Whilst that makes perfect sense, i wonder why people like lewis hamilton say they prefer a little bit of engine braking. edit: I found this extract on wiki... So it's used like a sort of dynamic brake bias tweak whilst under braking? Putting aside the fact that a driver can sometimes tweak the brake bias on the fly (e.g. in f1) to suit each corner better, the fact that during the trail braking phase the rate of deceleration is constantly reduced which means load at the front starts to shift to the rear and the car now requires a more rear bias setting to get the peak braking efficiency out of all four tyres. Engine braking sounds like the perfect solution to this dynamic problem.
Because thats his style to race with. I downshift through all the gears just to hear the engine with some meaty heel/toe blips XD I guess in terms of physics/whatever though, engine braking is an uncontrollable variable, and can upset the braking depending on the revs, rear wheel speed, when the driver downshifts, etc. What you are quoting is in regards to road driving/riding. Yes, you should shift to a lower gear going down a hill... But for racing, like above, for real bang on consistent braking you would want to limit the number of variables outside the racers control. So he can really know the limit and consistently hit it. Course like all electronic aids in racing, it all gets a bit expensive...maybe thats why its the top level of racing that uses it predominatly. EDIT: Also, with the fuel control in the modern engines, engine braking I guess would change depending on how rich the engine is running. Then again, with their advanced control, they would already be controlling the off throttle fuel usage, and controlling that engine braking that is at an extreme level. If using some EB right in the final section of entry would be beneficial, I'm sure they are already doing it. Getting the GP riders to blip their throttles when going down the gears (like they used too) used up a substantial amount more fuel, especially when they have only 21 odd litres for a race. Gosh darn humans and their non-robotness...XD Just for ****s and giggles, you can hear the revs as he enters the corner after leaving the pits, and while going round Sepang in the braking zones. The revs hold quite steady, and helps to control the rear of the bike hopping and sliding under braking.
Sorry minibull, i just finished with my edits. You might want to check what i changed/added whilst i read your post now. edit: Very cool video. I have a lot of respect for how much more dangerous that sport is. edit 2: I just realised, my last post's last paragraph... ...also extends to the beginning of threshold braking as the car will prefer a neutral brake bias initially to get the peak braking performance of each tyre. I don't know how significant this is to the net duration of braking, but in racing, so long as it's not overly risky but in fact a little advantageous, then even if it were only a 1% gain....certainly in terms of F1 that can mean a heck of a lot.
I appreciate your point here but i think the quote i referenced from wiki was in poor choice and is somewhat ambiguous between the meaning in the first sentence and the remaining paragraph. So here's something about one of Hamilton crash back in 2008 and what he had to say... I can't help but think that it's telling me that engine braking (but as well as ofc TC) contribute to a sort of stabilising effect under braking by helping the driving remain more in control. Also, even if his decision to use engine braking was purely a driving style preference/choice, surely it would not be considered if it was detrimental to the stability of the car and also if it had the affect of reducing the maximum efficiency of braking. If either of those are/were true, lewis or anyone else would be giving themselves an inherent disadvantage. The fact that hamilton is one of the fastest drivers (if not the fastest driver in my view) without trying to insinuate it is therefore down to engine braking (as there are a million other variables that contribute to the fastest lap times) it does however arouse suspicion for me, the question of how much difference it makes and whether a positive or detrimental net affect. I apologise if i'm taking this thread on a Merry-Go-Round, it's not my intent, i just wish to get to the very bottom of this for my own sake of fully understanding the absolute truth on the matter. I really appreciate the responses and enjoy being questioned back and hope no-one minds me picking their brains.
No matter what people say, I still believe that braking with the engine is essential for fast lap times. In my opinion it reduces the travel distance when braking by at least 30%. I rarely downshift after I have started the turn in to a corner but I'm sure you can when blipping correctly. The only reason I'm avoiding it is to minimise the risk of locking the rear tyres while turning. We all know what the end result of this will be, unless you have jedi reflexes. Countless times I managed to avoid going off track by downshifting, even in mid corner situations. Afaik, even karts use engine braking.
While i'm inclined to agree that it helps maximise the overall braking potential (my reasons are in the previous posts), do you have any empirical evidence to demonstrate how it can reduce the travel distance (I assume this is the same meaning as brake distance?) by up to 30%?
ok, fair enough. And if it were found to be only a mere 1% reduction, that would still be reason enough to use it.
Well I've tried with the lola, both normal downshifting and block downshifting. The car is much steadier while braking, and I feel I could push my markers back a bit as it was stopping quicker, but as I have always driven going down each gear, I haven't been able to get a nice smooth corner entry. Dealing with the skip shift and big blip while keeping it tidy. Who knows about any percentage. If I drop down the gears so I'm bouncing off the limiter with each downshift, I would have to deal with more engine braking than if I was leaving it till the revs got quite low. In any case, this only seems to matter in the straight line braking, the right gear should be selected by the entry and then you have what ever engine braking you would have had normally when coming to the end of the trail brake. Just do what it takes for you to be consistent with your braking, that is what matters. I'm not going to try and retrain my braking and shifting style. Whats more, it changes corner to corner. I've seen the V8 Supercar drivers doing both styles for braking (back when they had H shifter boxes). Then go watch Alain Prost back in the day...I'm sure we have all seen this XD And in terms of Hamilton complaining about the lack of engine braking, in testing with a new car with what looks to be a fair reduction in driver aids...who knows. Were they trying to emulate the EBM with some form of injection trickery, I guess noone knows but them.
The engine braking vs brakes only braking discussion is an evergreen topic.. I personally view it like this - if the brakes are strong enough to provide enough brake force to lock the wheels at any speed, there's no point in utilising engine braking because brakes provide more or less constant braking that depends only on your feet control and doesn't change with revs, so it's more predictable. If using even maximum brake force isn't enough to use max grip the tyres have then you of course have to combine it with engine braking and downshift agressively to have the smallest braking distance. Generally I would say I am not a fan of engine braking and try to rely only on brakes themselves, although I'm not saying it's the only and correct way, I find it to work better.
F1 car is actually one of those where engine braking would be totally necessary because I know that F1 brakes are definitely NOT able to utilise that insane grip the car has at top speeds, despite being the most powerful brakes (I think so?) on a racing car, it's not enough to top the grip. The brakes are limited to certain rotor size and materials, probably to limit costs, although it's doubtful how much it helps because those brakes still cost more than a whole brand new family car. As for the "banning" of engine braking, as I understand it they didn't actually ban engine braking itself, more like the opposite: they banned electronic aid that was automatically reducing engine braking when the engine braking produced so strong braking at the rear wheels that the car started to oversteer so now the car behaves more similar to a road car, ie. drivers need to be more careful when combining too much brakes + engine braking. It's interesting to realize that in many ways F1 has been becoming more difficult to drive during last few years, not easier like so many people think, I think that in mid 90s and early 2000s those cars had much more "electronic gizmos" than now.
That has nothing to do with actual engine braking. That was an electronic aid, that they stupidly called "engine braking" just to confuse us all (should have been called t.r.w.a.b.s or p.r.w.a.b.s. throttle/power rear wheel antilock braking system) that they were allowed to use (until 2008), that was basically a reverse traction control. Under braking, when the computer senses the rear wheels starting to slip/lock up, it would ADD just the smallest amount of throttle in order to unlock the rears, its as if you were releasing the brakes a tiny, tiny bit, in order to prevent lock up, but this way the computer sort of does it for you by making throttle adjustments. Make sure you dont confuse this "engine braking" throttle induced rear wheel anti-lock braking system electronic aid, with actual normal engine braking that we all know about and experience in every single car. Anyways, if you can threshold brake perfectly so that the wheels are on the perfect edge of lockup during the entire braking phase, then engine braking cannot slow you down more due to the tyre being at its maximum grip before it slips/locks, but how many of us can do that corner after corner, for the entire braking phase each time? Regardless though, the engine braking, especially in cars where you can adjust it (like many racecars in RFactor), is not used to help you slow down more, because you are "supposed" to be doing that properly yourself, its used as another setup tweak to affect handling characteristics of the car, especially in the entry to apex area. You sometimes can tune more engine braking to help rotate the car (as it is offering more retardation, through rear-wheel forward-rotating resistance, whenever you are in any sort of deceleration). Some people use very little of it though, and get the car more turned into the corner by using the dampers, or rear brake bias, or a more aggressive coast diff lock, or more this, or less of that, etc etc. Its used to tune your handling, not to help you brake better, but of course, it will naturally help you brake better IF you arent braking efficiently, but may also make it easier to lock the rears because along with your own brakes, you have the engine attempting to slow the rear wheels down as well. I am assuming, all things being equal, in a perfectly set-up car, that when lessening engine braking, that that will allow a slight addition of rear brake bias? Its just a another handling setup tweak.
Talking about down shifting while braking brings a related question to my mind. This should apply to classic cars only if I'm informed correctly. How many of you guys are actually double clutching when shifting gears? If there should really be someone using this technique, please could you explain to me how and what is happening exactly.
I don't double declutch, no sim requires you to do it so it's hard to force oneself to do it.. it's no rocket science but surely requires a lot of practice to do it well every time http://en.wikipedia.org/wiki/Double_clutch
I see the engine braking as a handling tweak too. It helps turning the car into corner i.e. can be used to make car oversteer. By applying some throttle you can fine tune the brake balance while trail braking (especially rear wheel driven vehicles). Actually with throttle you can fine tune the balance throughout the whole trail braking. Of course this requires both feet so you have to brake with your left foot.
Thanks Spinelli and everyone. So earlier downshift for engine braking effect is only used during braking to affect car control with a little helpful oversteer when needed. I have found that when I've trail braked into a corner with the correct starting speed at my throttle application point but with my nose still not pointed properly, i will sometimes downshift (if available) to quickly oversteer into the correct direction or if during the turn i have a little too much speed that's causing understeer.
