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Speed in gears

deckofficer

deckofficer

Banned
Most all of you already know of the nice web based calculators to determine max speed in each gear, but for the one or two of you that don't.....

http://precisionsite.com/auto-x/tools/

What are your speeds in each gear?
I redline at 6400 rpms and have a M20 Muncie 4-speed with 30" diameter tires and 3.54 rear gears
1st 63 mph
2nd 84 mph
3rd 109 mph
4th 161 mph
 
That link had a group of cars with preloaded specs that were a bit interesting. You have heard of cars being refered to as "long legged" meaning geared tall. For the fun of it I compared the Fiat X1/9, Viper, and my car all at 2600 rpms in top gear. The Fiat is rolling along at 38 mph, my Track-T at 66 mph and the long legged Viper is going 137 mph at just 2600 rpms. To try and get more people to plug in their ratios on the link, for you guys running the most popular tranny........



TH350 1st-2.52 2nd-1.50 3rd-1.00

700R4 1st-3.06 2nd-1.62 3rd-1.00 4th-.70



A really great selection of gears can be found in the 93 Camero/Firebird w/out the G92 axle. Of course your engine should not produce over 400 lb/ft of torque

Borg T56 1st-3.36 2nd-2.07 3rd-1.35 4th-1.00 5th-.80 6th-.62



The 6 speed that can handle 600 lb/ft

1st-2.66 2nd-1.78 3rd-1.30 4th-1.00 5th-.74 6th-.50



My little M20 Muncie

1st-2.56 2nd-1.91 3rd-1.48 4th-1.00



With all this prompting, looking forward to seeing your numbers.



Bob
 
Here ya go, I'm running a Turbo 350 and 3.00 geared 8 inch. :)


RPM 1st 2nd 3rd
6500 76.5 128.6 192.8
 
One problem with using the calculator to show speed-in-gear is that it does not take into account HP vs. drag at a given RPM. I have a spread sheet that does do that. Taking aerodynamics, rolling friction and engine torque vs. RPM into account, I estimate a theoretical top speed of about 150 MPH with about 260 HP at the wheels. I would never, ever try to see if it's true for two reasons. First, no place to do it and second, most important, I'm not stupid. I did read an article about guys who got a 27 Track T up to 200 MPH; it took about 600 HP.
 
Mr. Bill said:
One problem with using the calculator to show speed-in-gear is that it does not take into account HP vs. drag at a given RPM. I have a spread sheet that does do that. Taking aerodynamics, rolling friction and engine torque vs. RPM into account, I estimate a theoretical top speed of about 150 MPH with about 260 HP at the wheels. I would never, ever try to see if it's true for two reasons. First, no place to do it and second, most important, I'm not stupid. I did read an article about guys who got a 27 Track T up to 200 MPH; it took about 600 HP.
Click to expand...
Mr. Bill,

I'm aware that speed in top gear is limited by power and aerodynamics, I was just curious as to how folks are geared. I remember in the early 70's when Detroit had to drop the compression ratio of all the cars to live with the new unleaded gas, the speed in gears that auto magazines were getting in their road test proved interesting, such as a 1973 Caddy going 116 mph in 2nd gear but dropping to 112 mph in 3rd for the reason you cited. Caddy's were designed to be quiet cruising cars with tall gears but when they lost 100 hp in the compression drop they no longer could pull that top gear.
 
OK, here's some theoretical numbers. 3.55 diff, Ford AOD tranny, 295/50R15 tires at 5500 RPM [need all four parameters].
1st gear - 49.6 mph. 2nd gear - 81.0 mph. 3rd gear - 119.1 mph. 4th gear - 177.8 mph. My engineering calculations indicate that with my engine I will run out of HP at about 4675 RPM going 151 mph with engine at about 260 HP. I'm not running a high RPM/HP setup. More interested in good idle and low end torque to teach my brothers-in-law a lesson; they both own Corvettes.
 
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