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Old 09-14-2007, 05:54 AM   #21
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No way I'd be considering any new car, unless I was buying a Lexus SC-430. That's the only car on the road today that IMO is worth paying new for, and that's just because I have a thing for hard top 2 seat convertibles. Yes, I know it's really a 2+2, but at 6ft 4in, nobody's going to fit behind me so if I bought one, I'd drive it straight to the upholstery shop to have the rear seats removed and the rear seat area carpeted and soundproofed so it looked and sounded like a factory 2 seater.

I'd suggest looking at an off-lease model, they tend to be thousands cheaper, usually have less than 30K miles, and are usually well-maintained since the maintenance has to be kept up as part of the lease deal to avoid penalties. Might be able to get an 05 for about 50-60 percent of the cost of a new car, and if you think about it, once you drive that new car off the lot, it's just as used as the off-lease model.
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Old 09-14-2007, 06:31 AM   #22
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Quote:
Originally Posted by omgwtfbyobbq View Post
The ratio of displacements to fifths is about the same at .2 over so engine efficiency should be similar . . .
Hmm, good point. Comparing rpms is not an apples to apples comparison given different engine specs. However, tire size should still be considered. Also, I think piston speed is the critical factor in engine efficiency, so stroke length is the more important number rather than displacement (though the two are generally related). So let's compare the corolla and yaris again:

At 70 mph, the corolla's engine rpm is 2,763, while the yaris's is 2,962. Since tire diameter was used to derive this number, we've accounted for the tires. Now multiply the rpm by the stroke length, and we have a relative measure of piston speed. Since the corolla's stroke is 3.60" and the yaris's stroke is 3.33", these numbers are 9,946.8 and 9,863.5 respectively. So the yaris pistons are actually moving a tad slower at a given vehicle speed, making it, in theory at least, the more efficient of the two. Combine this information with the yaris's lighter curb weight, slightly better drag coefficient (0.29 for the sedan), smaller diameter and narrower tires, and I suppose the nod has to got to the yaris. But, of course, the corolla has a better crash rating and is a little roomier, though it's $2,000 more expensive. . .

By the way the rpm x stroke length numbers for the civic and fit are 10,141 and 11,746 respectively.
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Old 09-14-2007, 08:00 AM   #23
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I went thru this too, but for my wife who needed an automatic. We ended up with a '08 civic 5spd auto. If you can live with an automatic (I can't), these seem FE minded.

I was curious, so doing some calculations to compare to the piston speed #s above... The engine has a 3.4" stroke a, I believe a 4.29 final drive, a .53 5th gear and 205-55-16 tires (about 811 rpm @ 60 mph according to http://www.miata.net/garage/tirecalc.html). So I calculate the engine to run 1844 rpm @ 60 mph and 2151.3 rpm @ 70mph giving a piston speed # of 7314.5 @ 70 mph. Note: This would be easier if I'd just find specs giving rpm @ 60 somewhere but oh well, or better yet drive the car @ 70 mph and read the tach . So these #s are just from specs I found at cars.com, but they seem to jive with what I remember seeing when I drove it last.

It has been very good on gas so far. With my wife driving her normal way she has had some 44 mpg trips (about 20 mpg better than her taurus averaged), not bad for an automatic that isn't broke in yet.

Edit: the final drive i spec'd above is for the stick, the auto is 4.435. 5th gear is exactly .525 in the auto giving 1889.2 rpm @ 60 mph and 2204.1 rpm @ 70 for a piston speed # of 7493.8.
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Old 09-17-2007, 12:03 PM   #24
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I have had a new 5spd toyota Corolla for about 1 and a half months. I just am learning hypermileing so I am FAR from being good at it.
I was originally wanting to buy a VW TDI of some kind but the price people want even for used cars changed my mind.

I have gotten 2 47mpg tanks in a row with 30% city and 60 % hwy. The only mods are 36psi in the tires and a scanguage. The temps around here have been 90+ deg. EVERY day since I purchassed it. So I had to use the AC some.
I think I should be able to break 50 mpg tanks once the engine is broken in and the weather gets cooler.

Since I have a scanguage I will see how many RPMs at 60MPH and report back.
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