The Need for Speed(s)

[rjundi]

In a manual I love 5 speeds. With 6 speeds I dislike shifting the extra gear. On 4 speed manuals the gaps are too large between 3rd and 4th typically.

Automatic who cares, I honestly never pay any attention to what the transmission or engine rpm is doing. Its a rolling appliance. Put it into drive and forgot about it. Need more power floor it.

 

[rpn453]

Originally Posted By: Shannow
Depends on the torque curve. Torquey engine and close ratios are an utter waste.

Remember the 80s? Corvettes that had a gate so that you went from 1st to 4th under specific throttle positions ?


Don't they still do that? My buddy had to delete that "feature" by wiring in a resistor on his '02 Trans Am.

I'd prefer a 6 speed with the same first and last gear on my Mazda3. I wouldn't drive it any differently in the city but I'd have more useful gearing for low speed city driving and an extra gear change when on the highway/freeway. It would also be an improvement if they simply shortened 2nd and 3rd.

Generally, I think I prefer 6 speeds in a manual and 5 in an auto, but I'd rather have a good transmission than one with a high number of speeds. I don't think there would be much benefit to having more than 5 speeds with a turbo though, unless it's a diesel truck used for towing.

 

[Shannow]

They may still do that.

None of the GM 6 speeds down here have that sort of lockout.

 

[rpn453]

Originally Posted By: XS650
That's basically what the 6 speed Corvette transmission is. A sporty ratioed 5 speed with a tall 6th gear added for economy cruise.


I wouldn't call it sporty; you can hit 50 mph in first gear! 4.10s really wake those cars up.

 

[rpn453]

Originally Posted By: Shannow
They may still do that.

None of the GM 6 speeds down here have that sort of lockout.


That makes sense; I think it's used only for the benefit of EPA fuel economy testing. It might be into "gas guzzler tax" territory without it.

 

[XS650]

Originally Posted By: rpn453
Originally Posted By: XS650
That's basically what the 6 speed Corvette transmission is. A sporty ratioed 5 speed with a tall 6th gear added for economy cruise.


I wouldn't call it sporty; you can hit 50 mph in first gear! 4.10s really wake those cars up.


I don't care what happens under 30 mph.

 

[moribundman]

Originally Posted By: XS650
I don't care what happens under 30 mph.

Exactly.

 

[rpn453]

Originally Posted By: XS650
I don't care what happens under 30 mph.


It tightens up the gear ratios when travelling over 30 mph too!

 

[XS650]

Originally Posted By: rpn453
Originally Posted By: XS650
I don't care what happens under 30 mph.


It tightens up the gear ratios when travelling over 30 mph too!

You shift more often for no purpose. It's 90% illusion.

 

[rpn453]

It could be. On my buddy's T/A (LS1, Tremec T56), it really seemed to make a difference in the launch (easier, since you can drop the clutch at lower rpms) and the run through first gear. He had a '98 that he put the 4.10s in and loved them. Before he had that car, I didn't know a 2WD car on street tires could pull you into the seat as hard as that thing could in 1st gear with the 4.10s. When he sold it and bought an '02, I was surprised at how much slower it felt despite being the even more powerful 345 hp Firehawk package. I did a couple of runs with it and, after you've hooked up, it seems like it takes forever to reach that next shift and the speed builds steadily but not urgently. I have no numbers to back anything up though, and my personal experience doesn't involve higher speeds or caring about the effect on fuel economy.

It probably doesn't seem like as good of a modification on a Vette as it did on the T/A; I imagine the Vette rips through first pretty quickly anyway. But if performance is the primary consideration in selection of the gear ratios, whether it be on a dragstrip or a race track, I think the 4.10s would have an advantage.

 

[BuickGN]

I sometimes wish the GN had a taller axle ratio. With the stock 3.42s I'm in first gear for maybe a second on slicks and on street tires first and second and some of third are unusable. 28" tires over the stock 26" tires help.

That's racing but driving in traffic I would worry about transmission fluid temps with a 3,800 stall and super tall gears.

 

[rpn453]

Originally Posted By: rpn453
It probably doesn't seem like as good of a modification on a Vette as it did on the T/A; I imagine the Vette rips through first pretty quickly anyway. But if performance is the primary consideration in selection of the gear ratios, whether it be on a dragstrip or a race track, I think the 4.10s would have an advantage.


I'll add to that the fact that supercars tend to have much shorter gearing than the Vette (as well as horrible fuel economy)!

 

[BuickGN]

I don't know about that. I've been lucky enough to ride in several exotics and drive a Murcialago(sp) which had a rediculously high mph per gear. I remember in the Lambo I could hit the speed limit in first gear.

 

[oilyriser]

Direct drive in top gear gives best transmission efficiency since each gear mesh loses a few %, but the differential would have to be geared for it.

 

[Tosh]

Lexus and Mercedes are having a spec war, so that smarmy stealers can point to the brochure and say to the clueless, status hogging customer "Look, that's one more than the S-class has." To anyone else, it's totally counter-intuitive to need more gears as the torque curve gets even wider with every new engine.

 

[Win]

6 speeds is about right for an automatic, but if I had the chance to drive a 7 or 8 speed, I might like that.

If the Camry 6 speed seemed shifty, I would attribute that to a flawed design, flawed software, insufficient torque, or a combination of all of the above.

The ZF 6HP26 six speed teamed with a dinky V8 (4.2L) in the wife's Jaguar XJ8 is nearly turbine like. First is low enough to launch the car off the line like a scalded cat (pun intended) while sixth is tall enough to deliver low 30's at 70+ on the highway. Not bad for a full size luxury car, and it still gets in the lower 20's around town.

I will never buy a manual transmission car again - with auto's like the ZF, there just is no need for a manual.

Torque monsters like the Xj12 and the GTO are just fine with a four speed, as long as you don't care about fuel economy (I don't) so like everything else in life, it just depends.

I like the CVT in my John Deere yard tractor - but I'm not ready for one in a car.

 

[rpn453]

Originally Posted By: BuickGN
I don't know about that. I've been lucky enough to ride in several exotics and drive a Murcialago(sp) which had a rediculously high mph per gear. I remember in the Lambo I could hit the speed limit in first gear.


First gear is unusually high on the Murcielago, but the gears are closely spaced after that. That car is geared more toward high speed than most supercars though. Not much of a city commuter! I grabbed some numbers from my C&D collection (gear ratios in mph/1000 rpm):

Car/1st Gear/Top Gear/Peak Power rpm

Murcielago, 10.1, 32.6, 7500
Gallardo, 8.4, 26.8, 7800
Enzo, 6.3, 26.1, 7800
F430, 5.5, 21.9, 8500
Carrera GT, 5.7, 24.2, 8000
911 Turbo S, 5.5, 27.9, 5700

Corvette, 7.6, 39.6, 6000
Z06, 8.4, 44.9, 6300
Ford GT, 9.5, 39.4, 6500
Viper, 9.4, 50.0, 5600
Mustang GT500, 7.9, 37.1, 6000
Saleen S7, 9.4, 34.3, 5900

I think the common American sports cars (Vette, Viper, Mustang) are sacrificing some performance for practicality in their choice of gearing. The Saleen S7 gives a good example of the shorter top-end gear ratio and closer spacing that would be used on a torquey, moderate-revving engine if the importance of cruising comfort and fuel economy were downgraded. The redlines are certainly lower on most of the American cars, but not proportionally to the taller gearing. I was surprised to see that the Vette actually has a fairly short first gear compared to many of the others! From there, the gear spacing is quite large though. The European sports car manufacturers lean more toward pure performance in their choice of closely spaced gear ratios, IMHO.

 

[Black Bart]

Originally Posted By: Shannow
Depends on the torque curve. Torquey engine and close ratios are an utter waste.

Remember the 80s? Corvettes that had a gate so that you went from 1st to 4th under specific throttle positions ?
Yea and remember how everyone unhooked the CAGS because they hated it.
That was the first mod that I did to mine.
4 gears are for maximum acceleration 5th gear is for max. speed 6 gear is for max economy

 

[Bror Jace]

Gears? The more the merrier.

I'm not an automatic fan as, like rjundi, I think they take the fun out of driving. But ideally, all automatic-equipped cars would be like Win's wife's Jag: seamless ... turbine-like. You should have a hard time counting the gears. Gears are probably on their way out, anyway, as CVTs begin to take hold of the industry.

My regular Civic has a 5-speed manual. The Si version has a 6-speed manual. I think the final drive ratios are the same with the 6-speed having more gears in between to able the driver to keep it in the power band more often.

Here's where Honda really irks me: They will gear the automatic version higher (numerically lower) for better fuel economy. Why? Cruise control. With the automatic, the car can downshift on steep hills so you can use a longer gear without issue. With the standard it can't automatically downshift so we (standard drivers) have to put up with a lower gear ratio in the highest (numerically) gear. That really stinks ... and it's why the automatic version of the same car gets another 2mpg highway.

So, at 70mph I'm turning 3,000 RPMs and getting 2-4 mpg less than I should be.

 

[ekpolk]

Great responses everyone, thanks.

Personally, I was thinking 5-spd for a manual, and CVT if one wants to go auto. Although I have not driven one, I think that transmissions like the 8-speed Lexus are approaching absurdity. It's bolted to a V-8, for cryin' out loud. Ironically, you'd think that it would be small, torque-free I-4s could best use such a trans (but of course the price of cars with small I-4s would never justify such an expensive slushbox).

As I suggested in the original post, my perspective is probably warped from driving a CVT for the last 18 months, but when I drive my wife's 07 Avalon (it has the 5-spd auto, 08s got the same suspect 6-spd as the Camry), I notice the shifting, though it's very smooth and civilized. The Camry I tried didn't seem mis-rigged, it just spent a disturbing (to me) amount of time shifting vs just propelling.