Yep, that's about what mine does at that 1500-1700 RPM range. I know that 2000rpm is an exaggeration though because that's going over 90mph! I averaged 38.8 mpg on a ~600 mile trip from FL to mom's place in OH. For the first half, I averaged around 36mpg, and for the second half I averaged better than 40mpg. This was not pulled from the driver's information center, but mathematically calculated based on the odometer and fuel measured by the gas station fuel pumps.
At a constant speed of 45 in 6th doing better than 40mpg isn't hard. No A/C, just running the fan to vent air in, and letting it drift in neutral down hills that are steep enough to maintain speed allowed me to average over 40 despite having to drive extensively through the hills of KY into OH. On a flat road it would do better. I'm not talking out of my ass here, and would bet you cash that I could pull the same from any other C5 as mine is just a bone stock '97.
Chris
Well with a 0.52 ratio,
you would have basically a 2000 RPM drop from 4th to 5th.
SO get your revs up in 4th, get ready to coast and then drop into 5th.
I definitely wouldnt try a WOT shift from 4th to 5th gear.
Only downside is cost. i want to do the same thing, but can't find a good source for cheap O/D gears...unless you've found one.
I beleive astro performance sells them for $200
I had a thought today, would it be feasible to have steep rear end gears for good around-town acceleration and then replace 5th gear in the tranny with a stronger overdrive to maintain highway cruising? I dont think Ive seen this done before, but it sort of makes sense
Yep, that's about what mine does at that 1500-1700 RPM range. I know that 2000rpm is an exaggeration though because that's going over 90mph! I averaged 38.8 mpg on a ~600 mile trip from FL to mom's place in OH. For the first half, I averaged around 36mpg, and for the second half I averaged better than 40mpg. This was not pulled from the driver's information center, but mathematically calculated based on the odometer and fuel measured by the gas station fuel pumps.
At a constant speed of 45 in 6th doing better than 40mpg isn't hard. No A/C, just running the fan to vent air in, and letting it drift in neutral down hills that are steep enough to maintain speed allowed me to average over 40 despite having to drive extensively through the hills of KY into OH. On a flat road it would do better. I'm not talking out of my ass here, and would bet you cash that I could pull the same from any other C5 as mine is just a bone stock '97.
Chris
If you were to purchase a TKO new you can option the 5th gear ratio to be either .82 or .64 and there is not much cost difference if any, depending on the supplier. Most people opt for the .82 overdrive as there is no huge drop off in rpm when banging thru the gears. At least that is my experience when installing the transmissions. Most of my customers are interested in either road racing or serious street performance and are not looking for or worried about Highway fuel economy.
Also, the thread you linked seems to be discussing the disadvantage of going into neutral in an auto, not a manual. Because the Tq converter allows slippage, it won't engine brake at the same rate as with the manual. If I get a chance when I start driving the vette again, I'll demonstrate on video for you.
Chris
And yes, the overdrive is the close to the same in a cobra t-56 as in t-5... I'd rather have a 5 speed anyway if you have enought power.. Shifting just slows you down
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