Competition Compression

[HVAC]

EGT

Christian, while testing some mean injectors at DD years ago we noticed something different. We laid a rag over the chrome tip on the full system stock exhaust. Then a pipe was used to direct the ex out the back of the shop from there. We did a couple pulls on the dyno when we noticed smoke. Kinda alarmed us . It turned out that the rag we laid over my chrome tip was trying to catch fire! Now that's EGT's.



Your right, pistons hold up no problem. But the cracks in the head are evidence to the heat. Of course we don't usually run as much Nos as you ya "Squeezehead" !:-laf :-laf

 

[Sled Puller]

Yea, that is a pretty tough question.



Big power and low egt, eh? Thats fine if you can get it.



Who do you know that is doing that?



I agree, extreme egt will hurt things eventually, and I wouldn't tow a trailer up a mountain with a pyro buried.





But, these engines will take extreme egt, for short periods, over and over.



Yes, it has risks, but winners take risks.

 

[HVAC]

Sleddy

I can't wait to drag race with ya



BTW, I've been taking risks since the 24v motor showed up.

 

[CRoth - BD-Power]

Re: Yuk It Up!

Originally posted by HVAC

I thought I was pretty studly with those high egt's. Not so. Do what you will, but big power and lower egts is where it's at.



Christian, where you still running that twin system that produced 600* discharge temps?

Actually, we were pushing the street twins (Enterprise's) way beyond what they were designed to do. But I'm sorry to disappoint you that our discharge temperatures were in the low 400° range.



There's is no doubt big power and low EGTs are were its at, if your under fueled



No seriously though, for the typical street trucks there is no doubt that high temperatures will kill an engine.



"Sometimes a little extra fuel, is good for the engine. " quote from Dave Mitchell.

 

[HoleshotHolset]

Are we talking about 400° post the second turbo?



If so... Why is everyone so amazed at that? The temperature delta across a single turbo is at least 300°... . so if you run your 900° exhaust through another 300+° heat sink (turbo)..... your EGTs post secondary (or primary... . depending on how you visualize things) would naturally be significantly less.



Low EGT's just means that you need more fuel... .



Matt

 

[Sled Puller]

Originally posted by HoleshotHolset

.



Low EGT's just means that you need more fuel... .



Matt

:--)

After 2465 posts, Matt finally got something right... ... . Oo.

 

[Sled Puller]

Uh-oh... ... ...



http://www.diesel-central.com/forums/thread.asp?ForumID=33&TopicID=818

 

[HVAC]

Brian's Getting Me Back

For ribbing him on the DHRA slogan topic.

 

[83 crew cab]

as far as the marine pistions I had a set in hand for the lil red's eng and sent them back I could not justify the $950 cummins wants for them

 

[Amianthus]

Re: Sleddy

Originally posted by HVAC

... BTW, I've been taking risks since the 24v motor showed up.

And I've been helping him pay for those risks ever since '99.

 

[R.E. Miller]

Re: Re: 1800*

Originally posted by CRoth - BD-Power



If your talking EGTs, 1800° is for sissy's how about 2050°. Last year at 300 ft mark in the quarter we had already surpassed 1600° with 75psi and the squeeeeeeeze. HVAC your right the head doesn't like it, but no cracks, and pistons are still beautiful. :

Ok, I know how tough the bottom ends are on these engines, and generally, they can take a lot more abuse then most before acting up and becoming a boat ancor. I would just like to know how an aluminum piston can withstand and observed EGT at the exhaust manifold over 1300*F for longer then 5 seconds without liquid pistons. I know that there is some fudge in these readings, but for guys that can creep into the 1500+ range, how? And I am asking this keeping in mind that very, very few of these people would have any piston or combustion chamber coating.



I work on cummins diesels everyday, and see melted pistons in everyday vehicles (not often, and not for just any reason) and just have to wonder. Thanks for the info,

Russell

 

[83 crew cab]

I am assume that it becouse the flame is not directed at one spot and not in the cylinder for very long how long does it take to melt aluminum with a 1500 degree torch and you get some cooling evertime the intake valve opens

 

[CRoth - BD-Power]

Piston crown termperatures are different than EGTs.

 

[Diesel Freak]

Pure aluminum melts at 1220F



I need more fuel!

 

[therabbittree]

well part of it is the carbon coating the pistons get on the top of them just from running the engine, and the oxidized top layer of aluminum under the carbon also helps. . the different alloys of aluminum could come into play. also are the pistons cast or forged?. . also oil cooling will help... oil cooled in the crown or oil squirted on the bottom or no oil squirter etc these all come into play in helping deal with egts

remember when mig or tig welding aluminum how if you don't really carefully clean the surface of the aluminum, you can actually melt the aluminum under the surface, and as the top layer that is oxidized finally melts at a much higher temp then the aluminum under it, then you have a big molten mess to deal with. same idea with the aluminum in the pistons. If your pistons literally melted at 1200 degress... a lot of people would be up a certain creek without a paddle

ha

i think the problem with pistons swelling from being a heatsink and scoring the piston skirts and cylinder walls would be more of a problem at those high temps?. . any one have any experience with that in the cummins? or cracked ring lands?... i know of a few turned up big cam 3 and 4 engines that cracked the piston ring lands when turned up alot . . and these were built with pittsburgh parts etc. . how do the b series hold up there? oh and Mahle also makes marine cummins 370 diamond b pistons. .

well just throwing out some ideas. . ha

later have a good weekend

deo

\x/ hillfolk!