New gears and vss - Third Generation F-Body Message Boards

shuanm · 01-15-2009, 10:38 PM

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??

pwdbychevy · 01-15-2009, 11:05 PM

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"

shuanm · 01-15-2009, 11:11 PM

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

That's one spookey avatar.

tyler92 · 01-15-2009, 11:16 PM

Quote:

Originally Posted by pwdbychevy

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"

that line has got me out of more than one ticket

shuanm · 01-15-2009, 11:18 PM

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.

pwdbychevy · 01-15-2009, 11:54 PM

Quote:

Originally Posted by shuanm

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??

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.