Knocking!

[test]

Im bad at engines but this is ridiculous.
I tried everything but every single engine I create has 100% knocking.
Than I try to fix knocking. Every single engine I create has less than 5hp. I mean literally 5 hp or is has 100% knocking if I tweak something to make it more powerfull.
sandbox mode how to make engines any tutorial for noobs or something?
p.s. I want to create cheap car so I don't like to use expensive fuel. There should be other way

[Prasiatko]

There should be a tutorial on knocking on the default branch. But what you want is your RON value to be below that of your chosen fuel type. If it's knocking then you the easiest way to get rid of it is to reduce compression.

[Killrob]

Indeed there are pretty good engine design tutorials (a series of ~20 scenarios that go into every aspect) in the default branch. Play those and you'll be fine :)

[HorseMeat]

If you're using the super low octane fuel, there's only so much you're going to get. If you want big power you're going to need big displacement.

Tips:

1) Especially on Low Quality fuel start with the absolute minimum of Advance and Compression, and go as low as you can on the Mixture without running too rich. You can dial up up all three to get better economy after you get the engine running in the first place. Increasing compression has the largest effecet on octane requirements, followed by Mixture, followed by Advance. My advice is to start by leaning the mixture, then advancing timing, THEN increasing Compression. It is very unlikley your engine will run high advance, compression and Stoic mixture while running low quality fuel.

2) Make sure your exhaust is not choking the engine to death. A little bit of restriction is ok and helps with economy (at the expense of power) but you'll notice that too tight of an exhaust will increase your Octane requirements.

3) If you are using carburetors, use more of them or use the same amount with more barrels. This reduces octane necessity. As more modern fuel injection becomes available this also lowers octane requirements (with Direct Injection current the lowest).

4) Check your pistons! Certain ones have higher octane requirements than others and you don't find out until you switch (it literally says nowhere that one kind of piston requires more octane than another)

5) If you are building cars on the cheap, skip over turbos entirely. The extra work it takes to get them working with low grade fuel is very difficult. Add more cylinders and displacement instead.

6) Quality sliders can have a huge effect on Octane requirements (especially negative sliders) make sure you are using an appropriate setting.

7) Be realistic. You're not going to get big performance out of any engine running low quality fuel. Expect at best, 50 HP per L of displacement for a well tuned motor on low quality fuel. That's just how it is.

All this aside, it CAN be done. In a CSR a while back we had to make Eastern Bloc cars that ran on low quality fuel. I was able to extract 74 hp out of a 1.7L I3 with fuel injecction, in the 90's. Less cylinders and bigger displacement helps and keeps costs down. ALSO Try using a longer stroke and a smaller bore. Big bore motors need more octane. You will have a lower revving engine as a result, but you will also have more wiggle room on the valves for valve float as they are smaller. This will also shorten development time a little and improve thermal efficiency.

Hope this wall of text helps.

[ErisNoRNG_RacingVTuberTTVfbYT]

Originally posted by BMax:

In a CSR a while back we had to make Eastern Bloc cars that ran on low quality fuel.

Which CSR was that?

[Doc Maccinakloutos]

recipe for low octane in layman terms:

small bore
long stroke (aka undersquare engine, let's say up to 1.5x the bore, above that it just wont run right)
set compression to 6
set cam timing between 15 and 20
mount a mid tier fuel system (point injection or two barrel, i've found 'eco' carb setups quite finicky unless you have a very small engine)
set mixture to 13 to 12.7
set advance to minimum
drop rpm limit to 4K (cam timing will float the ♥♥♥♥ out of the valves otherwise)
no catalytic converter. pointless in most cases due to ♥♥♥♥ mixture.
set exshaust bigger than necessary
then adjust the exshaust between .80 and .98
push the cam a bit, then the compression, then the advance.

you should be able to reach about 40 to 60hp/L

[Soilaf]

Try putting compression down to 0, and if that doesn't work, try fiddling with the RPM a bit.
That's how I do it, though knocking only happens about 1/6th of the time.

[Boudewijn]

Originally posted by GrandMarshal:

Try putting compression down to 0, and if that doesn't work, try fiddling with the RPM a bit.
That's how I do it, though knocking only happens about 1/6th of the time.

You are over half a year too late

[Soilaf]

OH CMON!