LoLsmileyFC

iTrader: (37)

What I usually do before a turn is blip 200 rpm below the proper rpm range, brake, and slowly let go of the clutch. The drive train speed is rotating faster than the engine speed; therefore, if you slowly release the clutch it will aid in braking. Works for me every time just don't snap your e shaft .

Jerry Stout

It is a means to set up for a turn optimally. The cars center of gravity drastically moves to the front outside of the car in turns a too high a speed. Engine braking not only slows the car while somehow transferring less mass to the outside front, and also sets the engine at optimal rpm for exit out of the turn and acceleration rate. Brakes are best applied prior to turn in in my opinion, while engine braking is coasted all the way into the apex.

Oh wow. Did that say 2012....whoops.

j9fd3s

iTrader: (3)

its funny you bumped this, i'm reading Jackie Stuarts book,
and he likes to be a gear high entering a corner. his basic philosophy is that he wants to be easy on the car, economical and drive with finesse. so being a gear high makes engine braking more gentle, and then you skip and upshift on the out, which can also upset the car.

its interesting to think about and worth a try

Jerry Stout

Im not exactly a racer but I know in more extreme braking situations such as setting up for a hairpin off of aca straightustraight awayon the turn you would be in whatever gear you managed to climb to while accelerating, and would apply gentle to moderate brake while skipping a gear down and rather gently falling into gear while easing off the brake pedal allowing the engine to take over control of the wheels; applying any more or less adjusting brake to best accommodate the turn. Ideally you wouldn't have to do that last step as you applied enough regular brake pedal prior to entering turn. The set up out of the turn with engine braking on pavement is paramount to most efficient or fastest turning capability in my opinion. Engine braking works on a front wheel drive too, but I don't know how well it would work actually in the turn.
Being too high a gear into the turn or prior would not accomplish any braking characteristics really.

j9fd3s

iTrader: (3)

Jackie Stewart is more worried about upsetting the car, which is totally applicable on the street. there is also a little thing where not having to shift down and then back up again frees up the driver to spend that time driving, if that makes any sense.

when he's talking about driving fast, part of the trouble is that the driver starts to need to do a lot of stuff, so if you give the driver slightly less to do, it helps.

its an interesting way to think about it for sure

Jerry Stout

I got ya. In an ideal situation you would transfer braking from pads to engine fluidly, not just dropping the clutch which will bark the tires and cause a disturbance in equilibrium. Some might say heel toe referring to matching engine and clutch speed but if you drop the clutch in incremental stages while also releasing brake in stages then it is smooth in operation.

Putting the car in too high a gear when entering the turn would leave it in way too high a gear upon exit of the turn. You would have to shift. Where as entering in lower gear would help slow the car for the turn, minimize brake heat, and have engine at best rpm upon exit of the turn for the fastest possible exit or acceleration rate. That's just how it seems to me. It is interesting.

mustanghammer

iTrader: (3)

I read Jackie Stewart's book a long time ago. Also Bob Bondurant's book. They were contemporaries but had a different approach to driving. I would recommend both books. The cool thing about the Stewart approach is that you can practice his technique on the street because it is all about smoooooooothhhhhh. C&D did an article about him when he was working for Ford and conducting street car driving instruction. They commented that riding with Stewart on the street was an effortless experience. Braking, gear changes and acceleration were imperceptible.

As a racer, I found it easier to apply Bondurant's approach for corner entry - trail braking - as a way to transition from entry to apex and then exit. However, when I was behind in a race, Stewart's approach to being smooth and focusing on car placement was the best way to make up ground on a competitor.

As far as engine braking.....ummm we are talking about RX7s? RX7s are momentum cars that don't accelerate very fast but they do corner faster than most cars. So you have to maximize the amount of time you have the throttle floored, brake at the LAST possible moment and set the car up to carry as much speed as possible through the corner . If you aren't either on the gas or the brake all the time you are doing it wrong and going slow.

Race cars or cars on a race track should be stopped by the brakes ONLY. Downshifts that occur before a corner are not intended to slow the car, they are intended to get the car in the right gear for corner exit. If you are chirping/locking the rear tires on downshifts you need to keep practicing. When you get it right, downshifts will be heard only and not felt by the car. There is also a practical side to this...clutches are harder to replace than brake pads. So let the brakes do the work.

All that said, yes, lift throttle and throttle modulation is something I use mid corner to correct my car's line. In my car, lifting slightly causes the car to rotate and tighten the line. If I have too do that too much it means that I got corner entry wrong so next lap I make an adjustment.

Jerry Stout

Sorry. I was talking about a car that is a little front heavy and with substantial power, maybe too much. And yes; chirping the tires would be a lagging indicator of a relatively poor entrance into the turn. Making downshifting a practice for turn entrance/ exit in an auto would take some practice I bet. And you would be always using either gas or brake; even when matching engine and driveline speed you would put foot on gas as soon as you moved it off the brake. More aggressive driving is like desperation. It can lead to mistakes. Being as efficient as possible in all driving maneuvers would entail smooth execution also.

j9fd3s

iTrader: (3)

that is essential Mr Stuarts point , he also mentions that driving like this is easier on the car. which is nice.

this is applicable to the street too, there are pictures with a salad bowl on the hood with a ball in it, if you can go around the course and keep the ball in.... kind of like the Initial D tofu challenge...

the next one i'm going to read is Alain Prosts book, it sits on the bookshelf next to Senna's book.

redmist336

WOW, thought this thread well dead.
Update.The lack of significant engine braking isn't as bad as I had thought. The issue mitigated by the very different chassis/ transaxle charastics. Specifically the new car turns in considerably better than my Jimco and the lack of a torsen mitigates a majority of the Push experienced in the previous car. In effect I drive the car around a corner more like a circuit car than flick it like a rally car. It's not as safe as having the ahrse wide, but it's quick, and manageable in anything other than extreme conditions (I have taken out a lower A-Arm on a strainer post).

I get enough engine braking to start a minor weight transfer, use the brake to slow while very balanced, soften the brake, turn in, trail the cutting brake on the inside tyre, work power into the corner, switch the cutting brake to the outside (to control spin). Again more of a circuit corner than anything traditionally dirt.. Looks slow and undramatic. But it's quick and has certainly woken up the worked V8 competitors.

Haven't had a lot of time in her yet, some budget issues and the development of the car has seen her with reasonably little use. However reasonably pleased with the engine. Certainly needs something to get her off the line quicker (thinking bang bang), and out of tight corners better (again bang bang). Currently pulling a very mild tune 490whp, but should be early to mid 600's once we upgrade the IC.