[schmedlap]

I just got my 3.73's installed this afternoon. When I left to test it out and go home for the day I noticed I now have a very smooth shift from 1st to 2nd (don't know what the rear end gear has anything to do with it) and I also noticed my speedometer and tach were registering the same speed/rpm as when I had the 3.27 rear end!

Anyone know why? Will the computer eventually catch up to the new speed/rpm or what????

 

[01GTB]

No it won't learn that :wink: Who did your superchip? Send it back to them and have it burnt for the 3.73's. Or buy a Speedcal for $100.

 

[schmedlap]

Thanks for the info. What's a speed cal and where could one be purchased?

 

[Dillo Dave]

http://www.dallasmustang.com/speedcal_about.htm

It's an electronic spedometer calibrator. You can use the SpeedCal or an Abbott ERA. The Abbott is a bit more expensive at around $150.

 

[Bullitt5094]

Until you scrape together the $100 (after dropping all your cash on the gears) your actual speed will be what your speedometer reads X .876 Just don't wreck the Bullitt while playing with the calculator! :razz:

70mph spedo X .876 = 61.3 actual mph
or
Wanna go 75? 75 /.876 = 85.6 speedo reading
or If you mulitply better than you divide
75 * 1.14 = 85.5

I can see it now, "Really officer, I just divided wrong!" :roll:

In the old days a speedometer calibration shop could fix this too. Do those guys still exist?

 

[schmedlap]

Thanks a lot for the conversion factor. I ordered the speedcal and took the Bullit to the Interstate. Using the mile markers and the watch I did a mile in one minute at 70 mph, which was infact 60 mph speed. So the .876 factor is right on. Thanks again.

 

[Bullitt5094]

Actually, basic math 3.27 / 3.73 = .8766

 

[BUL2294]

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2002-02-23 22:24, Bullitt5094 wrote:
[...]

70mph spedo X .876 = 61.3 actual mph
or
Wanna go 75? 75 /.876 = 85.6 speedo reading
or If you mulitply better than you divide
75 * 1.14 = 85.5</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

I'm assuming that this also means that you're putting ~15% more miles on your odometer/trip than you're actually driving (until you get the correction), right? If that's the case, then your 36000 mile warranty would be valid for only ~31536 actual miles... All the more reason to wait on the gears until you have enough cash to have a speedo correction done at the same time!

 

[kaylan1521]

Very good point bul. This was something I wasn't originally aware of until the guy installing the gears pointed out.

 

[schmedlap]

I had the gears done last Friday, have put less than 100 miles on the car so far and the speedcal should be here Wednesday. I don't think I'll have much of a mileage problem.