Egt

[Mark #2]

I am surprised by how little information there is on EGT sensors in the L community. The go-kart guys live and die on this data, so do Turbo cars. Just surprised by how little data.:confused:

Mark

[L8 APEX]

Turbos both gas and diesel are watching EGT to pretect the turbo mostly. A diesel makes more power the more fuel you give it. Unfortunately the impeller fins in a turbo start melting around 15-1600'F. Carts are 2 stroke so they probably benefit from the data more than injected 4 strokes as well. I know they help tune carburated NA 4 strokes. All modern fuel injected 4 strokes seek stioch most of the time while cruising 14.7 +/- using the O2 sensors feedback. EGT's are nice but they don't tell you A/F. They are even more deceiving in forced induction apps vs natural.

[03LightningRocks]

snip........... They are even more deceiving in forced induction apps vs natural.Why do you believe this Terry? How are they more deceiving in forced induction?

Thanks Terry,

Rocks:confused:

[cpeapea]

i definitly figure that an egt is a valuably gauge, also will tell you when you are about to melt a piston:banana:

[L8 APEX]

Why do you believe this Terry? How are they more deceiving in forced induction?

Thanks Terry,

Rocks:confused:Because the air is hotter due to said devices and back pressures into the turbo not because of lean A/F.

[03LightningRocks]

Because the air is hotter due to said devices and back pressures into the turbo not because of lean A/F.

That is not really an entirely true statement. Leaning out the fuel mixture does generate more heat in the combustion gas and in the cylinder.

Here is a paragraph from the link below it. There are several others that state the same.

"As mentioned before, exhaust gas temperature, in combination with air/fuel ratio, is a good measure of the state of engine tune. This is because the air/fuel ratio affects the heat generated during the combustion phase of the engine cycle. Fuel acts as a cooling agent for the cycle, and thus having a numerically lower air/fuel ratio - which is considered to be a RICHER air/fuel ratio (ie., richer in the amount of gas exiting) will result in lower exhaust gas temperatures. Similarly, leaning out the mixture by injecting less gasoline causes the overall exhaust gas temperatures (commonly referred to as EGTs) to rise. Frequently a change from a lean to a rich mixture can cool the exhaust charge by as much as 400 degrees Fahreinheit, so this is a very practical matter".

http://www.sficc.net/tech/airfuel.php

[03LightningRocks]

Here is a write up on turbos stating that turbos don't generate heat.....but can be damaged by too high of an EGT.

"Exhaust Gas Temperature (EGT) is a good indicator of your engine's performance. Accuracy in Exhaust Gas Temp (EGT) is very important. The turbo doesn't make heat; it absorbs the heat and uses the exhaust pressure. As the exhaust is blown across the turbine blades, the blades spin at incredible speeds. The shaft of the turbine wheel is slaved to the compressor wheel so they spin together. When you spool up the turbine, the compressor turns as well. Generally speaking, the faster it spins, the more boost the turbo will make. The problem comes when you're trying to turn the turbine too fast. To do this, it takes a lot of heat and pressure. If you get the turbine too hot, it can damage the turbo. At 1270 degrees F, the tips of the turbine blades begin to blow. If you get them too hot, they'll straighten out or even melt and you'll ruin the turbo. The factory Garrett turbocharger will pull all day long at 1250 degrees, but in our opinion, 1270 degrees is the DO NOT EXCEED temp for sustained use".


http://www.portadiesel.com/docs/egt.html

[L8 APEX]

Why ask if you have the internet:D Why is it the more fuel you pump in a diesel the more the EGT goes up?

[03LightningRocks]

Why ask if you have the internet:D ...snip?

I asked because I am always wanting to learn:cool: . Your answer didn't seem right to me....so I checked back with some of the sources I have read about this whole issue on.

I thought maybe there was some sort of issue with forced induction creating factors that would invalidate an EGT gage, that I did not know about.

Here is one for you. With my stock super charger, spinning it's arse off to make 16 lbs of boost, my EGT would read 1450 degrees at the end of the quarter mile.
I then ported the Apten and the 16lbs of boost would generate a top temp of 1400 degrees. I have wondered if the heat from the "overspinning" of the heaton, may have had a hand in this. I kind of thought that this was where you where going.

Now, with my Kenne Bell making 15lbs of boost, at the end of the track I am seeing 1300 degrees.....again making me wonder if heat from the super charger makes for higher combustion gas temps.

Believe me Terry, I am not commited to any one idea when it comes to go fast.

Rocks

[SILVER2000SVT]

Here are a couple of links that I ran across a while back. Don't flame me for where these things come from...But I do think there is some good infomation in them...

http://www.sebringmiata.com/page57.html

http://www.foxvalleykart.com/egt.html

[wesman]

I asked because I am always wanting to learn:cool: . Your answer didn't seem right to me....so I checked back with some of the sources I have read about this whole issue on.

I thought maybe there was some sort of issue with forced induction creating factors that would invalidate an EGT gage, that I did not know about.

Here is one for you. With my stock super charger, spinning it's arse off to make 16 lbs of boost, my EGT would read 1450 degrees at the end of the quarter mile.
I then ported the Apten and the 16lbs of boost would generate a top temp of 1400 degrees. I have wondered if the heat from the "overspinning" of the heaton, may have had a hand in this. I kind of thought that this was where you where going.

Now, with my Kenne Bell making 15lbs of boost, at the end of the track I am seeing 1300 degrees.....again making me wonder if heat from the super charger makes for higher combustion gas temps.

Believe me Terry, I am not commited to any one idea when it comes to go fast.

Rocks
Rocks,

You're right on with the heat coming from the less efficient methods of making power. I've run into the same issues with turbos, a smaller wheel and turbine that makes good torque would always run hot and have EGT issues, where a larger turbo that produced more HP but ran more efficiently resulted in lower EGT's.

[L8 APEX]

Rocks, I bet all three of those setups ran about the same A/F the only diff in temp was compressor efficiency.

[Tex Arcana]

I asked because I am always wanting to learn:cool: . Your answer didn't seem right to me....so I checked back with some of the sources I have read about this whole issue on.

I thought maybe there was some sort of issue with forced induction creating factors that would invalidate an EGT gage, that I did not know about.

Here is one for you. With my stock super charger, spinning it's arse off to make 16 lbs of boost, my EGT would read 1450 degrees at the end of the quarter mile.
I then ported the Apten and the 16lbs of boost would generate a top temp of 1400 degrees. I have wondered if the heat from the "overspinning" of the heaton, may have had a hand in this. I kind of thought that this was where you where going.

Now, with my Kenne Bell making 15lbs of boost, at the end of the track I am seeing 1300 degrees.....again making me wonder if heat from the super charger makes for higher combustion gas temps.

Believe me Terry, I am not commited to any one idea when it comes to go fast.

Rocks

Yanno.. the other thread had me ready to http://img.photobucket.com/albums/v111/texarcana/kthxdie.gif ya.

Then you go and post THIS stuff, and yer confusin' me!! :confused: Nice bit of research there... :tu:

[03LightningRocks]

Rocks, I bet all three of those setups ran about the same A/F the only diff in temp was compressor efficiency.
Yep........the A/F was from 11.8-12.1..............In my mind, that seems like a pretty small variation..

Timing on all three set up's was from a high of 21 degrees to the 19 degrees I am set up on now.

The only major change is the Kenne Bell.....which we know makes more boost with less heat production.

So is the general consensus that the blower can affect the EGT?

[Tex Arcana]

Yep........the A/F was from 11.8-12.1..............In my mind, that seems like a pretty small variation..

Timing on all three set up's was from a high of 21 degrees to the 19 degrees I am set up on now.

The only major change is the Kenne Bell.....which we know makes more boost with less heat production.

So is the general consensus that the blower can affect the EGT?

Makes sense.. hotter air in, hotter air out.