Manual vs. automatic

jtsanders wrote:
If you multiply 5th gear by the final drive ratio, the manual is 3.12 and the auto is 2.33.

This is interesting information. I always heard that there was a difference, but I never realized that it was so large. I guess the theory must be that the automatic can drop into fourth easily when more power is needed, but the driver of a manual would find it annoying to shift so often.

By the way, your numbers show that this particular Civic should be parked in reverse and not first, as this question is sometimes asked here.

EPA requires that all vehicles tested to achieve certain acceleration numbers. And this sometimes requires several downshifts when a manual is tested. Despite the fact that the engine usually turns faster with a manual, less throttle is required.

Any manual trans owner who is concern with fuel mileage and stay in the top gear as much as reasonable should get better mileage than what the EPA gets. Achieving EPA rating with an automatic is doable only where its flat.

Manual transmissions cost more than autos to manufacture anyhow. The traditional surcharge for autos is only an implied value–they actually cost more. Manuals have far tighter tolerances, more expensive metallurgic requirements and don’t forget that the chassis setup fior the clutch actuator and shifter mechanisms are all absent in the automatic versions. There was a comment about parasitic load from an oil pump too. I think the manual transmission consumes roughly the same energy in spinning up the counter shaft which is continually “pumping” oil by being immersed in it. As time goes on I bet the traditional simpson planetary autos will be replaced by what we now know as manual transmissions but with computer controlled clutch and “shifter”…servos on the shift forks. This has already happend in the heavy truck industry. ZF automatics have supplanted Allison. You can get a 15 speed automatic ZF but 7 is the best from Allison(really only 6 norrmally used with one deep reduction). The ZF is a “manual” with computer controls. Rockwell Road-Rangers are exactly that as well.

Quote from kawasaga: Manual transmissions cost more than autos to manufacture anyhow. Unquote

I seriously doubt this. If you go by parts count alone, a manual has far fewer parts than an automatic. More parts also means more assembly time resulting in higher cost. Gear cutting and hardening is mature technology for mfrs.; has been done for many years. Can you say that auto trans gears do not need hardening?

Furthermore, if an automatic was cheaper to make than a manual, then some mfr. would break from the pack to make a manual trans an extra cost option. Automatics have been an extra cost option since the GM Hydramatic was released in 1941.

quote from kawasaga: "There was a comment about parasitic load from an oil pump too. I think the manual transmission consumes roughly the same energy in spinning up the counter shaft which is continually “pumping” oil by being immersed in it. "

Yes, that is true, and maybe because of that, the increased oil drag of having more than five or six gears in the transmission may offset the benefit of having the extra ratios in cars.
In a lot of motorcycle engines, the countershaft is not submerged in oil and the gears are pressure lubed by an oil spraybar, the transmission sharing the engine’s oil, a design seldom seen in cars. I think the Ford Model T used the same oil in the engine and transmission.

I agree that manuals cost less theoretically to manufacture. But, during a visit to an automotive subcontractor plant, a tour guide engineer was emphatic about tooling for a particular option was less expensive when the majority of cars were ordered that way. Retooling for things like roll up windows results in more expensive cars in the end, fewer parts and less labor not withstanding. I’ll assume it’s the same for autos. I think though it’s really model dependent and a bean counter prerogative. And yes, it would cost a lot of extra money to make a manual available in the Lexus GS 450 h.

When I bought my '06 Honda Civic (4 dr EX), the manual transmission version was rated at 30 city mpg, 38 highway mpg, while the automatic version was rated at 30 city, 40 highway. The dealer’s lot had only automatics, and I had to special order a manual transmission car (which I heard a dealership employee say was “the only one in the state”). I get 40-43 mpg on secondary roads (no more than 65 mph), and 35-40 in Interstate highway driving (70-80 mph, some long uphill stretches).

Benefits of the manual transmission include better engine braking on long downgrades, better acceleration, and a lower purchase price. The one drawback is that the engine stalls very easily when starting out, it took some practice before I could consistently start from rest without using more revs than I like. Newer cars seem to be designed so that the fuel injection feeds barely enough fuel into the engine to keep it running when idling, unlike older cars with carburetors. The clutch on my '95 Civic was still good at 180,000 miles, so clutch life is not an issue for a sensible driver.

My advice to the OP, based on my experience, is to keep looking for a manual transmission Civic, even if he/she has to special order one.

Quote from dagosa: “And yes, it would cost a lot of extra money to make a manual available in the Lexus GS 450 h.” Unquote.

With manual transmission vendors available and willing to sell you one such as Aisin, ZF, Tremec and Getrag, it would be a relatively simple engineering matter for Lexus to offer a manual transmission option without having to design and tool up a new one.

I guess you missed my point. No one says they aren’t simple and available but it 's not a simple engineering matter to offer one… In a Lexus hybrid (h model) it would essentially be a custom installation with the price to match. You would start with a car with an auto to begin with off line then remove and replace. That’s less expensive ? I think not. You think Much of the rest of the drive system doesn’t have to be re engineered too given it was designed with an Electronically control continuously variable auto ? Fitment alone would be a big chore.

To Mr. dagosa,

I did not realize that the Lexus you refer to was a hybrid; did not look it up before I commented and in that case, it changes things a lot regarding what I posted.

No problem. Do it myself sometimes.

@nerdnic
You’re in luck. Porsche announced awhile back that some of it’s cars will have SEVEN gears in stick form

Yes, manuals cost more to manufacture…the metallurgy and fine machining of synchros, blocking rings, shift forks, etc., require for more precision than the relatively easy to make planetary gears. So seriously doubt it if you like, I don’t.

Not all automatics use planetary gearing. A front wheel drive Honda Accord transmission that I saw apart worked a lot like the manual, using clutch packs instead of syncros to do the shifting.

I have two points to make in this discussion:

  1. The difference in fuel economy between automatics and manuasl in days past was about more than just the direct connection in the drivetrain. It was also about the difference in the number of gears. In most 1980s era cars, it was a choice between a three speed automatic and a four speed manual. In most 1990s era cars, it was a choice between a four speed automatic and a five speed manual. Many of today’s automatics have just as many gears as their manual counterparts, leveling the field in terms of fuel economy.

  2. The “economy of scale” argument seems bogus to me. Yes, in the US, we buy a lot more automatics than we do manuals, but that isn’t the case worldwide, and we are in a global economy, like it or not. Manual transmissions are still popular outside the US.

Since a clutch does not multiply torque the way a torque converter in an automatic transmission does, a manual typically needs a considerably lower first gear than an automatic does.
Take my Yaris, gear ratios given in a previous post. Even though the automatic version only has four gear ratios, the gaps between those ratios are only slightly greater than the gaps between the ratios of the five speed manual. It just sort of skips first gear.

Now now…keep to the important part of the conversation and be careful not to dwell on technical details that matter little. So observant BLE.;…great statement to proclaim as if it were an omission on my part. My comment ( a few ago) mentioned dual shaft transmissions…essentially a manual with computer control. My point back then was that many autos today are simply “traditional” manuals but with computer control…that seems to be an more scalable, changeable and reliable way to go rather than coming up with some other Simpson, clutch, band, sprag, converter…blah, blah, blah arrangement every few years . An example is the new Ford Focus…the auatomatic is a dual-shaft…no planets, converters, etc. just two clutches and alternating speed gears on either input shaft…not a Ford original idea, but good to see them doing that.

While all the technical talk is interesting, if the only reason to buy a manual over an auto is mpg then I guess go with an auto. For me, I just feel more connected to the car and the experience driving a car with a manual trans, it is more fun. I think the maintenance on a manual is less, and I think in the real world the manual does as good or better in mpg than an auto trans in the same car. But, in the end it is which the driver prefers to drive.

Most drivers in the US will choose an automatic trans and a few of us will choose a manual. I wish my T’bird was a manual, but it is fun to drive with an auto. My Sequoia isn’t much fun to drive period, but it is very useful so the auto trans if is fine in that type of vehicle, a full sized SUV.

To me a Mazda Miata with an auto trans is like chalk squeeking on the blackboard at school, ouch.

Agreed. If fuel economy is your only motivator, get an automatic. I drive a manual because I would rather replace a clutch than replace a transmission. A new clutch is about half the cost of a rebuilt transmission. The same goes for the manual transmission. It’s less expensive to replace, and easier to rebuild. I think it’s more fun to drive too, but if I was really concerned about fuel economy, I would want a CVT transmission, which beats a manual in fuel economy hands down.

“if I was really concerned about fuel economy, I would want a CVT transmission, which beats a manual in fuel economy hands down.”

Seriously? The original Honda Insight pulled 70 hwy mpg with a MT versus 60 with CVT. The original Civic Hybrid did 51 hwy mpg with MT versus 47 with CVT. The last time I rented a Civic Hybrid with a CVT, it downshifted in many situations where I would dip into the go pedal in high gear had I been driving my own car. If fuel efficiency is my endeavor, I’d have a manual with a tall final drive.