That 'on rails' statement is Speed Secret #22 from Ross Bentley's excellent book. I believe it's a paraphrase of the classic Mario Andretti quote:
“If everything seems under control, you're not going fast enough.”
The question is not "how?" but "should I?". You shouldn't, your car is great but not a good platform for power. Before wasting your money on the car, spend it on improving the driver. Get into Autocross/Track days or whatever the equivalent is where you live. Maintain your car, learn not to buy shit parts or tires. Get this book: Ross Bentley's Speed Secrets. Improve your skills and car knowledge, save money, read automotive press, watch automotive videos, and frequent this sub. You'll be able to make good decisions very soon.
For years I never bought a single car pack or a single DLC car (Horizon 1, Forza 5, Horizon 2). Then recently I gave in and only purchased a small set 3 or 4 unique cars that I really like. What pushed me over the edge was this irresistible curiosity about "experiencing the interior" of these cars.
Personally, it would be crazy for me to purchase a season pass or ultimate edition or any of that stuff. I'm into racing and driving (also tuning and painting). I'm not into car packs. I don't have any fond feelings for all these souped up overpowered luxury status symbols. I like street-style cars from the 1960's-1995. (Also I have always personally found it unpleasant that a car pack, which represents a tiny material add-on to the core game, costs like 10% of the base price of the game.) If there were track packs, I would pay money for those. To me, more tracks means more game, while more cars just means more pairs of underwear to race in.
SOURCE: like... level 500 in Horizon 2 and Forza 5, top 1% leaderboard times, former top 10 holder (I assume I've been surpassed), extensive posts to the subreddit on tuning and driving technique, used to suck at Forza until I read Ross Bentley's book
You seem to be very analytical - you need to understand the principles of what the kart is doing in relation to your inputs, combined with video analysis, seat time and lead-follow sessions with someone willing to mentor you.
Don’t use that at all. Find a guide that describes the main parts (AR bars, springs, differential, etc) then go from there and tinker.
Also look for where a person talks and knows about real cars, because in most Forza discussions people have no idea what they’re talking about and will give you false info. I think 100% of Reddit posts that describes talked about dampers in Forza don’t know what dampers actually do. (They change the SPEED at which the springs move.)
It sounds like you’re probably just starting out. I think it’s worthwhile to read one of the basic race driving books like Speed Secrets. (Speed Secrets: Professional Race Driving Techniques https://smile.amazon.com/dp/0760305188/ref=cm_sw_r_cp_api_glt_fabc_V6ZZ1XW7E2R3SVCCGKAF)
You can also check out Driver 61 on YouTube for great entry-level explanations of lots of basic racing/performance driving concepts.
A cool thing about iRacing (and other good sims) is that they really do a decent job of recreating all the stuff you have to keep in mind IRL, so books, videos, and articles meant for driving IRL are highly applicable here.
Once you’ve got a handle on the basics you will also have the vocabulary and general conceptual understanding to ask better questions and get better answers (maybe!) as well.
Speed Secrets: Professional Race Driving Techniques
The purpose here isn't to drive fast on the street. Rather, you can take a number of habits and practices from racing and put them to use on the street, making you a safer driver. After all, these techniques keep racers safe at high speed, so they can work for you at 40mph.
There's a section in the book with learning exercises that you can practice even at parking lot speeds.
When I started driving at 14. I liked cars back when I was in the single digits and learned a lot of reading from car magazines, but I still didn't want to drive because I was afraid of having accidents or getting a ticket.
When I was 21, I found a book on racing techniques. I liked how it made off-track application of the skills, showing how you could safely practice them on the street and how the principles of the techniques could make you safer at street speeds.
For example: Look ahead as far as possible, so that you can be ready for what's in front of you. Practice by finding a long, straight road, and pick out an object on it. Drive toward it and count the seconds until you reach it. At least 5-10secs was supposed to be good, if memory serves. Get used to looking that far ahead, and you can catch things and give yourself more time to react.
Because of physics.
To oversimplify, if a tire needs to split its traction duties between acceleration and steering one or both will suffer.
This is a good book to read if you're actually interested in what's going on between you, your car, and the road.
As some anecdotal evidence, take a look at the SCCA Solo PAX modifiers. As a rule, FWD car times are adjusted more than AWD which are adjusted more than RWD. This reflects that the same driver in a FWD, AWD, and RWD cars would post faster times in each (more or less).
More anecdotal evidence - name a single racing team who choose a FWD car (and leaves it FWD).
I'm not saying that FWD cars are bad, I'm saying that they make bad "wonderful track cars."
Another good one is Ross Bentley's Speed Secrets: Professional Race Driving Techniques (Amazon and iTunes). I now look up to him like my greatest teachers from school as a child, and I merely read his book.
He covers driving, handling, racecraft, even tuning, your mindset, etc. He's an astoundingly good communicator. My Forza performance launched into the sky as I absorbed each chapter.
DRIVING TIPS
A great piece of advice I once read is, "Brake slightly before you think you have to." No human being can drive at 100% consistently for any long period. Braking slightly before you think you have to is a way of avoiding an incredibly costly mistake by sacrificing a small amount of speed. Braking at the literal last possible moment would get even the world's greatest driver killed if the race is long enough, though they might set a great lap time before dying.
SLOW IN and FAST OUT is better than going in fast and coming out slow. (But remember that the faster the corner is, the more important it is that you maintain every possible MPH.) So-called "late braking" technique will not gain you much for the risk. You'll gain much more by carefully setting up for maximum speed after the turn, not by traveling at X mph for an addition 30 milliseconds.
Controller Settings
Also, make sure simulation steering is off (unlike other assists, it's not really a difficulty setting, it's not for controllers). I recommend decreasing the analog stick deadzone under advanced controller settings (press "X" button inside Player Profile, or control setup, or somewhere like that).
TAKING THE TURN
I don't want to go into too much detail here, so let me just expand on a new version of your bullet list, by filling in the important transitions. Notice that the transitions overlap:
More reading about overlapping your steering with your braking ("Trail braking") here: http://www.drivingfast.net/techniques/track-corner.htm#3
About downshifts: honestly I'd say downshifts are irrelevant to the technique. Do not downshift to "slow down". The only reason to downshift is because you need to be in a low gear when you start accelerating again. The transmission is not for slowing the car down, that's what brakes are for.
I also highly recommend Ross Bentley's excellent Speed Secrets: Professional Race Driving Techniques, available on Amazon.com and iTunes. He is the best racing teacher you will ever have. He's talking about real-life racing, but almost every sentence in the book applies just as well to playing Forza. Driving, handling, racecraft, tuning, your mindset, etc. His teachings are great on cornering and utilizing your traction, especially.
DO NOT MASH
Mashing on brakes usually upsets the balance of the car. Instead, if you keep the car balanced, the more you allow all four brakes to slow the car down, thus you will slow down faster the smoother you brake. That being said, at the same time, you must & should reach "pedal to the floor" maximum braking (or maximum throttle for that matter) at some point and as quickly as possible while maintaining control.
Good comments. I want to add a few things (from the OP, etc.)
> I was thinking that maybe under acceleration from a slow corner the weight transfer to the back of the car could cause understeer?
It absolutely could. Understanding weight transfer is critical to managing the handling of a Miata. They respond to weight transfer very well. Put weight on the front (slow down) to get the front to grip. Put weight on the rear (speed up) to get the rear to grip. Obviously, you can still overwhelm the tires by being too harsh or giving too large an input. Overwhelm the fronts and you cause understeer. Overwhelm the rears and you cause oversteer.
> Understeer at high speed. Why does this occur instead of all four tyres going? Would all four tyres generally only lose grip in a perfectly balanced car where the tyres have perfectly equal grip?
It varies significantly by the exact situation, the setup of the vehicle (Miatas are extremely configurable), etc. If grip is balanced equally between all four tires and that grip is overwhelmed, all four will slip.
> During turn-in, this happens because you're heavy on the brakes and so your front tires must handle the majority of braking force AS WELL AS the majority of turning forces. They get easily overwhelmed, and understeer results.
Understeer at turn-in can also happen because entry was at too fast a speed (even without simultaneous braking). There isn't enough grip to get the car to turn that much at that speed. If that's the case, smoothly adding some braking can help.
There's a lot more to this, and there's a lot of further information out there. For more, I strongly recommend Speed Secrets by Ross Bentley. Consider subscribing to his Speed Secrets Weekly, too. While it talks about racing, the techniques apply to any time you're nearing the limit of grip. It's really useful and informative. And for practical application, autocross, etc. is great.
If you like this, then you'll love "The Sim Racing Bible":
https://www.amazon.com/Speed-Secrets-Professional-Driving-Techniques/dp/0760305188/
Speed Secrets: Professional Race Driving Techniques https://www.amazon.com/dp/0760305188/ref=cm_sw_r_cp_api_i_BXPV4MH8KN5G0DWXATWJ
It's not the transmission.
The important things are:
In that order.
The reason to use manual is because it will feel better and give you a better playing experience, once you get used to it. The performance gain is marginal. I have all assists off (no ABS, traction off, etc) but I use manual without clutch.
I also recommend going into controller settings > Advanced and setting the steering deadzone to 0 or 1. Will give you a more direct and smooth control over steering using the analog stick.
We've all been there before. You're going to have to get real smooth.
Try this guide to learn your racing line.
Make sure you are smooth and gradual on the gas trigger, and smooth on the brake trigger. Don't just jam the triggers ON/OFF. Depress them like pressing pedals in a car. Be smooth and gradual when you steer the analog stick. Use your brakes A LOT. Start with B or C class.
Turn off the assists and get smooth. Keep Normal steering on. I recommend keeping ABS on for now while you learn, and turn it off later.
You can also read my recent comment on racing tips.
You can also read Jawshe's 7 Steps to Becoming a Better Forza Player.
You have to read Ross Bentley's excellent Speed Secrets: Professional Race Driving Techniques, available on Amazon.com and iTunes. He is the best racing teacher you will ever have. He's talking about real-life racing, but almost every sentence in the book applies just as well to playing Forza. Driving, handling, racecraft, tuning, your mindset, etc. I literally started winning at Forza after reading this book. But this will only apply if you are truly interested in the craft of racing, not just playing a game.
The game is complex enough that it's easy to play it wrong and do badly. Especially if you are used to "Arcade"-style racing games. You have to build up your discipline and your fingers. And then you will be SMOKING THE COMPETITION.
You might want to try reading: https://www.amazon.com/Speed-Secrets-Professional-Driving-Techniques/dp/0760305188
This isn't a drive to the shops for groceries.
On the track, you are generally either a) Braking, or b) Accelerating. Engine braking is effective when a car is coasting.
Check this out: https://images.cdn.circlesix.co/image/1/700/0/uploads/posts/2016/01/455b7f5a4c7c42d22c3c3d40dd6b88e1.jpg
The stages of a corner are: 1) Breaking, 2) Trail braking, 3) Gently commencing acceleration, 4) Accelerating.
I don't think there's any room for engine braking in amongst this.
You have to read Ross Bentley's excellent Speed Secrets: Professional Race Driving Techniques, available on Amazon.com and iTunes. He is the best racing teacher you will ever have. He's talking about real-life racing, but almost every sentence in the book applies just as well to playing racing games. Driving, handling, racecraft, tuning, your mindset, etc.
You should also read this guide to learn your racing line. Make sure you are smooth and gradual on the gas trigger, and smooth on the brake trigger. Be smooth and gradual when you steer the analog stick. Use your brakes A LOT. Start with lower-power cars.
However, aside from all that, Project Cars uses what I would call "Simulation" analog stick steering rather than "Normal" analog stick steering. I'm using Forza terminology here. The practical consequence of this is that I find it very difficult to control counter-steer in Project Cars. Basically when I have to counter-steer for a correction, I spin out. I believe I could fix this with training, but, it's too much of an investment right now "unlearn" years of Forza. It's complicated by the fact that in the control option menu, what's referred to as "Deadzone" is not actually a deadzone, and there's no documentation on how the Presets change the coding of sensitivity/deadzone/filtering. Contrary to what you may assume, the presets are not merely preset slider positions, they actually change how the control algorithms function, and there's no documentation on this last time I checked.