I need tips on how to make a car wiht high MPG because everytime I try it ends up at max 18 MPG. Need help!

The fuel economy for my cars has generally never been a strong point for me either…

There are the simple techniques, such as making your engine run maximum lean fuel mixture, and making your exhaust smaller, to including an “Overdrive” gear, where you select a 5 speed transmission for example, but make the fourth gear max out at the top speed.


Here’s a sample car I made for a different thread, it has about 40mpg and made to compete with the European ford focus.

You just gotta mess around with tuning. Compression, bore/stroke, cam profile, turbo settings (if you’re using one), A/F mixture, timing, exhaust type/size, all have an effect on MPG. Higher compression/timings and lower cam/fuel/exhaust will all help raise MPG. Turbos can destroy MPG if you do it wrong, but I sure can’t help with those things. Keep fuel lower than 13.9-ish, keep cam below 60 (25-ish is just about ideal for MPG on most engines), keep timing above 50, and go with higher compression ratios. Keep the exhaust tuned for the engine output. Better airflow usually equals better efficiency, up to a point. Same for intakes. Flatter torque curves generally give better efficiency too. If you keep efficiency above 25% and don’t put hamster wheels in barges, you should be seeing 25-30 mpg easily. Negating top gear by pushing it above top speed is a good trick for the numbers game, but won’t really help if you’re looking to do a challenge like BRC, though.

I still think that carbs are massively nerfed/broken on MPGs, a well tuned Ford 300 from the 60s-80s with a single barrel could get well into the 20s (even in the trucks), in game the single barrels never get more than the low teens, you need to put a 2bbl or 4bbl on to get better efficiency.

I agree. It isn’t likely to get 40+ mpg from a carb setup (but not really impossible either), but 20+ should certainly be doable with regularity on a variety of engines using single or double barrel carbs.