Hi, I've mangad to get my RX8 up to 130 MPH leaving a 2003 Mustang GT in the dust. I was wondering if anyone has gone to the limit, and discovered the RX8's top speed.

2004 Titanium, RX8 GT

 

At a local airport, last summer - 241km/hr, I think that's about 146 mph.

S

 

StealthTL, was that running any mods?

 

138 gps indicated, ran out of room was still accelerating. no mods.

beers

 

No, bone stock, 2000 miles of break-in, then flat out in 5th until buzzer.
Probably could have beat it if I had changed up, but I thought (at the time) 5th would give my best power.

S

 

Sorry for the newb question but which buzzer are you talking about.

 

he's talking about the red line audible indicator.

 

you know there are already several threads about. this for instance a quick SEARCH found these threads-

this one

and thes two using "maximum" instead of top-

here

and here

also perhaps you left the mustang in the dust because the driver thought doing 130 neck and neck with someone on a public road was not really the smart thing to do and didn't have as much to prove as you seemingly do.

 

zoom44

Do you always adhere exactly to the posted limit?

 

There is a big difference between not adhering to the posted limit and doing 130 MPH, especially with a second car next to you.

 

what he said.

 

Fastest I've gone was about 140, I wasn't trying to find the limit...was just having a nice little Sunday drive

 

241 kilometer/hour = 149.7504573 mile/hour (mph)

 

138

 

are any of these GPS speeds or speedo speeds. The speedo at that speed can be off by like 10 miles an hour and GPS is the only way to get a true speed. I had two speedos on a ski-boat before and they both read different speeds so I used a GPS when accurate speeds were needed.

 

Top Speed is Electronically limited to 148mph (at least that's what the Mag review said and they are ALWAYS right!)

 

Are you sure about that? Just because your boat had a messed up speedo doesn't mean that they are all messed up. Especially if your boat was American made, Japanese cars have more accurate gauges in my opinion.

Anyway do you have any other proof to say the RX-8 speedo is off by 10 mph???

 

The RX-8 speedo is definitely off by a few percent or so- Mazda intentionally makes them read faster than they actually are... my Miata was the same way. I have noticed in one of the nav systems hidden menus there is the input from the vehicle speed sensors that shows a slower speed than the speedo, meaning the PCM knows how fast it's really going, it just sends a modified reading to the digital speedo.

 

my speedo is off by 1.6mph at 70. waas enabled gps.

not bad i think. the odometer is dead accurate.

beers

 

Here's a good question who's more accurate the gps or the speedometer they both have there room for error.

 

waas enabled gps are accurate to 6 feet i think it is. so the time speed distance calcutations are damn accurate.

beers

 

many of us have tested the rx8 speedo thru various methods. my speedo is off by 1-2mph at 45. it reads high so when the speedo says 45 radar says i am going 43 or 44.

 

WAAS GPS is not even up and running just yet. GPS is, but the WAAS system is not. GPS is accurate to less than 6 feet since they turned off the selective availability thing. When WAAS comes online it will bring the accuracy down to inches.

 

really,
amazing that my garmin V has it and often gives me reading of 7 ft. accuracy.

beers

 

Your GPS might have it, but the WAAS is not active yet. The nationwide system has not been turned on. It will be capable of using it once it is turned on, but it is not active yet. I am a pilot and am eager for the WAAS system to be activated. I think it is active in certain parts of the US, but not the whole thing.