VVL seems very OP to me (costs vs benefits), compared to how common it is in real world application. Is this being addressed in the engine rework, or do engine manufacturers have no idea what they are doing?
It seems pretty realistic though, and donât forget, it is used quite a lot in real life, hint: VTEC=VVL, a lot of companies are running VVL, they just call it by some other fancier name (ex: BMW calls it Vanos)
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Well it really isnât that OP once you play more. Youâll gain like what 2-3-4-5 MPG for the price of alot more weight and inability to use 5 valves.
Besides some guy got 40 MPG out of a pushrod motor so itâs not like itâs completely impossible to get good economy without VVL.
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Toyota and Volkswagen, two of the biggest car manufacturers in the world, barely have any VVL engines, and have only committed to producing them since the late 00s. Surely they would have adopted the technology earlier if it was required to keep their engines competitive with VVL engines, like Hondaâs engines equipped with VTEC, that had been around almost two decades earlier.
I feel it could use a slight hand of âbalancingâ in the way of increasing development and/or production times a little more, and with a more significant reliability and maintenance cost hit.
As for the performance side; it is hard to judge if VVL is working as it should in game because we have only an arbitrary number for the cam profile; which accounts for not only the valveâs lift, but also duration. I donât know if VVL in game affects the whole cam profile, or just the lift; as it should in reality. I feel it is the former. I assume thatâll be rectified during the engine calculation overhaul though.
Iâd love to see a continuously variable valve lift system added to the game too; such as Nissanâs VVEL. (With an even greater development time penalty) The VTEC stigma of our current system is too much. 
@Leedar It also has to do with a companyâs school-of-thought. Honda always used highly-strung inline-4s producing around 100hp/L, but Toyota prefers to use a larger V6 engine to achieve similar performance. Nissan played around with VVL in the SR16VEs for a while, with amazing results, but ultimately dropped it for further engines until their VVEL system in the VQ37VHR debuted.
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As far as VVL being OP in the game, it lets you create very high specific output engines that are also smooth, economical, and have a high drivability near flat torque curve, but the cost to reliability and production expenses is relatively low (perhaps the engineering time cost is more significant than I appreciate?).
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Difference really isnât that big. If you tune it properly no VVL isnât much worse off, and significantly lighter.
@KA24DE Toyotaâs 2ZZ VVL engine is one of their most famous motors, while their V6s have been in exactly zero sports cars Lotus models aside. Honda hasnât used a highly strung Inline 4 since the F20C, the newer K series engines are significantly less highly strung.
I wasnât talking about sports cars, but yes; gone is the day of Hondaâs 100hp/L inline-4s. I keep forgetting that Iâm in 2017.
VVL is extremely OP, and for good reason - itâs just as OP in real life. Every modern automaker uses it. Iâm not sure what your source is but Toyota and VW absolutely use VVL in their engines, Toyota has VVTL-i and VW uses Audiâs Valvelift. See here: http://www.autozine.org/technical_school/engine/vvt_31.htm
Sure if you only care about making sports cars then VVL isnât a must (again, as in real life), but for just about any sort of regular econobox, VVL is an absolute necessity.
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Youâre implying I said they donât use VVL at all, which I never said. My point was that theyâve taken their sweet time adopting a technology some of their competitors adopted a long time ago, which seemingly did not give their competitors such a significant advantage, and that (perhaps until very recently) they only use the technology on select engines. Fiatâs MultiAir was first introduced in 2009, Toyotaâs Valvematic in 2008 (although they had a different VVL technology in a single engine back in 1999), VWâs Audi Valvelift in 2007, BMWâs Valvetronic in 2001, Porscheâs VarioCam Plus in 1999, Nissanâs Neo VVL in 1997. VTEC was introduced in 1989.
From what I can tell, more brand new cars today than not will not have an engine that uses VVL, but theyâre far more likely to use a turbo and VVT.
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Iâd suppose that the reason for the rather late adoption is that when VVL was first introduced in the 90s, gas prices were at record lows (after adjusting for inflation), so there was not a big push for economy. So you can probably figure out why VVL started coming into its own in the late 2000s!
I donât have exact numbers for you, but a quick google search tells me that around 30-40% of cars today are turbocharged. And of course, VVL and turbocharging are not mutually exclusive. My guess is that the percentage of total cars sold that donât use either VVL or turbo is something like 5%.
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For the record, here are the top 10 selling small cars in the US for 2016, VVL available as standard in bold or an optional engine in italics:
- Honda Civic (no VVL w/ upgrade turbo engine)
- Toyota Corolla
- Nissan Sentra
- Ford Focus (Ford doesnât have a VVL technology, AFAIK)
- Hyundai Elantra (Ditto Ford)
- Chevy Cruze
- Kia Soul
- VW Jetta
- Kia Forte
- Mazda3 (VVL on diesel engines)
As you can see, it is very uncommon, even in the âeconoboxâ primary segment.
Unless youâre building cars that are exceedingly realistic, I donât see why that should stop you from using it.
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That sounds off by an order of magnitude, at least for the US market. Iâd guess itâs closer to 50% here, and the bulk of that is due to turbos, not VVL. Chevy LS motors alone probably make up more than 5% of vehicle sales and have neither. Popular cars like the Toyota Camry have neither. I know Mercedes has a system called Camtronic, but Iâm not aware of any US market cars that use it. Even my FR-S doesnât have VVL despite making 100 hp per liter. Overall, itâs really not that common.
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Yeah, okay, looks like I was mistaken (and partially getting it confused with VVT). I know the difference between VVL and VVT but I kind of just assumed that most cars that have VVT also have VVL.
Hyundai actually has a CVVL system (which looks nearly identical to Nissanâs VVEL) but I donât know if itâs used in any vehicles: https://youtu.be/_Svr0eqR06U?t=2m55s
Anyway, going back to the original question, I think the difference is that many automakers now use variable intake manifolds, which basically do the same thing as VVL. However this is currently not implemented in Automation.
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What those two technologies do is vastly different. Variable valve lift allows for variances in how much intake charge can fill the cylinder. Variable intake manifolds allow an engine to exploit multiple resonance frequencies for better volumetric efficiency across a wider RPM range, as well as switching between a low volume runner to a high volume runner to keep intake velocities high at a wider range of engine speed.
I could be wrong, but I thought that variable intake manifolds actually died out by the new millennium, rather than gained more widespread use.
Sorry, I meant that in a more general sense, in that they both optimize intake airflow for different speeds. They both serve the same purpose, although of course they accomplish it in very different ways.
Iâm pretty sure that variable intakes are still being used, itâs in that Hyundai video I posted earlier and itâs also in the Camryâs engine: https://en.wikipedia.org/wiki/Toyota_AR_engine
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âŚwithout VVL. If you play more with VVL, then it becomes so OP that the only reason to not use it might be the strict weight saving. And 5 MPG difference for numbers around 40 is quite a lot. And in most cars that fancy interior will add a lot more weight than VVL, giving back far less.
And some others regularly get way over 40 with VVL and similar power, probably.
@KA24DE In some real engines VVL changes the whole cam profile, not only the lift. And continuous VVL would be so perfectâŚ
toyota GR v6âs power the evoras
but yes toyota did the 2zz with VVTi-L but they focus more on the timing and the intake control for the rest same as most manufacturers. Except for some in the lexus brand thereâs another system for some of them i think.
While the discussion here is informative, the original question is symptomatic of the common misframing the question based on the world of Automation: the design choices presented to you by Automation had to be discovered and engineered first, and Automation merely presents to you the most commonly used and most viable technologies. Also consider that individual companies patent their own technologies so while there are umbrellas of common technologies of which valvetrains are such, itâs not as if they open source and allow shortcuts of R&D because that would be bad for competition.
As mentioned before, the decision and motivation to pursue one technology over another depends on circumstance and, ultimately, whether a company deems it in line with their development goals and/or is it cost effective. Consider that it wasnât until the late noughties that we started being concerned about there being potentially limited reserves of oil in the world, and that it wasnât until well into this decade that weâre seeing true mainstream market proliferation of specific measures taken to maximise economy or minimise fossil fuel use (and even then this focus and its other concurrent environmental concerns are under active threat from certain administrations).
In short, your decisions as to which technologies youâll invest in will surely make more sense once the tycoon mode is better fleshed out, as opposed to throwing stuff together in the sandbox without real world reference.
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