highway off/on ramps of various angles.

Tom Deutsch

I may be new to my Rx-7, but not quite off the apple cart. I'm sure I was either mid throttle or accelerating into the turn. I'm sure just the cheapo rear tires, maybe the road was a little wet, swaybar still attached - could be a number of things. I'm more than capable of driver error, but neutral throttle mid corner is an old habit by now. Your advice was good though, as I'm used to front drivers and it might be good for me to shift weight to the back to keep the rear planted now that I know it is twitchy in corners.
As for left foot braking, skidtron is right. The instructors at Mid-Ohio taught us the mantra "quick hands, smooth feet". They also taught us to imagine a string connecting the bottom of the steering wheel to the brake pedal - in other words, as you turn, you must go easier on the brakes. Visualization helps cure the "stab the brakes mid corner" impulse. There's a curvy road ont he way to church. My wife gets annoyed because the truck, minivan or corvette ahead of me invariably blasts down the straight bits and lights up the brake lights once they hit the corners. I play a game where I only go as fast on the straights as I can carry out of the turn and try to catch them. Fun! Should be even more so now that I'm back in a proper RWD car!

85 FB

This is the problem I always face and end up having to find the truth out on my own via my own experimentation.

Your source says to use left-foot braking. The article I read the guy said that there's no point. So, really, what does one do or who to believe?


The road may have been a little wet. It doesn't take much for the rear end to come out depending on angle and speed. My car had its rear come out when I was keeping mid-throttle in a 90-degree lefthand turn on a wet road. During then I realized I should've let off the gas and let the weight go to the front right tire and keep the turn a bit wider. But, only through learning we learn.

Skidtron

iTrader: (1)

They are all techniques use them all. No one person is right. Try everything and see what works. That is what I've found to be benefical to me. I started out in only FF cars so I like to left foot brake. Some people do not like it like the guy you talked about. It's not neccessary in all situations but it is in some. Just explore your car and have fun.

One thing to keep in mind is that the car's setting determines the way it will be driven. So it's more complex than saying one thing or another is better than another. You can build two cars of the same kind and they can drive completely different. It's hard to say what' sthe exact correct way to do things sometimes. This is a good thread though.....

justint5387

iTrader: (1)

Left foot braking is not a technique that everyone use... Randy Pobst, one of the best Pro driver in the US does not use left foot braking, he drives FWD, AWD, and RWD.