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Efficient Performance - The Engine Design Challenge

Wow. I suck at maxing the efficiency quotient. I was able to get 37%, but the performance sucked, so I’m only reaching turbo scores of 120 or so. Guess that’s what I get for using the turbo solely for performance applications!

That said I do enjoy building eco hypercars, but they do require a fair bit of tech pool, especially on injectors.

Spent about an hour on this one.
Score = 154.196

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Yo, isn’t your AKI rating too high? It’s max 95RON!

I was getting a 108 aprox with a turbo mOHV v8

I rated higher in a 7.3 v12 twin turbo but I believe I discovered that large engines are still at a disadvantage in this challenge

Well, I think V engines are at a disadvantage due to their high frictional losses. I’m not sure but when I build V engines they either perform poorly at low rpm (hurting economy) or at high rpm (hurting power). It’s harder for me to get the nice torque curves I get with inlines.

Curse the different measurements, scored dropped a little.

149.06

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Wow! That’s really impressive! Care to share any special tips? (I want this challenge to be as much about learning and sharing knowledge as it is about showing off :smiley: )

Another take, this time a 1.6L

Score: 90.1
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Looks like you’re knocking in that screenshot - some further tweaks to ignition, compression and cam timing should make it even better!

Sure, I’ll give this a shot!

A naturally-aspirated engine good for a score of 91.507.

Not good at teaching, but you have to find the proper balance of compression, ignition timing and boost along with getting the cam value right to match the low end power and vvl for high end. Also make sure the engine is over square to keep piston speed down to keep reliability at a decent number. Also, use cast iron heads and block. I6 also seems to be the most efficient way of making power with hilarious fuel economy. I could get an I4 to around 140 points but no higher.

I have also found that short stroke (oversquare) engines give the best score. However, realistically speaking, a 1.6L oversquare takes up as much total volume as a 2.0L square. The 2.0L square gets both better performance and efficiency, but gets a lower score because of its greater displacement. But if I were picking an engine to put into a car, I’d take the 2.0L. So I’m considering changing the rules again to account for total volume instead of displacement - this would tip the balance towards long stroke, which would be counter-balanced by the reliability factor. I think this would give some advantage to I4s and Vs, right? Plus give a reason to not use DOHC. Thoughts?

Its difficult just to have a simple formula to calculate this as the 2.0 might get better fuel economy on paper, but may get worse fuel economy in an actual car(according to in game calculations). Such as an example for my Leopard Hatchback, the base 200 hp non turbo version gets the same fuel economy rating as the turbo 300 hp one which has a much lower economy rating in the engine tab. The best way to do it, in my opinion would be to make a a series of cars and have people design an engine for each one. So for example:

fwd city car ~2500lbs
rwd 4 door ~3500lbs
suv ~5000lbs

Allow each person to add their own engine and modify the gearing to match the engine.

Or to forgo all of that, i would just change the liters to weight in kgs.

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=“phale”]

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 :slight_smile:

Once the open beta releases i think the factory tab will have the cost per engine, including the factory options of course. Could use that.

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.

EDIT: Here’s my one take

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 normally don’t ever double post anywhere less there’s no real option for a post to be noticed.

Either that or I’m too impatient, something I’m doing wrong (including breathing)…

But I got to making a few more engines, a turboed version of the AJ6, a smaller i4 and a larger i6.

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 …

Which is infantile and insecure but screw it…

The point here isn’t necessarily to get the highest number, but to learn how to design efficient and powerful engines :wink:

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?

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