Is there really a big difference between a uppipe with or without the EGT Probe...They say is the probe can easily be broken within the uppipe after uppin the boost later on?

 

When I my gutted uppipe I reinstalled the EGT probe...only because I wasnt aware that it could burn up and crumble into the turbo. Its been a year now, and havent had any problems but if I were to do it over I would plug it up. Why risk it?

I dont reallly think this is a common occurence though, it would have to get REALLY hot or go through lots of heat cycles to destroy it I think.

 

the stock egt probe is good for one thing ONLY.......and that is to determine the 'health' of the cat in the UP.

No cat in the UP = no possible need for the stock egt probe----which can not be used for any other gauge or purpose.....spitcan it.

A 2.2k ohm, 1/2 watt resistor inserted in the harness plug on the passengers side strut tower is the generally accepted and used way of preventing any CEL from not using the probe.


ANY aftermarket EGT probe should be installed in one of the manifolds. I prefer the drivers side manifold, at the casting 'button', due to it's easy location and not having to fark with the UP.

 

Actually, the probe gives a degree-accurate reading of your EGTs; my ECUtek dash display reads it every 1/4 second, and it is quite interesting to keep an eye on. For a modded car, knowing your EGTs is extremely important; a jump from 1400 to 1650 at WOT could cost you a turbo or an engine. I absolutely agree that anyone serious about tweaking their car should replace or install a supplemental EGT sensor (there are several good locations) and hook it up to an accurate gauge. Add a fuel pressure sensor too, that's a lifesaver!

 

....oh boy.

The egt in the UP is useless for ENGINE exhaust temperature.

That stock probe is known to fail when subjected to temperatures much beyond what it would read under stock conditions....most non-stock cars run hotter temperatures which usually kills those probes fairly quickly.

Most of us do not have Delta Dash and/or any other ability to monitor the stock probe which makes its use useless.

 

Of course, I was just pointing out that you can hook an actual digital gauge to the EGT probe and get a real reading; it isn't just a fail-safe and the ECU is keeping track of the range of temperature and not just setting a fail point (which is about 1650 degrees F).

 

Bullspit.

The ECU reads the probe temp to keep the UP cat from melting.....too high a temp = limp mode and no meltdown.
THAT IS ALL.

The 2.2k ohm resistor just makes sure the ECU 'sees' a nice comfy temp and no CEL.

 

Funny story:

I took the probe out of my old WRX when I installed an uppipe and applied the resistor fix. I always had a GReddy probe in my exhaust manifold hooked to a GReddy gauge.

I actually had the GReddy probe fail on me after about 25,000 miles. When I pulled the probe to replace it, the entire metal sheath around the thermocouple was gone. The car ran fine for the next 5,000 miles before I traded it in on my STi, but I always wondered what happened to the bits o' sheath.

 

My stock probe broke when I installed my first uppipe. I say scrap it.

OT: what causes high egts' and how do you fix them? Also is this a condition that happens at cruising speeds, or only when you're on boost? Sorry for being a noob.

 

High EGT temp = high temp in cylinder. This can be caused by too lean of a mixture and/or improper timing. When you go into boost, you're adding a lot more air than a N/A car and the car needs to respond with an appropriate increase in fuel. Not enough fuel results in higher temperature combustion, higher temperature cylinder, and higher temperature exhaust gases.

Case in point, I had the vacuum line for the fuel pressure regulator blow off my intake manifold on a recent track day (STi, running 18+psi of boost + cold weather). I noticed my EGT's rising and staying in a high range around the track. I looked at my fuel pressure gauge and realized I had idle pressure while on boost.

That is exactly why I always recommend a fuel pressure gauge for a modded car. I was instantly able to isolate my problem.

 

Let me explain my last post for those that may search and find this thread in the future:

Fuel pressure on our turbo cars is designed to increase 1:1 with boost pressure. So if at zero psi of boost you normally see 43 psi of fuel pressure, at 10 psi of boost you'll see 53 psi of fuel pressure, and at 15 psi of boost you'll see 58 psi of fuel pressure, etc.

 

Take up the issue with my dash display... You seem keen to disagree with something you clearly believe is true.