I've read a lot of post on this site about the topic, but I'm not finding what I need. I have a 7730 ecm and a 5speed transmission from a 92 RS. The RS was geared 3.08, and my gear is 3.73. I'm not even a little concerned about the Speedo since it's cable driven and I don't really use it anyway. I have the calculations in my head for the RPM in each gear and don't really care if anyone else can drive it. Prefer if they didn't. I just want the ECM to recognize the speed properly. Currently it shows the speed I would be going with the 3.08 gears. can i just 3.73/3.08*4000 and plug that into the constant to fix this issue or is there a whole lot more to it than that??

 

I wish it was that easy when I had that issue. I went ahead and bought the SGI-5 box from Dakota Digital wired it in. Now I can't say "Seriously officer, I really don't know how fast I was going"

 

But I'm not concerned with the speedo just the speed that the ECM sees.

That's one spookey avatar.

 

that line has got me out of more than one ticket

 

I'll try that next time even though I really do. They'll probably give me ticket for my car not being street legal because of no speedo.

 

But seriously, I tried changing the constant in the chip before I bought the box and one setting was WAY OFF and the other was WAYER OFFER if there ever was such a phrase. It also may cause a rich or lean condition on your motor because the ECM will think the car is moving or not moving and adjust for fueling.