rx8 - smooth!

I have just completed my fifth track day and as I get faster I am finding that I am getting a lot of push / understeer on the car in tight radius corners. I have the Racing Beat Front and rear sway bars fitted. I am thinking of maybe going back to stock at the front to fix this. Has anyone else had this or am I just pushing the car too hard?

murix

That is the way they are set up. Use more throttle to steer and less of the wheel.

brothervoodoo

The RB front sways will give you more bite in the turns. Listen to murix, he knows what he is talking about.

RotaryZZ

>....... as I get faster I am finding that I am getting a lot of
>push / understeer on the car in tight radius corners.
Almost all street cars are set up to have slight understeer. You can play with alignments and tire pressure to dial out some of the understeer.


>Use more throttle to steer and less of the wheel.
Yeap, the chassis is quite responsive to throttle steer ;-)

Ophitoxaemia

if you are getting understeer on corner entry, then your entry speed is too fast or you need to trail brake more. if you set up the car to be more neutral in the slow corners you may find too much oversteer in the fast ones. it is better to have the situation you mention because in slower corners you can trail brake and hop on the gas to help rotate the car.

and lastly, a slightly understeering car feels slower but is faster than a slightly oversteering car.

the relative temperatures of your front and rear tires can also have a dramatic effect on balance. if you are too fast in corner entry, the fronts will scrub, get too hot and then it will understeer even worse. (one of many scenarios- dont mean to say this is what you are doing).

hth,

james

ps if you think the rx8 pushes a little in slow corners, try a camaro or mustang!

rx8 - smooth!

Thanks for the replies guys,
I will try more of this next time. I assume you mean less throttle so the car will tuck in better.
What changes do you make?
Most of the time I was ok with corner entry speed. If the car pushes at this stage of the corner then that is going to be purely the driver. What I wasn't expecting was the amount of push I was getting when I was getting on the gas to get out of a corner. (I thought the back end would come out)
Yesterday we had 12 RX-8s out on the track at one time and I was the quickest and as I have now had some experience with this car on the track I was really pushing it. It sounds like I just need to feed the power on more carefully until I really have the exit lined up.

Ophitoxaemia

do you have the stock front bump stops? i noticed on my car if i was brakin heavily into a corner (autox on concrete in my case), the front would start washing away with great enthusiasm, and my thought was i was on the front bump stops. before the last event i cut the bump stops down and picked up more than a second (which is a huge amount in autox). i could drive much deeper into the corner and fling the car around more without the front skating away from me.

but your power-on push might be too much rear toe-in also. i had this problem on my regular autocross car- too much rear toe-in and the rear overpowered the front and it went straight.

james

PoLaK

iTrader: (1)

I aggree with what the others have said ,but if you still find them unpleasant i'll be glad to take them off your hands.

murix

There are a lot of reasons why you might be pushing, but ultimately I think you are just running into how the car handles and is setup.

If you are heavy into the throttle on your exit and feel it pushing, let up on it some and let the weight shift forward so it can get a bit more bite and let the rear come around more. After it comes around and points where you want it togo, get back into the throttle and zoom away.

AlexCisneros

what are your alignment specs, what size tires, what tire pressure?

I agree with what has been said so far, but realize... you may be able to enter at that speed and exit with more

rx8 - smooth!

Alignment - stock, Tyres - stock-Bridgestone RE40s, Tyre pressure - 40psi

Thanks for all the advice but what I was really looking for is someone that has really pushed the car with the stock sway bars then changed to the RB set up. I only used the car once with the stock sway bars and I didn't really push it so I am interested if this behaviour is the result of the Racing Bear Sway bars or just what the car does anyway. BTW I think the RB sway bars are a vast improvement over stock in normal road driving.

Jay Goldfarb

Forget going back to stock. You will have more push. Get the alignment worked on. You can easily get 1.5 degree neg. camber in the front or more. Set the toe in to combined 0 is possible. At the track play with tire pressures. Check temperatures across all tires after a few hot laps. I am running the racing beat sway bars with Eibach pro springs. Front camber is 1.5 degree and could have gone to almost 2, but held back to keep tire wear down for the street.

Also helpful is a front splitter. I will be working with Pettit on one that can be bolted to the stock bumper. Currently have MS spoiler that has added push and need to counter that.

Jay Goldfarb
20 years of road racing and too many drivers schools to list
Instructor with NASA, BMWCCA and PCA

murix

The answer is yes on the stock sway bars to RB sway bars. RB kept some of the stock driving charecteristics just moved them to a higher level. I should mention I played around with the stock alignment as well to set it more aggressive and have it balanced with me in the car.

You said you have 40psi tire pressure? Why so high? Am I missing something? I run the stock 32psi on the track and have no rollover.

Stock



RB Springs & swaybars

RotaryZZ

Jay,

I'm just wondering have you experienced any back end fishtailing under heavy braking on the track with the 8? While I was squeezing hard on the brake at the end of any straightaway (~120 mph), I've found the back end to be too squirely and it just won't stayed planted!! I realized it has something to do with the abrupt weight transfer but I've never experienced similar effects on my previous car which is a bimmer E36 325.

Someone suggests me to dial in some toe-in at the rear, possibly 1.5mm on both sides. Plus possibly include swapping in some stiffer suspension pieces to control the nose diving condition which may help lessen the toe-out at the rear under hard braking.

TIA,
Pete

guy321

I find when the tire pressures are higher than 32psi (cold) that the car feels ALOT rougher and is harder to control. Mine were overinflated, and I thought something was wrong with my suspension..

RotaryZZ

Murix,

>.... I played around with the stock alignment as well to set
>it more aggressive .......

So what kind of alignments you have for the car now?
Btw, does anyone know what's the stock spec as far as the alignment goes??

TIA,
Pete

RotaryZZ

Jay,

>.....Set the toe in to combined 0 is possible ......
What exactly do you mean by that?
Any what kind of alignment do you have for your car? I presume its for dual purpose and not a dedicated track toy :-)

murix

Because of street use I am still in the spec range for stock to save tires but on the more aggressive side. I forget the exact settings but I have them written down. I went with the recommendations of the shop I use which sets up several cars. I can tell you this does mean close to 0 toe and negative camber all around. I am not 100% on what the best specific settings are yet. It will change a little from car to car anyway.

PUR NRG

When you say "alignment - stock" do you mean you had it aligned to stock specs or is it whatever the car had when it left the factory?

It's amazing how many people throw money into suspension upgrades and/or complain about poor handling without doing one of the most basic things of all--a good alignment. I took my car almost straight from the showroom to an alignment shop and found the factory settings weren't even consistent from one side--or wheel--to the next.

GeorgeH

iTrader: (2)

I've experienced this with the stock setup. In the same corner I drive often, I can get oversteer or understeer depending on my technique. The first time I got understeer it really surprised me - it was the same circumstance you describe. Lots of mid-corner speed and squeeze the gas early, and the front end pushes. I attribute this to the fact that the car doesn't have enough torque in that situation to break the rear tires loose, and since the fronts are already loaded to nearly 100%, all the throttle does is unweight the fronts and then they wash out.

On the other hand, toss the car in with a little more steering lock and it sets up a nice drift that can be modulated with the throttle. Not sure wich is faster, but I know which is funner! :D

PUR NRG

Gee murix the body roll in your track photo makes me look like a piker. 'Course my springs are 3x stiffer than stock so that has something to do with it. Here's a picture of me coming out of Turn 11 at Laguna Seca. There's so little body roll it looks like I'm just puttering along.
________
DODGE POWERBOX HISTORY

Jay Goldfarb

What I meant by Zero Toe was exactly that. Try to get both sides as close to "0" as possible. This combined with negative camber will help with initial turn in. My compromise for street is not running 2 1/2 + degrees Negative camber front and rear. This would be a better track setup, but for everyday will wear the living hell out of the inside edge of your tires.

Pressure: I am still playing with that issue, but find that around 35 psi cold is working, but I do adjust side to side and front to rear based on track and tire temp readings.

Rear wings: If you have an adjustable wing put it at the zero setting unless you have made provisions for more downforce in the front.

What this all comes down to is simple: Learn to drive the car you have. Some corners will take whatever setup you have great. The rest will take adjustments in driving style. Learn to trail brake, but be careful to know if and when the rear breaks loose. Power oversteer isn't a problem, because we don't have enough torge to push the rear around. Throtle off and then on can help in some corners to rotate back.

Braking:
If your car is wiggly under straight line braking, than you have several possible problems. first is hot brake fluid. Make sure you are running a good fluid. Next is pad compound. I run Hawk Blues with slotted rotors. Stop on a dime and haven't had a problem with overheating. Also check for hot spots on rotors. The brakes are heavy front bias and back should not get out on you. Toe setting can also cause front to wiggle.

Jay

AlexCisneros

One thing Jay didn't mention... There is front toe and rear toe. I'm not sure if Jay has all 4 corners at 0, but I have the fronts at 0 and the rear slightly toed in.

You can check out my specs in my Vb garage on this forum.
https://www.rx8club.com/vbgarage.php?do=view&id=5323

I also agree with Jay on the front needing more downforce, especially with the rear wing (even at 0°)

RotaryZZ

>first is hot brake fluid.........
I honestly don't believe it was due to overheating issue. Btw, I've the MazdaSpeed pads on and they're very good :-)

>Toe setting can also cause front to wiggle.
In my case, its the rear. Btw, I've talked to folks at SpeedSource and that's what they suggest me to do. Dial in 1.5mm toe-in at the rear on both sides. I just hope this won't induce too much understeer.

GeorgeH

iTrader: (2)

Alex, I noticed that you run staggered tire sizes. Did this affect your front/rear camber split? I'm wondering if running more negative camber in the front than in the rear would lead to oversteer on a car with equal tire widths front & rear.