I can't get my truck over 1400F with the mods in my signature. If you want to know more about the htb2 sledpuller here is there site www.htturbo.com. I'd say that's impressive with 150hp edm's and a drag comp at 5000ft elevation!

 

1700? Man that's hot. I know trucks that hit 2000 in the quarter but for 10 secs , what does it matter? A fool can burn up anything. If you're using the truck everyday, then use the foot as the controller. It won't get that hot if you use your head. Jeff's truck at 70 mph will sit at 650. On the floor with the water/meth on, not even 1400.

I guess I just don't understand.

.. Preston..

 

turbo thom I consider proper cooling at full load and all boxes etc turned up, and if you still can get over 1400 then you need more air ie bigger turbo or twins, who would want to run thier engine to 2000 degrees unless they like rebuilding expensive engines, even brief bursts will hurt over a period of time. My truck turned to 5x5 and the big nozzles will run at 650 down the higway too, but there is little load and the skinny pedal ain't on the floor, tell Jeff to turn up the boxes and put in it high gear with no boost and hammer it to the trucks governed point I bet he'll pull out for Egt's way before the truck governs out.

I guess I don't understand your point?

Joefarmer has one of the badest trucks on here watch the dyno run with the gauges he doesn't even hit 1200 degrees with 600rwhp or so, that is proper cooling, not running huge fuel with little turbo way past there effective horsepower range, if thats the csae my orginal HX35 would probably keep the egt'sunder 2000 also.

J

 

I think what Preston is trying to say is it all depends on who's driving.

If he can run his truck flat out, the way HE drives it, and it cools to his liking, then that is fine.

Same with anyone else. dodgeman01 on the board is happy with insane EGT's while sledpulling with his stock charger so he can stay in the stock class. It just depends on what YOU are comfortable with.

Me, I'm barely at 300 hp (guesstimate) and my EGT's are out of control already, Pyro's pegged at 80 mph. SO, I just bought a B2 and plan on building a set of twins that will cool anything I can afford to throw at the truck for a long time.

My $.02
Chris

 

1700 is hot, my truck just creeps up to 1400 with my current mods, and i think i might need to get the ATS soon.....

 

Now I see what you're gettin at. The trucks I'm talking about are 12V's. No boxes to turn up and petal to the metal he does. The only difference is the maturity level seems to be a little higher here. If the idea is the destroy the truck, that's easy enough. What we do is upgrade the truck and dyno. Change things and dyno.
And as far as 1700 hurting the truck in burst, we've done it 4 years on the same engine. Best run so far is 9.97 at 138 in the quarter. I really don't think these engines are as tender as you think.

End of story.

..Preston..

 

I hope that wasn't directed that you are more mature than the rest of us that run at cummins recommendations for egt values. I am thinking you are meaning guys that run high temps because of ignorance.

 

Guys, guys, guys.. remember what we are talking about here. Its EGTs and that is ALL THEY ARE... EGTs.... This is so beaten to death on here....

Listen.....Not all EGTs are created equal....

Want to do a little experiment.... set your timing way retarded, go out on the highway for a ride, floor it in 6th gear.... You’ll have your 1,700°F EGT and then some, with not much more than stock fueling and guess what? You wont hurt anything put possibly the exhaust valves or turbine and probably not even that.... This is because you are burning your fuel late and its still burning when the exhaust valve opens and it continues to burn in the manifold and turbine housing... Thus crazy high EGTs are measured in the manifold, but the pistons don’t see that heat or care about it. They are expanding gasses that never got very hot in the first place because the peak pressure is down and the combustion is not being completed as rapidly as the piston is dropping, and furthermore the pistons are being cooled with oil and contact with a relatively cool cylinder wall.

Now, put the timing back where it should be, do the same thing with lots of fuel on a hot day, and a less than adequate cooling system and really hot oil and gues what, you could melt a piston easy with EGT's of 1,200....


In the first case, the EGT’s may be 1,700°F but the peak combustion temperature is could be as low as 2,000° and mean piston top surface temp could be only 700°F.

In the second case, EGT’s may be 1,200°F but peak combustion temperature could in fact be as high as 3,000°F and mean piston top surface temp could be right at the 1,100° melting point for aluminum.


Furthermore, TIME is probably the most important part of the enemy.... So Preston pulls 1,700° for 9 seconds... How much of that heat actually gets driven into his pistons??? Not much at all. And that’s why he is correct and he's fine. Now take Billy Bob and Velma pullin their horses to the farm show, with the go peddle on the floormat for 10 minutes straight pulling Devils Hill grade in 6th gear with the EGTs at 1,200° on a hot summer day with the oil at 350°F and coolant at 250°F. Guess who's pistons are closer to the melting point, Preston’s or Billy Bob’s...



This has been nagging me for years as I listen to EGTs beat to death on this forum. There is WAY more to engine damage than EGTs. In my opinion, this is the single most misunderstood techincal aspect discussed on this forum.... The talk of "turbos" that 'cool' better than others.... Do any of you actually realize why more boost is 'cooling' your EGTs???? Its cuz its increasing your excess air, lowering your adiabatic flame temperature and REDUCING YOUR POWER AND EFFICIENCY !!!!!.

I am gonna really stirr it up now and make some people upset.....

If your timing is right, and you cant see 1,300°F EGT with the go peddle smashed ..THAN YOU ARE WASTING HORESPOWER PUSHING UNNECCESARY AMOUNTS OF AIR THROUGH YOUR ENGINE. Either add more fuel or LOOSE some boost, because you are INEFFECIENT and you are down on power.


Kevin

 

kevin that was a well writen article, can you try to explain the manifold temp vs piston temp over I can't get my head around that part (if it is 1700 on the probe why wouldn't it be 1700 on a valve I can see a piston being lower with oil etc, maybe a better question is what is the first part that will take heat damage usually. lastly if what your saying is true why would we need twins for say a 500 hp or even 600 rwhp rig? I find this info very intersting since nobody has ever put it this way.... that I have read. Everyone I have ever talked to talks of Egt over 1400 hurting and some are very knowledgable guys that sell alot of products on these sites, on the other hand most of the article I understood..... your post makes sense when I think about it

I guess if this new info is the way it reads, I was wrong, however I still am going to keep it under 1400 for sanity reasons, If I melt this thing the wife will beat me and the kids are eating Kraft dinner

J

 

I'm still crackin' up about "Billy Bob and Velma"

 

Hey, dont get me wrong, I am not advocating extended runs at 1,400°F or anything. I was just trying to explain how EGTs are an indicator of the temperature in the exhaust manifold, nothing more nothing less. That being said, with everything else correct like timing, oil temp, coolant temp, it does happen to be an excellent indicator of the heat being generated within the cylinders and how close you are to disaster..

The reason you need twins for comfortable 500+ HP, is that the amount of air required for proper combustion, plus about 20% or more excess air, requires a very large single charger. The lag associated with that charger is excessive. Plus with one charger, even a good one, when the Pressure ratio exceeds 3.5 it really starts to heat the intake charge, which is of course detremental to keeping your pistons from melting. Twin turbos compounded, each with a 2.2 pressure ratio, puts you at a very cool 50 Psi and with quick spoolup if they are set up right...


Plus the overall effeciency of the engine is higher with twins, because remember what a turbocharger is... it is a heat recovery device.... It recovers the wasted energy in the engine exhaust and performs a usefull function with it.... With two turbines, the amount of heat recoeverd from the exhaust and put to work is higher than with one large single... In our case the usefull function is the building of intake charge boost. In large marine diesels and large diesel generator sets, there is sometimes a turbo without the compressor.... There is essentially a turbine wheel and housing which is piped to engine exhaust just like ours, only it doesnt drive a compressor, it actually is geared down and phsyically connected to the engine crankshaft to deliver mechanical horsepower to the crank....



Kevin

 

I run a s-300 with non w/g 18.5 hsg. Egt's are pegged when its to the floor at 52lbs. But it cools down alot faster after a run. Talk about lag I havent dynoed with this turbo yet but id guess its around 500rwhp compared to my last dyno with the stock charger on. i ll know for sure in a couple weeks when i get on the dyno again.
carty