Hey all,

I'm going to go from a 110 to 150 speedo on my 94 Z28 Conv., and get a full tune from mad z28 when it's all set up, but I'd like to know first if there's any way I can keep the odometer on the new one reading the same as the older one? What would I have to do, if even possible?

 

^ I was thinking if maybe it was possible to buy a 150 mph overlay and install it on a 110 speedo, and then have the pcm tuned to read that it has a 150 mph speedo... is there a way that could be done?

 

It's really simple. Just buy a 150mph cluster and have it calibrated to reflect the correct odo reading. I went to a 150 but I didnt worry about the odo, I just swapped'em.

 

You dont need to calibrate anything. I have done this exact mod on my 94 Z28. The 150 mph cluster is plug and play. You can re-use your old odometer. It is held to the back of the gauge face with 3 screws, just transfer it over. The gauge face is easy to remove, just pry it up and it pops right off.

Here is a picture of the back of the odometer, showing the 3 screws. The gauge face is clear because there is not any face on it at the time. I was in the process of installing white faced gauges on my new 150 mph cluster when I took the picture.

 

Yes, with a tune. BUT, when you calibrate the speedometer to read correctly, you will also be messing up the odometer. There is no way to tune one and not the other.

 

Good info. Would he have to report anything when it comes time to sell the car?

 

Takes more than a tune. Heres a good link
http://web.camaross.com/forums/showthread.php?t=462561

 

He wouldnt have to report anything... It's the original odometer and the reading would be accurate. It's never been tampered with.

 

Yeah, I saw that. He was using an external correction box, but it can also be done more simply with a tune. There are constants you can change to correct the speedometer reading.

Really, anyone wanting a 150 mph cluster should just go and buy one. Trying to modify a 110 mph cluster to read 150 is way more work, and will cost more in the long run.

 

Yeah I heard it could be done with a tune. Someone made a thread about using LS1 cluster in a pre LS1 and was told it could be done with some adjustments through the tune.

 

is there any way to just change the old analog odometer to a digital one tho?? and if so what do you need to do to go about doing that?