It would be nice to see the option of rod length in the engine builder since rod to stroke ratio can have a decent effect on engine dynamics. For example you could have 2 engines that are identical except one has very short rods, the short rod’ed engine would just run out of steam on the top end while the long rod engine would be able to keep on chugging up there. Just a thought of something to add.
I dont think it is needed and also think it wont be included. you have bore/stroke and compression you can play around with already. It would be to much information for people with not alot of experience with engines, its just recently that i even got it 
I know that in reality its quite important, but for our use, long stroke-short stroke is enough!
And the stroke bore ratio already impacts the max rpm… (if im not mistaken)
Well, the total amount of stroke does, the more stroke the faster the piston has to travel at a given RPM, and there is a limit to how fast your pistons can go before something breaks 
Yes that. I didnt figure you guys would be able to add it the more I think about it. Not many, if any, engine models include.
isnt it the length of the rods that determines the stroke anyways?
for example… longer connection rods = longer stroke
and shorter connection rods = shorter stroke
and here is a similar question when adjusting stroke in the engine designer isnt that basically making the connection rods longer ?
No the stroke is determined by the crankshaft throw ( the distance between the axis off where the con-rods connects and the axis of the crankshaft)
Yup
And longer stroke typically means shorter rods. Because stroke + rod length + piston height (distance between the wrist pin and the top of the piston) need to be equal to or less than the deck height of the engine (distance between center of the crank and the top of the block). Well unless you have the weirdest designed head ever that actually has room for the piston to go into the head. Also increasing rod length does not increase compression.
i see
let me write you a story (please bear with me… 
)
rod ratio really has nothing to do with stroke length. it might be necessary to change rod ratio due to a long stroke (to get more of the lower, rotating end of the rod out of the bore for clearance) but rod ratio is basically a number dependent on the manufactured deck height and wrist pin height, considering stroke as a constant for a sec.
placing a feature in-game to alter deck height (cylinder deck to crank CL) AND compression height (wrist pin CL to piston crown; general “piston size”) would both be effective tools for adjusting rod ratio, which could always just be a stat that gets pumped out by the simulating side of the game. obviously using different pistons would require that the deck height be reset to maintain a previously set stroke length. let me list a few supporting reasons for adjustable deck height/rod ratio:
[ul]]the ability to specify a short rod engine would be intensely beneficial in short-stroke, high-RPM engines. this would increase the amount of available peak torque due to a better relationship between rod and crank throw as power is delivered through the “levers” that are these two items./:m]
]being able to adjust this ratio ultimately determines how much mechanical stress the engine sees through each impulse of power, and will logically work for contributing to a reliability factor in the game. generally long rod engines see less stress at the rod journal and experience less eccentric wear on the mains, while sacrificing a bit of peak torque and gaining a heavier internal “hybrid” mass./:m]
]the ability to incorrectly adjust the rod ratio is just one factor than can contribute to an unsuccessful engine, and since the development is intended to be infinite… this will play a major part in the “difficulty” aspect of the game. if you make a poor engine, i would assume it might not sell as well./*:m]
]piston acceleration out of intake-stroke TDC plays a HUGE part in determining how the valve acceleration and port shape/intake work together to create effective inflow. the effect of a minimum-length vs. maximum-length rod in a long-stroke (undersquare) engine will accelerate the piston out of its TDC position earlier and simulate the same effect that increasing RPM will have on witnessed flow, and thus performance. by this same token, a short-stroke engine with longer rods will (dependent on the exhaust system) have a slightly longer hesitation period at BDC before the exhaust stroke, and this will allow expanding gasses a fractionally larger period of time in which to escape through an already-open exhaust valve and reduce pumping losses/increase scavenging effect (up to a point) without altering bore-to-stroke./:m][/ul]
if you still believe rod ratio is an unimportant factor, it might be beneficial to spend a few hours researching the topic. it basically amounts to utilizing adaptive-fit cylinder blocks/sleeves, coolant passages, and belts/pushrods that will automatically resize when given the command to increase deck height - and this is obviously independent of stroke length, i.e. the respective positions of the piston must move with the same offset that the deck uses. i am sure a feature to identify clearance issues and prevent adjustments resulting in interference can be included as well.
to anyone saying this relationship isn’t realistic, go ahead and compare the rod ratios of many different engines (obviously you need to look outside of one class of engine) and see how they differ. wholly dependent on application, rod ratio can hurt or help the situation. i’m hoping the game isn’t JUST cars… but that’s all for the future.
it goes without saying that this will also affect packaging of the engine, and allow the user to create a much wider array of performance values for the same given bore, stroke, and number of cylinders. in reality, this is just another dimension that is seriously considered when designing an engine.
i apologize for saying this when one of the developers has already said it flies in the face of their intentions, but i am hoping it is a convincing argument when considering long-term future developments. you said you wanted a “techie” game, well here’s how the techies might want it. IMHO.
oh, and since this is my first post… awesome game! you guys really hit the nail on the head when it comes to gearhead gaming. so thanks for investing so much time and money, i will not forget the title.
- kyle
*also involved in the reliability argument is an addition to adjustable rod ratio: adjustable compression height of the piston, and primarily their overall physical dimensions. some designs do indeed lend themselves to higher out-of-round wear in the thrust direction, and more rocking of the piston perpendicular to thrust. this presents even another factor to use when calculating reliability.
pst, you want a long rod high reving engine. So that you get better peak torque from better leverage on the crank, and higher piston speeds at better leverage angles, and higher piston speeds later for more open intake valves on the intake stroke.
Who doesn’t? I couldn’t resist! 
I won’t argue that its not a key factor in real world engine design, but we do need to stop somewhere with detail unfortunately as we do need to actually FINISH this game.
Excellent post kyle, I appreciate the how you make a proper argument for the importance of the rod to stroke ratio! You do convince me that it’s an important factor, and I’m sure the developers are convinced as well.
This would definitely be considered feature-creep though, and feature-creep is the downfall of small and big development teams. Daffy and Zeussy know well enough that they (sadly) need to ignore the calls for more detail - which can be frustrating both to them and the ones calling. The game needs to be finished, and the features which will be included are set in stone for the release version already… it will be hard enough to actually get all those out.
If the game has success and our devs can make a living off it, I can imagine that their drive for such a technical feature would not stop them including it in an “Automation 1.5” DLC or “Automation 2” release But first things first 
^As usual, Killrob sums it up perfectly
i understand the whole feature creep thing. just trying to get word in on that 2.0 list-of-options.
with this kind of community, i can only see a great game becoming even better.
I am pretty sure it will be considered for future releases if Camshaft Software does not go casual at least xD j/k
Still a bit too early for a 2.0 feature wish-list I guess. But It’ll be one of the first threads I’ll create once the game is released haha
Don’t let this “blocking” stop you from posting/contributing, kyle, this community needs people (like you) who know more about cars than the average Joe and can put this knowledge into words in an appropriate way!