HP & TQ gains through fuel lubrication

What about Scheid race fuel? I'm pretty sure they use lots of Stanadyne in it. Wondering if anyone has used it and seen any gains.
 
I still add a bit of 2 stroke oil to mine but don't spend the cash on the high dollar additives much... Diesel Klean every now and again..

Never notices gains or losses... But wasn't testing for it either.
 
Lucas always got me 1mpg every time I used it. Nothing else ever did that.
 
I was talking to a guy today that adds about 10% mix of waste engine oil to his fuel. Runs it through a 1 micron filter first..... Says it picked him up 2 mpg on his 4BT chevy......
 
There's no "burn" efficiency to be gained from an additive. Diesel is incredibly efficient at combusting completely...look up the number, but it's 99% roughly.

Cetane of over 55 offers basically nothing to the regular guy, as above that mark it is diminishing returns. High cetane offers reduced ignition delay, and thus tighter control over combustion phasing, if you can take advantage of that. Most don't have the instrumentation necessary to tune via in-cylinder pressure and combustion data...and thus won't be able to realize any benefit from the synthetic 60+ cetane fuel.

--Eric
 
Is that what soot is? Completely burned diesel?
Any increase in the cetane in pump fuel is good. It will help combustion efficiency. Because America does have the crappiest diesel of any country out there.
Now you are correct in the high cetane numbers most people can't use. That's why syndiesel and the like are used by folks who are set up enough to take advantage of it, that and they want the consistency of such a fuel..
 
You can have a higher combustion efficiency through additives, its just a matter if this or that even provides a cleaner burn cycle when 'its' used. I am speaking of through fuel lubrication itself. The less we have as far as flow-friction of our fuel, the easier it is on not only the fuel system but you aren't struggling to produce a proper fuel to air ratio when you want to get to the bare bones of a top notch balls out performance engine.

If friction became higher as our system pressures or injector pressures became higher, wouldn't you employ the lubrication additive too? Its cheap power, may not be alot, but when its the piece of the puzzle that puts you over the finish line or farther than the other guy's pull, I think its worth it.

This all leads to the lowering of what you can call shear-stress of the fluid caused by the fuel system wall. The flow in the center of the duct we can call it will be the fastest and least amount of friction as you moved towards the wall, you see lower fluid speeds do to increasing friction between molecules, at the wall you have the most friction and lowest speed going through. Draw two lines and write the letter D and you have the basic picture of fluid flow in a pipe or gallery or whatever you choose to name it.

EDITR: Think about your frictional losses in the injector nozzle tip that could possibly be effecting your spray quality with the pressures in use.
 
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Is that what soot is? Completely burned diesel?
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Come on, you know the answer to that. Heavy soot formation isn't because of inefficiency of combusting lowly 42 cetane ULSD...maybe it has something to do with lambda? Do you think cetane has a huge effect on stoichiometry?

This all leads to the lowering of what you can call shear-stress of the fluid caused by the fuel system wall. The flow in the center of the duct we can call it will be the fastest and least amount of friction as you moved towards the wall, you see lower fluid speeds do to increasing friction between molecules, at the wall you have the most friction and lowest speed going through. Draw two lines and write the letter D and you have the basic picture of fluid flow in a pipe or gallery or whatever you choose to name it.

EDITR: Think about your frictional losses in the injector nozzle tip that could possibly be effecting your spray quality with the pressures in use.
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It's been a few years since I've had computational fluid dynamics, but yes I understand a little about fluid flow. If friction is truly what is limiting your flow, you should think about increasing the line diameter...that has a much greater effect than shear stress between molecules. Do you think that there is an additive that will change kinematic viscosity enough to make an appreciable difference in pressure drop?

It's not really flow velocity that you should be concerned about. Frictional losses (pressure drop) goes up quickly with increasing fluid velocity. Increasing line diameter increases mass flow while lowering velocity. Isn't that what you're after?

Do you have any evidence to say that "friction" of the fuel is limiting flow at 2000 bar + through the nozzle?

--Eric
 
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mikmaze said:
The red fuel has not had the sulfer removed yet, find yourself a closed course and run a tank of red, and see what mpg gains you have. The list of lubricants tested that showed bio as a great additive also tested ashless 2 stroke oil, it placed 7th in the test for lubricity, however, they tested at 1/2 oz per gallon, where most of us that run it, use 1 oz per gallon.
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I've been running 2strok for years in my box truck with a CAT. And i'll i can say is that there is a bit of a tick if i don't use the oil compared to when I do on my 03.5 dodge
 
Using the incorrect cetane rated fuel will create a inefficient burn plain and simple. Inefficient meaning our burn cycle is incomplete entailing excess carbon buildup and hydrocarbons. With everyone using the number 1 or 2, we don;t have to really dwell on this unless operating parameters are off for some odd reason.

Stoich may be stoich throughout the combustion chamber as far as fuel to air quantities, but once our injection begins and fuel propagates from the spray direction, spray strength, spray angle and in-cylinder mixture motion etc, this does no constitute a completely homogenous situation like theory says. Our burn begins where the most favorable air/fuel ratio is and is also dictated by the evaporation rate of our injected fuel droplet.

If removing the sulfur content enough for emissions effects mileage and wear, I believe its a big enough concern for a high performance application thats all. Thats, just my opinion. If I were to decide on a larger tube, it would be because of the simple fact of increasing my amount of fuel delivery to the pump. I am sure the amount of friction in the tip is nominal, I wasn't pointing out the possibly limiting of flow through the tips but the overall quality of the spray once everything has come full circle, albeit, friction has a hand in it through the entire fuel system. No, I have nothing to provide as far 'evidence', it was merely a thought provoking post.

Testing the tips with differently design fuels in relation to fuels with additives only adds to nozzle design and fuel engineering IMO.

I just bring up things most leave behind :ylsuper:
 
I just bring up things most leave behind
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I commend you for that! I love being provoked to think outside the box :)

That being said, I don't think there is any performance benefit to be realized from lowering the friction of diesel fuel.

Higher Cetane diesel does/will/can provide benefit. However, we've tested cetane effects on engine efficiency, and there is no measureable benefit above 55...and hardly any benefit above 52. The only way you can utilize a synthetic 60 cetane fuel to its potential, is to have accurate in-cylinder combustion data and tune things to the ragged edge of combustion stability/pressure rise rate/peak pressure/etc. Then, and only then, will a 60+ cetane fuel benefit you, by minimizing the variation in ignition delay that could be experienced with lower cetane fuels.

Flow enhancers, fuel magnets, aligning fuel molecules, blah blah blah, will not do anything for burn efficiency.

Even a low (40) cetane fuel still has a very high burn efficiency when it lights...it's just prone to more variation on when it lights, sometimes making it more difficult to optimize brake thermal efficiency.

Do you have access to the SAE library? If so, look up SAE Paper 2012-01-0863. It's a paper that we submitted earlier this year that gives a good characterization of fuels from 41 - 56 cetane, along with several Bio blends.

--Eric
 
ENafziger said:
I commend you for that! I love being provoked to think outside the box :)

That being said, I don't think there is any performance benefit to be realized from lowering the friction of diesel fuel.

Higher Cetane diesel does/will/can provide benefit. However, we've tested cetane effects on engine efficiency, and there is no measureable benefit above 55...and hardly any benefit above 52. The only way you can utilize a synthetic 60 cetane fuel to its potential, is to have accurate in-cylinder combustion data and tune things to the ragged edge of combustion stability/pressure rise rate/peak pressure/etc. Then, and only then, will a 60+ cetane fuel benefit you, by minimizing the variation in ignition delay that could be experienced with lower cetane fuels.

Flow enhancers, fuel magnets, aligning fuel molecules, blah blah blah, will not do anything for burn efficiency.

Even a low (40) cetane fuel still has a very high burn efficiency when it lights...it's just prone to more variation on when it lights, sometimes making it more difficult to optimize brake thermal efficiency.

Do you have access to the SAE library? If so, look up SAE Paper 2012-01-0863. It's a paper that we submitted earlier this year that gives a good characterization of fuels from 41 - 56 cetane, along with several Bio blends.

--Eric
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Well I'll be! Cool sandbox you got there.

A really nasty copyright watermark is keeping me from posting a couple of graphs but.....

I noted a pretty significant spread in the rate of heat release between D3 and D5 and the different bioblends. Interesting data no question.
 
biodiesel kills the seals inside my fuel pressure sender. Not sure about how dilute with #2 it was, but Ive gone through two of them =(
 
Well I'll be! Cool sandbox you got there.

A really nasty copyright watermark is keeping me from posting a couple of graphs but.....

I noted a pretty significant spread in the rate of heat release between D3 and D5 and the different bioblends. Interesting data no question.
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Maybe I can post the graphs without the watermark here when I get a chance.

Yes, there is quite a spread in heat release. The lower cetane fuels have a lot higher initial heat release during the pre-mixed combustion event due to better vaporization (more of the charge lights off at once). For that reason, it's actually preferable to use a lower cetane fuel in some advanced combustion modes where you're looking for a sharp initial heat release. Bio blends have an advantage in the diffusion burn period, as they tend to not vaporize as readily.

The sharp heat release of lower cetane fuels can sometimes be heard, as the heat release spike causes noticeably louder combustion.

Give me a day or two heads up if you're ever coming to the Knoxville area, and I'll give you a tour of the engine labs...

biodiesel kills the seals inside my fuel pressure sender. Not sure about how dilute with #2 it was, but Ive gone through two of them =(
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Bio ate the seal out of my Isspro fuel pressure isolator too.

--Eric
 
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Pretty interesting, I lit some fires under some. Some day I will fork out some money for the SAE stuff after I get all my current literature read first. I will keep the SAE paper number in my notes for my combustion literature.

Perhaps this should be re-initiated into a "burning rates" thread for Diesel fuel hmmmmm beautiful.

Thanks for the insight guys!
 
ENafziger said:
Maybe I can post the graphs without the watermark here when I get a chance.

Yes, there is quite a spread in heat release. The lower cetane fuels have a lot higher initial heat release during the pre-mixed combustion event due to better vaporization (more of the charge lights off at once). For that reason, it's actually preferable to use a lower cetane fuel in some advanced combustion modes where you're looking for a sharp initial heat release. Bio blends have an advantage in the diffusion burn period, as they tend to not vaporize as readily.

The sharp heat release of lower cetane fuels can sometimes be heard, as the heat release spike causes noticeably louder combustion.

Give me a day or two heads up if you're ever coming to the Knoxville area, and I'll give you a tour of the engine labs...



Bio ate the seal out of my Isspro fuel pressure isolator too.

--Eric
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I see the watermark is just at top of the pages with my name.....so i just took the graph....

If limited to only taking a couple these two are pretty good,

Cetaneandrateofheatrelease.jpg
 
Cummins forum had something like this. They had a chart optilube was at the top but was made up of all solvents. So don't see how it scored so high when it's eating the fuel system. The number one was bio.
 
Good posts, Eric - thanks for keeping the physics-challenged on track. :Cheer:
 
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