I'm getting ready to order a 2008 Convertible with paddle shift and am considering ordering the "2.73 Performance Rear Axle Ratio". Can anybody give me a description of what that is, and difference it makes in acceleration or speed? Is it worth $395?
Thanks, Scott
Sure, this principle is the same in all vehicles, although there are many other contributing factors that alter the details. Generally, a lower gear ratio (3.55/1 being a lower gear ratio than 3.00/1) reflects a quicker launch, quicker run through each gear, and ultimately (theoretically) a lower top end speed.
And on a car driven on the road, higher gas bills.
2.73 does not seem like a performance ratio. Could it be 3.73? What is the standard ratio?
Al
2.56
On or about Sat, 20 Oct 2007 07:01:34 -0700, "Big Al" wrote or did cause to be written:
In an older car it wouldn't be but the six speed automatic makes up for it with a much lower first gear and wider range to the top.
In a 2005 the rear gears from the factory are: auto: 2.73:1 or 3.15:1; manual: 3.42:1, limited slip. Would the be the same in a 2008?
I have a 2004 Auto with a 2.73 ratio. The good news: 21 MPG around town, 25 highway. The bad news: Could be faster, IMHO. A 2.73 rear end ratio IS NOT a "performance" item. It gives you better MPG and slower 0-60.....0-100 on up times. Helps Chevy meet their CAFE numbers. The higher the number, the more "performance" from the rear axle ratio.
2.73.....bad. 3.48...good 4.11....better Gas mileage?? Who cares. That's not why I have it. It's a 'Vette not a Vega!
On or about Tue, 23 Oct 2007 23:05:57 -0500, "bill kolofa" wrote or did cause to be written:
The final gear ratio is a combination of the gears in the transmission and the differential. The higher the number the faster the car accelerates and the worse the gas mileage. Your 2004 automatic with a
2.73 differential has the following ratios: (gear/transmission/final) 1st 3.06 8.35 2nd 1.63 4.45 3rd 1.00 2.73 4th 0.70 1.91The C6 Z06 (which I think most would consider has a performance transmission has a 3.42 differential which results in:
1st 2.66 9.097 2nd 1.78 6.088 3rd 1.30 4.446 4th 1.00 3.420 5th 0.74 2.531 6th 0.50 1.710It has more low end grunt and better top end mileage than your 2004.
Now for the 2008 automatic. The first final ratio is for the standard
2.56 differential and the second is for the 2.73. 1st 4.027 10.309 10.994 2nd 2.364 6.052 6.454 3rd 1.532 3.922 4.182 4th 1.152 2.949 3.145 5th 0.852 2.181 2.326 6th 0.667 1.707 1.821In other words, leaving the line the standard automatic with the 2.56 is equivalent to a Z06 manual with a 3.88 differential and the 2.73 auto would be a 4.13 differential. As far as mileage, the standard auto and manual are the same ratios while the 2.73 would be a 3.64 manual.
On or about Sun, 21 Oct 2007 18:23:13 -0400, "Paul J. Veres" wrote or did cause to be written:
What Bob said. The difference is the 2005 had a 4 speed auto while the
08 has a 6 speed with a much wider range. See my other post below.Have something to add? Share your thoughts — no account required.
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