rear end ratios ?
cruzing at 130 kmh (78 mph) is a lofty 4000 rpm
any other ratios out there ? love the car though its a total blast ! tons of brakes and sooooooooooo balanced ! |
My 07 6spd auto would be running about 2700 rpm @78 mph, and I even geared it down 3% with 225/40r18 tires.:)
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my 07, at 78mph is around 4k possibly higher.. i have 225/45//18..
^^ how is yours a 6spd auto...?? |
The 8 has always come with auto. The early models were 4spd, my 07 is 6spd.
I really like to shift gears, but I don't like all the associated troubles like throw out bearing noise, and 2nd gear synchro grinding. This 6spd auto is really good on the track because I can concentrate on driving while the car does the shifting. I don't even use the manual shift, I just leave in gear, it shifts @7krpm, and if I jump off the gas before 7k it stays in gear to be ready for the throttle in the corner. |
My 2nd gear synchro stopped grinding when I put better oil in the gearbox. Chances are, there's still some rubbing and grinding going on even in your automatic, you just can't tell because you don't have a metal rod connecting your hand directly to the transmission. A gearbox is a noisy place to live.
My car also runs 4000rpm @ 78mph in 6th gear. Don't bother me none -- rotaries run 50% higher rpms than piston engines anyway. So to do the math, it's the equivalent of running 2667rpm @ 78mph in a piston engine. That's quite reasonable. |
[quote=fyrstormer;
My car also runs 4000rpm @ 78mph in 6th gear. Don't bother me none -- rotaries run 50% higher rpms than piston engines anyway. So to do the math, it's the equivalent of running 2667rpm @ 78mph in a piston engine. That's quite reasonable.[/quote] I think you should reconsider this statement, and your math is wrong. |
it might just be me but....
perhaps the reason the gas mileage on the highway sucks is the gearing ? |
Originally Posted by REDRX3RX8
(Post 3782077)
The 8 has always come with auto. The early models were 4spd, my 07 is 6spd.
I really like to shift gears, but I don't like all the associated troubles like throw out bearing noise, and 2nd gear synchro grinding. This 6spd auto is really good on the track because I can concentrate on driving while the car does the shifting. I don't even use the manual shift, I just leave in gear, it shifts @7krpm, and if I jump off the gas before 7k it stays in gear to be ready for the throttle in the corner. thank god for stability control... i prefer to balance the car and keep in the same gear as god intended lol |
Originally Posted by waNkLeR
(Post 3782246)
ever had the car "decide" to shift at 9/10ths in a corner ?
thank god for stability control... i prefer to balance the car and keep in the same gear as god intended lol So right after I yank the wheel, (all at once is the proper way anyway, not slowly turn) I jump the gas. As I'm settling in on the drift after slowing from say 90mph to 60mph, the tranny is shifting down hunting the right gear, and I feel the (low torque remember) power smoothly come in. I did say that the tranny stays in gear when I jump off the gas on a slow speed corner (say 40mph). The auto doesn't sound like a pure race car, but its my dream car, and the newer supercars are gonna shift similiarly.:eyetwitch |
Originally Posted by waNkLeR
(Post 3781743)
cruzing at 130 kmh (78 mph) is a lofty 4000 rpm
any other ratios out there ? love the car though its a total blast ! tons of brakes and sooooooooooo balanced ! Even with 6spd Automatic. I also got the highway EPA mileage of 25mpg when I drove it to Dallas recently at 70-80mph with AC on.;) |
It will take a lot of gas mileage improvement to justify the expense, about $1000 or so installed
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there are 3 rear diff ratios that I know of.
the 4:44---04-08 6 speed car? the 4:77--S2 6 speed ? a 4:3 something--the autos? The s2 trans also will change things for you lower rpms will improve your mpg--but like team said--may not be worth it. OD OD |
Originally Posted by olddragger
(Post 3783201)
there are 3 rear diff ratios that I know of.
the 4:44---04-08 6 speed car? the 4:77--S2 6 speed ? a 4:3 something--the autos? The s2 trans also will change things for you lower rpms will improve your mpg--but like team said--may not be worth it. OD OD |
All the FD3 gears, all the SE3P gears, and the Motorsport 5.12 gear
https://www.rx8club.com/mazmart-88/every-diff-ratio-180758/ . |
i belive the 04-08 autos have the 4:10
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My 6spd auto has 4.3 like OD said, but with 225/40r18 tires, I now have 4.44 like the big boys.:lol:
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Originally Posted by TeamRX8
(Post 3782911)
It will take a lot of gas mileage improvement to justify the expense, about $1000 or so installed
|
I changed my rear ratio from the standard 4.4-1 to 3.9-1 and that dropped the revs down by around 500rpm. So now at cruise speed which is around 130kph or about 80mph, my car sits at around 3500rpm. My car is a JDM 6speed.
The gear ratio set that I used was from a fd RX7. I also hated the high revs the RX8 revved at on the open road. I was used to my RX2 which had a 5speed and 3.9 gears and sat at around 3-3500rpm at around the same speed. |
Originally Posted by Rotaman
(Post 3783560)
So now at cruise speed which is around 130kph or about 80mph, .
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i put the 09 trans into my 04 model--so my cruising rpms are lower.
i can get 25 mpg with my s.c'ed car. od |
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