6th gear change 2005 MazdaSpeed?

So would I. One of the problems is that the Miata speedometer and tachometer
often are set from the factory to over read.
In the process of doing a bunch of mods on my 99, we reset the speedometer
and tachometer to be as acurate as we could.
The speedometer now overreads by about 1 to 1.5 mi at 60 to 70 mph, and the
tach about 150 rpm at readline. (My Garmin marine GPS and other instruments
that can read the ECU digital output only read in one mph increments.) (I
can change the rep rate on the marine unit, unlike the inexpensive
automotive GPS units.
The re "calibration" was done after the 5th gear change, and I did not
(oops) record the values before we readjusted things.
What I remember was that the speedometer was originally set by the factory
right at the 5% high limit for 70 mph. I believe, but cannot swear to the
tach before "calibration" was off in a similar manner at readline. (~350-375
rpm)

"Chris D'Agnolo" > wrote in message
...
> Chuck. would love to hear from this club member about his satisfaction and
> about what rpm at what speed, he is seeing.
>
> Chris
> 99BBB
>
> "Chuck" > wrote in message
> ...
>> What I can tell you is that my 99 (turbo,SBB,with 5th gear mod & 4.11
>> rear) can be annoying at times, due to the 5th gear change. Seems that
>> around 45 mph, which is a common "speed limit" around here, 5th is a bit
>> too high, and 4th a bit to low. Other than that, the gear change was
>> useful, in that it helped reduce the noise at normal highway speeds, and
>> may have helped slightly with fuel consumption during cruise. The tires,
>> while larger than stock, are within 1% or so of the stock diameter.
>>
>> One local club member has changed a stock NA to a 3.6 ratio, in order to
>> save fuel. He was not concerned about other preformance losses. I haven't
>> heard much about his satisfaction, other than the rear end is/was a bit
>> noisier than it was before.
>>
>> "Carbon" > wrote in message
>> ng.com...
>>> On Mon, 06 Jul 2009 18:20:36 -0400, Chas Hurst wrote:
>>>> "Lanny Chambers" > wrote in message
>>>> ...
>>>>> In article >, "Chas
>>>>> Hurst" > wrote:
>>>>>
>>>>>> The MSM has a 4.1 final drive-
>>>>>
>>>>> Ah. I didn't know that. Thanks.
>>>>>
>>>>>> I guess to offset the larger tires.
>>>>>
>>>>> More likely, to make them seem actually quick, without dipping too
>>>>> deeply into the parts bin.
>>>>
>>>> The MSM has a turbo, intercooler, 17" wheels, dunno about the brakes.
>>>> But I'd say they dipped fairly deep into the parts bin.
>>>>
>>>>>> A switch to the much more common (than 3.6) 3.9 rear ratio will give
>>>>>> about a 5% reduction in rpm vs speed.
>>>>>
>>>>> That's only a 150 rpm drop at 60. Doesn't seem worth doing.
>>>>
>>>> Nope, it don't. Even the taller gear, the 3.63 only drops the rpm
>>>> about 12%. The Miata engine doesn't have the power curve to drag the
>>>> car along at 2500/60 mph.
>>>
>>> The MSM does. I have one.
>>
>>
>