A while ago I set out to buy a monster tach and shift light. The guy at the shop convinced me that I didn't need one, so I bought a shift light instead. (Much wiser move)
Now the thing is this, having recently got my all new supercharged A15 up and running. I had the chance to have a wee play the other afternoon. It came to my attention that the shift light was coming on before the factory tacho reached the shift speed. (in fifth gear too!)
So do you think the old tacho is out, or the taiwanese shift light is telling lies?
If the tacho is reading too low, I may inadvertantly push the revs too high.

Id be inclined to think that the factory tacho is out. Im pretty sure it has an adjustment on the back so you should be able to correct it. When reving the crap out of mine i used to get the feeling it was showing inproper revs when sudden changes occur. Ie. Quick gear shift, up and down revs. The needle is a bit bouncy when compared to these late model tachos. Accurate at constant revs though. I checked it by having another tacho running at the same time.

Thanks for the input. That sounds like it's worth a try..

I would concur with what freak says. As an aside the whole shift light thing always puzzles me for cicuit racing I do not bother as I shift in the exact same spot each and every lap.
For Rally it's handy becuase who has time to look at a tach. The best use of a shift light seems to be on a street car.....yet they are sold as racing products???

Tom

i use a tacho with an inbuilt shift light (you can adjst the manual knob for when the light kicks in at the set revs). It was a cheapy one that cme in the ute but works accurately and looks ok where the stock tacho (that was dead) used to live in the coupe dash.

I may yet go down that road myself. Having a big ass tacho on the dash is what put me off buying one. A mate of mine has an auto gage (With no "U") for sale I found today. It'd have to be mounted in the dash though.