Rx-8 Gears
 

I thing that one issue of the RX-8 is the ''long'' gearing. Pls check the graph of the normal gearbox and compare it with the HONDA CIVIC TYPE R 200 bhp and the one with shorter final gear. CIVIC TYPE R 200 bhp is sold here in europe and along with the ACCURA RSX are the only cars equiped with high reving engines so we can compare them. You can get the QSPEED calculator from www.quaife.co.uk I hope that tuners are working for a shorter final gear or even better with shorter gear ratios. If anyone know something pls post http://www.quaife.co.uk/downloads/QSpeedCalc.exe Gearbox:- RX - 8
Tyre:- 225 45 18
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Top Gear gives 20.619 MPH/1000 RPM and a top speed of 185.571 MPH at 9000 RPM

Engine speeds in top gear:-
30 MPH = 1455 RPM 40 MPH = 1940 RPM 50 MPH = 2425 RPM 60 MPH = 2910 RPM
70 MPH = 3395 RPM 80 MPH = 3880 RPM 90 MPH = 4365 RPM 100 MPH = 4850 RPM

Top Speed in 1 gear = 41.605 MPH
And changes into 2 gear at 5431 RPM dropping 3569 RPM
Top Speed in 2 gear = 68.945 MPH
And changes into 3 gear at 6104 RPM dropping 2896 RPM
Top Speed in 3 gear = 101.648 MPH
And changes into 4 gear at 6942 RPM dropping 2058 RPM
Top Speed in 4 gear = 131.791 MPH
And changes into 5 gear at 7582 RPM dropping 1418 RPM
Top Speed in 5 gear = 156.437 MPH
And changes into 6 gear at 7587 RPM dropping 1413 RPM
Top Speed in 6 gear = 185.571 MPH
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Gearbox:- RX - 8 17/80
Tyre:- 225 45 18
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Top Gear gives 19.474 MPH/1000 RPM and a top speed of 175.262 MPH at 9000 RPM

Engine speeds in top gear:-
30 MPH = 1541 RPM 40 MPH = 2054 RPM 50 MPH = 2568 RPM 60 MPH = 3081 RPM
70 MPH = 3595 RPM 80 MPH = 4108 RPM 90 MPH = 4622 RPM 100 MPH = 5135 RPM

Top Speed in 1 gear = 39.294 MPH
And changes into 2 gear at 5431 RPM dropping 3569 RPM
Top Speed in 2 gear = 65.115 MPH
And changes into 3 gear at 6104 RPM dropping 2896 RPM
Top Speed in 3 gear = 96.001 MPH
And changes into 4 gear at 6942 RPM dropping 2058 RPM
Top Speed in 4 gear = 124.470 MPH
And changes into 5 gear at 7582 RPM dropping 1418 RPM
Top Speed in 5 gear = 147.746 MPH
And changes into 6 gear at 7587 RPM dropping 1413 RPM
Top Speed in 6 gear = 175.262 MPH
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Gearbox:- TYPE R
Tyre:- 205 45 17
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Top Gear gives 20.480 MPH/1000 RPM and a top speed of 172.031 MPH at 8400 RPM

Engine speeds in top gear:-
30 MPH = 1465 RPM 40 MPH = 1953 RPM 50 MPH = 2441 RPM 60 MPH = 2930 RPM
70 MPH = 3418 RPM 80 MPH = 3906 RPM 90 MPH = 4395 RPM 100 MPH = 4883 RPM

Top Speed in 1 gear = 34.221 MPH
And changes into 2 gear at 4810 RPM dropping 3590 RPM
Top Speed in 2 gear = 59.767 MPH
And changes into 3 gear at 5994 RPM dropping 2406 RPM
Top Speed in 3 gear = 83.752 MPH
And changes into 4 gear at 6355 RPM dropping 2045 RPM
Top Speed in 4 gear = 110.698 MPH
And changes into 5 gear at 6720 RPM dropping 1680 RPM
Top Speed in 5 gear = 138.373 MPH
And changes into 6 gear at 6757 RPM dropping 1643 RPM
Top Speed in 6 gear = 172.031 MPH
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I hate it when I'm on it, then have to shift into 4th... It seems a bit flat.

Just my guess but..I think mazda engies would have thought of this.The reason for gearing is to keep under the dreaded port opening when at cruising speeds on beltway.When i drive under75 average speed and keep revs below 3750 my gas consumption really decreases.Not a matter of top speeds and so forth but a gas issue.

What's the difference between RX-8 and RX-8 17/80 ????

The original final gear of the rx-8 is 18/80 ( 4.444 ). In my opinion a shorter ratio of the diff. like 17/80 ( 4.705 ) will help the engine especially at low - mid revs. The HONDA engine uses shorter gears for good accellaration with the 6th gear matching the RX-8s for fuel economy at cruising.

First of all NONE of those cars can even come anywhere near the top speed potential of the gearbox at max rpm so that is totally irrelevant. The factory gears their cars around the usable powerband and daily driving on public roads. The RX-8 develops more average horsepower than the Honda's do. The Honda's need a diffeent gearing to get them moving in a decent amount of time. You'll notcie that the RX-8 would be at a lower rpm in top gear at freeway speeds and this helps fuel economy. Too bad the ecu is tuned like crap. The Honda engines get much better fuel economy and can be run at a higher rpm and still get great gas mileage. Since none of these cars can top out their higher gears Honda obviously found it more useful to gear their cars where the power would be best utilized due to the weakness of their engine in the power department. They just need to get all the help they can from gearing. While the RX-8 is also not able to hit top speed in high gear, it has a wider usable powerband that is less peaky than the Honda engines. Therefore it can utilize a wider ratio and its gearing can be setup different for economy reasons. No manufacturer designs their street car transmissions for racing. Different types of racing demands different gear ratios. A Chevy V8 wouldn't need the same gearing as a rotary. It wouldn't even be the same if you had a purpose built, 9000 rpm capable, tunnel ram, high lift cam V8. It still is a different gearing as a 9000 rpm capable rotary. If it isn't the exact same type of engine, with the exact same timing, it isn't a valid comparison.

I agree !!!!. But the purpose of the comparison is to understand the ''no power'' feeling at mid revs especially with 4th gear. I will ask MAZDA if i can use the 5th gear of the 5MT model (0,806) instead of the 6th in my car so i can use a shorter FD 4,7 to 4,8 . Here is an example http://C:\Documents and Settings\bil...\CARS\RX-8\TR7

Hey greek rx8, I agree with you 100%.

The gears on the 8 are a bit too long to fit the powerband.
Seeing as how power (stock) drops after 8500rpms and the tq starts to drop around 8000rpms. WHich is not true for the hondas you used as a comparo.

Based on Canzoomers ecu mod, I don't think that there is really a problem with the cars sluggishness at all once the ecu is tuned right.

The normal car has very good acceleration from stand but the tq at mid band along with the long gears are giving slow times . We have to see accel. times from canzoomers ecu before and after the mod to have a clear picture