I like that idea! There are some very interesting balance decisions to be made there (VVL vs. no VVL, NA vs. Air/Air turbo vs. Water/Air turbo, exhaust size, etc). It would definitely require a different ruleset, I don’t want everyone choosing titanium conrods just to save a few kgs…
I want to keep this simple and restricted to engines, but it does look like a full competition with cars would be more realistic and accurate. I liked Packbat’s engine competition so a modern 2016 version of that would be pretty cool. I’ll think about it.[/quote]
Then add a cost component to the calculation. I could try to help with the calcs if need be, i run a review thread in the car design sharing forum. viewtopic.php?f=41&t=10029
Right - but I would have to differentiate material costs and production costs, and by the time I put all of those into an overly-complicated equation it would be simpler to just do the full car. I would like to do a car competition, but that would require a lot of effort and organization, haha. The idea behind this was to keep things simple
I’m going to see if I can give this a shot.
Been working on two pushrod 5l motors of different scales on bore and stroke. …Well 3 of them. One with a maximum emphasis on bore, keeping stroke at a minimum while again aiming for being economical. The 2nd being the AJ5 motor from that engine supply challenge, and finally a new one with a nearly squared bore x stroke.
I’ll show em once I can make them as efficent as I can with an N/A V8, which has been… a lot of trial and error.
I thought about bringing up the other two but maybe another time. This is…the best I can do for right now.
I’m sure someonecould get 10% more out of this easy but maybe not. But I’m a bit proud of my V8, Dubed the Weiler AJ6 motor series. It wasn’t easy getting these results.
I could probably keep going since I’m sure someone has far higher numbers. I’m almost tempted to keep going more out of spite than seeking a challenge …
The point here isn’t necessarily to get the highest number, but to learn how to design efficient and powerful engines
Here’s a tip for you: When designing turbos, you actually want them to be red in the airflow diagram. This is because turbos, by design, capture the energy of the airflow to make power. Check out this thread for videos on how to tune turbochargers: My Video Guide Series on How to Tune and Optimize an Engine
By the way, I had another idea - how about a Car Shopping Round for engines? The round master could start by specifying a certain displacement or total volume and certain requirements. For example, I might say, design a 1965 3.5L V8 DAOHC with a carburetor, and I put special emphasis on efficiency. I would choose a winner and he/she would become the next round master and choose different requirements and judging criteria. Engines are quicker to design than cars so the rounds could be much quicker or each round could have more submissions. This way there would be a little bit of subjectivity which I think is better than just splitting hairs over the numbers. What do you think?
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!
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.
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.
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.
