My speedo is way off....35mph is actually 51.....this problem was there before we changed the wheels and they are only were supposed to be about 5% error. When I first take off it takes forever to move up too.
I got a ticket because of it as we did not realize....I wondered why people were going so slow all the time!!!!!

Anyway, please help. We know the car used to be an auto and was converted by the Rotary guy in Arlington but we do not know if the speedo info was changed or even if it would have needed to be.

Thanks again! You guys always help!!!!

P.S. We won 2nd at our first car show last weekend even before we had the interior and engine done!!! RX7s ROCK!

 

P.S Our fuel gauge also does not work. Just the light, right about the time it dies!!!! Any ideas there??? Do we just need a new gauge or are the electrical tricks with this one?
thanks again!

 

missing tooth on the speedo gear, maybe?

Do FDs have speedo gears?

 

they have a speedo sensor in the tranny.. i heard its $150 for a new one at ray malloy. i am going to need one soon aswell

 

Since the auto has a higher ratio rear end I would imagine that's where your error is stock 5 speed has IIRC a 411 where an Auto had 3XX gears, add that to your tire size issue and I would imagine you'll find what you need to correct the difference.

 

Anyone have an idea how I can find my rear end gear size? Are there marking numbers on the rear end that should tell me?
Also, where can I buy the sensor at???? Our OKc dealer sucks. I took it there and they sent me away saying noone was familiar with the rx7, only the 8! Got to love Bob Moore! Mazda!

Thanks!

 

should be easy enough to figure out by marking the drive shaft pinion, and marking the rear disk. Turn the rear disk (or drive shaft) and count the revolutions of the pinion to the rear disk. If you go 4 full turns on the drive shaft and the rear disk doesn't quite make a full revolution it's the higher 3.90 rear end, if it goes just a bit past one full turn it's the 4.11 rear end. You know you'll have to jack the car up to accomplish this ?