EGT---what is too high??
 

My truck that I recently purchased (pictured below) has had some fuel pump tuning and timing advance done to it and runs pretty strong. Like pretty damn strong. I have purchased an egt gauge that I will be putting on it but I was wondering, what is really too high?

For my truck I will not be doing any serious towing or going up any serious grades. Mainly straight line acceleration for relatively short bursts (maybe 2nd gear, 3rd gear , and shut down in 4th). For these short times, what is reasonable??

I am relatively new to the diesel performance world and appreciate any help.

I am very new as well, SO TAKE WITH A GRAIN OF SALT haha but.. I happen to know that most of your question has to deal with whether or not you are going to place your probe pre or post turbo.. and these figures may be off, and im sure someone will steer us both in the right direction if they are.. but 900 (Pre-turbo) is getting up there as far as danger zone which is roughly equivalent to 600 (Post-turbo).. But, thats just overly cautious me, I hear of guys that get scared around 1200 but I wouldn't recommend this since aluminum melts around 1300.. However, if thats all the work you plan to put her through I don't think you'll even get close to those temperatures.. Again, I could be very wrong.. lol Hope I helped more than hurt haha :tu:

Sweet looking truck! :tu: Single cab duallys are my favourite. :jump: Great looking Ramcharger too dude! :c:

So, to answer the question, 1250° is considered the maximum sustained temperature you should run at. That's a pre-turbo temp too, as DRC referred to. But doing short runs, (like a quarter mile :rocking:), I've heard of 1600° and more being achieved, to no harm. That was Jason Sands with his Project Rust Bucket, and he pulled his head afterwards and found no damage.
However, I will in no way be held accountable if you try that and it cooks your engine! I personally wouldn't recommend it, and wouldn't do it to my engine, but if you feel the need...
Several things need to pointed out. i) When you drill the hole for the probe, make sure it's on either side of the centreline of the manifold. Say, 3/4 to the left. The manifold is divided down the centre, and you won't get a reading, if you can even get the probe in! Some folks also run the engine when drilling to blow any metal out. You'll need to take your turbo off first though.
And ii) with regards the temperatures, the actual temperature inside the cylinder gets much hotter than whatever your pyro is reading. Just the air being compressed gets to around 750°, then add some fuel in there for the bang, and you're looking at cylinder temps of 3000°, (with a 'standard' tune) give or take a few. So, while Al. melts at 1300° or so, it's a bit misleading taking that at face value. The more advanced your timing is, the higher your cylinder temps will be, even though your pyro will say you're running cooler. This is because the fuel spends a longer time in the cylinder being burned. So, be careful adjusting your timing. Of course, there are guys running HUGE timing, but mostly they're not using the truck as a DD.
Hope this helped. :s: Have fun and enjoy the truck! :c:

I agree with KD93, try to keep the EGT's below 1250*, but short bursts to higher temperatures are ok as lon as they are less than 30 seconds. You need to remember that this is your engine and you are the one that has to pay for any damage, not anyone else.

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In this pic, you can see both pre and post turbo EGT probe locations. The difference in readings is anywhere between 300* and 500*.




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This pic is of a '93 D250 where I placed he EGT probe. Make sure to mark the manifold into quarters and drill in the back quarter, this is where you will have the hottest EGT's.

Others will chime in.

thanks a lot for the info, I am still learning about all this stuff as it pertains to diesels. I believe I have a good handle on it, but I am always willing to learn.

Crazy how egt works with diesels vs gas. You almost have to think in reverse with respect to controlling airflow with gas vs fuel flow with diesels. It's a whole new world.

From what little I understand about gasoline engines, (and diesels for that matter :s:!!) they're about like chalk and cheese. i.e. almost total opposites. The more air you can cram into a diesel, the better.... to a point! :w2:

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And thanks stodg73 for the fine pics! :c:

My truck would blow by 1600* on a 0-80mph run for about a year before i finally got the EGT's under control, no harm done,

i have seen over 2,000* on some pulling trucks but thats insane.

a good rule to live by is no higher than 12-1300* for a sustained time.
on short bursts like a 1/4 mile run it all depends on how big your ba!!s are.
its better for your engine if you can keep them down below 1200*.:tu:

Dar

Well I pretty much want to build this thing for acceleration under short burst, quarter mile would be the maximum length/time it would see sustained max fuel conditions so no more than 15 seconds.

As for the ba!!s part, we will see. I have the stock turbo on it so I guess all I can hope for is that it takes the turbo out first!

It will.....but it mite blow part of your turbo in your cylinders. :pca1:

if you don't go gigantic with your injectors you will be able to cool it with other mods. :tu:

STODG73:

What do you mean by divide the manifold into quarters and drill in the back quarter? From the pic I can see where you mounted it but I don't understand the description.

Are you talking about distance from the head mounting flange back towards the turbo?