Which model overdrive unit is appropriate for a series V

[beamdream]

Yeah, Math IS funny. But I am 95% sure you got it wrong. If you were cruising along at 60 MPH with no OD, turning 3000 RPM, and you turned on your .80/1 OD, you would only be turning 2400 RPM, a drop of 600 RPM, 20 % of the original 3000 . On the other hand if you were turning 3000 RPM going 60 MPH, then turned on the OD but maintained 3000 RPM, you'd now be going 75 MPH, a 25% Increase in speed!

As I said, I'm only 95% sure of this due to thinking about it at this late hour. But am I not correct?

Tom

Your giving me a headache

 

[RootesRacer]

Yeah, Math IS funny. But I am 95% sure you got it wrong. If you were cruising along at 60 MPH with no OD, turning 3000 RPM, and you turned on your .80/1 OD, you would only be turning 2400 RPM, a drop of 600 RPM, 20 % of the original 3000 . On the other hand if you were turning 3000 RPM going 60 MPH, then turned on the OD but maintained 3000 RPM, you'd now be going 75 MPH, a 25% Increase in speed!

As I said, I'm only 95% sure of this due to thinking about it at this late hour. But am I not correct?

Tom

Yeah, Math IS funny. But I am 95% sure you got it wrong. If you were cruising along at 60 MPH with no OD, turning 3000 RPM, and you turned on your .80/1 OD, you would only be turning 2400 RPM, a drop of 600 RPM, 20 % of the original 3000 . On the other hand if you were turning 3000 RPM going 60 MPH, then turned on the OD but maintained 3000 RPM, you'd now be going 75 MPH, a 25% Increase in speed!

As I said, I'm only 95% sure of this due to thinking about it at this late hour. But am I not correct?

Tom

Tom, you are correct.
The revs drop 20%. and speed increases 25% at a fixed RPM.

Other than the incorrect RPM ratio, the point was that the Alpine D type OD ratio is 0.80. or 25% OD.

 

[Jeff Howarth]

Just noticed this topic, I have recently added a com0,eye conversion kit to the for sale section of the forum if anyone is interested.

Jeff