Fiddling with a gearbox's individual gear ratios

[Killrob]

The gearing mention in the article / blog you linked is just wrong. The gearing top speed, I guarantee you, will not be 155 km/h while 4th is 150 km/h. That is just nonsense. Overdrive gears work perfectly well in Automation, I regularly build cars like that where they reach their top speed in the second to last gear.

Overall I find this whole discussion to be mostly centered around general misunderstandings.
Like @stm316 pointed out, when you get it there are very few gearings that you cannot reproduce to very good accuracy.

The only thing you need is the gearing length in speed of the top gear (not its ratio, and not the car’s actual top speed), then set that on the top speed slider and then adjust first or second gear top speed by only touching the spacing slider.

I challenge you to find any “normal” gearbox car that cannot closely be built with that system. IMO there is no need to change a system that works REALLY well despite its simplicity. If you have proof to the contrary, I can be convinced and open for a discussion, otherwise you are beating a horse that is so dead there are only bones left to beat

[Gewehrztraminer_1664]

Maybe there is something I misunderstand about the way Automation handle gears ratio but Automation UI mention “top speed for a given gear” and fact is the page linked is using data provided by the reference book about the said vehicle and engine especially about top speed for a given gear

As you can read there, bieg being gear, the relevant engine really has max speed for 150 and 155 in 4th and 5th gears respectively.

It is similar also with 1600 CB engine (150/160) if mounted with the same rear drive axle 10/41.

Here’s the relevant data regarding ratio

You can clearly see that the 5th gears is an extra one, but that changes nothing to the 1/2/3/4 ratios. So it is consistent with the provided top speed.

For comparison purpose

So many there is a mistake in the book. But it does not looks like it. And having a 4th gear with 1:1 ratio is not extraordinary. That’s the case of Corvette C5 Z06 from 2004, for instance Gear train - Wikipedia

So, well, you asked: assuming now that the book from master engineer Morawski isn’t wrong can you reproduce Polonez 1500 with BA engine gearbox setup - and you’ll admit we are far from it!

Also, since we are at it, usually, car manual mention ability to climb hill depending on gears. That would clearly be a cool thing to include in automation (or maybe it is already and I missed it - but it could be visible in this gearbox section, since it relates to it). It clearly matters regarding usability of an utility/offroad/delivery vehicle

[Killrob]

The Top Speed gearing you need to set in the game according to the data provided is 186.8 km/h. That is because you can hit 150 in 4th and the ratio to fifth is 0.803, then you get the gearing top speed by 150 / 0.803 = 186.8 km/h.

That is what you set the top speed slider to, then you change the spacing till the rest fits, which should be easy to do, setting the spacing such that 4th gets you to 150. What speeds you actually reach then comes from the engine power and transmission power loss.

Top Speed is NOT Gearing Top Speed (which is what the top speed slider sets). Also, the same applies to reality just because the FSO Polonez does reach 150 km/h in fifth doesn’t mean its gearing top speed is 150 km/h, making it 900 km/h won’t make it the fastest car in the world

[Gewehrztraminer_1664]

Ok, that is actually very interesting (cannot test right now, no time to boot on Windows).

Nonetheless, level up (down?) with me: we want an UI that tells something that match maintainance vehicle manual, dont we? I do not know about so many maintainance vehicle manuals but I can name you at least 3 vehicules which present the data in the same way ; and what matters, in the end, to the user: the real top speed they can match at a given gear.

It think this “top speed” in Automation means much more than it says. When you toy with the game, you understand it has effect on the sales but you really do not see how it could fit, for instance to reproduce this Polonez with BA engine setup.
So far, in campaign mode, I was mostly using this parameters to influence 0 to 100 kmh time and top speed, to the effect that it was usually lower than the actual theoretical top speed.
With the real vehicle case, it is quite the opposite, in the end.

[Killrob]

we want an UI that tells something that match maintainance vehicle manual, dont we?

Sure, but we can’t have that because of other variables: wheel diameter, diff ratio, final drive. Which is why this is beating a dead horse: you can actually do almost everything that exists IRL with just the two sliders, but due to other variables we cannot show you the “correct” ratios.

The real top speed at a given ratio is provided in the gearing graph, that can be adjusted with the sliders as discussed.

Why you are gearing it lower in campaign could be due to tire costs, because if you give your vehicles too much power (which many seem to do) then of course the car is going to be so fast with normal gearing that it needs really expensive tires, lowering its competitiveness. Automation just isn’t that simple and that comes with quite a bit of pain for devs and players, but also makes for the best car builder there is.

And with that, I’m out of this discussion again until someone provides data that shows that our system is rather inadequate for reproducing IRL cars, which so far no one has done. Semantic tweaks could of course be in order for improving clarity though.

[Gewehrztraminer_1664]

Thanks for your attention, I’ll do further test as suggested.

And I thank you for being opened to semantics tweaks, anything that could give better understanding of the “top speed” setting would improve the game.

[Gewehrztraminer_1664]

OK, so I set gearing top speed to 186.8 kmh as suggested (well, 185.5, because the slider isnt that precise).

Here’s the result:

high spacing to match 1st gear top speed, all other gears are wrong

to match 2nd gear top speed, all other are still wrong

to match 3rd and 4th, then 1st one is severely wrong

I dont get how is this supposed to enable to reproduce the real ratios. The ratios are the one in the date provided in my previous post. The slider adjusts ratio in a proportional way, I assume. So it cannot match anything designed with other proportions. It might be even much worse with delivery vehicles.

[mcp928]

I can’t provide any overtly technical (real) reason why the current system doesn’t work (mostly because it actually does work quiet well). I did post something previously about a transmission designer that was on par with the current engine designer, but it was shot down (also pretty sure I annoyed Mr. Killrob).

All that aside, I have two small things to add to this thread.

1. If you have Beam.NG you can tweak the ratios after import. Doesn’t change Automation, but it does fix when you are “actually driving” (your made up car in another game).
2. My turn on the dead horse. If you look at the existing sliders (Top Speed and Spacing) adding a +/- radio buttons for overdrives would be nice (kinda like the top speed limiter on the top speed slider is). Having the top gear forever locked at 0.75 means that old low power cars have a basically unusable overdrive due to lack of power. I may be mistaken, but overdrive wasn’t really a thing until the 60’s, and those were usually external units (at lease here in the states).

How this would work is the top speed slider would work as it does (primarily affecting the final drive). On the spacing slider if overdrive was 0, then your top most gear would be 1:1. If overdrive was 1 the top most gear would be 0.75, and the next gear down would be 1:1 +/-0.15. You could the add overdrives up to (total gears) -2 (if you had a two speed, you get no overdrive, a three speed could have one, a four speed two overdrives, and so forth). The spacing would then count down from your highest available gear with the current algorithm.

My mechanical reasoning for this is low power engines tend to bog down under the load of overdrive, and Automation uses a gear whether it is useful or not. Say you are building a car in the 50’s, and the ratios are 2.31, 1.83, 1.00, and 0.75 (I just made those up, probably cant get those exact figures in game) your 150HP carburated V8 engine hauling that steel chassis isn’t going to like overdrive and your top speed/fuel economy will suffer, but lets use those same ratios in the 90’s with a 240HP injected V6, and the 0.75 overdrive is a blessing on the highway.

Again, the current system does work, but the overdrive count would be a nice addition for reproduction cars, old cars, cars made my people with OCD, etc. ad-nausiam.

[Kyuu77]

A distinct weakness for the current system is that plenty of road cars don’t use evenly spaced gears ( even on a curve).

For example, My IS200 has a short 1st and 3rd gear for better revs at set speed limits which is economically sensible. TRD offer a different gear set that evens out the spacing for those 2 gears, but that’s done for better racing power delivery, and Automation is pretty firmly focused on the production car end.

[stm316]

@mcp928

Having the top gear forever locked at 0.75 means that old low power cars have a basically unusable overdrive due to lack of power.

Only if you don’t compensate by changing the diff ratio.

I had a 1984 car IRL (the trans ratios are mentioned above) with a 2.77:1 diff. 1370kg and only 150hp. To model it in game, diff ratio needs to be set at… wait for it…
3.69:1

[mcp928]

Yes, you are correct. Like I said the current system isn’t wrong, it’s just not correct. While it doesn’t sound like much the jump from 2.77 to 3.69 is actually pretty big. My 1986 car (well Jeep) IRL had a factory ratio of 3.07 (actually it was 3.55, but I swapped the engine to one that would have come with the 3.07), but I have re-geared it to a 3.73. So for my engine/trans setup I effectively went from 3.07 to 3.73, so at 70 MPH on 215/75R16 (29") my RPM went from 1990 to 2415 RPM, but I can (and have) towed over 6500Lbs, something I have struggled to do with a similar vehicle (210HP to my 190, 3880 curb to my 3400) with a 3.31 final.

215/65R15 was a pretty common tire size in the 80’s, so I will use it. I will use the Tremec T4/T5 for the manual and the TH350/700R4 ratios since they was pretty common in the 80’s too.

The T4 was non OD the T5 had 0.68OD.
The TH350 was non OD, the 700R4 had 0.69.

T4 + 2.77 @ 55 = 1970RPM
T4 + 3.69 @ 55 = 2620RPM
T5 + 2.77 @ 55 = 1340RPM
T5 + 3.69 @ 55 = 1780RPM

TH350 + 2.77 @ 55 = 1970RPM
TH350 + 3.69 @ 55 = 2620RPM
700R4 + 2.77 @ 55 = 1360RPM
700R4 + 3.69 @ 55 = 1810RPM

So as we see final drive, and top gear can be compensated pretty easily. Now where the problem lies is the low gear, and gear span. The SM420 had an extremely low first gear 7.0:1 for breakaway so the final drive could be tall enough for the 1:1 top gear to get a vehicle to highway speeds, the T4/5 had a bottom gear of only 4.03:1 so if you ran a 2.77 rear end then at idle (say 600 RPM) you had to slip the clutch for 4 MPH on takeoff, but with a 3.69 final drive your clutch slippage is only 3 MPH (25% less strain on the clutch). This is less important with automatics since viscous coupling (most vehicles with an auto or manual option had a different standard gear ratio for each). That additional breakaway force is almost exponential in cars (engine power X trans ratio X axle ratio) - drive line friction = wheel power.

All of this is overtly technical, and has little bearing on a tycoon game, but what does affect game play is that a longer final drive (bigger number) will accelerate faster while a shorter final drive (smaller number) will have a higher top speed (all other factors being even). The ability to forego an overdrive means less of a balancing act when it comes to acceleration vs speed, and that is advantageous for early cars in many categories. Plus a longer final applies more power (remember power is multiplied in each gear set) so wheel spin becomes a factor in lower gears despite the car being drag limited way before its theoretical top speed (shown in the top speed slider).

Again, it is not necessary to modify the current system, but it is technically a good idea.

[stm316]

Just to further this discussion, which I’m enjoying (not because I’m stirring shit)…

I have no idea what an FSO Polonez is, other than “some European car”.

Depending on how much of an imagination you’ve got, in this game you can make a 9 speed with 8 overdrive gears. Correct me if I’m wrong, but “Overdrive” is nothing more than the output shaft spinning faster than the crank/trans input. The devs have simply chosen to have the “ratio” in top gear represented by 0.75, making it look like it’s overdrive. On paper (decades ago) I made cars with 1.2:1 top gear, and a final ratio to compensate (numbers like 2:1). I even calculated with 1:1 diff and 3.5 top, just to illustrate.

In the case of the OP car (with tyres as 175SR13, I think thats around 600mm diam, so says Automobile-catalog), ratios are as follows -
3.778, 1.944, 1.307, 1, 0.803, with FD 4.10
overall bottom ratio 15.49:1
overall top ratio 3.29:1.
In game -
3.53, 2.22, 1.50, 1.06, 0.75, with FD as 4.40
overall bottom ratio 15.53
overall top ratio 3.307

The OP’s calcs give an FD ratio of 3.97, so either the figures I’ve got are wrong, or his are.
Although it’s true that his other gears aren’t all matching as accurately as he wants the end result will be close enough.

I doubt there’s a reason to worry about the speed achieved in each gear, as much as there is to get the spacing… if we change the max rpm, we change the in-gear speed.

As for “All other things being equal”, I beg to differ. Having a shorter final ratio won’t necessarily give a higher top speed, unless the engine is either revving proportionally much higher or producing more power.

On a side note, I changed the diff in my aforementioned car from 2.77 to 2.92, still only reached 180km/h (115mph for you) - a whole 5%. Yes, I did test it. Come to think of it, your towing example;
3.73:1 w 190hp = 708.7 over 1542Kg
3.31:1 w 210hp = 695.1 over 1759Kg
(I know thats not a formula, but power to weight is kinda relevant)
That there itself explains why the towing was harder.

[mcp928]

Yes, fun intellectual debate and once again, you are overall correct. I think the main issue we are having is you are thinking in the games mechanics, I am thinking real world (since that’s where my automotive knowledge comes from). In reality a simple ratio change isn’t that simple, friction and rotating mass are more of a factor than in the games slightly simplified (mechanically ideal) representation. Furthermore the final drive isn’t actually the final drive, the OD of the tire is. A 28 (710MM)" tire on a 3.73 final has roughly the same engine speed (at 1:1 transmission) as a 37(940MM)" tire on a 4.88. In fact if you take a gear limited car (one that pulls faster until red line) and just install larger tires it will actually go faster. This was my example in the all other things being equal (I neglected to mention gear limited). In a drag limited car (one that lacks the horsepower to overcome the air resistance) installer a deeper (numerically higher) final drive could actually make it faster since the multiplication would be higher. A drag limited car with overdrive would need a massive under drive in the rear axle since horses (and torques for that matter) are actively lost (or traded) for speed in the gearbox where as a non overdrive only has friction losses. Both cars do benefit from overdrive at median speeds, but it is more advantageous to use a taller final, and a lower first via trading the overdrive gear if the top speeds will be equal to help with break away.

I will admit that reading a 2:1 overdrive in the rear diff caused my brain to hurt, but on paper it works. It is technically and mechanically possible to do so, but cars are under driven for a reason. That being said gear vendors has been producing the ranger overdrive for 50 years because over drive does do something useful. It drops engine revs (and therefore fuel consumption) at cruise when less power is needed to maintain current velocity. However, you know that some hills require a downshift, and that going to pass usually evokes a downshift. Overdrive means less power is delivered to the wheels because it is traded for speed in the gearbox. The overdrive in the game actually is overdrive, until you get to the final (axle) drive, which is more or less self contained to the drive.

As for the towing descrepency, I think another contributing factor for the difference is my Cherokee is in better shape than his Explorer was despite being 12 years older. Most cars will vastly exceed their ratings, but you must take care of them. Even a gently driven car will succumb to neglect faster than anything.

[stm316]

@mcp928

2:1 overdrive in the rear diff

Except it isn’t overdrive, 0.999999:1… now THAT’s an overdrive diff… sure a car could only use it with a road ranger 'box, but now I’m just being silly

[mcp928]

Well, that’s what I get for posing tired. 2:1 is under drive. 1:2 would be overdrive. If memory serves the early 90’s F-150 came with something like a 2.21 gear with the L6 and manual. It was marketed as the fuel economy package, and did have overdrive (same Mazda(?) 5-speed as the normal ones). Tow/haul was 0Lbs, I think the total weight capacity was 500Lbs, which was fine for a single cab that pre-dated drive through culture. First of the F-150 sedans (well coupe, but…).

I guess all that really matters with gear selection is having the engine in its power band at a typical road speed. That’s why I geared 3.73, from third to fifth I am at about 2200RPM at 45, 55, and 70, and the vehicle seems happy with it. Somebody posted earlier about a Lexus with a non-linear third and fifth to match engine revs to road speeds, and while that is a good idea it is way too detailed for a tycoon game.

[findRED19]

If you are trying to make an exact replica of something, it would be best to edit the jbeam file instead. Otherwise the automation system works well without being too hard to understand (for newcomers or those without much mechanical knowledge) and is very good at getting a “working approximate”.

If you want to try to match gearing as best as Automation can allow, I do have a spreadsheet I made to help out with that (and other things too).
RedsAutomationWorkbook.zip (14.6 KB)

Otherwise I agree with this:

@mcp928

I guess all that really matters with gear selection is having the engine in its power band at a typical road speed. … Somebody posted earlier about a Lexus with a non-linear third and fifth to match engine revs to road speeds, and while that is a good idea it is way too detailed for a tycoon game

Too detailed for a “car company tycoon” game. (If it was just a car creator simulator of sorts, then it might be better to have control over every single gear ratio).

[XTJCoX]

I find that setting a 1:1 ratio on the 4/5/6th gear (as they do in most real-world transmissions, depending on # of gears) usually works best.

Fine tuning with the final drive has been working fine so far.

[Gewehrztraminer_1664]

Thanks for the workbook!

The whole thread is indeed very interesting.

Obviously, I did not even mentioned the various rear axle ratios that comes along with the Polonez example.

Sure, the game is already fine as it it. But the notion that gearboxes could be designed and produced in the same way as engines is interesting. Because that’s how it is, isn’t it? So that’s something in the real car tycoon equation, it could as well be in the game. It is especially true when you play a game with a poor country, with cheap vehicles: you would not design a gearbox per vehicle.

The game proposes various difficulty mode, this layer of complexity does not have to be in casual mode.

[Killrob]

But the notion that gearboxes could be designed and produced in the same way as engines is interesting. Because that’s how it is, isn’t it? So that’s something in the real car tycoon equation, it could as well be in the game.

That is exactly what was in the game and it sucked, which is why we removed it. You were able to set individual ratios too.

To be fair, that was a long time ago and we’ve learned a lot about design in the meantime, but at this point, looking at what that would do to the scope of the game, it is just not something we even want to touch. The game is taking long enough to make as is, thank you very much