Economical engine for a family car

[xwing]

I tried to make a viable engine for family cars with good economy and reasonable price. I went for naturally aspirated and not very demanding engines for manufacturing (no forge works, CNC shop, no turbos...). Fuel requirements are 95 octane unleaded, pretty much standard fuel where I live, premiums are 98 and 100 octane and you couldnt find 91 octane even if you tried (and the last time I saw it the price difference was negligible). What are your opinions?

The first engine is meant for small family cars (Renault Megane, Kia Ceed, Skoda Octavia...) - 80kW is more than enough, and more importantly torque comes from low rpm, has great reliability and the efficiency is around 40%. Not sure about the costs, how they compare to real life engines, I tried to make 1.4L engine from my car and without any quality adjustments it was about half as cheap... maybe this could be a better alternative to relatively unreliable expensive turbo diesels?

2L 80kW eco engine.png (1.94 MiB) Viewed 2415 times

2.0L 20V DI EcoRev2.lua

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The second one is a small but cheap and efficient engine for small cars (Renault Twingo, Kia Picanto, Skoda Fabia...) - 45kW is not much, but gets the job done, and with 38% efficiency it should allow for a nice small cheap car with a very good mileage.

1L 45kW eco engine.png (1.85 MiB) Viewed 2415 times

I tried them for my Hyundai Accent (2007 model) analog, a cca 1150kg car with 1.4L engine (100km/h in 12,4s and 6,5L/100km real life, in-game analog was pretty close with 11,5s and 6,2L/100km, couldnt tune the engine for the exact specs). My 2.0L engine returned 100km/h in 10.9s and 4,3L/100km and 1.0L returned 100km/h in 15.9s and 3,86L/100km, not too bad I think compared to what the car companies are selling currently

[Pleb]

I think you have a bit of room to turn up the rpm limit, this will increase the usable power band and it shouldn't hurt MTBF too much. Other than that, a darn good engine.

[Dragawn]

1st engine requires quite a lot of time to make, and the 2nd engine has high servicing costs for your target audience, and both really are on the bottom of amount of minimum power, but you got a good torque curve, and well done on the efficiency!

Edit: phenomenal mtbf on the first engine too!

[xwing]

First engine was designed as low revving with torque coming from low rpm as an alternative to diesels. When I up the rpm limit to 5000 I gain just 3kW but MTBF drops by 20 000km... its low bore high stroke to keep costs down, and as I said no advanced materials to make it easy to manufacture anywhere

How are the service costs calculated? I dont think there is any reason service costs should be so high, but that can be my business model - sell the car cheap and make money on service, like with printers