Pistonhead's Steve after gear selection issue at Donny today

[rudeboy]

You'll enjoy this one. Taken today at Donny.

http://uk.youtube.com/watch?v=eKstcSXKynE

I'm in the Elise being video'd from behind in my brother's 205. This was v.close indeed.

[SimonV8ster]

Was that going through the Craner curves ??

[GravelBen]

Bit of a close call there, nice evasive action

[steil]

SimonV8ster said:

Was that going through the Craner curves ??

Old Hairpin. Nice evasive action though!

[mikey_p]

Loved the noises the 205 was making. You could hear it creaking and squeaking .

[rudeboy]

Yeah just on the last right hander of the craner curves, known to me now as the 'brown trouser curves'. I was pushing 100+ through the left hander and doing at least 90 at the time of the incident, luckily I was already on the brakes and the beamer went the right way. From inside the cockpit it was very very close indeed, no harm done so 'Happy Days!!'

We gave Steve a right ribbing yesterday, I'm sure it must have been the sun-burn that was making his face red.

[trackdemon]

Blimey, did the engine survive? Looks like you did exactly the right thing, ie drive in a straight line - spinning cars will (almost) always rotate out of your way.....

[rudeboy]

Yeah the M3 was fine. I couldn't understand it at first, it looked like he'd just hand braked it. As there was no harm done we all had a good chuckle about it (well, after I'd slipped on a spare pair of undies)

[LocoBlade]

I had a similar albeit not quite so close shave following one of the BaT Caterhams at Anglesey last year

http://uk.youtube.com/watch?v=-CaeD6HJ3y8

[bad_roo]

Never driven at Donington. Is it standard drill to downchange in the middle of that bend? Seems an odd place to start grabbing gears.

[rudeboy]

Nice footage, I think you obliged to get the back out on those BAT cars (its somewhere in the contract)

For the first 2-3 sessions I was changing down under braking around the 'old hairpin' but later on I just left it in 4th.

[instructormike]

The view from the passenger seat of the M3 was even more "interesting"! All in a day's work for an instructor ( and also M3 owner!). Ha!!!
The reason for the spin was simple. Coming into the braking area for the Old Hairpin our driver braked - but put his attention on the looming Elise - and went for a somewhat rushed gearchange. We had discussed 4th being a gear that could be stayed in on this corner, which would aid turn-in accuracy and weight transfer management, but a gear was (mis)-selected anyway. I instructed to keep the clutch in but this didn't register in time and another stab at the gear lever put us in 1st. By this time enough speed had been lost that, as the clutch came up, the revs were down to idle, the torque change broke traction, and we spun. I watched Elise-man as he locked the O/S front-relatively unloaded- aimed left, and missed us. Thanks Nick! Once on the grass I suggested not giving it the boot as it would bring grass on the track - ever thoughtful me. So, we booted it, brought grass on the track and into the tyres and carried on.
The gearchange had been a bit of an issue (with heel&toe downchanging) through the day and, subjected to a bit of following car stress, manifested itself at corner entry. C'est la vie

[bad_roo]

I recall a long while back before I'd learned heel and toe that I used to brake in a straight line for a corner, clutch in, turn the car in and then downchange, while lifting the clutch and feeding the power back on. Only as I learned more about driving quickly did I realise how horribly wrong this technique was but I still see it being used a lot on track days by novice drivers. Can't blame them as, like me, many will only learn by falling off.

[instructormike]

You are correct. Being able to get the gearchanging done whilst maintaining the braking force that you want and also keep a little for the turn-in is one of the biggest issues that people have on track as it can't really be properly achieved without a H&T change. If any "conscious" thought is applied to this during the brake/turn-in phase it invariably messes up the corner entry/approach. I usually spend the first half of any day with the M3 (or Leon Diesel we used to use) leaving the car in 4th for the whole lap(!) and getting decent turn-ins. Once this is mastered put the gearchange back in and then the pilot can usually see that the lack of gerachanging skill really does hamper the smoothness that they have developed far more than any advantage in drive out of the corner that a lower gear would give them. Then they spend a day with me off-track learning to gearchange:-)
If you can't H&T just put the gear in over the last phase of the braking, coming off brake/clutch together. Less engine speed increase -> less torque change -> less transient introduced.
MikeC

[chris_w]

instructormike said:

You are correct. Being able to get the gearchanging done whilst maintaining the braking force that you want and also keep a little for the turn-in is one of the biggest issues that people have on track as it can't really be properly achieved without a H&T change.

Hi Mike,
interesting comment as it's something I've been thinking about recently and nearly posted a whole thread on...

I do some sprinting in a 1380 mini stripped and prepped for track work with CR box, LSD and slicks. Last year I was H&T'ing quite happily but the introduction of a lightweight flywheel during the off season means that H&T'ing seems to be redundant. You can now bang the gears home quite happily during braking without any problems with locking (due to the lack of the engines inertia?) so I now concentrate on braking alone rather than confusing things with what would now have to be an extremely finely timed H&T due to the revvy nature of the new engine. Does this just mean that I'm not braking hard enough hence why the theoretically more violent non-H&T downshift is not proving a problem?

Any thoughts much appreciated!

Chris

PS apologies for the thread hi-jack, nice avoidance by the way!

[instructormike]

Hi Chris,
It's a really interesting aspect of the drive the brake/downchange/turn in. You are almost always, by its very nature, braking for a turn. The braking helps the turn - this is why the new circuit at Ty Croes generates understeer as there are a couple of elements to some corners where you can't get the braking to work for you - Bet it would be a better circuit the other way around.BUt that's yet another post.....
Simply put there is a rev rise in the engine on a down-change, unless you are braking so hard that during the clutching the drop in speed almost takes you to the same revs in the next lower gear - ponder on that for a while. Also think on these aspects:-
The less rotational inertia the engine has the less energy is needed to speed it up.
If the speed up of the engine isn't fuelled the energy has to come out of the car - the twitch or torque change.
The harder you brake the easier a H&T change becomes. Holding a significant force on the brake pedal accepts a small deviation as you rotate your foot slightly.
Boxes can sometimes benefit from a double declutch (I double declutch on every h&t downshift) or even no clutch at all - crash/non-synchro...
I used to find I could reduce the stopping distances in a Leon Diesel that we used to use by going down through all the gears. So, for example, at Donington main straight before the esses you'd do a 5/4/3/2 downshift braking from about 120-45. That car had reasonable engine inertia but would blip quite well once remapped - REVO doing its stuff. With 330mm AP discs it would take distance out of virtually every car I've been behind at that point on the circuit. Of course the greater the rotating mass of the engine the more engine braking you get.
Incidentally, changing the dual mass to a single mass flywheel on the GT3 improved the h&t braking into corners more than the drive out.

These posts get longer by the day :-)

MikeC

Edited by instructormike on Friday 10th August 23:16