Effects of intercooler sizes and non-intercooled setups on turbo engines

Here’s an example of a non-intercooled turbo engine, in reference to another thread about them (you can find it here):

I couldn’t pull this off in the Kee engine version of the game, because it would cause excessive knocking that would destroy the engine. Now, adjusting the intercooler size (or omitting it completely) simply adjusts the overall output - there is no change in efficiency, assuming everything else is unchanged. Why is this so?

Probably to allow players to create pre-intercooler turbo engines.

Especially since in real life, non-intercooled turbo engines were virtually the norm in 1975, and removing the limitations of such an engine in 4.2 make it easier to replicate them.

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Interesting you brought up the Kee version of the game! I generally didn’t try making non-intercooled engines then though I did occasionally. Now I’m not sure what you were pulling off exactly without the stats being shown but can see how with 1.2 Bar (17 psi?) of boast, it likely wouldn’t have been possible there for sure!

I agree with @Restomod’s conclusion of the reason for why it was changed.

Typically the only times I made a non-intercooled engine was if it was also carbureted as that kinda forced you to use low boast anyway due to the reliability penalty you’d get for having more than 10 psi of boast. However I also remember finding something like .3 Bar of boast back then being the limit before you needed to reduce your compression compared to when your engine was N/A, so I sometimes made even injected engines with super low boast like that which probably weren’t intercooled either.

Surprisingly (to me at least), the I3 non-intercooled Turbo I made in another thread as it turns out actually makes LESS power with an intercooler, 4 hp to be exact and the game only allows 0.3:1 more compression, though that is 5% more compression given it was only 6.0:1 lol!

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I had a different purpose originally for these screenshots, but, maybe they’re still worth sharing.

Last of those first three is probably the only relevant to anything lol! Showing the huge drop off in performance when using a way too small intercooler compared to none (2nd row of stats) (Same engine aforementioned).

I did also test how much more compression it’d let me get away with given the spare octane (which is why there’s the blue notification) and it turns out quite a lot! A full extra 1.0:1 upto 7.0:1! Still not worth though lol!

Here showing a correct size and doubled size intercooler, doubled size only allowed 0.2:1 more compression, less than correct sized, odd isn't it? It kept making more power and torque upto a quadrupled size intercooler, but I'd say doubled is where it stopped being worthwhile as the gains beyond that were super tiny above it, only up to 148.5 hp, 0.3 more.
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