Help / tachometer calibration - Batee eprom
Thread Starter
Heel & Toe
Joined: Mar 2023
Posts: 20
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Help / tachometer calibration - Batee eprom
Hello everyone,I have just installed an eprom from Batee to fix my tachometer.
It now seems to be accurate at idle but it seems to read too low at higher rpm. I have a 6-speed 1990 with a 3.33 rear diff.
Can anyone share with me rpm references in 4th gear at a given speed?
Also, does someone know how to recalibrate it so that it becomes accurate?
Thanks a lot!
It now seems to be accurate at idle but it seems to read too low at higher rpm. I have a 6-speed 1990 with a 3.33 rear diff.
Can anyone share with me rpm references in 4th gear at a given speed?
Also, does someone know how to recalibrate it so that it becomes accurate?
Thanks a lot!
Team Owner
Joined: Sep 2003
Posts: 25,394
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What tire size?
There are very accurate calculators out there BUT first of all you'll need to check the accuracy of your speedometer. Check your speedo using a GPS for accuracy and then it's very easy to compare RPM to speed, any gear, speed to RPM any gear.
There are very accurate calculators out there BUT first of all you'll need to check the accuracy of your speedometer. Check your speedo using a GPS for accuracy and then it's very easy to compare RPM to speed, any gear, speed to RPM any gear.
Thread Starter
Heel & Toe
Joined: Mar 2023
Posts: 20
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Oh and based on my RPO (I don't know if it is relevant) I have G87 code meaning "ring gear 8.50 inches".
Can you help me with the calculation? 🙂
Last edited by Kardigan_b; Jul 28, 2023 at 06:17 PM.
Thread Starter
Heel & Toe
Joined: Mar 2023
Posts: 20
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I just got the car so maybe I'm not used to it enough, but when at 4k rpm, I have the impression the engine is screaming. Maybe I'm not used to low revving engines 🙂
Thanks a lot anyway!
