84.1x90mm bore/stroke, lambda=1 at all times, 1.5-2k more rpms than current gen, 120kw @ 7.2k rpm and 165kw @ 7.6k rpm respectively
not the most responsive NA engines but still
Both options would be viable in real life, although a heavy aluminum/silicon block would have a higher safe power density threshold.
selected al/si light for weight savings tbh but yes that would be true
TBH those weight savings are very minor, but then also the impact of the power density limit is pretty minor too.
Those are some really loud engines. Have you tested them in some car for emissions compliance? Because I’ve bumped against that several times when trying to make modern high performance N/A engines.
that sound level is with high flow CC and straight thru muffler, so yes it could be done a little more quieter
havent put engines in a car yet but will do
For a hardcore track-focused variant, the high-flow 3-way catalytic converter + single or dual straight-through muffler setup actually makes a lot of sense. Lesser, more road-focused trims should have a regular 3-way catalytic converter and at least one reverse-flow muffler, though.
I have now changed it to 2 reverse flow mufflers but I also want to ask you guys something
so this is the new flow graph of the 3 cyl, which is now 1.2L because I wanted to actually try and increase valve flow which was around 50-55% on both engines with 84x90 bore/stroke
now for 3 cyl I have changed it to 72.4x96.8 b/s which is very undersquare
up until now I didnt really care about valve flow, always tried to match E-H-M flow on either 100% or sometimes lower for more power on turbo engines, for now I know that lowering the EHM flow moves the torque to higher rpm
but my question is does the valve flow really matter, is it influenced by just borexstroke or anything else? also if its important, roughly where should I aim for road engines or race engines
Flow - of every kind! - should be your guide, not your target.
Don’t worry about how much flow you have, because the game never judges you directly on it and others usually don’t either. Flow gets filtered through to other stats, and those are what matters. Tweak the values and see where that leads to the other stats and the curve. Sometimes, choking the engine off will allow you to hit 100% at a lower threshold, boosting scavenging and hence torque - 110% flow can be a good way to trade some high-end to get better low-end. Other times, providing spare flow will allow you to use resonance or shift the rev range up higher, boosting power and such.
The best flow number is “whatever makes sense for your car”.
As a further aside, based on your torque graph and your loudness with reverse mufflers - is that a perf intake? I’d consider using standard mid. It might choke flow a little bit at high RPMs, but the benefits to loudness (and hence comfort) and reliability are pretty worthwhile. It also frequently adds torque down low, helping for acceleration which is good for the whole “slow car fast” vibe.
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