GooRoo

OK, so I don't have an RX-8, but the easiest way to check the speedo is with a GPS. Just run at a steady speed for a while and see what it says.

Using this method I found my '93 RX-7 speedo to be within ~5 mph at 140 and my '02 Liberty to be off by 6-7 at 70. Go figure.

I know the GPS (Garmin Legend) I have is good to at least 650 mph as that's the highest I've been able to verify on it. The accuracy is good to within 3 meters when using WAAS so that means at 120 it's good to within a couple mph for 1 second increments, and the faster you go and the more time you track for the more accurate it is. :D

Ned M

iTrader: (2)

FWIW, the RX-8 6-speed does 20mph per 1000 rpm in 6th gear, so at 7K rpm the car should be doing 140. At 9K, 180mph would be possible if there were enough ponies underhood.

DreamWarrior

115 is the fastest I've had it and not for very long. I was just toying with another Rx-8 on the Jersey Parkway and then realized how fast I was going. With 8 points on my license already, I don't need any more.

The scary thing was I knew I was speeding, but didn't think I was going that fast.

qberror

I am going over 150 mph all the time without any problems. No speed limits in Germany. It's a free country

Rx8Freehk

<------- note the location hehe I recently got stationed over here in germany and i must tell you..... The Rx-8 is AWSOME on the Autobahn's. Matter of fact, I Take Autobahn A60 to work EVERY DAY lol i love this car... Top speed so far is 158 @ c9000 rpm in 5th, and then i got my *** handed to me by a F50. pics to come hehehe

Felix W.

My fastest so far is "fifth gear + buzzer."

Theory says that is 143+ mph. Could probably have got more if I changed up.
felix.

grogiefrog

In my 1st gen RX-7, I hit around 120 on I-70 in Colorado at 7000 feet elevation. Later in Wyoming, I hit 95 coming down out of the mountains towards Laramie, and this time I got tagged by a highway patrolman. He gave me my license back and told me that my home state of Colorado would have a warrent issued for my arrest if Wyoming didn't receive payment in seven days. In my defense, Wyoming has wide open and nicely paved roads. I stay to the speed limit out here in the midwest... too much traffic.

Those rotaries can cruise that's for sure.

qberror

cool sounds like fun! you will have problems when you will go home someday isn`t there no speed limit in montana now?

Gord96BRG

Yep, a bunch of us independently have used GPSs to calibrate the speedo - at normal highway speeds (60-70mph), the RX-8 speedo indicates less than 2 mph higher than actual speed.

Not to be rude, but... that's complete BS, unless you're talking 158 km/h @5K rpm in 5th. With the RX-8 gearing, 9K rpm in 5th gear is 148 mph actual. It doesn't matter whether you're in Germany or the US, your number is completely bogus (ie physically impossible).

Regards,
Gordon

GooRoo

Re: Speed Limits in Montana... There most definitely is, for interstates during the day it's 75. Check the chart here http://www.mdt.state.mt.us/speed_limit/

Although sometimes you can get away with more if you have Montana plates. :D

Jump120MPH

I got up to 141mph in 5th before slowing down back down to 65mph I got clocked at 75 and got pulled over. Only got a warning. If I would have held on at that speed any longer I would have been screwed.

qberror

I researched the no speed limit issue in Montana a little further, and there was a time when there were no day time speed limits.

There is also a study that shows that it was a lot safer without the speed limits then with speed limits. The fatal rate doubled after they implemented speed limits again.

We conclude: it is safer to have no speed limits !

Germany has the lowest accident rate (and fatality rate) in the world, and we do not have a speed limit.

Here is the link to the facts (data) of accidents/fatality rates in Montana with speed limits and without (for those who dont belive me):

http://www.hwysafety.com/hwy_montana_2001.htm

So I suggest you write an email to your governour to take a look at these facts and take action

o_town_racer

There is definitely speedo error....and it gets worse the faster you go. I've got a Garmin IQue 3600 and it not only shows where you're going, but how fast you're going as well. At around 30 MPH it is dead on with the speedo. At 80 MPH on the speedo, the GPS says 76 MPH. The faster I go, the more it is off. I've read threads on this before and it usually boils down to the VERY stiff fines levied on auto manufacturers from European countries for speedos that read slower than actual travel. The BMWs are exactly the same. The faster you go, the more off the reading. The most accurate speedos (believe it or not) are on American autos where not nearly as many are sold over-seas.

qberror

o_town_racer: this is done on purpose. since most people tend to go a "little" faster then the speed limit the speedo shows higher speed then the actual speed you are going at. At higher speeds who cares if you are going 150 mph or 155 mph ?

So its not an engineering problem its simple psychology

mdw33333

When I did the 141 mph, I was in 6th at 7500 rpm. With 1500 rpm's left, I would have come really close to 148-150 mph. I had to back off because of traffic in front of me.

The car was still accelorating in 6th for me, so I believe a top speed could be achieved in this gear.

Rx8Freehk

MY BAD lol thanks for the correction... it was c9000rpm in 5th

(original post edited)


-matt

jax8

I calculate that the 8 speedo is "only" 3/4% optimistic at 110 to 130kph. I say only because my sti was close to 10%, which provided a fairly big safety zone re. posted speed limits.

idle0ne

i have been pulled over 3 times in my driving career with no tickets.

1.) driving a 1998 Mazda B2500 doing 90 and passed an undercover cop in a 55 asked why i was going so fast. i was honest and said i had been late for work a few times and if i was late again i would be fired. He asked why i didnt stop right away and i was yet again honest. all he had for lights were his headlights flashing back and forth in a bright summer day. Warning Issued.

2.) Driving my 2001 pontiac grand prix. i was at a stop light and someone wanted to race me in town. they were reving thier engine and when the light hit green we both headed. the other guy squeeled his tires and drew attention of a nearby cop who got behind me and didnt flash the lights. i went to the light on the last turn by my house and wanted to have some fun. when the light hit green i hit the pedal and hit 30mph as fast as i could and with a super charged v6 it doesnt take long. he blue lighted me and asked where i was going in such a hurry i said i live right there and i gotta **** really bad. that excuse didnt work and he tried to issue me a ticket for display of power or something but i told him that if he issued me a ticket we would be in court and would waste his time because i never once squeeled my tires all i did was get up to the speed limit. Issued A Warning.

3.) Pulled over in my 2001 pontiac grand prix, license suspended on xmas eve. The cop could very well have pulled me off to jail or something but i "acted" honest with him. He said you know your license is suspended? i said yes. he asked why i was driving... thank god i had my step daughter with me and she was 5 so i said someone had to get her from daycare... He handed me my license and stuff and said merry xmas, dont let me catch you driving again before your license is re-instated.

i have a feeling that after getting my 8 i will get pulled over a time or 2 just because the cops here are jerks and they will see a 23 year old male driving a sweet *** car like that and hassle me. i had my grand prix and they were questioning how i could afford a car like that... i told them that was none of thier concern all that mattered was that it was mine.

idle0ne

the fastest i ever had the grand prix up to was 130 somewhere in minnesota when i went x-country.

cardinal35

I lived in Montana when "There wasn't a speed limit" there was in fact one actually- I believe it was a resonable and prudent manner, is what they called it! Whenever I was in the eastern part of the state without mountains it was a dream!!! I had two vehicles at the time- a 300z and a jeep wrangler, I buried the needle lots of times in the wrangler and it was VERY scary at times- the z- well I broke the cruise control trying to set it at 125!!! pretty funny huh>? oh the good ol' days!!!

Rotary Nut

Was that Km or mph? :p

s13lover

I know that the RX-8, Corvette, and all other 6 speed cars have different 6 gear ratios, but I fine it hard to believe that while almost all 6 speed cars top out in 5th, that the RX-8 can do it in 6th, especially considering the low torque of the motor (for those who say they topped out in 6th).

And just a reminder, speedometers are not too accurate over 100 mph. So, you may think your doing 150 mph and still pulling, but you may only be doing 140 mph. Which means the limiter is still there at 147 mph, you just haven't reached it yet.

stickman

Ya know, that sound barrier thing is a real drag; right around mach 1 that vibration just takes the thrill out of it.

doccable

When I was 17, I was a pizza guy. In a very small town where all the police officers knew all the kids and so on and so forth. Anyway, one night about 1 in the morning, I was trying to "beat the clock" for a tremendous tip, guy said he'd give $20 if I got his pie to him in less than twenty minutes after his call.... anyway, he lived out in the country, so once I hit the town limits, I floored it. (In a 70 Cougar) I had the speedo buried in no time.... 120+ in that car was no problem whatsoever. There was a cop at sitting at the town limits, who said he clocked me doing 157 MPH. He let me go with a verbal warning... so to speak, he yelled at me for ten minutes after I made my delivery, and I had to give him the $20! Best $20 ever spent. :D

zoom44

104 mph on the speedo the other night. i've checked my speedo a few times against one of those radar signs that reads "your speed is" and the sign has always shown 1-2 mph slower than the speedo in my rx-8. so i was probably going 102 actual mph.