Quote from Mikkomattic :

Not entirely correct. The brakes ability to lock up the wheels is dependant on how fast the car is moving. On parking lot speeds, yes, almost any crappy brakes will be able to lock it up. But at higher speeds they might not. That's why you need mega brakes on cars with powerful engines to slow them down fast enough, because they get up to higher speeds faster.

Hmm, good point.

Good points I'm seeing here.

The only way I could possible argue that engine braking doesn't matter (in LFS) if that LFS doesn't, that I know of, doesn't have disk wear, pad wear, overheating brakes resulting in fade. I suppose if it did then using engine braking a little could help maintain the integrity of the brakes longer during racing. Though, this could have adverse effects on the drive train components. But still. If the vehicle was setup in a manner where the coast effect of a limited slip diff could stabilize the car when throttle is applied during braking and down shifting??? Maybe?? Especially toward the end of braking at turn in where you would need to try roll to more throttle from the brake switching to power effect of LSD?? The torque of the engine applied to the wheels though the gearbox, diff should allow the car to be pulled toward the road at the rear?? Or I guess we could say keeping the chassis loaded at the transition point?

Pretty sure I just babbled about this like "W". Sorry if it sounds a bit skewed...

My wife is bugging me to go to the store and then comes in here and then drops a jury duty notice on my keyboard.... bah!!

Maybe the honey do's list is over for the day.

Jay

Quote from scipy :

engine braking? It should be avoided at all cost, especially in racing.

Depends on the car and the setup. Lift throttle induced oversteer (coast differential setting) is used in some real race cars, and was heavily used in Grand Prix Legends. Part of the idea of left foot braking by the "aliens" in racing games is that it allows a setup with a bit of excessive lift throttle induced oversteer to be controlled by applying throttle and brake at the same time.

Virtually all racing motorcycles all use "slipper" clutches that limit engine braking, as well as some street bikes. Other than cars that use motorcycle engines, I'm not sure if any racing cars use slipper clutches. However, in the case of Formula 1 race cars, who knows what the ECU and computer controlled clutch management does in those cars these days?

Getting back to the OP, as mentioned, a driver gets a lot of feedback from braking in a real car, the deceleration and the amount of pressue on the pedal, something that can't be duplicated with a game. You could set up a car so max pressure wouldn't lock up the tires, but in a high downforce car, you'd have to allow for some potential lock up at slow speeds for optimal high speed breaking. Then again, in high downforce race cars, like Formula 1, it's not possible to lock up the tires at high speed because of the huge amount of downforce (don't know if it's a limitation of brakes, or for a safety margin).

Quote from Hallen :

Another problem with sim brakes, especially while using something like the tennis ball, is the brake pedal wants to spring back with quite a bit of force. Real brake pedals don't do that. The obviously spring back to full up, but not with that much force. Having this force pushing back against your foot makes it much hard to heal toe smoothly. It keeps pushing against your foot and when you roll your foot to hit the gas, the brakes let up some. This leads to jerky braking and tire lockups, etc.

From experience I'd say this is true, interesting..

I wonder if G25 could be modified to reflect this behaviour by weakening the original spring and adding a piece of rubber or whatever to far end of the travel. The brake resistance would then be extremely progressive, and dxtweak could be used to alter the "travel".



Any thoughts?

Quote from Not Sure :

From experience I'd say this is true, interesting..

I wonder if G25 could be modified to reflect this behaviour by weakening the original spring and adding a piece of rubber or whatever to far end of the travel. The brake resistance would then be extremely progressive, and dxtweak could be used to alter the "travel".



Any thoughts?

I have used G25 pedals then went to Frex pedals (no sim brake) then went to CST pedals.

In the G25 I cut a stress ball and placed it into the brakes spring (prolly not as good as nixim) but it did the trick, it gave a pressure effect like a real car.
Then I went to Frex pedals that had just a 3cm rubber cylinder, it felt too hard to compress (close to how Skip barber racing schoold cars feel). Perhaps too hard so I added a 2cm spring to give very little play in the travel of the pedal. I must say even after going to CST pedals which use a Load Sensor the Frex pedals feel closer to real life. While the G25 w/ stress ball felt good too and no need to tweak it with dxtweak.

I find the idea that you should simply avoid engine braking frankly laughable. Unless you have a problem with locking the driving wheels - in fact even if you have this problem - you still want to be in the required gear for the approaching corner as early as possible. That issue might affect how early or aggressively you can make the gear change, but you still do it as early as possible.

If you stayed in, say, 2nd gear between 2 corners and were on the red line as you brake for the second would you declutch so you avoid engine braking? Maybe in "avoid engine braking at all costs" world. It's not a case of using the engine braking as a brake, but to say you should avoid it actually occuring is just nonsense.

I have my brakes set just to limit before they lock the tires, so I can floor the pedal without locking (or just a little bit), but I help my brakes with fast downshifting.

What I've seen in real races, they are often able to fully lock their wheels, mostly in F1. I bet if you do a quick search on youtube, you can find many videos of this situation.

Quote from majod :

What I've seen in real races, they are often able to fully lock their wheels, mostly in F1. I bet if you do a quick search on youtube, you can find many videos of this situation.

Note that I mentioned at high speed, say 160mph, where the cars experience over 2 g's of downforce. At low speeds, the F1 cars easily lock up the brakes.

Quote from lerts :

i set brakes to full force so if i overpush it skids, i do it because if irl i need to emergency brake i have the habit of the modulation needed for a real car

im pretty sure real racers do the same than me, they set it so they lock the brakes if they over push the pedal

what do you know about this?

lol, I'd imagine that situation if in a race they pushed it full way and there was no ABS in the car(s)...

Minimaxman, I read in two racing books that a driver only jabs the brakes before a corner if he senses his brakes are fading/close to being finished. One of those books was Skip Barber's the other Alain Prost's.

Hope they were right)

Quote from Minimaxman :

Yeh I'm still not completely convinced the reason they do it is to make sure they've still got brake pressure. What if they did one of these quick jabs only to realise the brakes weren't working, when they come to brake they still won't work.

This is taken from one of the comments from the video NotAnIllusion posted, and sums up what I was getting at in my first post in this thread using the correct terminology:

"My guess is pad knock back. Any lateral movement of the brake rotors can push the pads back into the caliper causing some brake pedal effort being wasted on just moving the pads back into place. In severe cases, it can cause enough knock back so a full pedal press does nothing, requiring another stomp on the pedal. The first time that happens when you're not ready for it is not fun, especially if you're at speed when it happens. Tap the brake down a straight and you reset the pads."


EDIT: When I say I don't think they are checking for brake pressure in my first sentence above, I mean actually checking to see that the brakes are slowing them down, not just tapping them to make sure all the pads are seated properly.

A mechanical engineer was telling me that even if you are on the limit of your braking, engine braking will slow the car down further. You have to discriminate between kinetic energy and potential energy here. Even if your brakes or tyres are on the limit of adhesion (ie. 15% slip), engine braking will help as the energy is not dissipated through the tyres.

The thing is, when you rev match, engine braking is working at its max, also. If you were to blip the engine any higher than the output shaft speed and then engage the lower gear, the car would jolt forward, increasing your braking distance.

Quote from obsolum :

From what I remember from that thread scipy mentioned, engine braking doesn't really help slow the car down if you're already using the brakes to their full extent (ie. the tyres are at their grip limit). So it's pointless. That's it in a nutshell.

BTW, I posted this in another thread. If the answer to my question is that drivers have set up the car that max pedal pressure = 100% braking, that is kind of like an aid, and certainly unrealistic. It's funny no one has a hint of trail braking, just 0% - 100% instantaneous response. I am very skeptical with regard to this. Schumacher's own braking for a hairpin shows significant trail braking...and that's in an F1 car!

'Looking at the telemetry for the best laps in the XFG, I noticed that all the top laps have seemingly digital braking. The brake pressure goes from 0% to exactly 100% for the needed period and then back to 0%. And all this instantaneous...not a slight hint of lockup or modulation - just 100%! Looking at real telemetry this is never the case, especially in the case of heel-toe, when the foot inevitably loses some of the pressure it is maintaining on the brakes.

Can anyone please explain this phenomenon?'

Vitali

Quote from vitali.88 :

BTW, I posted this in another thread. If the answer to my question is that drivers have set up the car that max pedal pressure = 100% braking, that is kind of like an aid, and certainly unrealistic. It's funny no one has a hint of trail braking, just 0% - 100% instantaneous response. I am very skeptical with regard to this. Schumacher's own braking for a hairpin shows significant trail braking...and that's in an F1 car!

'Looking at the telemetry for the best laps in the XFG, I noticed that all the top laps have seemingly digital braking. The brake pressure goes from 0% to exactly 100% for the needed period and then back to 0%. And all this instantaneous...not a slight hint of lockup or modulation - just 100%! Looking at real telemetry this is never the case, especially in the case of heel-toe, when the foot inevitably loses some of the pressure it is maintaining on the brakes.

Can anyone please explain this phenomenon?'

Vitali

Laps perhaps done with mouse?

Otherwise it might be a locked diff which creates lift-off-understeer crapness, so you have to brake hard and then hit the throttle hard and avoid wasting time in that lift-off-understeer situation, trail braking often isn't the fastest way with those setups necessarily.