Will EGT guage cover for my Water/Temp one?
 

I have a stock Water/Temp Gauge and want to know if my aftermarket DEFI, EGT gauge will tell me enough of whats going on before things go Kaboom? I mean if shits running hot the EGT will tell me right? What do you guys think?

I wouldn't think that exhaust temperature would necissarily be indicative of water temperature. It might give you a good idea of what is going on, but I, personally, wouldn't take the risk.

Nope, an EGT will not tell you anything about how hot (water temp wise) your engine is running. You need an aftermarket water temp gauge for sure, along with a boost gauge.. an EGT will help when you get to tuning, but even then a good wideband O2 sensor is still much better. EGT's will help more if you plan on tuning your timing/split.

I guess Ill try and linearize my stock W/T gauge.
How can I tune using an EGT?
Do the Temps go up when Im running lean or something?

Yes, the temps will rise as you run leaner.. as will advancing the timing. But an EGT is a sneaky thing, the temps drop as you add more fuel.. but add too much fuel and the temps will start to rise again because the excess fuel is now burning off inside the exhaust manifold. This is why a wideband is a must when you do serious tuning, with an EGT there is still a good amount of guesstimation.

Right on. Another thing to mention is that when tuning, it's easier if you use both an EGT and an A/F Ratio meter. If you just have an A/F Ratio meter it kind of helps but is generally uselss. If you just have an EGT it helps more, but having both will be much more beneficial to find out what's happening.