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Help my lap sector 3 at Knockhill

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Thu Jul 17, 2014 1:30 pm PostPost subject: Help my lap sector 3 at Knockhill
andybell
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So I had a track day last Friday and was trying to break my fastest (1:00:55 in red) but managed a 1:00:88in blue. The weather was perfect on Friday so expected better but hey ho. So in looking at sector 3 I can get 0.21 faster but I am struggling to understand how I should be driving it. Sector 3 being the bit in yellow in picture below

http://1drv.ms/1nAeONR

Now the difference between lap is:

    I exit out of the chicane pretty much same and sector starts with ~1mph difference
    Now due to my rev range/gearing I hit redline halfway between chicane exit/next corner so have to go 3rd-4th
    Then to get round corner I have to drop to 3rd - wasteful I know other possibility is bounce redline for a bit. The distance between going 3rd-4th-3rd is only about 70meters.
    On the lap where I was 0.21 quicker rather than brake before corner I use the change down to drop my speed - I was trying different things to see speed difference
    I still think that I should be able to hold more speed round corner
    asdas


So given my gearing should I bounce off limiter to keep things going
Brake v's let car slow down via gear chance - I presume better to hard on brake later so car is better balanced

Or should I get an instructor Smile
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Thu Jul 17, 2014 1:59 pm PostPost subject:
David Long
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I'd be looking at your line - difficult to see on your image but looks like blue cuts the apex harder. Red you are much deeper but are able to get on the power a lot earlier. Select 'average' throttle trace on CT and you see that time on the throttle is more for the red. More = faster lap.

IMHO it is worth staying off the kerb at Clarks (easier said than done) otherwise your rear wheels will be off the ground when you want to put the power on.
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Thu Jul 17, 2014 2:34 pm PostPost subject:
HummuH
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Also bear in mind that weather conditions can have an affect on your times too and that the track will evolve in some form throughout a day.

Last Friday was baking. For me, when it's hot at Knockhill (not often admittedly) I find the track c. 0.5 to 0.75 secs slower. I can be pounding round, convinced I've set a PB only to find out I'm 0.75secs slower.

That aside, get as much instruction as you can, it will help when trying to find 1/10ths as well as making you better all round.
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Fri Jul 18, 2014 8:21 am PostPost subject:
andybell
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thanks both for feedback and hummuh that was exactly feeling I was getting driving round I thought 'that was a really good lap' and looked at the lap timer and it said 1:02 :/ I just assumed more heat=more grip!

Yeh i guess i have to keep in mind the apex as you can almost feel the car becoming slightly unhinged at times - it appears that clarks is my biggest challenge at the mo!
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Fri Jul 18, 2014 8:45 am PostPost subject:
HummuH
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andybell wrote:
thanks both for feedback and hummuh that was exactly feeling I was getting driving round I thought 'that was a really good lap' and looked at the lap timer and it said 1:02 :/ I just assumed more heat=more grip!

Yeh i guess i have to keep in mind the apex as you can almost feel the car becoming slightly unhinged at times - it appears that clarks is my biggest challenge at the mo!


As David says, for a good exit you need to avoid the kerb IMO. You can get on the throttle earlier with a later turn in and avoiding the kerb.

I think you'd make up more time by having less apex speed but better exit speed as that counts massively going down the back straight where more time will be gained.

If you look at my video of race 2 of SMRC last weekend, that's how I got past Chris. He took too much kerb at Clarks which allowed me to get on the throttle earlier letting me past a car with equal acceleration.

My 2p's worth.
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Mon Sep 01, 2014 11:52 am PostPost subject:
Haggis
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Andy, I know that we have exchanged messages before, so I do understand that you are experience-limited when it comes to the track.

I think that what is going on here is indicative of that fact.

The first couple of things to be aware of, in my view, are track evolution related and unless these were back to back laps on a fairly fresh (ie not over-temperature or over-pressure, irrespective of wear rate) tyres, then the comparison doesn't really make any sense. Where the laps were in different sessions and at different times of day, you can expect far more variance than you will ever expect due to track temperature and condition, tyre temperature and condition, engine temperature and ambient temperature just for starters. Beyond that you can look into track contaminants and grip co-efficient, none of which the data trace can show you.

There are further questions too here, such as when you have lap times as close as this (and I don't know if you have further laps in this bracket or not, or whether these two are close but you have no others close to them) perhaps you could assume that this is about as fast as you and the car will go in it's current configuration - a lap time grouping span of 0.2 would be utopia to most racers, for example. This may not be the case, but you can start to get an idea of the exact number of variables that what looked like a simple starter question throw up.

In short, if that is possible, the data trace is all very well but it shows so little of what you are doing with the car that drawing any meaningful conclusion is nigh on impossible, as the minimal number of respondents to the thread should allude to. It tells nothing of exactly where you were on track and whether or not you were more left or right of the track than the faster lap, aiming more into or out of the corner than on the faster lap, arriving with more front or rearward weight bias than on the faster lap, and all of this is before we dissect the fact that on lap you braked and accelerated and on the other used the drag of the lower gear to set the corner speed up. What the data does show is that you were on the throttle earlier and as a consequence the sector was faster - in other words are you chasing the unicorn here, and if everything else is discountable as being identical, then is it just as straightforward as that?

If this is beginning to sound complicated then there is the chance that there is a very good reason for that. I know it's really easy to tell people to walk before they can run, and difficult sometimes to explain why, but this is a case in point. Data traces are only helpful when you can exploit the car to it's best effect in it's current configuration and beyond that, as you are experiencing, they can tie you in knots you didn't even know existed - there have been quite a number that I have seen of late and to folk who are still learning they can be as counter-productive as they can be helpful.

H.
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Mon Sep 01, 2014 12:01 pm PostPost subject:
AK
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VBOX data can show you lines... and you can compare lines against other laps to quantify or at least try and understand what is helping and where :/

I cant load the pic so just guessing what it is just now Laughing
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Mon Sep 01, 2014 1:21 pm PostPost subject:
andybell
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So I am now in midst of changing tyres which give a bit more grip but are slightly heavier (cr500 to A048) so something I will need to bear in mind at next trackday. Conditions are indeed key and yes my experience is sum total maybe 13-14 trackdays so newbie!

One thing I am noticing is that it appears that whilst the car could do very slightly under a minute it appears I am far from this Smile I need to learn that the limit of the car is something that I need to reach rather than backing off.

Looking at my typical lap times it appears I can get 1:02's totally fine, 1:01's every few laps and 1:00's pretty much not at all. No real consistency but with less power I am more susceptible to having to pull over which does mean less chance to do a clean lap (cough excuse)

Spending lots of time looking at laps I think its coming down to:
more balls at the s's as you come up the brow of the hill - my typical laps show me hitting 60mph as I exit ready for the mini-straight. Fastest lap was 70mph! More balls please! I basically go hard on throttle and then half way up hill lift off and no brake - shameful eh? I need to get into habit of throttle or brake not coast.
Clarks - It appears the 'no brake use gears to slowdown' is not a recipe for a faster lap and it unbalances the car.
Interestingly if I get more speed on straight it means I carry more speed down hill but less ability to get on power and get a better line to first McIntyre

So how do people get the bigger balls - just trusting in the car and risk taking a little trip into the gravel occasionally? I feel myself going up s's and then not keeping power on.

Due to work this year (nearly made redundant and not wanting to spend money) I didn't get track time I desired but next year looking to get some instruction for sure
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Mon Sep 01, 2014 1:43 pm PostPost subject:
AK
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different approaches for different folk... i tend to over drive or try to take a corner too fast/brake too late <wheres Davids vid Laughing then wind it back Laughing I can then usually creep onwards again, lap after lap just holding foot to the floor a little longer, braking a little later, or holding more speed through corners. In the later case i'll start to alter lines/trail brake to see what helps get the car round the corner (McIntyres especially)

Big areas where I have felt I gained in the past were having the trust in the car to take the base of duffus and butchers (between McIntyres and Chicane ) flat in my car, with the faintest of taps on the brakes to get the weight on the nose of the car for going over the hill at the chicane (just under 80mph). Its been so long since I've been out in my own car on the normal direction that i'll prob need to build up to it again.

Clarks for me is a funny one... I had a sweet line after some tuition with Hamish, but I find my self quite inconsistent on using lines Very Happy Def avoid the kerbs, and experiment with lines, taking a late turn in. Do 5 laps with a late turn in, 5 laps early etc etc

From looking and and comparing VBOX traces It does appear that squaring off clarks (later turn, early on power) helps cars with a bit more grunt. Cars like the Minis just need to get round it with out losing any speed Very Happy

100% lifting and not braking but using gears is going to cost a lot of time at clarks. I cant pin point my exact braking point from memory but its way past half way up the straight and require lots of braking. Time off the throttle or brake is lost time.
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Mon Sep 01, 2014 1:56 pm PostPost subject:
AK
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is there any way you can link the img rather than url to dropbox? I cant access it
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Mon Sep 01, 2014 2:06 pm PostPost subject:
AK
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https://www.youtube.com/watch?v=SsKtFo-Rx_U

Using your video vbox to see lines/positioning and what not
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Sun Sep 14, 2014 12:26 pm PostPost subject:
andybell
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as others have said avoiding kerb is definitely the way to drive clarks as I can make up 0.3 on that alone
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Mon Sep 15, 2014 3:37 pm PostPost subject:
Olivera
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andybell wrote:
as others have said avoiding kerb is definitely the way to drive clarks as I can make up 0.3 on that alone


Turkington put his car on pole (and IIRC also a lap record) at the BTCC this year using lots of kerb at Clarks!
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