88 n/a overheat ?
 

I was driving yesterday and it was a pretty hot day. My temp gauge went much higher than usual and i was wondering at what level does it start to be bad for the engine. Also i changed my alternator last week, i have put a 93.

This is the wrong section, you probably want to post this in the technical forum. I'm just coming back in to rx7s but there are a few possibilities. You might clean off your water temp gauge sensor because they can get dirty and sometimes that's all it takes for the sensor to give weird results; iirc it is to the right of the rear bottom spark plug.

Also, is your voltage normal? It could be possible that the new alternator is somehow causing the gauge to read a little high.

I wouldn't drive it too much if it consistently stays that high until you figure out what's going on because the temp gauges aren't accurate at all; the s4's aren't that bad but the s5's usually go from cold, warm, new engine.

Thanks for answering, my alt gauge reads about 15 or 16. It depends if my lights are opened or stuff like that