Hey, I am swaping out my D16y8 for a B16a2 this spring. I was wondering if instead of buying a whole new cluster, Could I just buy the SI gauge faces with out messing up the tach? I know the EX tach only goes up to 8K while the SI goes up to 9k. My whole reason for this is I want the tach to work right. I hope this makes sence.

 

It will work correctly without changing anything, the redline will be off though. As long as you know that the redline is higher there's no need to really worry about it. However, if you just put Si faces on the EX gauges the readings would be way off. The gauge would think it was pointing to the right number but the numbers aren't in the same place so it would be wrong. The only way to get an Si tach would be to swap out the whole cluster. I don't think it's possable to just change the tach either but, I could be wrong.

 

Im not sure how this all works. I thought the gauges were controlled by the ECU. So if I swaped the engine, ecu, wiring harness, ect. Wouldn't that throw the EX gauges off? Thats why I thought if I just bought new gauge faces it would fix it. I dont know either?

 

Alright, I'll try to explain it a little better. I could however be wrong, in which case someone correct me!

You're right about the ECU controlling the gauges but, the ECU doesn't tell the needle where to point, it just gives the gauges the info they need. The gauges then take the info the ECU gives them and adjusts the needles to the correct position. Take this for an example:

1. Engine is at 4,000 RPM
2. ECU tells the gauges the engine is at 4,000 RPM
3. The gauges take the info and move the needle to point at the 4 on the tach

This is what would happen if you just put new faces on the gauges:

1. Engine is at 4,000 RPM
2. ECU tells the gauges the engine is at 4,000 RPM
3. The gauges take the info and point to where they think the 4 should be, but in reality it's not there anymore because you changed where the numbers on the face of the gauge are.

Basically, the tach can't see the numbers on the gauge, it just assumes they're where it thinks they are so if you move them around it points to the wrong place.

PS. the ECU and gauges don't really talk or think, it's just an example.