Page 1 of 3

Auto Bore/Stroke adjustment??

PostPosted: Sat Jan 19, 2013 10:49 pm
by Se7enUpMustang
I've never noticed it before or I wold have said something but why does the Bore/stoke auotmatically adjust when one is set too high or too low compared to the other

Example:
I was trying to reproduce the Ford "Thriftpower Six" straight six engine found in Falcon's and a few other vehicals between 1960 and 1964 http://en.wikipedia.org/wiki/Ford_Straight-6_engine

The bore is 3.5 inches(89mm) and the Stroke is 2.5 inches(64mm) but when I tried this the bore would automatically start to decrease from 3.5 inches if I tried to set the Stroke any lower than 2.594 inches. Why does it do this? surely if it was done in real life it can be done in the game.

Re: Auto Bore/Stroke adjustment??

PostPosted: Sun Jan 20, 2013 4:34 am
by bodi
As far as I know, in the last update the maximum delta in the bore x stroke ratio is around 30%, 89mm is around 39% bigger than 64mm so you won't be able to use it.

Re: Auto Bore/Stroke adjustment??

PostPosted: Sun Jan 20, 2013 12:47 pm
by Daffyflyer
Yeah, the ratio we've allowed covers almost every engine ever, but there are a few crazy outliers you can't make.

Re: Auto Bore/Stroke adjustment??

PostPosted: Sun Jan 20, 2013 2:31 pm
by mtm84
Any particular technical reason you chose that ratio?

Re: Auto Bore/Stroke adjustment??

PostPosted: Sun Jan 20, 2013 4:00 pm
by Se7enUpMustang
mtm84 wrote:Any particular technical reason you chose that ratio?



I wanted to see how close I could get the engine in the game to match its real life counterpart like some other people have been doing, Ford's 2.4 liter (144ci) "Thriftpower Six" has those Bore and Stroke measurements. I'm disappointed that I can't match both, I can either have the correct Bore or the correct Stroke not both.

Re: Auto Bore/Stroke adjustment??

PostPosted: Sun Jan 20, 2013 4:21 pm
by Daffyflyer
I think he means why we chose that ratio to limit it at. We chose it as it was a good balance of preventing you from building stupidly long stroke engines and fitting them in tiny cars because the block was still tiny, and also because it covers about 98% of real engines out there (besides ones like this)

Re: Auto Bore/Stroke adjustment??

PostPosted: Sun Jan 20, 2013 4:28 pm
by mtm84
Yes daffy, that is what I meant. I actually did try to make a 144 thriftpower and ran into the same problem. I ended up decreasing the bore and increasing the stroke and calling it "close enough". I think a bigger issue is figuring out what the actual HP of that engine should be in Automation terms, since I believe it was only ever rated in SAE gross HP as opposed to the more modern/accurate SAE net HP.

Re: Auto Bore/Stroke adjustment??

PostPosted: Sun Jan 20, 2013 5:12 pm
by Daffyflyer
Yeah, SAE Gross HP makes it a real pain to work out! :P

Re: Auto Bore/Stroke adjustment??

PostPosted: Sun Jan 20, 2013 10:19 pm
by Se7enUpMustang
Well I was just going to try to shoot for the wiki listed 84hp but I wanted to get it at the right rpm's which I haven't had much luck with on other engines. My OCD got the best of me this time, it stomped its foot and said "Close enough isn't good enough complain now!" anyways thanks for the quick answer guys.

Re: Auto Bore/Stroke adjustment??

PostPosted: Fri Feb 01, 2013 11:12 pm
by apvkt
Bore to stroke ratio

The diameter of the cylinder bore should be determined by measuring straight around the hollow interior of the bore and make a note of it. Next, the length between the main bearing (engine's crankshaft rotate) and the rod bearing (articulating joint on which the piston rotates) of the engine. Make a note of the value and multiply the length between the main and rod bearing by two. eg.If length is 2.5 inches, then it is multiplied by 2 =>5.The final step is to divide the diameter of the cylinder bore by the piston stroke length. eg.If the cylinder bore is 4 inches and the piston stroke length is 4, then 5/4=1.25

Re: Auto Bore/Stroke adjustment??

PostPosted: Sat Feb 02, 2013 11:20 am
by eecer
I recently asked the same question on the developer question board, viewtopic.php?f=15&t=1827, I understand that you guys developed the limit to prevent huge engines from being in small cars but why not have the bore stroke ration develop the height and width of the block and each vehicle type have a size limit on the height and width that can fit in it? I understand that you guys were developing limits to ensure that there are no glitch cheats but at the same time I see this game as not redeveloping the engines created in the past or present but allow us to make our own ridiculous or awesome engine.

What would you guys think of limiting the size Engine that each vehicle can handle, not how big we can make the engine

Re: Auto Bore/Stroke adjustment??

PostPosted: Sat Feb 02, 2013 7:10 pm
by Killrob
Indeed we need to put the limits somewhere, and I think we got a nice compromise going that allows for a lot of variety without breaking the game in the process. Yes, stupid engines are fun, but balancing stupid engines/extreme engines is NOT fun (or impossible)... so the question is the following:

What would you like to have?
a) A better game without ultra-extreme engines.
b) A worse game with ultra-extreme engines.

Our decision on that matter was pretty simple. ;)

Re: Auto Bore/Stroke adjustment??

PostPosted: Sat Feb 02, 2013 8:22 pm
by eecer
Killrob wrote:Indeed we need to put the limits somewhere, and I think we got a nice compromise going that allows for a lot of variety without breaking the game in the process. Yes, stupid engines are fun, but balancing stupid engines/extreme engines is NOT fun (or impossible)... so the question is the following:

What would you like to have?
a) A better game without ultra-extreme engines.
b) A worse game with ultra-extreme engines.

Our decision on that matter was pretty simple. ;)


I suppose every dream has a compromise :cry: :cry: :cry: :lol:

Re: Auto Bore/Stroke adjustment??

PostPosted: Wed Feb 13, 2013 9:20 pm
by Soop
Could you perhaps allow for the ridiculous in the sandbox mode and limit it in the campaign mode?

Re: Auto Bore/Stroke adjustment??

PostPosted: Wed Feb 13, 2013 9:31 pm
by Killrob
Could: yes
Would: no

Why would we show off how broken things are in Sandbox mode? In my opinion that sends the wrong signals and does the game a disservice. Also, we would get some 100 questions per day asking why you can't build that super cool engine in campaign mode...