Exhaust Gas Temp Questions

[turbonola]

i just wanna know a few things about it before i get a gauge and probe. what can egt tell you when tuning? where does the probe have to be hooked up at? what is good egt for a ka-t?

[480sx]

EGT can tell you where the limits of your engine with its current fuel are before you find them by melting internals, turbine wheels, ect. They can also tell you where your making peak torque in your motors powerband to aid in ignition timing. VERY helpful(needed really) when using something like Meth injection, or changing to race fuel, E85, w/e. Remember, especially in a turbo setup heat IS power, so your trying to find that limit.

As far as a safe level for EGT's, that varies on what you have done to your motor, and what fuel you are using.

For a stock block, 800C i think is a safe limit. If you upgrade your pistons and valves you can mess with 900-950C if you really know what your doing and have the motor built to handle it.

Here is a good link on EGT/AFR.

http://www.sdsefi.com/techegt.htm

[turbonola]

you're a ka-t god

[turbonola]

one more question, what runner should an egt be hooked up to? the third or fourth runner?

[480sx]

3rd, but its been debated before with no real proof either way that i have seen. I say 3rd because it makes the most sense. 3rd cylinder has only two sides exposed to air, while 1 and 4 have 3 sides. Two stays cooler because coolant gets to it before the rest of the cylinders. The only way that 4 would be the hottest is because it is the last in the cooling circuit to receive coolant, but i think thats negated by having the third cylinder exposed to air.

[chad b.]

I would think that by 1600+ you will be on the break of melting an exhaust valve.

[480sx]

On the brink, yes, but again it all depends on your internals. There are valves(engines) that can handle 1000c.

[turbonola]

sweet, thanks. i'm trying to get one since i don't have a wideband yet. that why when i do get my wideband i'll have everything i need to monitor the car properly

[480sx]

Man if your going all out with EGT and AFR, go with zeitronix. Best bang for the buck by far. You can tune it and data log it with a lap top, then use a 5-1 gage to monitor everything. I really wana get that damned gage they are so trick.

You can add a 100 dollar boost sensor as well and you will be able to data log boost/rpm/egt/afr/TPS/and a 0-5 volt signal of your choice. Knock or MAF signal voltage are most common, i use maf signal.

[turbonola]

i'm going all out, don't get me wrong. but this is being done on the cheap side of things. so basically i'll be getting an aem from jegs.com $218

[WDRacing]

Man if your going all out with EGT and AFR, go with zeitronix. Best bang for the buck by far. You can tune it and data log it with a lap top, then use a 5-1 gage to monitor everything. I really wana get that damned gage they are so trick.

You can add a 100 dollar boost sensor as well and you will be able to data log boost/rpm/egt/afr/TPS/and a 0-5 volt signal of your choice. Knock or MAF signal voltage are most common, i use maf signal.

Agreed ^^^

Adding and removing timing raises and lowers your EGT's and AFRs, not a well known event, but true just the same. Tuning for peak torque like Nate said is also key to making the most power.

When running race gas and or meth injection, tune for lambda and use EGT as a way to tell just how far you can go. It's really the best way to see when you're running into octane limitations. I'm pretty sure you can rig up a fail safe to the EGT gauge as well. So once it hits 950* you cut spark, or once it hits 875* you start water injection...you get the point.

AFR + EGT = WIN