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-   -   Oversteer Control (https://www.rx7club.com/1st-generation-specific-1979-1985-18/oversteer-control-125033/)

sberge01 10-19-02 08:26 AM

Oversteer Control
 
Hi all...just finished the replacement of the rear bushings (rubber), front sway bar (to a Racing Beat), front bushings (used included RB poly bushings and changed others to new rubber) and tension bar bushings. Already had replaced shocks to Tokia adjustables and Eibach shocks. Ride is great...except I experience oversteer a bit often. I have the shocks set at three all around and the tire pressure is to recomendations.

Other than taking it slow around corners (no fun!), any suggestions? Stiffen up the rear and loosen up the front shocks? More tire pressure in the rear and less in the front?

Thanks for the advice!

SB

Rx7carl 10-19-02 08:53 AM

Please tell me you didnt put poly bushings in the rear. Dont do anything to stiffen the rear, thats what will make the car oversteer. You got it backwards. You soften the end of the car that isint sticking, or stiffen the end that is.

sberge01 10-19-02 09:18 AM

nope...rubber in the back...

and I guess I thought we were saying the same thing...The rear end swings around when I turn...the front seems to hold the line fine...Isn't that oversteer?

851stgen12a 10-19-02 09:50 AM

Yup thats oversteer.
You want the front shocks stiffer than the rears. I keep mine set 4 at the front and 3 at the rear for daily driving. when it gets slick (rain) I set the rear to 2.
It has just the perfect balance between at the limit oversteer and light understeer at lower speeds. I love it, can really rock the corners.

Rx7carl 10-19-02 10:25 AM


Originally posted by sberge01
nope...rubber in the back...

and I guess I thought we were saying the same thing...The rear end swings around when I turn...the front seems to hold the line fine...Isn't that oversteer?

Yes, what I meant was that your tuning idea was backwards. Soften the rear/and/or/stiffen the front.

diabolical1 10-19-02 06:36 PM

Re: Oversteer Control
 

Originally posted by sberge01
I have the shocks set at three all around and the tire pressure is to recomendations.
well, yeah, like rx7carl and 851stgen12a said, you want to stiffen the front and soften the rear. so try turning the rear down two notches. you may also want to run a wider tire on the rear wheels.

851stgen12a 10-19-02 07:55 PM

When I first got my shocks and springs, I didnt have anywhere to do my fromt struts so Ijust did the rears. Holy shit was that scary!!!! I set the rear ones to 5 (as stiff as they go) driving in a straight line if i turned the steering wheel even a little sharpley the rear end wanted to snap around on me. Was really fun for drifting though....


Ohh by the way, I dont know if anyone cares, but my name is Micah. feel free to call me by my name

diabolical1 10-19-02 08:45 PM


Originally posted by 851stgen12a
Holy shit was that scary!!!!
:rofl:


Ohh by the way, I dont know if anyone cares, but my name is Micah. feel free to call me by my name
hell yeah, i care! it's much easier than having to type 851stgen12a all the time ... :D

inittab 10-20-02 07:32 AM

Try playing around with your tire pressure. The 1st Gen is VERY sensitive to tire pressures. I had similar oversteer problems untill I lowered the pressure in my rear tires. That's all it took to tame the beast. Give it a try it might work for you.

sberge01 10-20-02 08:44 AM

thanks for all the great ideas...i'll let you know how it goes

Rx7carl 10-20-02 03:38 PM

Yea inittab makes a good point. Lowering your rear tire pressures is a way to soften the rear axle and youll get more rear bite, just dont go too low.

sberge01 10-20-02 04:21 PM

seems to be under control now...front shocks at 4 rear at 3; front tire pressure at 28 rear at 30. Handled great. Now on to my alternator problem...but that is another story for this money pit...i mean hobby!

inittab 10-20-02 05:25 PM

I've been run'n 32 psi front and 28 psi rear on my 205/60/13's. Not that that's optimum but seems to work pretty well for me.

31rx7 10-20-02 11:45 PM

Another thought if the other items don't work is to disconnect / remove your rear sway bar. This is a bit more drastic than the other items mentioned, but will certainly reduce oversteer.


Along these lines, different year 1st gens have different rear bars. I have three different ones I've collected: 15mm, 17mm, and 18mm. You could try also going to a smaller bar if you have one of the larger ones.

voodooracing 01-07-03 04:55 AM

31rx7,

which year/model 1st gens comes with 15mm? and which is 17mm, 18mm?

fatboy7 01-07-03 12:10 PM

I think the SA's came with the larger bars, but I only thought there was 15mm and 18mm choices, so I could be way off.

specRX7_22 01-07-03 03:09 PM

as 31rx7 said, you dont need rear sway bar at all. alot of people think that it will drastically change your handling, etc, etc. not true at all. removing the rear sway completely will help alot in lessening oversteer.

peejay 01-07-03 03:18 PM


Originally posted by Rx7carl
Yea inittab makes a good point. Lowering your rear tire pressures is a way to soften the rear axle and youll get more rear bite, just dont go too low.
That's kind of too much of a blanket statement, no?

I know that with 50 front and 20 rear (stock sire size) the car will be an oversteering *bitch*. :)

With 205/60-13s on stock rims, I had good success with 24-22psi in the front at 20 rear. Higher pressure than that would cause horrific center tread wear because the tires are simply too large for stock rims. With stock size tires I normally ran 44/40, or 40/35, couldn't really tell the difference between either setting.

peejay 01-07-03 03:23 PM


Originally posted by voodooracing
31rx7,

which year/model 1st gens comes with 15mm? and which is 17mm, 18mm?

'79-80 models with rear sways came with 18mm. '81-85 models with rear sways had 15mm, which is about half as stiff.

I personally like the 18mm bar. I feel rear stiffness is a Good Thing to keep the rear suspension from moving around too much. Past a certain lean angle, the 4-link binds up and then you have snap oversteer. Drilling holes in the upper link bushings is supposed to help (haven't tried yet) but the real solution is to throw away the upper arms and convert to a 3-link, which also requires throwing away the Watts and getting a Panhard rod. The Panhard generally lowers your rear roll center, making handling much more predictable, but this reduces the rear roll stiffness meaning you need some *strong* rear springs and/or a fat rear sway.

With the 15mm bar, I find that I have to brake too deep into the corners to keep the car from plowing like Farmer John. It's a driver preference.

inittab 01-07-03 03:25 PM

I've got over 8k miles on my 205/60-13s running 32 front and they show no abnormally high center tread wear.

DriveFast7 01-07-03 04:00 PM

Drilling holes in upper rear link bushings causes torsional windup. Not good. Putting new factory soft rubber bushings in the rear links and Watts is a good idea. Stockers that are in there now are dried and hard = stiffer = more oversteer in 1st gen.

Ditch the rear sway bar and run rear tire pressures 2 lbs higher than front.

Brad

Rx7carl 01-07-03 07:25 PM


Originally posted by peejay


That's kind of too much of a blanket statement, no?


Yes your correct. Its a general rule of thumb.


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