hehe I was just adding to your question to the post above you!

 

I tapped cylinder #2, and my AFR is about 11.5 as well. I'm on a conservative tune, and run about 24psi WITH alky. My EGT stays almost completely stable when the alky starts spraying -- that and my tune are definintely helping keep the EGT safe.

 

Thanks guys, this is really helpful. Looks like I'll go with the #2 runner. Just out of curiosity though does running meth change your EGT's at all?

 

I am sure it does affect them in one way or another, but I don't see how it would affect what the safe zone is for the engine. You still should have about the same "redline" as the rest of us as far as EGTs go.

 

#2 here as well. My Zetronix EGT is no longer working properly tho

 

How long did it last and whats wrong with it?

 

Did you melt the insulation and short the wires?

 

One other thing is I notice people are running the wires under the valve cover. I heard this is a bad thing to do as the ignition wires can cause interference? Any thoughts on this?

 

No clue what's wrong with it. I haven't taken the sensor out yet but the wires look OK and the connections are tight. I've had it between 6 months and a year.

I was hitting around 1600F by redline tho... I try to keep mine under 1650.

 

Without tuning the EGT's will be drastically lower. Cooler charge air in, cooler exhaust out.

With tuning you would lean back out the AFR and the EGTs would come back up again.

 

The zeitronix EGT probe is a LOW MASS- HIGH RESPONSE thermocouple. What this means is that the ceramic coating is light and more brittle BUT the sensor speed is lightning fast and runs circles around the HIGH MASS/ LOW RESPONSE EGT sensor probes such as the big bulky Autometer Pyrometer units.

What this means is you have virtually the fastest reacting EGT sensor on the market to protect you from potential engine damage at a small cost of a more brittle probe. Things such as excessive 2 step use, excessive and prolonged high EGT, nitrous oxide, backfires, leaking manifold can lead to premature probe failure.

On the other side you can have a crappy high mass probe that will last longer, but at a cost of a SLOW reacting and moving signal.

The joke about high mass probes such as autometer is that the EGT's are still climbing as the tow truck is picking up your car with the blown engine.

 

TTP - I have Defi guages and suffer from a very reactive EGT reading. Is there a sensor you can recommend to replace what comes stock with the Defi?

One of these days I'll go Zeitronix... Too many other projects right now...

 

So can you replace just the probe on the Zeitronix EGT or do you have to swap out the entire unit?

 

Just the probe and ss braided end is all that needs replacement.

 

Rich/low AFR will lead to early failure of the probes too, they are typically inconel 600 or 304SS sheath - carburizing exhaust gas stream will encourage the formation of brittle carbide phase which accelerates failure due crack formation from thermal cycling and vibration