4GEvo63

of all the posts i've seen about AFR bein somewhere in the 11's, i've never seen anything on the EGT temp....i'm assuming that around here is where max temp (1700 F (930 C)) is or almost reached?....btw, what EGT you guyz runnin and at what AFR?....

kf6ytc

iTrader: (10)

Try to keep your EGT's below 1600* f

TTP Engineering

iTrader: (465)

Blah... 930-950*C is on the upper edge of 93 oct, preignition and detonation to follow. 950-1000*C you are in dangerous territory depending on location of probe, type of fuel, etc. You better know what you are doing if you get in this range often.

Zeitronix

iTrader: (2)

Simplifying some.
AFR does not make power, at least not directly. Heat makes power. Too much heat and things get hurt. Every car is different, find your magic AFR number based on the EGTs then tune for that AFR across load and RPM range. Why do you think we designed the Zt-2 Wideband with the EGT input?

Zeitronix

4GEvo63

so what is the EGT range on 91 gas then before it starts to get too hot?

RazorLab

iTrader: (8)

some people like to flirt with 900c.

I tune for mid 800c on the street on 91 in 4th gear.

probe in the 1st or 2nd exhaust manifold runner.

yesevo

iTrader: (13)

do u have to take out the manifold in order to install probe in the exhaust manifold runner?
got pic?
is EGT a must thing to have if u making how much whp?

DanJ

iTrader: (2)

It's not really a must thing but always a good safe way to tune your car. You do not have to remove the manifold in order to tap the EGT bung, but it does take a bit of skill because if you screw up you will get chunks of metal running through your turbo. evomoto.com has a write up on this.

kjewer1

iTrader: (4)

EGT is about as close to worthless as you can get, at least on turbo cars. It is a much better indicator of timing advance, so much so that it completely masks changes made to AFR. Unless of course you get zero knock, but that is almost never the case. 99% of all the pulls I've logged have at least some knock "noise." I ran an EGT guage on the 2g, but after a year or two realized what was really going on. They are much more appropriate on NA cars IMHO.

TTP Engineering

iTrader: (465)

Until you take off your training wheels and move to methanol injection and or n20.

kjewer1

iTrader: (4)

Everything I said also applies to my track experience, where I only run C16 or Sunoco 117. Regardless of fuel, make a pull at 18 degrees of timing, and another with it set to 20. EGT changes. Sounds like a worthless number to me. But again, this is just my opinion.

bluebyu36

i heard you cant run race gas with air fuel guage cause it works off of your front o2 sensor and a egt is the best gausge to have for a turbo car????????

TTP Engineering

iTrader: (465)

Ignition timing does affect egts. Hot EGTs will STILL MELT YOUR MOTOR on top of indicate heat levels prone to causing knock. EGT is an imperative piece of the puzzle for both drag and roadrace applications regardless of fuel type. The best of tuners will use EGTs. Personally I would move to 4x egts, 1 @ each runner if I could.

kjewer1

iTrader: (4)

I had situations where the EGT would go very high, and the motor would be fine, and situations where EGT was low and the corners of my pistons got rounded right off I gave up on it. I'm not trying to be arguementative, I just enjoy technical discussion.

A couple scenarios to ponder. Very rich AFR, usually from a nasty boost leak, will cause very high EGTs, since the excess fuel is still burning as it passes the probe. The motor is perfectly safe in this situation. The temp probe is not in the cylinder, but after it, so the heat is not in a place that will do damage. But this will cause poeple to ADD fuel.

Running low timing advance, like I tend to do on pump gas at high airflow/rev for safety, results in very high EGTs. Again, no risk to the motor, timing is low.

Running high timing advance, like the time I made an adjustment to the intake cam gear and did not compensate for it with the CAS for example (dumbass), causes lower EGTs to be seen on the gauge, and the motor is certainly not safe. In fact I lost cylinder two on the motor in this example.

SO many variables go into EGT, especially on turbo cars, I found I just could not rely on it for anything meaningful.

WBO2 on the other hand, which I log directly in DSMlink fed through the MDP input, has been extremely reliable and useful. In all of the scenarios above the AFR is what it is. The only thing that can throw it off is a failing sensor, which in my experience with bosch sensors is easy to spot. And being able to compare it to the ECUs calculated "target" AFR is even more usefull, since it makes fuel deilvery (running out of fuel pump, bad pressure, etc) or air metering (boost leaks, etc) problems immediately apparent.

Based on what I have learned over the last 6 years using both tools, I can only in good concience recomend WBO2s to poeple. If someone understands all the intracacies and variables related to monitoring EGT, it's certainly not a bad thing to have. But I certainly wouldn't want to rely solely on EGT, or have novice tuners making important decisions based on it, without knowing all of it's potential drawbacks.

Monitoring all 4 cylinders makes much more sense, since you could focus more in difference between cylinders rather than absolute numbers, so any interference from timing and other factors could be accounted for by getting a mean baseline.

And again, this is all just my humble opinion based on my own experience. Everyone has different needs, goals, and experience. Use whaever suits your situation.

TTP Engineering

iTrader: (465)

Your problem is that you do not have enough collective information. If you were running a Zeitronix wideband such as mine, you would be able to decipher what was happening and when, long ago.

I am one of two authorized dealers that stock these units. If anyone is interested in actually using EGT's to tune with collectively, send me a pm for pricing.