EGT temps or A/F meter

[Sgt Turbo]

I have mine in the #1 runner, I think most guys do, but I have read several good thoughts about installing the probe in #2.

#4 is a new one on me.

Just checking your not looking at it backwards and it's really in #1? #1 is closest to the timeing belt. Sorry if i'm stating the obvious.

 

[candela]

Well thats the thing...its already tapped in the #4, ehich is beyond me. I always knew it was #1, which is said to get the hottest. I just wanted to know if any of you knew around how much a difference you think it coul be? If its not a big difference Ill keep it, but if it is then Im going to have to plug it and tap the #1.

 

[SPEEDY]

I have mine tapped in #1 also. I have also heard of some people even tapping some where around the down pipe. I don't know why though.

 

[Kevin Jewer]

80% of poeple melt #2 the worst, so put it there. I had already tapped #1 before I realized this, but 1 is good too.

EGT has nothing to do with when your engine is "going to melt". What it deas tell you is a bit about your timing. As you start to knock, timing is pulled, which is the same as later conbustion. So the mixture is still burning when the exhaust valve opens. Fire in the manifold tends to heat up the probe. Now the problem is that other factors affect EGT also. One example is when I went from the t25 to the 14b (bigger turbine hosuing) my crusing temps dropped almost 100 degrees C. At WOT they were about 20-30 degrees C lower than they were previously. There are many other things that affect it as well making EGT completely usless by itself. Some days I was knocking bad at 860 degrees C, other days I ran my best times ever at 22 degrees timing advance at 940 degrees celcius. See my point?

Another thing is EGT gauges are not "precise" at all. Even worse, they fail on the low side, which is obviusly bad. Os is equally useless. Not because its not using a wideband O2 sensor either. The number is perfectly repeatable and accurate for a given car and sesor. The problem is that the number you want to run is different for every car.

With that I say tune with EGT and O2 at your own risk, and its a big one. The only real use for those guages in after you have logged the right way, and know what EGT and O2 values your combination likes. Then those guages do two things. One is that since knock/lack of timing can come from being too lean or too rich. Those two will help you determine which way to go. The other purpose is the two guages become somewhat of a at a glance warning device when you are tooling down the highway with the logger in the glovebox But again, you need to have logged previously to see what is actually safe or unsafe.

Hope this novel makes some sense. Enjoy