EGT and 02 sensors

[RCJ]

if you are using 02 sensors on a dyno, what useful information to you from EGT?

[anix]

EGT will be on each individual cylinder and O2 will be an average of 4 cylinders. I have always said the ultimate engine management system would utilize EGTs on each cylinder....a good window of whats going on! Just my 2 cents

[Warp Speed]

EGTs are all but useless for tuning AFR.
Actually, not really sure what they are good for.......lol

[In-Tech]

You can have the same AFR/Lambda on each cylinder and the EGT can vary widely. More mass flow will raise the EGT and you will think that cylinder is lean. EGT lies
Use both if you want. I'm finishing this one this morning.

8L_A.jpg

[David Redszus]

if you are using 02 sensors on a dyno, what useful information to you from EGT?

A lambda sensor will provide information about air/fuel mixture. But a lambda sensor
is sensitive to tip temperature. Ideally, we use one lambda for each cylinder; which makes us
unhappy when the readings across the cylinders do not match.

EGT provides information about combustion timing. They are very sensitive with regard to
combustion pressure location. A late burn will raise EGT while an early burn will lower EGT
but raise piston and chamber temperature. Equal (or nearly equal) EGTs indicate a good
combustion balance across the cylinders.

EGTs are not a substitute for lambda and do not provide reliable mixture information.

While the above principles apply to both two and four stroke engines, a two stroke adds additional
complexity to proper tuning. Two stroke tuning requires several more beers.

[GARY C]

When I dynoed my nitrous engine we had no 02's, we read plugs for fuel and egt's for timing.

[1972ho]

Don’t all the automotive factory cars come with at least (2) O2 sensors for letting the system know when to make adjustments.

[Firedome8]

if you are using 02 sensors on a dyno, what useful information to you from EGT?

A lambda sensor will provide information about air/fuel mixture. But a lambda sensor
is sensitive to tip temperature. Ideally, we use one lambda for each cylinder; which makes us
unhappy when the readings across the cylinders do not match.

EGT provides information about combustion timing. They are very sensitive with regard to
combustion pressure location. A late burn will raise EGT while an early burn will lower EGT
but raise piston and chamber temperature. Equal (or nearly equal) EGTs indicate a good
combustion balance across the cylinders.

EGTs are not a substitute for lambda and do not provide reliable mixture information.

While the above principles apply to both two and four stroke engines, a two stroke adds additional
complexity to proper tuning. Two stroke tuning requires several more beers.

Could lower egt redings indicate detonation ?

[Firedome8]

When I dynoed my nitrous engine we had no 02's, we read plugs for fuel and egt's for timing.

David V book on nitrous tuning suggests at least a 50* drop in EGT when full power N20. If i remember correctly?

[GARY C]

When I dynoed my nitrous engine we had no 02's, we read plugs for fuel and egt's for timing.

David V book on nitrous tuning suggests at least a 50* drop in EGT when full power N20. If i remember correctly?

He did tell me later that they try to keep EGT's around the same as what they are naturally aspirated, I only caught the egt deal towards the end when I started trying to tune the fogger, the plugs were lean so we added a cpl of jet sizes to the fuel but it didn't gain any power and I noticed the headers starting to glow so we added 2 degrees of timing and picked up 20+ hp, when i looked at the egt's on the good pull they were in the 1300's like the NA pulls but the bad pull they were up in the 1500's.

I wish I had realized it sooner as I think I could have tuned more power into the plate systems when we were playing with those, then again it was only a 2 bolt block so more probably would not have been better.

[David Redszus]

if you are using 02 sensors on a dyno, what useful information to you from EGT?

A lambda sensor will provide information about air/fuel mixture. But a lambda sensor
is sensitive to tip temperature. Ideally, we use one lambda for each cylinder; which makes us
unhappy when the readings across the cylinders do not match.

EGT provides information about combustion timing. They are very sensitive with regard to
combustion pressure location. A late burn will raise EGT while an early burn will lower EGT
but raise piston and chamber temperature. Equal (or nearly equal) EGTs indicate a good
combustion balance across the cylinders.

EGTs are not a substitute for lambda and do not provide reliable mixture information.

While the above principles apply to both two and four stroke engines, a two stroke adds additional
complexity to proper tuning. Two stroke tuning requires several more beers.

Could lower egt readings indicate detonation ?

Yes, that's very possible. Lower EGTs can also signal the onset of pre-ignition.

EGTs are subject to variation due to combustion timing, throttle position, length of time at
full throttle, but not to mixture except at the extreme limits.

[hoodeng]

+1 on Davids observations. On a Pro Stock M/C engine we ran some years back we were given the O2 parameter of 13.1:1 as the optimal with Sunoco Maximal fuel, and an EGT figure of 1300°at the end of the pass, the engine was set at 30°and we were given a range of 2°retard max and no more advance.
As David said, EGT would go up with late timing and go down with early timing [big no no] if the O2 was stable at the end of the pass.

Cheers.

[Newold1]

EGT's are usefull sometimes in watching for timing that could be out of a safe range,especially retarded timing which will cause EGT numbers to climb very quickly.

On another subject, it's pretty amazing when you see one of Whipples superchargers sitting on top of one of their huge aftercoolers! Looks like a Big Dog marine racing engine. That package is as big as the engine under it! Very nice! You should post up the best dyno pull when done for all to see.

[ptuomov]

Can you get an EGT estimate from the new lambda sensors? Not a rhetorical question.

[David Redszus]

Can you get an EGT estimate from the new lambda sensors? Not a rhetorical question.

Bosch lambda sensors can provide a digital output to the ECU, an analog output to the data logger as well as measured sensor tip temperature. We use them all the time.