Speedo recalc box question

[rcdice]

Just had a set of 3.33's installed along with the appropriate Unitrax speedo recalc box. Here's my question:

When I picked up the car, the Viper tech said everything went fine (I also had a number of other things done to the car). However, when he test drove it after installation, he thought the speedo seemed a little sluggish from zero to about 30 mph. As I drove it home, I noticed the same thing. Kind of seemed to move rather slow then kind of catch up. From about 30 mph up, seemed very normal. Now here's the weird part, since then I've put about 80 miles on the car, 25 or so of which were tonight. Speedo seems totally normal now. I'm actually wondering if I was just imagining it or was it really sticking early on. The recalc box is wired into the PCM. Is it possible the PCM needs to "learn" the new routine?

Am I nuts or has anyone else experienced this? Thanks.

 

[FE 065]

Maybe your brain was just used to sensing the rpms vs mph you were getting before the gear swap? Each gear giving you more mph at the same shift points-less mph now, so it seemed 'off ' after getting back in it ?

So - how do those 3.33s feel ?

Peppy now?

 

[Ulysses]

The PCM doesn't learn the speed, it's a calculated ratio. FE065's explanation is a good one, but if I suspected something was wrong I would guess the recalc box. Have someone follow you and clock you at a certain speed for a few mph points and compare.