New Valve Train

[pkoko]

Can we have V-Tec or VVT? DOHC isn't the latest and greatest valvetrain setup even in the past decade

[Eric.B]

V-Tec and VVT are improvements on DOHC and SOHC. They are not completely their own style of valve systems, they just work off existing DOHC and SOHC systems. In the case of VVT, the cam just moves forward or back in relation to the crankshafts. Thus adjusting the timing and giving you late or early intake.

V-Tec generally comes in either SOHC V-Tec or DOHC V-Tec. VVT is generally implemented with DOHC as it's difficult to do correctly with a SOHC.

They're both mainly used to adjust timing. By delaying valve opening or closing in existing DOHC or SOHC systems.

Anyhoo, these are all abstracted with the technology sliders in the game. However, if you want to implement them as a stand alone valve types, you're more than welcome to, using the mod tools: http://wiki.gearcity.info/doku.php?id=modtools:componentseditor#valves

[Jacob Longwell]

It seems from my game play, with the relatively low cost of valve systems it’s never needed to use anything other than DOHC. (unless you have a special engine like rotary) is that the way it really goes in real life?

[Eric.B]

Originally posted by Jacob Longwell:

It seems from my game play, with the relatively low cost of valve systems it’s never needed to use anything other than DOHC. (unless you have a special engine like rotary) is that the way it really goes in real life?

Most modern vehicles use SOHC and DOHC exclusively. With some timing tweaks like VVT to improve fuel economy. In the past, OHV were extremely common, there are a few holdovers using OHV still. (I valve in the game.) Like GM.

The main thing is lubrication. In an OHC engine you have to work the oil up to the top of engine. In an OHV you don't, since the cam is down by the crankcase. Unfortunately I didn't work in a way to adjust reliability of sub-components. So I couldn't make OHC's unreliable at the start of the game and make them more reliable toward the end. Perhaps someone would be interested in modding something like that in. Much like how I did turbos.

[Eric.B]

I forgot to mention RPMs as well. OHV doesn't handle high RPMs well, which is why almost all smaller engines have moved to SOHC/DOHC. Mechanisms for how this is handled in game aren't added either. Both would be a good idea for an expansion though.

[stevo]

In my opinion this is one of the major drawbacks of the whole game - the evolution of the valve trains. Basically, there is no incentive whatsoever towards using anything else than the latest and best valve train. And this is very, very far from reality.

The easiest way to fix it would be to tweak the cost of different valve trains - e.g. in 1900 all of them (2 stroke, L and T) differ by just ONE DOLLAR, regardless of the cost of the whole engine. There should be a significant difference, to justify the worse performance of the less sophisticated systems, and, also, reduced reliability of every new technology.

(apart of that I do not like the total absence of fuel systems and brake systems, but we discussed it earlier on - it's just that I really miss them ;-) )

P.S. Once again - kudos for the game in general!! One of the best games I've ever seen!!

[Eric.B]

All of this stuff is easily moddable, including adding in brake systems and fuel systems (they just wouldn't be separate from suspension and fuel type respectively). So if you don't like how I implemented it in the game, fix it! :)

The problem is different valve systems don't cost a whole lot different. So to make them wildly priced different would break the realism as well. The major difference in valve systems is performance, reliability, fuel economy, and emissions. The later is not implemented in the game but would be the great equalizer.

That being said, most of this tech all died pretty early, 2-Stroke, L, and T, are all no longer used in automobiles. They all eventually lost to I-head (OHV). 2-Stroke due to emissions, L in the 1950s due to ford finally dropping it because OHV was more efficient, and T in the 1920s because it just wasn't any good.

Essentially everything other than OHV and the OHC were experimental attempts at trying to make something better than OHV and OHC. They all failed. Anything after DOHC, isn't a new valvetrain, it's a modification for timing systems, for example V-Tec is just an extra rocker arm between the valves that will occasionally hold the valves open longer. Thus allowing the engine to run engine lean or rich depending on RPMs. It's not a new valve type. It's a timing adjuster.

But again, it's a couple clicks in the mod tools to add it in. :) Perhaps after I make some mod tool tutorial videos someone will add it and distribute it.

[stevo]

Thanks for the reply ans sorry for the delay,

I agree that today no one uses anything but OHC/DOHC, but earlier on this was not the case. Side valve engines were standard till the IIWW, and OHV were common at least till the 70s, despite OHC being available already before WWI. There were reasons for that and they are not reflected at all in the game.

I am Polish and I know the story of one of the most important cars in the humble history of our own car industry - the Polski Fiat 125p. It was a licence version of the Fiat 125, but with the older mechanical components of the Fiats 1300/1500 (including the OHV engine of Aurelio Lampredi). The main reason here was that the modern DOHC engine of the 125 was considered too complex for the Polish factory, the mechanics and their equipment. The same strategy was used in Argentina, where Fiat used to sell the 125, but later on replaced it with the Polish version - because in Latin America, just like in Poland, it was better suited to the local conditions, for many reasons.

Also the 2 stroke engines were popular in some periods, mostly the 1950s. In the game the post-war poverty and the demand for very simple, cheap means of basic transportation is not reflected at all, and 2-stroke is never a good option, in any period. I love the wide choice of technology that the game offers, but a large portion of it is useless.

P.S. Yes, I am willing to learn a bit about modding and try to propose my own vision, but it can take some time, since I mostly write blog articles after work, with little time left for gaming. I am also not an IT guy at all and I cannot create any artwork - is it obligatory in modding?

[Eric.B]

Originally posted by stevo:

I agree that today no one uses anything but OHC/DOHC, but earlier on this was not the case. Side valve engines were standard till the IIWW, and OHV were common at least till the 70s. There were reasons for that and they are not reflected at all in the game.

Reread what I wrote, that's pretty much what I said. T's died by WW1, L's died in the 1950s after Ford gave up on them, and OHV is still around today. The game does not simulate how well the valves work based on RPM, nor does it have a system where I can gradually improve component's stats (other than skill requirements). It's all in the post I made in this thread. :)

OHC is overpowered in the early game, but I have the option to make them either overpowered early in the game or extremely under powered in the later stages of the game. Code to make gradual changes to components will not be added to the game unless we can fund an expansion.

Also the 2 stroke engines were popular in some periods, mostly the 1950s. In the game the post-war poverty and the demand for very simple, cheap means of basic transportation is not reflected at all, and 2-stroke is never a good option, in any period. I love the wide choice of technology that the game offers, but a large portion of it is useless.

Again, this already pretty much says what I said. 2-Stroke had to be nerfed in the game because it was too powerful. It was too powerful because the game lacks emissions. Emissions requirements is a major reason why 2-Stroke died.

I am also not an IT guy at all and I cannot create any artwork - is it obligatory in modding?

You just need to convert image file to .dds and make sure the resolution is a power of 2. The quality is up to you. It's your mod. :) (Note, you are responsible for any copyright violations, so use public domain work or make it yourself.)