The best NA I can do w/o building a new engine. Rating 85.26561059
You could do that yeah, it’d also encourage a more active market on engines which is just a little lacking right now.
No fancy vvl here, just a little high revving v8
161.5*[.2964^1.5]*[74.7^0.5]/2.414 = total score of 93.3067
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Here is my 1 hour build:
The Schack IFB 20DLT Eco Engine
Score : 127.0 x 0.3123^1.5 x 76.1^0.5 / 1.999 = 96.726
I4TW!!
I’m glad to see that this is getting some attention again 
I’d like to announce that I will no longer be updating the leaderboards. This is not because I’m lazy (OK, maybe a little) but because I’ve discovered that engine efficiency and car efficiency are not perfectly related, so a less efficient engine may actually result in a more efficient car. So while it’s good in general to strive to build engines that are powerful and efficient, it may actually be counterproductive to try to squeeze out every last drop of efficiency in hopes of getting a higher score.
This thread will remain a place to post your efficient and powerful engines, kind of like those 3000hp threads but actually meaningful 
I’m glad to see that most of you are doing this already, imposing limits on yourself and designing engines that are unique and still very efficient. Keep 'em coming guys! 
I’d also like to encourage you to put your engines up for download if you want. By sharing your designs we can help each other improve, and I may do a review on some engines that I find interesting!
For reference, my engines are available for download in this thread: Inline Designs - open source engines and consulting
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i… wait…
- i thought you knew that before you made this challenge
- didn’t i posted here before anyway that the priority when making efficient is cars lower weight> higher engine efficiency?
but it’s still a good practice to make a good effective engine
Not really, I didn’t know how big a difference there could be. Obviously weight is important but I always thought of that as something to worry about outside the engine designer. Even among engines of similar weight, a less efficient engine can sometimes get better mpg (even with identical gearing).
For example, increasing compressor size usually reduces engine efficiency while adding weight in the process. But sometimes a larger compressor gets better mpg, even though the engine is less efficient.
How hard does the engine have to work? There’s a reason why you won’t see an 18-wheeler driven by a tiny four-cylinder. Even if you could get the required output with modern technology, the stress from the extra workload would kill that engine in short order.
as requested here is my engine in a sporty MR 2 seater, the styling is pretty basic as this was just a proof of concept, uses workshop mods.
Edited with the proper pictures.
.nialloftara - efficent prototype.zip (92.1 KB)
but i found that unless it’s something modern like 2008 and forth.
going turbo just doesn’t give enough efficiency boost to justify the cost and reliability penalty.
and even then, turbo engines are super tricky to work around with.
i’ll try and make a comparison car later today
edit: i lied. didn’t have the time
It worked for me in 1982
I do agree to some extent, turbos really come into their own when paired with VVL in 1992 which allows for some really impressive efficiency and power, although that makes them even harder to tune, lol.
The VVL VVT part is easy at least. Just crank the VVT to lowest economy. Then crank the VVL to maximum performance index. You can figure out the turbo part (depending on what AR ratio you need to run), and then rerun the VVT and VVL values one more time.
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why is that blue 
Red green color blind setting.
I saw this challenge and decided to see what I could do, so I chose my 280ci V8 just to see what that would do.
I plugged the numbers into the calculator and got a score of 63.5, from the 4.6L dubbed the 280 Challenge
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Here we have a cheeky el natu-ral, 2 litre V12, which produces 196(hp) stallions, and comes in with a mighty fine score of:
142.5 x (0.2931^1.5) x (71^0.5) / 1.997 = 95.4
I don’t have my original engine I posted in this thread before, so I built another instead of retuning the one I had.
