noticed today,
Might be a lot more handy if you can input some values like bore and stroke for example, with the numeric pad of the keyboard?
Regards
I see where you are coming from, but it would unnecessarily complicate the UI. Also, what benefits does that have over the slider that make it worth implementing?
Easier entry. I’m actually all for this idea, I’d find it very convenient.
I think this isnt a bad idea after all really. I think it’s worth it and more user-friendly. But doing it there means you have to do it for all the other sliders too.
Currently it’s ok to click, drag and then click a couple of times to select the value. But what do you do when you put in an invalid number? Will you get an error message? How will this message be displayed? Are you getting an error message at all? Will it jump back to its old value or the standard value (which currently is 40 I believe)? These are all things you have to think about when game designing and putting them into the game. So it might just look like adding keyboard controls to a text-area, but there really is a lot more to it!
Be alot easier to make replica engines. Just would save time.
Decimals, maybe
Decimals take extra betatesting and balancing. This means the devs can throw all they scenarios and everything overboard, because they are not based on decimals.
Besides that, decimals make it even harder for the general player, so not going to happen. Only ends up being more hassle for the player than a real benefit to gameplay experience.
Then on the design part, just like adding in textboxes. What will do you when a player types 64 COMMA 3 Cam profile? or what happens when they type 64 DOT 3 Cam profile? Its not as easy as all of you think! Comes with so much things to take care about.
In short: Decimals, probably never (99% accuracy, not being an Automation Dev here) Numerical input, maybe sometime when main lines of car designer and tycoon part are done. My guess at the percentage it will be there? probably 20-30%, but only if it really proves to be of an addition, as the sliders currently work just fine really.
Well, I don’t know about inputting custom numbers (though some of my favorite motors are not “quite” right in the current configurations) but I would like to see numbers assigned to the sliders (especially the gears!) as it would make replication (and understanding them) much easier. But there is the validation of inputs which could be problematic. It’s not impossible, but it does require additional coding, as it would have to pass a valid range to a validation function, or maybe even more if it can’t be simplified enough to function properly as such.
The coding part of the numeric input is probably not an issue, the feel of it may be though: are you still playing a game or are you filling spreadsheets? 
Anyway, numeric input will probably make an appearance when we switch to a new UI, if we can make it look, feel and flow well putting in those numbers.
Well, my thought for errors is that Automation would automatically fill in the closest number, like if the person types in 800 and the max is 99, that automation picks 99. If someone types in 66.3, then it goes to 66. And if there’s letters or other invalid input entered, it jumps back to the old value. Just some if-cases coding (or atleast I think so)
I wouldn’t provide it for things like cam profile or timing, but maybe for bore/stroke and gearing.
So what you say is, I want 800, but then it goes to 99 and I dont know why it does that? I have to just guess the max is 99? Maybe normal for regular gamers like you and me or for some others, but really its a hole in the design.
As for the 66.3 jumps to rounded numbers, then whats the use of making it even possible to give in more than 2 characters? You can simply tell the code to allow only 2 numerical characters in the textbox, so no need for decimal hassle.
As for what KillRob said: Indeed the coding might not be the issue for numerical input, but when adding decimals to effectively affect gameplaymechanics, A LOT has to be retested and redesigned. Also, you shouldnt be feeling like filling in spreadsheets. I think this way the sliders is still good to keep with an ADDITION of numerical input only on certain parts, like CobaltGirl stated; In the gearbox ratio designpart for example.
Maybe just a tab in the UI, Normal or Geek. 
For everyday players, they keep it to Normal setting, the rest of us, we who try to find that little bit extra, we activate Geek setting.
One place where numericals would be a godsent; placing stuff on a car body. Exact size and spacing of rear lights(if multiple is used), replicating a look for the front or rear between body styles, and so on.