Ok so this weekend I was traveling and had a chance to open it up. I got to 135MPH and to my suprise the car felt very unstable. It felt like it was barely floating over the road. The car is bone stock but does have a rear spoiler and front facia, is this normal ? There were no winds that could have had any effect on how the car was driving.

Was it being pushed around or was there wheel vibration?

IS your car stock ?

and I mean, 135 is really fast, dont expect it to have the same feeling as you're going 35Mph

how many stock cars DO feel stable at 135?

that's really f'n fast

I, for one, was pleased by how stable the car was at an indicated 133mph, practically one-hand-on-the-wheel kind of stable... Bone stock with the "appearance package". :dunno:

Maybe that last two mph gets it all squirrelly. :)

I've done this once before too. I don't think the car creates enough downforce to really keep us stable at those kind of speeds. 135 mph is pretty fast and I don't know any car that is going to be sticking to the road and feeling like it is a rock.

It also could have been the road. The barely perceptable grooves from the traffic that start to form over time are hitting your car a lot faster and more often at that speed as opposed to 60.

Check your alignment.

... and tire pressures

Ok lemme answer a few of the replies but please keep them coming. Im going to be at a open track event next month, while I know I wont be running 135 in the straights, I do want to know if something is wrong.



My tire pressures were all set at 37PSI(Hot Tire Pressure) before I left on the trip. As for what I expect a car to feel like at 135MPH, I had my Ford Lightning (5200#s)over 140MPH, my Mustang(3400#s) over 150MPH and they felt way more in touch with the ground than the RX8 did. In comparision to the Mustang and Lightning, this car is way lower, should have more downforce and way lighter. I actually got out of the throttle because it felt like the car was too unstable. The road I was on wasnt a interstate but was a very wide and smooth road(HWY 71 for those in Texas) Its almost like the car was Dancing over every bump I hit on the road, All Im asking is if this is a normal characteristic of the car. Ive been impressed with every aspect of this car vs previous mentioned. However I was disapointed and scared when I hit 130-133(This is where I actually backed off) this weekend.

Perhaps I will take it in to have the alignment varified even though it doesnt pull and has never met a pothole or curb.


Again :icon_tup: Thanks

Ive taken my 8 above 135 more than once and if it was on anything other than a straight, flat surface, im fairly sure i would have lost control. The OEM rear spoiler doesnt do much, and the front feels like its about to lift off!

I spent several hours at 125 MPH and at least dozens of minutes over 130 on my move to Phoenix. There was a spot in Oklahoma where we sat at 140+ for a bunch of miles.
The car does lighten at 115 to 120, even when severely lowered as mine is.
I have the MS stuff all the way around the body.

I suspect that it is simply too smooth and causing the air to speed up too much over the top, which makes lift.

Since a Cessna 152 can leave the ground at 50 MPH, don't underestimate the power of a virtual airfoil.

The road I was on wasnt a interstate but was a very wide and smooth road(HWY 71 for those in Texas) Its almost like the car was Dancing over every bump I hit on the road, All Im asking is if this is a normal characteristic of the car. Ive been impressed with every aspect of this car vs previous mentioned. However I was disapointed and scared when I hit 130-133(This is where I actually backed off) this weekend.


LOL, I live off of highway 71. It is one of the most dangerous roads going west in Texas.... prolly because of people going 135!

Anyway, I have cruised at 120-130 in short bursts and it felt a bit light, but not unstable.

I agree when I went a little over 130 it felt very light to me too.

wonder what the euro lip spoiler would do... looks very similar to the audi TT spoiler that prevents those cars from flying off the road

Most street cars dont create any downforce.

Might need to ad some body work like this to hold it down.

But seriously I have not been over about 120 and it felt pretty good up to that point. I know that drag (air resistance) increases with speed.
Maybe you just found the limit with stock on a highway.
Is this a Base model or a Sport or GT package?
Sport and GT have stiffer springs than the Base model.

How often have your driven that speed? Mine feels very stable at that speed... for a car going that speed. 135 is not going to feel like 70. I've had mine to 150 (took a loooong time to get there even slightly downhill) It's not a speed for public roads and will feel light without functional chin and rear spoilers if the road (read track) isn't pancake flat. At that kind of speed steering input, tire design, tire pressure, and of coarse alignment get very important very quickly.

The 8 is pretty light even stock(already) so as you go faster, it will feel lighter.

Well, To keep it stable, I guess u need to get some really good bodykit, yes it does help alot. (stock ones dont do shit, its for the looks ONLY)

I tried the highest and lowest setting on my MS spoiler, and there is a noticeable differents when its at the lowest setting. The rear is way more stable. but if you want max speed, put it to the highest.

Ever watch nascar even at shortr tracks? One car close to another can cause a car to spin out, and those cars are built to be perfect at high speed. Do you expect any stock car to feel very stable at 135mph?

Solvine- It sounds like you know the exact area I was driving. It was a strech between 281 and LLano.


Thank you all for the replies based on all your posts, Im going to just chalk it up and say the car isnt that stable at those speeds. Now to all those who wanna say the car shouldnt handle at those speeds, maybe the RX8 shouldnt but Ive driven at least a dozen vehicles at or above 135 and none have given me the uneasy feeling I felt in this car. Im not dogging the car one bit, it is incredible the way it brakes and goes into corners. It is by far no where near the fastest(1/4 mile) but it is the fastest corner carver Ive ever had.


Thanks again to all :ylsuper:

I actually got out of the throttle because it felt like the car was too unstable. The road I was on wasnt a interstate but was a very wide and smooth road(HWY 71 for those in Texas)

Texas 71 is a very nice road, but if you were doing 135 (twice the legal speed) you were way too fast for safety (yours and mine) and you should thank your lucky stars the car cautioned you to back off.

Save the high speed driving for the track, or let me know the next time you plan a stunt like this, so I can be sure to be out of the State.

P.S.: Yes, I have driven this road (Brady to Austin, Austin to Houston) many times.

PS everytime someone posts something like this someone comes out and says this exact thing. I don't think he really is going to suddenly say "boy I'm reckless and foolish" and never speed again, so just save it.

Sorry to be so blunt and its nothing personal it just gets on my nerves. It's like telling someone who smokes that smoking is bad for them and second hand smoke kills.

PS everytime someone posts something like this someone comes out and says this exact thing. I don't think he really is going to suddenly say "boy I'm reckless and foolish" and never speed again, so just save it.

Sorry to be so blunt and its nothing personal it just gets on my nerves. It's like telling someone who smokes that smoking is bad for them and second hand smoke kills.

It is something personal--my family uses these roads, too; and it really gets on my nerves whenever I read about some horrendous wreck taking innocent lives. I speed, too--all the time. (Thank God for Valentine). But recklessness pisses me off. (Of course, no one ever judges themselves to be reckless.)

Soo funny...

I just had my 8 the fastest I have ever been Saturday night. 142. That was pretty fun. Prolly a lil stupid too, 2am, high beams on. Oh did I mention I live in NH/VT where there is no more than 1 1/2 miles of STRAIGHT road and lots of deer and moose? I was extremely impressed with how well the car handled any type of turning at that speed. Very slight turns of course!

It did feel a lil light but the interstate I was on was freshly paved a couple months ago.

I have a stock GT.

Oh and the reason for this stupid maneuver? The same reason men do most stupid things. A very attractive woman turned on by speed!

Soo funny...

I just had my 8 the fastest I have ever been Saturday night. 142. That was pretty fun. Prolly a lil stupid too, 2am, high beams on. Oh did I mention I live in NH/VT where there is no more than 1 1/2 miles of STRAIGHT road and lots of deer and moose? I was extremely impressed with how well the car handled any type of turning at that speed. Very slight turns of course!

It did feel a lil light but the interstate I was on was freshly paved a couple months ago.

I have a stock GT.

Oh and the reason for this stupid maneuver? The same reason men do most stupid things. A very attractive woman turned on by speed!

Your lucky to have such a woman. I'm thankful that mine can't see the speedometer from her seat; or I'd be nagged viciously.

She could only see the speedo because she was practically in my lap... Believe it or not she kept saying FASTER! I told her she was crazy and we were either going to die or I was going to get pulled over and lose my car and my license!

She could only see the speedo because she was practically in my lap... Believe it or not she kept saying FASTER! I told her she was crazy and we were either going to die or I was going to get pulled over and lose my car and my license!

Well, your fears were justified. Good to see that they didn't come true--this time.

I could be your shocks are getting old. Mine bounced a little more than I like when I exceeded 110, so I got new shocks, Tokico D-Specs. Now it's solid as a rock at high speeds. :)

Most street cars dont create any downforce.

Most street cars create lift (opposite of downforce) because if you look at the profile of a car it looks generally like an aerofoil or airplane wing.

On something like the audi TT the small lip spoiler removes something like 70% of the lift the car generates.

I've had mine up to 143 mph w/o any problems with stability...

Maybe I should find a place around me to try it out at 135 .... then I'll let you guys know how I feel

Here's a good place...
www.scca.org

Signed up. Looking at it.

Will try Lime Rock or Pocono.

WEEEeeeEEEEE !

She could only see the speedo because she was practically in my lap...

Wearing a speedo? j/k

LOL nice one... Won't EVER catch me in a speedo! Let's just say it was a GOOD night and the 142 was worth it in the end! :boink:

I'm wondering if the euro lip spoiler would do anything to help. I was considering adding that and springs as my next mods. Hmm..

The euro lip spoiler will help, since it breaks up (spoils) some of the airfoil effect. A larger spoiler would be better. I prefer spoilers to wings, though mostly for aesthetics.

Hi there

Do you still have the original factory tires up front ?

The original tires on my RX 8 had a straight profile (parallel lines). Tires with such a profile have that downside.. bad choice Mazda...

I had to be very focussed driving at higher speeds with those tires; the car was all over the place.. :banghead:

I changed the front tires to Dunlops with another profile because of that issue, and now everything is ok.

Cheers

Steve

Oh man, please don't do 135 just West of Austin. That road claims about 1 / month. Curvy, hilly, and full of recreational / tourist traffic...one of the most dangerous in the area.

LOL nice one... Won't EVER catch me in a speedo! Let's just say it was a GOOD night and the 142 was worth it in the end! :boink:

Heh, I do find that adrenaline has nothing but good effects in the bedroom ;)

Back OT, I've been up to 140 indicated on a fairly rough highway. Car felt very stable, but this whas when I had less than 15k miles on it. How many miles are on yours? The car will feel a bit light, but generally not unstable. My guess is you might need new shocks, those will greatly enhance your track experiance as well. I run the Koni Sports and love them. I may go to the D-specs though for those rear external adjuster cables at some point.

Most street cars create lift (opposite of downforce) because if you look at the profile of a car it looks generally like an aerofoil or airplane wing.

Right. There is more to it than that, but that is the main reason. Air does very strange things with moving bodies with irregular shapes (some of which move also). Its pretty much almost impossible to calculate, thats why everything is tunnel tested.

Many times the instability may only be partitially to blame from the amount of lift, but with the way the air just flows off the car. If there are corners or shapes that make the air vortex or buffet in an unusual way, that will deffinatly give you a wild ride. :ylsuper:

Ok lemme answer a few of the replies but please keep them coming. Im going to be at a open track event next month, while I know I wont be running 135 in the straights, I do want to know if something is wrong.



my Mustang(3400#s) over 150MPH and they felt way more in touch
Again :icon_tup: Thanks

Not to sound condescending but if the Mustang with its ancient suspension design and aerodynamic lift at speed felt more in touch, you may want to take the Mazda to a good alignment shop and have it checked out.

Also I would highly recommend a Bondurant driving & suspension tuning school before driving triple digits. Obviously you could benefit from that quite a bit. It might even save your life.

Here's a good place...
www.scca.org
Accually, in the SCCA (I'm a 30 yr member), without doing a lot of safety mods to the car you won't get on the racetrack. For anyone that wants to go fast on the public roads legally, enter the Silver State Classic road race. http://www.silverstateclassic.com/
They have hi-speed classes for unmodified cars.

You could also start with track days, like the ones mazdadrivers.com does in Virginia. Check out tracks in your area - many of them do similar track days.

Amazing, I ask a simple question and 1/2 the answers do nothing but preach how unsafe I was.


Yeah I could lose control but I was on a strech where I had a clear view of no traffic at all in either direction. For those who wanna know where I will be driving, Im currently working in Jonesboro,AR and Friday head back to San Antonio. I drive a 06 F350 with Lumber truck suspension and utility bed, Im also pulling a 20ft trailer with a 8ft Microwave dish that not only weighs over 1000# but creates a wind load of over 10,000#s. I drive from Jonesboro to just East of Dallas between 80-90MPH so just warning you, beware of IH40/30. If traffic would allow, I would drive the same speed from Dallas to SA but traffic makes it impossible. :bootyshak :mdrmed:


To those who have not side tracked this post, I really appreciate the help and info :grouphug: :icon_tup:


www.skittlesracing.com

Thats probably why insurance companies raise their rates every year.