Hartsk8s

Either its not opening up fully or its stuck closed... stated messing up about 4 days after mazda did a carbon cleaning. I think some broke loose and jammed the cylenders closed. When i get back i will try to spin the gear, and if i cant break it loose then i will just replace the LIM. That is if I still have problems when I get back. Which I Probably will. And I rev it to redline almost every time I drive it, but about a day before it had the P2004 code, it felt sluggish in the upper RPM's which is why I think its stuck closed, or possibly the motor is burnt out, I will test both when I get back.

Hartsk8s

How much lower are they then stock? I have not driven the car on a track yet, but i have however driven it on some roads that i know very very well, and I niticed the car had quite a bit of understeer, any way to start eliminating this? and the best route to do this... I know while braking (transfering the weight to the front of the car) helps, but any setup features that could help?

04Green

iTrader: (1)

Check out
http://www.tirerack.com/tires/tirete...jsp?techid=58&

Lot of data in one place. Also, it will be nice to see what this group thinks of it.


The raw text is inserted below, use the link above to see pretty tables.


Air Pressure for Competition Tires


The table below suggests tire inflation pressures to be used during competition. Tires should be reset to normal inflation pressures when returned to the street. These recommendations should be used as a starting point. Pressure can be adjusted to match the driver's preferences. Adjust pressure in 2 lb. increments.


Type of Vehicle Position Pressure
Front Wheel Drive Front
Rear 35-45 psi
30-40 psi
Front Engine/Rear Drive Front
Rear 35-45 psi
30-40 psi
Rear Engine/Rear Drive Front
Rear 35-45 psi
35-40psi

When racing on D.O.T. approved tires air pressure is a major consideration in tuning the handling of your car, especially in cases where suspension adjustments are limited. The chart below shows some of the changes you can make to change the balance of the car.
Guide To High Performance Handling

Adjustments Decrease Understeer Decrease Oversteer
Front Tire Pressure Higher Lower
Rear Tire Pressure Lower Higher
Front Tire Section Larger Smaller
Rear Tire Section Smaller Larger
Front Wheel Camber More Negative More Positive
Rear Wheel Camber More Positive More Negative
Front Wheel Toe Toward Toe-Out Toward Toe-In
Rear Wheel Toe Toward Toe-In Toward Toe-Out
Front Wheel Caster More Positive More Negative
Front Springs Soften Stiffen
Rear Springs Stiffen Soften
Front Anti-sway Bar Soften (Thinner) Stiffen (Thicken)
Rear Anti-sway Bar Stiffen (Thicker) Soften (Thinner)
Weight Distribution More Rearward More Forward

To get even tire wear when using D.O.T. tires you must be very careful not to use too low of a tire pressure. The Hoosier Radials can wear unevenly if underflated and seem to work best at much higher pressures, such as the mid 30s to as high as 50 psi. Underinflation will cause a thin ring of wear at the very edge of the tread. The best results on the Hoosiers seem to come when they are properly inflated, on fairly wide wheels, and with a good amount of negative camber. If properly inflated, these problems can be avoided. Probably the biggest adjustment you can make to improve tire wear is the driver. Avoided sliding the tires, locking up the wheels under braking and drive as smooth as possible.

TIRE PRESSURES IN THE RAIN

For both autocross and road racing, increase tire pressures 6-10 psi from what you would normally run in dry conditions. Hydroplaning occurs when a wedge of water develops between the tire and road surface. This wedge can actually lift the tire off the road and eliminate traction. Increasing the pressure rounds the profile of the tire by decreasing the deflection of the tire. This results in a smaller contact patch - narrower and shorter. It also helps keep the grooves in the tread open so they can channel the water out from under the tire.

TeamRX8

iTrader: (25)

Understeer in an unmodified RX-8 is mostly an alignment/tire choice-pressure/driving style issue. The OE shocks are not particularly good and they wear out quicker than most people recognize.

As for the previous post, generalities are only that. Sometimes a change can result in the opposite effect depending on what the actual cause is.

.

Hartsk8s

i can get some oversteer out of the car but it seems to be a little more tighter than i would like, almost like the front end loses grip too easily. I agree could be alignment or driving skills since i have never actually raced a car, did race ATV/s back home but I want all attention turned to the car. I was thinking about getting the TEIN BASIC Coilovers, for that look. Will give a little bit of adjustability but nothing that dramatic. Am i correct?

EricMeyer

If your driving a stock car and nothing is broken, your understeer beliefs are most likely originating from your driving style. Please record an incar video and share. Many a new driver experiences understeer (my experience) when adding generous throttle with the wheel turned. As a general rule of thumb, if you are adding throttle AND turning in more wheel input at the same time then the driver is the cause of the u-steer.

EricMeyer

At what rpm does the problem occur when you drive your car in 3 rd gear starting at a low rpm, depressing and holding the throttle at 100% up to 8,000 rpm?

EricMeyer

May u also suggest please to take this topic to another thread to retain the integrity of this topic. Thank you.

04Green

iTrader: (1)

Eric, what you are referring to is not managing the weight on the front end, right? Ideal turn process is Brake (weight on front), lift (still some weight transfer to front), turn (weight forward keeps front wheels planted better), now that car is turning, add throttle (weight shifts back to keep rear planted). Too much throttle moves weight back, off front, and you lose ability to generate turning force (understeer). Fix is to go back to the right order, or, if it happens in a turn, back off throttle to re-plant front while praying that you have not confused the hell out of the suspension and driver behind you, right?

EricMeyer

Your on the right track big Mike.

MOST new drivers who have an aggressive driving style will try and go flat with their throttle (full throttle) too early in a turn. Add an early apex (because type A personalities often can do this) and you have a situation where the car is headed off the track under power. To avoid going off track the driver cranks in more steering AND keeps his/her foot planted. The car understeers like a pig. MANY A NEW DRIVER DOES NOT KNOW WHAT THIS "FEELS" LIKE. So they continue this driving style. Again, this is often heavily influenced by the early apex line. Your weight transfer theory is correct however it is possible to settle the car down, go to 100% throttle, turn the wheel big time and get the car to understeer. Add a decreasing radius corner and the problem gets worse. Add an off camber surface to this corner and it will also get worse. Add too high front tire pressures or bad tires or big, grippy rear tires and the problem gets worse.

The biggest issue here is usually the driver as he can be the contributor to the most influential components of understeer.

To put this another way...........you can drive a car with understeer. You just have to drive it differently. I am fortunate to know guys that can drive a car that handles like a POS. A few years ago I didn't have the skill set to drive this type of car. I "NEEDED" a well setup car to go fast. As I learned and learned and learned a new skill set arose---the ability to better understand small nuances in the car, adjust my driving style and get much more out of her. Often big time patience is required to accomplish this. WAAAY more than a new driver can often conjure up.

What's the moral of the story? Get good instruction. Listen. Have somebody better than you evaluate your line/driving style/application of throttle/wheel input rate/all of the above and see IF IT'S YOU. One of the reasons for data collection is to quantify what the driver is doing. If you have data many of this issues are quickly discovered.

And in my experience understeer experienced by a new and even novice (most novice actually) is due to an desire to go faster and going to full throttle too early.

Cheerio

Hartsk8s

I agree its most likely my driving, or the alignment/setup. And to get a video will be impossible because im in IRAQ until spring time. When I get back I will start to do some AutoX and see if some of the experienced drivers will ride along and give me critiques... (or however you spell it.) I know I do want to get the car a little lower, even if it barely increases handling. "As long as it does not make it worse, which i doubt it will." The car grips great but on agressive driving i would prefer to get oversteer vs. understeer if you know what i mean.

cBJr

I understand what you're saying Eric, but what if you don't want to adapt to this understeer? My car is my fun toy/daily driver and I won't be doing trackdays. I race motorcycles, and don't have the time/money to take my car there too right now.

My last sports car was a 90 Miata, only mods were Azeni tires and an alignment. I never had the front end issues with it that I'm currently fighting in my 8. After reading alignment threads on here, I took my 8 in and maximized the front negative camber. I even took Team's advice and gave up over 1 to 1.5 degrees of caster just for that last 0.1 degree of negative camber. Initial turn-in was immediately improved, but overall grip is still very low in the front. Currently, I'm speculating that the rear shocks are shot, as there is an excess of rearward weight transfer during throttle application.

As it sits, I feel like I have to drive my 8 like a FWD car, where I'm tossing it into a corner to rotate the rear, then straightening it up with the throttle.

EricMeyer

I think you have two options:

1. Something is hosed with the car. Find it, fix it and hope that your cars handling woes are gone/understeer is reduced.

2. Your car is fine and keep driving it with your current style.

I'm not sure your car's issue might be. But if it's fine, it's your driving style inducing understeer.

If you don't want to adapt to understeer then don't. Tiger woods could choose not to adapt to playing out of a sand trap (if he wanted to) but he wouldn't be as good as he is. Let us know about the rear shocks (and anything else).

Hartsk8s

I didnt buy the car new... is the rear suppose to look lower than the front??? its not drastic but it is noticable" to me atleast" if not then i believe rear shocks could be bad? could cause understeer as well

bulletproof21

the rear "does" look a little lower in the back. The gab between the top of the tire and the fender is less in the rear vs. the front. Alot of lowering springs will fix that and lower more in the front to even out the look.

Hartsk8s

I dont know why, but I really dont like that...

EricMeyer

Please be careful everyone when using the gap or space between the top of the tire and the bottom of the fender. Purposeful manufacturing processes (Mercedes as an exsmple), cars that have broken or damaged suspension or frame items or (my favorite), cars that have been in accidents can give you false readings. The proper way to measure a car is to get underneath it (w driver) and measure hard points to the ground. 4.5 front and 5 rear is a great place to play (hint, hint)

More_Revs

I have been doing autocross in the 8 for a few years now, as well as a few track days. Suspension is pretty much stock with the exception of Koni yellows. I'm looking to reduce some body roll, and not ready to spend big on coilovers. Would the Progress sway bars be a good match with the stock springs, or too stiff? I'm not really looking to do springs, most of the them are only marginally stiffer than stock, so it seems like they are more for looks than anything else. MS springs would be nice, but there seems to be some debate over whether the rate was true. It'll help my limited LF camber though (1deg at most, even with min. caster).

EricMeyer

Another inexpensive option you have if you want more camber (which is limited with ride height on the RX8: the higher the car in the front the less negative camber you can get), is to go to an offset front lower control arm bushing. SpeedSource makes these and their available via MazdaSpeed Development website. Made of Delrin. Will not hurt anything.

Basically you'll gain more neg camber opportunity.

Spin9k

Certainly sways over coilovers are the easy and cheap way to help eliminate some body roll + or - depending on the stiffness of the bar you choose. Because bar stiffness is pretty much a crap shoot depending on brand... the way to avoid that problem is to buy an adjustable bar (one with 2 or 3 holes at the link attachment point). Benefits are you can (actually) tune the under /over steer of your setup plus you can decide how much roll you want by choosing soft to hard settings. Cost over a fixed bar in minor.... Advantages are major.

For any serious improved camber however, you'll need coilovers, or (less good as they won't be as good match to your shocks) lowering springs.

More_Revs

Any idea how much the bushings are, and how difficult to install? Last time I install bushing in a different car, everything has to be taken apart and was quite a pain.

Highway8

iTrader: (11)

Mazdatrix is selling both the Mazdaspeed bushings and a cheeper set by drop engineering. Both upper and lower are available. Upper MS- $251, DE $212, Lower MS $386, DE $260.

Not mentioned here, but Eric made and installed some upper control arm delrin bushings to remove the stiction on the control arm. See post for explanation https://www.rx8club.com/showpost.php...8&postcount=15

I heard someone else installed some poly bushings that also removed the stiction, not sure how accurate that is.

Pstone

iTrader: (4)

Well, thanks for all the replies everyone even though the discusion went completely off topic. I'm going to start auto crossing next year and will start in novice and move to STX once I get booted. I've decided STX since I need to use an aftermarket seat thats lower which would automatically kick me out of the stock class.

I already have progress tech sways installed and then just need to pick up some new endlinks. Tokico D-Specs are sitting in the basement and I'm still trying to decide on H&R's or Teins S-Techs. Hawk HPS pads will be ordered along with the Corbeau Forza race seat.

I currently have the RB dual res midpipe installed, so I either need to switch to my stock midpipe or build a midpipe with a high flow cat.

Lastly, I still can't decide on running 245's on the 18x8's or shelling out the extra cash for Enkei RPF1 17x9's. Total package on tirerack for RPF1's including Hankook RS3's is about $1550. We'll see how much tax returns and work bonuses pay out in the spring before I decide.

04Green

iTrader: (1)

Um,

depending on how low you need to go, you can lower the seat.

Pstone

iTrader: (4)

I've read the posts on trimming the padding or modifying the bracket, but it's still not enough clearance. Those usually net about 3/8" extra clearance, I need about 1 - 1.5".