VX Tranny Mystery

[GasSavers_James]

OK I have brought this up once before, but we never figured it out.

what rpm does your vx spin at 60 MPH? Anyone with a VX please post so we can compare rpms.

It seems people have two different answers. Some are above 2000 at 60, like mine, but some like jadiazman's are below 2000. Maybe the 92's have a taller tranny? Mine is a 94. Mine hits 2000 at 56-57 and I have the 175/70 tires on stock rims. You would think that it is the original tranny as the car only had 112k and looked mint when I got it. It feels like it has quite a tall 2nd and 3rd so i doubt it is just a dx tranny. 2nd is good for over 65 mph. could they have made the 5th gear shorter for highway acceleration in 94-95?

[Sigifrith]

94 VX with HX rims & Insight tires.
2000 RPMs +/- at 60.

[jadziasman]

It's a mystery to me too. Personally, I think it's an error in the tachometer gearing that's responsible. I want to buy another tach that connects to the single wire port in the engine bay. Maybe a digital tach will be more accurate than the analog one in the instrument panel. I have not been able find one that is reasonably priced yet. Then, I will have a way of directly comparing it. Too bad my GPS can't tell me. Works really good for mph - I won't need a new speedo if it fails!

[92VX]

At 53-55mph the tach is right at 2,000rpm in my car, '92 VX. Last two tanks of gas went 58.7 and 56.5 MPG. I mainly drive highway with the unavoidable California freeway traffic thrown in.

[GasSavers_James]

It looks so far like we are about the same, the only differences being in the tires/wheels. I think the hx wheels with insight tires are a little larger than the 175/70s on stock wheels, or the stock tire size.

So how are you liking the hx wheel/insight tire combo? I was thinking of doing that but am holding off cause I don't have the money right now.
It looks like it has helped your mpg so far!

[mrmcg1]

I have an additional tranny mystery along the same lines. I have a recently purchased stock '92 VX. When I first started driving it I recall that it cruised at 55mph at 1750- 1800 RPM's, and I was getting 62mph at 2000 RPM's (5th gear of course).

Recently at 2000 RPM's it seems to be cruising at 55. Tires/ wheels/ tire pressure have not changed, tranny has not changed. How can this be? The only explaination I can come up with is variations in the Tach or Speedo? I did swap out one VX ECU with another VX ECU, could that make a difference?

[roadsterbum]

I'm in the same camp as jadziasman. My '92 reads a bit below 2,000 rpm at 60 mph.