dynamho

Apparently, the transmission was matched for the slightly different power profile. That's seems to be a logical conclusion.

BoosTED

iTrader: (2)

I didn't get a chance to run third gear out last night the temperature dropped to 20 degrees Fahrenheit (approximately -12 C) and I was very tired (up for 24 hours).

Razz1

Umm.... What a challenge to see speed without being on track.

I swear I've seen mine over 68 in second and I thought I have seen 103 in third before.

In fact I think I even posted 103 a couple of years ago.

Mines in the shop right now. And the body kit may make a differance.

rotor_man

My car is pretty much the same as yours Brett and i only get about 158km out of third 108km in second. its an 03 as well

The only mod i have is the racing beat air duct, but mods will only make you get there quicker. I don't think its a model difference

Brettus

iTrader: (2)

I never intended to imply that my car was faster or anything like that - just that it had a different 3rd gear ratio to others on the site.

Rotor man - try taking it to the rev limiter - bet you will get more like 165-170 km/hr .
Is yours a jap import as well ?

rotor_man

yeah mines an imporrt. you might be right i will check it again though, i usually change 3rd at the beep not the engine kill.

Brettus

iTrader: (2)

Just take it to the limiter to get a feel for it ( won't do any harm ) & you will see you have plenty left after the beep .

Am trying to get some nz 8 owners together for a run around Pukekohe early next yr - you keen ?

Paul_in_DC

There's a way to calculate the Speed vs. RPM, but you need to know several things first: tire size, final drive ratio, and the individual gear ratios for 1st through 6th gears. Use those values at the following URL to create a Speed/RPM table. You can then cut & paste it into something like MS Word or Excel and end up with something like the following table. I've checked it against real speed/rpm, and it's very accurate.

Speed/RPM Calculator

dynamho

Thread answered.

Just as I thought, the Japanese spec RX-8 S-Type, the high-powered 6MT version has 1.530 as 3rd gear ratio as opposed to US spec 1.645 to match the higher output of the Japanese version.

Image attached.

Thanks for sharing your observation Brettus!

swoope

iTrader: (5)

great find, bravo!!!!



beers

Brettus

iTrader: (2)

thanks for finding that Dynamho .
Can you tell me if all the other ratios are the same ?
I'm sure the stock HP is not 250 though . When it was stock on a Dyno Dynamics dynamometer (which reads low campared to Dynajet) it made 170hp to the wheels & talking to the operator this is pretty std for all the 8's he has tested here.

ineffable13

ive got mine up to 93mph in 3rd gear

Razz1

Nah, I checked the Mazda Web site that's the only gear that seems to be different.

Brettus

iTrader: (2)

Mazda Maniac

RX8_20

mine is only a 4 speed (04' automatic)

dynamho

BTW, the E-Type is their base, which is the low output 5 speed you see on one of the columns.

dynamho

Not exactly. Mazda_Maniac was right in saying that your smaller wheel setup gave you elevated speed readings, but if my calculations are correct, your speedo with your wheels is only around 2-4 mph inaccurate. It's significant, but not to the degree that you're talking about.

Another side effect is that you will depreciate your car faster because more revolutions mean more mileage put on your odo.

BTW, except for 3rd gear, everything else, including reverse and final drive are the same.

Cheers.

Brettus

iTrader: (2)

did you read the analogy I did of a car up on jacks with wheels not touching the ground ?

Yes my speedo will be inacurate - with smaller tyre I'll be going slower- but the speed readout will be the same for a given gear ratio & rpm no matter what sized tyre I have on .

dynamho

Yes I did read it.

Right, with a smaller tyre, you'll be going slower in reality even if your speedo says you're going faster.

Right, the speedo readout will be the same for a given gear ratio, but that speedo was calibrated for a stock wheel set up.

Remember, speedos detect revolution pulses. If the wheel is bigger, it will take a longer time to go around. If your wheels are smaller than stock setup, it will generate more revolution pulses than stock, which falsely elevates your speedo reading. That's as far as I'll go to try to explain it. Good luck.

Brettus

iTrader: (2)

So you are saying that ....... with smaller tyres, my speedo will read a higher number at 9000 rpm even if the wheels are off the ground and the car is stationary ?
I suspect you are not - what makes you think the number will be any different when the wheels are on the ground ??????

dynamho

On the ground or off the ground, wheel size doesn't matter Brettus. Your speedo will show you a speed reading as if it had stock wheels on even if you're spinning nothing but your axle or a monster 21 inch bling chrome.

Brettus

iTrader: (2)

Yes - correct . I think we are on the same wavelength now .
I thought you mean't by the "falsely elevates your speedo reading" comment that the speedo would read higher (at 9000rpm) with smaller wheels .......

dynamho

Imagine that you're on 3rd gear at 9000RPM and your speedo says 100 mph.
Oh snap, you realize that your car is on jack stands. What's your real speed Brettus? Isn't it zero mph? You're not going anywhere, but your speedo says you're going 100 mph. It's falsely elevated, isn't it?

Brettus

iTrader: (2)

Like I said - we are both saying the same thing - its just that the way you explained it sounded (to me) like you thought the speedo would read higher for a given rpm.

we both know that it won't so I think we can give this up now - yes ?

dynamho

Agreed.