Tim McCreary

I have a question, when swapping auto to 5 speed in the 3rd gen cars, I have heard you can keep the 3.90 gears by just changing the companion flange. How does this affect the speedometer reading. If I keep the rear end, do I need to keep the auto speedo for correct mileage calibration?

Thanks,
Tim McCreary

maxpesce

afik the Auto & Manual use the SAME speedo (only the Tachometer is different) - the calabration is done in the sender unit on the tranny - if you keep the 3.9 gears you may be able to use the sender from the auto in the manual but I don't know if it will fit.

These guys:

http://www.speedometershop.com/

make an adjustable "black Box" fo recalibrating electronic speedos.

BoostedRex

My question would be, why do you want to keep the 3.90 rear end instead of the 4.11 that comes with the 5 speed? It will make a difference in your 1/4 mile times. I have a full swap for sale if you need it. Just PM BanzaiToyota if you are interested. Best of luck to you. Laterz.

Zach

ejmack1

Because some people dont have money to waste on non essential items, I barely noticed a difference when switching my 3.9 gears for 4.11. But whatever.

cover8

I have to agree with ejmack1, I did not feel it on the but dyno...unfortunately a new companion flange is $110 from mazdaformance. I could not find anyone (junkyards) that would sell just the flange out of a 4:10 without the whole pumpkin...

Tim McCreary

Time is the factor. I have all of the parts from a wrecked donor car. It would be much easier to leave the 3.90 rear end in and just let the tach go. For some reason, I thought it was the speedo that needed changed.

I may later change the rear end to the 4.10 gears, but not right now.

Thanks for the help everyone.
Tim