Efficiency, calculated, FINALLY

[ISX]

I'm still working on all this so it's a mess but you can see some things amidst it haha. On the very right hand side (injection crap) the first column is my truck and the second column is variables if my truck had 50% efficiency. Bigger engines are pulling off 50-60% efficiency...so its not impossible! Now the issues I'm running into is I have no way of knowing the HP of my truck based on mpg and other things. Just because I get XX mpg doesn't tell me anything as to how much power it takes to go 60mph even if I stayed at that speed the entire time. You might think it sounds easy enough if I used BTU content but I have no clue knowing how efficient the engine is at that time (how much of this BTU is being thrown out of the radiator...) I have to use the data plate information to get an efficiency and all of my calculations are based on THAT efficiency. So my 25mpg at 60mph is based on 33.4% efficiency, which means it is using 40.52HP. However, 12 valves are completely static so it is wrong to assume it is 33.4% at every RPM/load, but I have no other way to measure it unless I was on a dyno ANDDDD measured fuel rate at the same time. You MUST have both. The fuel BTU/lb is also an assumption based on what I found on the internet, different fuels have different BTU contents so theoretically the fuel you use should be tested as well. This all sucks because obviously a guy getting 20mpg and 25mpg with identical trucks is going to have different efficiencies, but I would need the HP as well. I have no clue how the scangauge measures HP but until I find out (from one of you if you know) then I will be very weary of it's accuracy. This is too big for the forum so you guys will have to click on it. http://www.mopar1973man.com/isx97/Efficiency/Efficiency1.jpg

[AH64ID]

The Scan Gauge computes HP based on fuel burn. From what I have read it's pretty accurate, for flywheel power and not rear wheel power. But there must be some conversion factor. Turbo engines are more efficient than NA. I wish I could get all the data for my CR as I can for the QSB 480, but I'll use the QSB 480 data. (I think I am really close to the same total power as the QSB 480 anyhow). Okay, so a gallon of #2 diesel contains 139,200 BTU's. Each hp is equivalent to 2546.098 BTU's. So a QSB 480 which makes 472 bhp is producing 1,201,758 BTU's. The burn rate is 25.7 gal/hr or 3,577,440. For a total efficiency of 33.6%, not too bad. So now using the same math let's look at a QSK50, 50L of marine fury! 1800 bhp burning 91.5 gal/hr, for an efficiency rating of 34.7%. What's interesting on that motor is that it makes 1800 hp from 1700-1900 rpm. The above rating is at 1900 rpms, but at 1700 rpms its 48% efficient! Now that is crazy.

[ISX]

My brother has a DTA360 also has an old 7.3 IDI turbod engine. I ran the numbers on the data plate.

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Scratch that, didn't put it on 8 cylinders. Here we go.

[*]7.3 IDI -- 29.1%

[*]DTA 360 -- 26.8%

[ISX]

Me and Mike are playing with this, figured you guys could if you wanted to as well. Basically you can only edit the blue. Read all the inscriptions and you'll know what to do. Everything ties into each other so it's kinda hard but I put plenty of errorproofing in it. Let me know if something doesn't work.

Efficiency.xlsx

[CUMMINSDIESELPWR]

my brain just exploded. lol

[Mopar1973Man]

ISX and myself have been playing with manifold temps and weather conditions looking at more angles. Heck when I got off the phone last night we burned better than 2 hours of phone time hashing out different theories. Figure out a web base calculator is wrong that we found.

[ISX]

ISX and myself have been playing with manifold temps and weather conditions looking at more angles. Heck when I got off the phone last night we burned better than 2 hours of phone time hashing out different theories. Figure out a web base calculator is wrong that we found.

I think it's right This thing I found might be using intercooler efficiency rather than turbo efficiency. I'll go through it today, was just looking at the pictures last night.

[Mopar1973Man]

It might be... :rolleyes:But like I told you lets get some measurements ourselves on a Dodge...

[ISX]

This is pretty interesting. This book I have doesn't get ungodly specific on what all the variables in the formulas are but this site does so I will turn it all into a spreadsheet to make it easy. Then maybe we can all be turbo experts http://www.gnttype.org/techarea/turbo/turboflow.html Here's the excel format. All of those blue things are variables and they are cumulative meaning you have to fill them in from the top to the bottom. As you go down, it uses all the previous ones.

Turbo Stuff.xls

[ISX]

Alright I added the excel to the last post. Under the corrected flow section, that info is listed on the compressor map. At the top of this one you see "Corrected to 85F and 14.425psi"..that is what you need for that section. All turbo maps use different standards.

[ISX]

Alright I cleaned that piece of crap up so here's the updated one. Make sure you have something in every blue field that isn't optional. I haven't added any error stuff to it so it will probably still give you an answer if one of them is blank. There is a drop down list under the corrected mass header, you can see the units there. All of these charts use different units so you can just click the one you are using and it converts it over to it. Be sure to look at that on charts as I screwed up yesterday while I was looking at that chart on here. The top line on the chart above uses one unit and the bottom line uses another, so yeah it can be tricky :moon:I am going to add something really fancyyy to it soon. But until then here you go.

Turbo Stuff 2.xls

[ISX]

And a video explaining it. Crap, when I say the variable turbos are big I mean common...not big in size.

[AH64ID]

What are you using to determine volumetric efficiency?

[ISX]

What are you using to determine volumetric efficiency?

Well if you flip a coin just right...

That site didn't mention anything about it so I just kept using their 85%. I'm going to make something very fancy to give a an actual table and then you can see where the turbo would be the best. I already made one really crappy one (no variables, and I colored it myself...) which I will post on here for something to come. Excel can do it alllll automatically, I just spent most of the time I had yesterday on reorganizing that original piece of crap.

But I will definitely look into what I can find for calculations on it, unless you already have an idea.

So here's whats to come. Because this is always just ONE scenario, it seemed best to vary boost. I mean I pull our trailer at 70mph in 5th gear and I never let it gain or drop a mph, so only boost changes as far as the compressor is concerned. But I will add a drop down so you guys can pick what you want to change.

The blue is the inner most efficient circle range and the green is the next circle out. That was on the HX30. Seems HX35 stuff is hard to find (a holset one anyways, not these homemade things).

[AH64ID]

From what I have been told it's in the low 90's, but the cam really has a big effect on that. Like with my truck, I increased airflow and decreased boost. What does that mean? Higher VE with the cam, and again higher with the turbo. Boost is just a measure of resistance, lower the resistance and increase VE and flow for the same boost.

[ISX]

From what I have been told it's in the low 90's, but the cam really has a big effect on that. Like with my truck, I increased airflow and decreased boost. What does that mean? Higher VE with the cam, and again higher with the turbo. Boost is just a measure of resistance, lower the resistance and increase VE and flow for the same boost.

Yeah the flow rate you get is basically everything according to that guys site. The "mass". And if you put in a colder temp for incoming air you can run a lot less boost and still get the same mass flow. So boost and temperature go hand in hand. But I also see where VE goes in as well since it is pointless if it's not even getting in the engine. One of these books shows the effects of scavenging and it mentioned something about it being harder to calculate so they just used an engine with no valve overlap. So I have no idea what the VE really is. I do know how much the valves open but I don't know any of their dimensions so I can't determine flow rate and all that other stuff. I have all that variable so you can change it if you know it. I guess I can change it to 90% and save it there since I think everyone is going to ignore that value as being something they don't know so maybe 90% is a better standard. But I have no idea and I don't like values I just see around forums because of the constant contradictions I see everywhere. If I can calculate it then ok but aside from a huge publication (though dieselpowermag is wrong a lot too), then I kinda get weary these days.