Originally Posted by thatguy

egt failsafe would be a good idea.l

Originally Posted by kjewer1

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.

Originally Posted by KawRider

My Meth kit from TTP is pretty nice. It uses the factory washer fluid reservoir. The fail-safes are awesome, but they do cost a few bucks. I have a Veitronix system that monitors the Boost, TPS, AFR, and the EGT. When ever the AFR or EGT gets over a certain value of lean-ness (I know that's not a word), it sends a signal to a solenoid that opens the waste gate and cuts boost momentarily. When I first got the system, I ran the tank out of alcohol, and it worked as advertised. The fail-safes are adjustable by the user, so it's awesome. The Zeitronix also gives you the ability to log your values on a laptop.

Originally Posted by SlowCar

what happens if the wideband or type k thermocouple craps out on you?

flow sensor supercedes wb...its the flow of injectants(r-oh, a fuel) that alter your afr, not the other way around

Originally Posted by EVO8LTW

That's my point on AFR (and EGT, for that matter) being a lagging indicator. If your AFR reads lean or your EGTs are high, you've already subjected yourself to the detonation-prone situation. You can break a piston almost instantly with severe enough detonation. Waiting for AFR to go lean (or EGTs to skyrocket) is almost like waiting for a knock sensor to detect detonation.

Originally Posted by Mivecless

Even if the EGT probe breaks off, the AFR reading supercedes the EGT. EGT is a backup failsafe to the AFR failsafe.

If the line pops off the meth injector and flow speed is not enough to trigger the high flow rate indicator, your motor is toast.

Originally Posted by Mivecless

High mass EGT probes are "slow". K thermocouples of the low mass variety are amongst the fastest reading there are. Zeitronix uses a K thermocouple with low mass.

I have seen a video of evoscan logging a laptop with this system in action, the meth tank was run empty, AFR and EGT triggers set off and ZERO knocksums registered on the screen. Boost was cut to 14psi any time the trigger was set off by the AFR alarm.

This was enough to set me over the fence. Now just waiting for some Christmas $ to come in. Hopefully they will hold over their Christmas sale long enough for me to pick up the Zeitronix + meth combo.

Originally Posted by SlowCar

the flow sensor in the aquamist dds3 is based on a turbine; the flow rate is proportional to a 0.5 to 4.5VDC output...a range of 10s all the way to 1000cc/min.

what you are talking about is the snow safeinject, which is a single lower trip point sensor, imo, worthless....eg, the pump will be limping along with a leaky in/out seal....or a partially clogged nozzle, failsafe doesnt act till flow rate drops below a certain FIXED rate