Slow in fast out?
Discussion
Sorry if this is the wrong forum, but "advanced driving" seems to only want to talk about when you should overtake on an A-road. This is certainly about advanced driving none the less.
Went on my PDE day this week and certainly got a lot out of it.
One thing which was advised against was (as I have always thought) brake late and in a straight line, turn in, clip apex, accelerate feathered until you are straight then floor it.
IT would seem that by trailing the braking through the turn-in at a faster speed and then progressive acceleration gives you a much faster corning speed as it dips the weight opf the car forward into the corner gaining the extra grip you needed to turn-in.
For example, round the figure of eight track I was corning at 29 mph in the standard manner before the front end would wash out, trailing the brakes allowed me to corner at more like 45 mph - it really made that much difference!
This certainly seems to blow in the face of slow in fast out - much more like fast in, fast round, faster out.....?!?!
Went on my PDE day this week and certainly got a lot out of it.
One thing which was advised against was (as I have always thought) brake late and in a straight line, turn in, clip apex, accelerate feathered until you are straight then floor it.
IT would seem that by trailing the braking through the turn-in at a faster speed and then progressive acceleration gives you a much faster corning speed as it dips the weight opf the car forward into the corner gaining the extra grip you needed to turn-in.
For example, round the figure of eight track I was corning at 29 mph in the standard manner before the front end would wash out, trailing the brakes allowed me to corner at more like 45 mph - it really made that much difference!
This certainly seems to blow in the face of slow in fast out - much more like fast in, fast round, faster out.....?!?!
Edited by chumley-warner on Thursday 30th August 14:27
its all relative.... slow in fast out, fast in faster out. Yes the method of cornering you have described is faster, obviously, i wouldnt recommend it for new or inexperienced drivers, or those who have little idea of high speed car control however. Braking into a bend in order to redisribute the weight of the car to the front end will give u more grip for the turn at the front of the car, but less at the rear, and therefore it will be easier to oversteer.
On the outer handling track at Millbrook, we certainly weren't hanging around and ultimately the car would always understeer at speed, could not get it to over steer without deliberate provocation.
I'll be interested to see how much the speed was down to my red mist versus the car as I was lapping a number of aston martins - and I'm due an aston day shortly.
I'll be interested to see how much the speed was down to my red mist versus the car as I was lapping a number of aston martins - and I'm due an aston day shortly.
In general:-
Brake hard initially in a straight line as late as possible, but then start to come off the brakes just before the turn-in point. You should still aim to continue braking into the corner entry, but not too hard otherwise you'll risk going off backwards. You should be completely off the brakes before the apex and already starting to progressively feed in the power. You should aim to be on full power as soon as possible after the apex. Any steering corrections or throttle lifts after the apex will lose a lot of time. The braking bit into the apex is the hardest part to master and that's where pro drivers make up most of their laptime.
All very general of course, different corners respond to different styles. But smooth and progressive = fast in track racing. Big leary opposite look slides look great, but slow you down.
Brake hard initially in a straight line as late as possible, but then start to come off the brakes just before the turn-in point. You should still aim to continue braking into the corner entry, but not too hard otherwise you'll risk going off backwards. You should be completely off the brakes before the apex and already starting to progressively feed in the power. You should aim to be on full power as soon as possible after the apex. Any steering corrections or throttle lifts after the apex will lose a lot of time. The braking bit into the apex is the hardest part to master and that's where pro drivers make up most of their laptime.
All very general of course, different corners respond to different styles. But smooth and progressive = fast in track racing. Big leary opposite look slides look great, but slow you down.
I think slow in fast out is safety 'catch all' for road use, in particular when you dont know what is around the bend or if therre is a chance that the bend will tighten 1/2 way around. In a well balanced car, you might get away with it, but if you have over-cooked it in a 911, then you most often wont.
Trailing brakes is no doubt faster on a circuit when you can see the bend and are not likely to have to fully back off mid way through it.
Trailing brakes is no doubt faster on a circuit when you can see the bend and are not likely to have to fully back off mid way through it.
Yes, this technique works extremely well with Porsche's and is what I teach to all my Porsche customers on track days and air field days. It does not work so much in front engine GT cars, because you take what little weight that is on the rear away and you will create lots of oversteer. It works well with mid engine cars also.
In the Porsche, when you trial brake into the apex, you negate the understeer and create a lot more front grip and with the engine in the rear, you still have a lot of weight on the back, there for giving you enough grip to carry lots of speed in without having oversteer. Obviously it will eventually oversteer if you do it too much.
In the Porsche, when you trial brake into the apex, you negate the understeer and create a lot more front grip and with the engine in the rear, you still have a lot of weight on the back, there for giving you enough grip to carry lots of speed in without having oversteer. Obviously it will eventually oversteer if you do it too much.
Edited by Sean Edwards on Thursday 30th August 16:10
Yes - it's not the sort of thing you want to practice on her majesty's track - better off to use a private one.
Conditions were dry, no real run off areas - like gravel traps - just grassy areas. I was getting closer and closer to the edges firstly as I got better, but also as the tyres started to go off. The brakes didn't however because even though it was "only" a C2S it was fitted with ceramics - which incidentally the PDE guys love and would have nothing else.
Conditions were dry, no real run off areas - like gravel traps - just grassy areas. I was getting closer and closer to the edges firstly as I got better, but also as the tyres started to go off. The brakes didn't however because even though it was "only" a C2S it was fitted with ceramics - which incidentally the PDE guys love and would have nothing else.
chumley-warner said:
The brakes didn't however because even though it was "only" a C2S it was fitted with ceramics - which incidentally the PDE guys love and would have nothing else.
They'd obviously had a push from Porsche for not selling enough ceramics. They were less than enthusiastic about them when I went and were trying to push the PSE on everyone!Great day out though, despite the covert sales tactics.
Actually, it all depends how much power over grip you have, or how fast the corner is. The trick is that you modify your entry line and speed sufficient to get the car pointing in the direction of travel required at the exit, to use full power early (the earlier you are on the power, the higher the speed achieved down the following straight.) So your line might be ‘tighter in’ and expanding on the exit; not quite what the theory would indicate, which is where the poster is coming from.
I think this saying came from early 911 racers. The car, notoriously tail happy, would oversteer hard if you braked on the limit in anything other than a straight line and turned in hard. So the stock line, which really still holds today for the majority, ‘slow in - fast out’ really means, keep under control, slow sufficiently to get fully turned, and if that’s all under control, get on the power early and use all the road on the exit, using the 911 strength of real good traction. It was a basic design weakness (engine hung outside the wheelbase at the rear, and basically unstable) which was engineered into an advantage by competition development.
Modern cars, tyres and suspension geos are so good, IMHO that it’s less relevant today than it was. So are perfect lines. You’re better off learning car control.
I think this saying came from early 911 racers. The car, notoriously tail happy, would oversteer hard if you braked on the limit in anything other than a straight line and turned in hard. So the stock line, which really still holds today for the majority, ‘slow in - fast out’ really means, keep under control, slow sufficiently to get fully turned, and if that’s all under control, get on the power early and use all the road on the exit, using the 911 strength of real good traction. It was a basic design weakness (engine hung outside the wheelbase at the rear, and basically unstable) which was engineered into an advantage by competition development.
Modern cars, tyres and suspension geos are so good, IMHO that it’s less relevant today than it was. So are perfect lines. You’re better off learning car control.
ph123 is spot on.
I would only add that with old school 911's stability was more of an issue so making sure that your braking was all done within a straight line prior to turn in was of far greater importance particulary into fast corners. This allowed a nailed throttle on the exit and therefore quicker down the straight.
With modern day technology this theory does not work so well. If you try this method in a latter day supercup car nailing the throttle will lighten the front end and promote understeer. You need to promote grip at the front by trail braking the car to the apex of the corner before nailing it. Why, because the car is far stiffer and the weight transfer is harder to achieve.
I would only add that with old school 911's stability was more of an issue so making sure that your braking was all done within a straight line prior to turn in was of far greater importance particulary into fast corners. This allowed a nailed throttle on the exit and therefore quicker down the straight.
With modern day technology this theory does not work so well. If you try this method in a latter day supercup car nailing the throttle will lighten the front end and promote understeer. You need to promote grip at the front by trail braking the car to the apex of the corner before nailing it. Why, because the car is far stiffer and the weight transfer is harder to achieve.
I can't think of any road-based car that has changed so much as a racer than a 911. (in terms of how to drive one quickly)
I remember reading an article by Tony Dron about the time he was racing 930's back in the late 70's/early 80's. The trick to getting the power down well was to apply power at the corner apex and then wait...wait...wait for the turbo to spool up. By the time the turbo kicked in the car would be out of the corner, onto the main straight, and with all wheels in a straight line.
The joys of turbo lag and mechanical injection!
I remember reading an article by Tony Dron about the time he was racing 930's back in the late 70's/early 80's. The trick to getting the power down well was to apply power at the corner apex and then wait...wait...wait for the turbo to spool up. By the time the turbo kicked in the car would be out of the corner, onto the main straight, and with all wheels in a straight line.
The joys of turbo lag and mechanical injection!
chumley-warner said:
Sorry if this is the wrong forum, but "advanced driving" seems to only want to talk about when you should overtake on an A-road. This is certainly about advanced driving none the less.
Went on my PDE day this week and certainly got a lot out of it.
One thing which was advised against was (as I have always thought) brake late and in a straight line, turn in, clip apex, accelerate feathered until you are straight then floor it.
IT would seem that by trailing the braking through the turn-in at a faster speed and then progressive acceleration gives you a much faster corning speed as it dips the weight opf the car forward into the corner gaining the extra grip you needed to turn-in.
For example, round the figure of eight track I was corning at 29 mph in the standard manner before the front end would wash out, trailing the brakes allowed me to corner at more like 45 mph - it really made that much difference!
This certainly seems to blow in the face of slow in fast out - much more like fast in, fast round, faster out.....?!?!
Good stuff above. The only thing I'd add is that for on road speed I was taught to take a wide entry into the corner if safe to do so as whilst it isn't the quickest way through the corner, it opens up the corner and your sight lines earlier. This then allows you to deploy the power earlier and with more safety. Not how you'd do it on track of course...Went on my PDE day this week and certainly got a lot out of it.
One thing which was advised against was (as I have always thought) brake late and in a straight line, turn in, clip apex, accelerate feathered until you are straight then floor it.
IT would seem that by trailing the braking through the turn-in at a faster speed and then progressive acceleration gives you a much faster corning speed as it dips the weight opf the car forward into the corner gaining the extra grip you needed to turn-in.
For example, round the figure of eight track I was corning at 29 mph in the standard manner before the front end would wash out, trailing the brakes allowed me to corner at more like 45 mph - it really made that much difference!
This certainly seems to blow in the face of slow in fast out - much more like fast in, fast round, faster out.....?!?!
Edited by chumley-warner on Thursday 30th August 14:27
Road and track driving is a world of difference (or at least it should be). Slow in and fast out is the ONLY way to drive on the road. If you don't allow large margins on corner entry it's going to hurt one day. A little power o/s on exit can be harmless fun in moderation, but steaming into the apex at full tilt under braking isn't really a good idea. On the road I usually do ALL the braking in a straight line and then power through the whole corner. It usually ends up being faster than some boy racer trying too hard on the way in and messing up the exit anyway. Plus it's a hell of a lot safer.
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