Melting pistons.
- Thread starter McRat
- Start date
That is my point we have the best of both worlds IMOMy 05 is a work truck:hello: I dont want to spend money on hardparts and luckily I dont have to, One money pit is enough:baby:
Looking at the Thermal
Missing from this conversation is the amount of energy that is absorbed by the engine to make the crank go around. Very, Very important number. We call it efficiency and when we get it right, we convert ~30% of the thermal energy in the chamber to rotational. This directly affects how much Thermal energy the piston is exposed to and is what all the pulse width and timing exercises are about. Or at least should be.
Missing from this conversation is the amount of energy that is absorbed by the engine to make the crank go around. Very, Very important number. We call it efficiency and when we get it right, we convert ~30% of the thermal energy in the chamber to rotational. This directly affects how much Thermal energy the piston is exposed to and is what all the pulse width and timing exercises are about. Or at least should be.
This is a fantastic thread! Keep it coming!
Just my personal experiance. My truck when i first got it, had a BullyBogg PMT and cranked up it ran decent but was rattley and not very smooth or progressive VS now with 50% nozzles and Pats tow tune i tweaked a tad, much better. Its not quite as aggressive, kinda tame really but its better in all aspects. Even on a bone stock tune it runs pretty good. All this makes me feel warm inside about having the honed inj. exept the whole balance issues scares me a bit, but havent had any problems knock on wood, far as the nozzles go. I did have the PMT and 50% in at the same time for a short bit and also beat on it with 50/50 meth-water. Im curious as to see my slugs are eroded a bit.
Just my personal experiance. My truck when i first got it, had a BullyBogg PMT and cranked up it ran decent but was rattley and not very smooth or progressive VS now with 50% nozzles and Pats tow tune i tweaked a tad, much better. Its not quite as aggressive, kinda tame really but its better in all aspects. Even on a bone stock tune it runs pretty good. All this makes me feel warm inside about having the honed inj. exept the whole balance issues scares me a bit, but havent had any problems knock on wood, far as the nozzles go. I did have the PMT and 50% in at the same time for a short bit and also beat on it with 50/50 meth-water. Im curious as to see my slugs are eroded a bit.
I am not Pat but I can take a stab. Bigger injectors and higher pressures you can not shrink the pilot shot size enough IMHO. It starts firing like it is the main shot. I do not run pilot above 2000rpm for this reason anymore.
Chamber temps
If you fine folk are interested, I can plot the estimated chamber temperatures from some pressure plots I have. From those, we should be able to estimate thermal transfer over time and thus have a handle on how many BTUs are being dumped into the piston. Assuming a fixed area of even exposure and the piston is some fixed temperature itself. Nether of which is strictly true.
What we can't pull from the data is how well the piston is dumping the BTU's it is absorbing or the affect of hot spots on the surface of the piston.
But we can compare two timing/duration schemes to see which is "Hotter" than the other.
If you fine folk are interested, I can plot the estimated chamber temperatures from some pressure plots I have. From those, we should be able to estimate thermal transfer over time and thus have a handle on how many BTUs are being dumped into the piston. Assuming a fixed area of even exposure and the piston is some fixed temperature itself. Nether of which is strictly true.
What we can't pull from the data is how well the piston is dumping the BTU's it is absorbing or the affect of hot spots on the surface of the piston.
But we can compare two timing/duration schemes to see which is "Hotter" than the other.
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Here's what continues to confuse me:
On the original engine, the pistons did not melt, it was running 3400 msec, factory uncut pistons, 50 psig, no water, stock injectors, 1600 EGT's, and 3800 rpm. 750 rwhp.
Last engine I melted pistons on, was running 2400 msec, de-lipped pistons, 60 psig boost, water injection, 10% injectors, 1450 EGT's and 5200 rpm. 800+ rwhp.
About the pilot, so far, Casper has been racing with a LLY ECM, and I have always left the pilot off. On the dyno, turning on the pilot dropped HP.
On the original engine, the pistons did not melt, it was running 3400 msec, factory uncut pistons, 50 psig, no water, stock injectors, 1600 EGT's, and 3800 rpm. 750 rwhp.
Last engine I melted pistons on, was running 2400 msec, de-lipped pistons, 60 psig boost, water injection, 10% injectors, 1450 EGT's and 5200 rpm. 800+ rwhp.
About the pilot, so far, Casper has been racing with a LLY ECM, and I have always left the pilot off. On the dyno, turning on the pilot dropped HP.
What we are changing with the Bonneville engine is to cool the piston better with what is available. Lower water jacket temp, lower oil temp, more oil sprayed on piston, lower RPM.
I think that in the long run, we will need pistons that aren't aluminum to run the RPM we want. Heat makes power, so putting out the fire will limit the output.
I think that in the long run, we will need pistons that aren't aluminum to run the RPM we want. Heat makes power, so putting out the fire will limit the output.
Whats the chances of unburnt fuel or remnants of fuel being left in the cylinder at high rpm......?
My guess is FICM over heat cause actual timing and pulse to vary greatly from commanded. Just a W.A.G.
If you can read the little orange sticker on that truck.. It says Fleece Performance
To keep it on topic though, that truck has very large injectors and we try to keep the programming sane as far as PW goes.
Brayden
Brayden your nuts!!! i own that truck!!! its the NGM diesel truck.......
No orange fleece sticker ever was on it........are you trying to take credit for my work or just joking?
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I think that all of this information has enlightened us all on the possibilities in the engine failures. tuning on the 7.1 will change tuning techniques drastically IMO because of the longer piston stall @ TDC and the longer stroke.
it seems to me that duration affect's rail pressure,
Rail pressure affects timing, and they all directly/indirectly affect each other, just depends on the circumstances, piston bowl design, material, even compression hight affect piston cooling and performance, greatly.
this is why i went on a limb to build a piston and rod combo, with "out of the box" thinking,dont know if it will work better or worse but i can tell you that on paper and in front of well over 70+ years of racing expirence, it's well recieved. all i can do is hope for the best.
Bosch offers schooling classes that really help to better understand the CR fuel system, i have learned alot.:cool2:
it seems to me that duration affect's rail pressure,
Rail pressure affects timing, and they all directly/indirectly affect each other, just depends on the circumstances, piston bowl design, material, even compression hight affect piston cooling and performance, greatly.
this is why i went on a limb to build a piston and rod combo, with "out of the box" thinking,dont know if it will work better or worse but i can tell you that on paper and in front of well over 70+ years of racing expirence, it's well recieved. all i can do is hope for the best.
Bosch offers schooling classes that really help to better understand the CR fuel system, i have learned alot.:cool2:
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Odd, you don't sound 90 years old. Nor do I see many 1940's era Duramaxes around.
"Out of the box" means using parts the way you buy them. You might be thinking of the term "outside the box". Aluminum rods themselves aren't exactly new, even Summit carries them. Using them in a Duramax might be new, but maybe not. It's not exactly something someone would make public if they were using them. But if you ever do actually run them, you are welcome to post about it on a tech level here.
I'm not sure what your opinion on stroker tuning has to do with this topic, but you won't be doing sales pitches in this thread. Take that to another board.
This is why you get a bad rep on the diesel boards. You jump into a tech thread, and at first you act normal. Then you end up sounding like the ShamWow guy on TV. It irritates the readers, the vendors, and often wrecks the topic. It's not going to fly here.
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Someone mentioned pistons other than aluminum.....Well Mahle has the steel monotherms but iirc they are for cummins only At the same time, i know they are heavy so if we were to get steel slugs, at what kind of penalty will it sick on us?
We shouldnt be able to tear those up should we get them.
At the same time, i know they are heavy so if we were to get steel slugs, at what kind of penalty will it sick on us? We shouldnt be able to tear those up should we get them.
I would be interested in the results of this testing...it would definately give us some more data to pull from.
This thread is really informative and thought provoking.
Same timing I was running with the stock sticks. at 100mm 1800rpm 16* at 100mm 3400rpm 33.5* table B no pilot, no post
Someone mentioned pistons other than aluminum.....Well Mahle has the steel monotherms but iirc they are for cummins only
We shouldnt be able to tear those up should we get them.
first off this is a great thread keep it up but as pistons have always been a problem i have always thought the same thing as above or atleast maybe a two piece with a aluminum body and a steel or even better Inconel top keep things in check but i know nothing at all so this is just something that keeps jumping in my mind
pat your missunderstanding what i was trying to get across...
it was not a sales pitch, it was a illistraition of how i came to the new design's or innovations, and how it applies to tuning. i found that there is a issue that excists in these diesels and i have made a attemp to remidy the issue, that included making different pistons, wrist pins, ring packages, and many other improvements, to allow the use of full fueling and much higher RPM and HP.
tuning has a lot to do with it but i felt that hard parts needed attention that it has not yet gotten to make the best of the availible tuning, and to increase reliability and make more HP, at higher RPM than is now achievable.
You might want it to sound like a sales pitch, but pat, i have nothing for sale!
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