Hey everyone. I am just wanting to know how much the diff gears may make a difference to the speed that the speedo is showing vs the car is actually going. The only thing that I have done is change it from a 3 speed auto to a 5 speed manual. The car still has the 4:30 gears in it. And with those gears from about 60km/h up the speedo is out. At about 100 by phone, the speedo sits between 110-115 km/h. But at 60km/h the car is doing 60km/h by phone. So I'm wondering will 4:11 gears fix this problem or make it worse?

Cheers 79rolla 

 

Edited September 5Sep 5 by 79rolla

If the boxes had a different final drive it would be a constant ratio out, like 6kph at 60 and 10kph at 100, so if its varying I reckon the speedo might be dodgy. You could pull the instrument cluster out and take the speedo apart to put some light oil on the shaft and bearing in there, they are driven by a magnet working against a tiny copper spiral coil spring. Have the cable out at the same time and hang it up somewhere so you can drip engine oil into it every time you walk past, until it comes out the bottom. Also a good idea with that clutch cable you've just fitted!

Same with the diffs, they would be a constant percentage out. They will change the speedo by 5%, as will tyre size and going to 14" rims, but in theory its all constant. I've run a  3.9, a 4.1 and it came with a 4.3 like yours, originally an auto car. Jap cars were well-known for their speedo over-reads, along with their pony-power figures.

I don't think it's going to be a speedo (dash) issue if it's over reading speed. Maybe the difference at 60 just isn't big enough to be easily noticed between the phone and dash. 

To answer your question - yes taller gears would correct it. From memory manual ke55s had 3.9 diffs. Changing the speedo sender unit could also. 

Probably more importantly, how does it drive? Do you like the current gearing?

The easiest solution might just be taller wheels/tyres.

Cheers taz and altezzaclub. 

I might give the speedo a bit of a oil up and the cable. Could it also be the fact that its a 3 speed auto cluster with a 5 speed manual with 4:30 gears and 205/60r13 tires. All mixing putting it so far out?

 

Cheers 79rolla 

 

Yes. Auto and manual cars came with different diff ratios. That tire size probably not so much.

Cheers taz

I thought they had different diff gears but I was told by a family member there was no difference. Might look at a different diff now

Cheers 79rolla