Specifically cast, hypereutectic cast, and low friction cast. Many modern engines use the latter two and can rev above 6000RPM, but in the game you need a quality setting above 9 to get them to work without issues and that seems unrealistic. It’s worse in under square engines, but again many i4s are under square and use such piston types. I’m sorry if this has been raised before, and didn’t find it with a piston search. Can we make the limit for these types between 6 and 7 thousand RPM that’s half the game limit, at least at a quality below 9?
Also Hypereutectic can also be called AlSi Cast it seems.
Just a note: in another test build of my own car’s engine (F23A1) with 86mm x 97mm using hyper cast pistons requires a quality setting of 13 for them to rev to 6300 RPM (the actual redline.) This is for a 2002-built engine. I’m sure the actual car has at least similar cast or even low-friction cast pistons.
In college I took apart a Toyota 2AZ-FE (2.4 litre) engine and was surprised to find a low-friction coating on the pistons. This engine has a red-line limit of 6500RPM and is also under-square (88.5mm x 96mm.)
I don’t know if it is deliberate or not, but you left out talking about for what bore and stroke values your concerns apply. That is rather vital information, as well as being more precise with real world data: which cars / engines and at what bore & stroke use these pistons at what revs?
Thanks for the edit to put the numbers in, that helps.
I also would say there is nothing wrong here, it is more skewed expectations. How come you assume that the very best engines that were built at that time in production cars are at zero tech-pool? These engines have at least +10 tech pool for what they did, and then probably a bit more quality on top of that. I tested that now and turns out exactly the way we want it: you’re right at the edge of getting MTBF reductions due to the high RPM, but nothing severe.
[quote=“Killrob”]Thanks for the edit to put the numbers in, that helps.
I also would say there is nothing wrong here, it is more skewed expectations. How come you assume that the very best engines that were built at that time in production cars are at zero tech-pool? These engines have at least +10 tech pool for what they did, and then probably a bit more quality on top of that. I tested that now and turns out exactly the way we want it: you’re right at the edge of getting MTBF reductions due to the high RPM, but nothing severe. [/quote]
The F23A1 engine for my car 98-02 has a bore and stroke of 86x97 which is only 0.886 under-square and has a relatively low max RPM of 6300. I’m not certain it uses low-friction coatings on the pistons, but from the sounds of the build I don’t see why not, or at least the AlSi (hyper)cast pistons. Generally I find that the non-high-strength pistons can barely rev to 6000. Now I agree that Honda engines are probably above 0, but 2002 which is the last year for that engine requires a 13 / 15 to not have any issues. I assumed 15 is for only the most premium engine makes (like AMG, Ferrari, Porsche, etc.)
Also, perhaps MTBF needs to be better explained. IMO a car with a part that is reducing longevity because it’s beyond the limits of its performance is a poorly made engine.
MTBF is “Mean Time Between Failures” and essentially means the PREDICTED time between failures. Note, this doesn’t necessarily mean entire engines falling apart, it’s just small parts failing in some cases. These can also theoretically be avoided with regular maintenance.
It’s basically just a more accurate form of displaying reliability than giving it a score.
In the current closed beta of the upcoming update we’ve already switched from MTBF to a plain reliability stat MTBF, for most people, is a concept unnecessarily hard to grasp. That doesn’t change anything though we just divide the MTBF in km by 1000. So 35400 km is a reliability stat of 35.4
Not necessarily, Ferrari & Co would probably be around +10-12 as well, but use the forged components instead. Don’t forget that this is a game, the parts you can select need to make sense from a gameplay point of view, if you can build just about everything with cast / standard stuff there is no reason to have any options there, which deprives the game of the need to make good decisions. While it is not 100% realistic and there are many real-life options missing, that is not our goal either
I totally agree with you here, KillRob. Its not Automation Simulator. I think the way its currently done, with the diversity and the pistons addressing a different issue, like Max Torque, Emissions, fuel efficiency and such, is a good way to handle the different options.