STi usdm tranny, 6th gear, 65mph, RPMS?
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From: blaine,WA
Car Info: 2002 wrx wagon black
usdm sti tranny
just a simple question when you are driving your car at 65mph in 6gear what is you're rpm cheers
Last edited by raazin; Sep 25, 2003 at 08:57 PM.
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I'll check tommorow but its right around 2600, theres a HUGE(almost 1000) rpm gap from 5 to 6. If you need to pass someone you better be ready to downshift to fifth
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why are you bumping? i have a related question...if you know the gear ratios and final drive and want to know whats the top speed in a gear ...whtas the formula?
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Formula for speed in gear @ RPM:
Divide engine RPM by top gear ratio and then by final drive ratio. This gives the rotational rate at the wheels.
Multiply that result by tire circumference in feet:
Tire diameter in inches, divided by 12, multiplied by pi (3.1416).
Multiply that result by 60 and divide by 5,280.
Example:
6500 RPM divided by 0.738 divided by 4.44 = 1,983.7 wheel RPM.
25" tire diameter, divided by 12, multiplied by pi = 6.545 feet traveled in 1 tire revolution.
1,983.7 wheel RPM x 6.545 feet times 60 divided by 5,280 equals 147.54 MPH - the speed a Forester XT would theoretically reach in 5th gear at the 6500 redline. Another common way of stating that is 22.7 MPH per 1000 RPMs in top gear.
Plug in other engine RPMs, transmission and final drive ratios, and and tire diameters for other vehicles.
Divide engine RPM by top gear ratio and then by final drive ratio. This gives the rotational rate at the wheels.
Multiply that result by tire circumference in feet:
Tire diameter in inches, divided by 12, multiplied by pi (3.1416).
Multiply that result by 60 and divide by 5,280.
Example:
6500 RPM divided by 0.738 divided by 4.44 = 1,983.7 wheel RPM.
25" tire diameter, divided by 12, multiplied by pi = 6.545 feet traveled in 1 tire revolution.
1,983.7 wheel RPM x 6.545 feet times 60 divided by 5,280 equals 147.54 MPH - the speed a Forester XT would theoretically reach in 5th gear at the 6500 redline. Another common way of stating that is 22.7 MPH per 1000 RPMs in top gear.
Plug in other engine RPMs, transmission and final drive ratios, and and tire diameters for other vehicles.
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The formula can be boiled down to:
pi x RPM x tire diameter (in inches)
----------------------------------------------
1056 x trans gear ratio x final drive ratio
For example:
3.1416 x 6500 x 25
---------------------------
1056 x 0.738 x 4.44
That equals:
510510
----------
3460.22
which works out to 147.54 MPH for a Forester XT in 5th.
The transmission gear ratio doesn't have to be top gear; the formula gives the speed at that RPM for any gear ratio that you plug in.
Jack
pi x RPM x tire diameter (in inches)
----------------------------------------------
1056 x trans gear ratio x final drive ratio
For example:
3.1416 x 6500 x 25
---------------------------
1056 x 0.738 x 4.44
That equals:
510510
----------
3460.22
which works out to 147.54 MPH for a Forester XT in 5th.
The transmission gear ratio doesn't have to be top gear; the formula gives the speed at that RPM for any gear ratio that you plug in.
Jack
Last edited by Ballistic; Oct 4, 2003 at 08:57 PM.
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I went over 150 mph in my STi last Sunday. Believe me, the car can do it and do it quickly. I was racing a Corvette with a lot of mods; my friend's car. He was right there with me, and could have passed me but very very slowly. Well, that's what he told me. He was behind me, so he was drafting me.
He should, because he has twice the engine as me, a V8.
He should, because he has twice the engine as me, a V8.
Last edited by STi City; Oct 28, 2003 at 01:51 PM.
