Upgrading the 410 Final Drive Ratio

John Keighley · #1 (**permalink**) 10-10-23, 10:16 AM

Quote:

Originally Posted by David C

I have just spotted that you say the fuel tank is not very big. Has your car had a smaller tank fitted? The standard tank seems huge when I'm paying to fill it!

David, it's a standard tank - 18 gal but given the distances we sometimes travel, the contents disappear rapidly.

AndrewA · #2 (**permalink**) 10-10-23, 12:31 PM

Sorry to fail you but it's been wired that you can't engage lockup unless overdrive also engaged - I did try.

David C · #3 (**permalink**) 10-10-23, 07:02 PM

No worries, Andrew. Having had a bit more time to think I'm not sure how much it would tell us. I was thinking of the torque converter purely as a fluid coupling but there's more to it than that. At lower speeds my understanding is that input RPM and output RPM can be quite different with attendant torque multiplication but I don't understand is how this relates to efficiency and therefore MPG.
Enough pontification, it's time for me to hurry up that gearbox installation and then report before and after EFI MPG figures.

Sam410 · #4 (**permalink**) 17-10-23, 01:41 PM

My 410 has a 2.88 LSD axle. I am not sure if this was from new or from when the car was restored in the early 90s by Spencer Lane-Jones (it was his own car, not a customer restoration). Sadly my rev counter is wildly inaccurate so I cannot report accurate figures. I saw 24mpg on one trip this summer, but 21-22 is more common on a long steady run. Spencer also told me he fitted mildly faster cam, and the engine was rebored so I think is about 5.5 litres now. Still on the standard carb.