Trackers, on a scale of 1 - 10...

[Shaun]

..with 1 being completely wrong, and 10 being completely correct, how do the following score in your opinion, assuming the aim is to drive the car well, and drive the track well:

1) T4 Sepang, you are supposed to brake hard a couple hundred millsec just before turn entry. The steering wheel input for this turn entry is supposed to be from 0 to ~170 degrees of steering wheel input in under a couple hundred millisec - nearly a step input

2) T5 and T6 of Sepang being described as "flat out acceleration corners".

The car in this case in a typical showroom stock road car, ~1.5 tons, street tires, ~220hp, RWD.

Just curious as to what most trackers think of the above.. thanks.

 

[jwwu]

Re: Trackers, on a scale of 1 - 10...

1) 1- braking a couple of hundred millsec (i.e. 0.2 seconds) = no way, the braking event is longer than that for sure. Super quick steering input (if it's even possible), it's probably going to destablise the car.
2) 1 - flat out all the way, based on the car assumptions = no way. 20hp car with slicks = maybe

 

[kuvesh]

Re: Trackers, on a scale of 1 - 10...

haven't driven a rwd with 220hp but my guess is:

1) from memory i am around 180km/hr going into t4. need to brake sooner than couple hundred milisec. 170degrees seem to sharp - give this is a 1

2) t5 i never have enough grip to go flat out. t6 can give a lot more but not flat out (have spun out there a few times in fact...) - give this a rating 2

 

[kai3323]

Re: Trackers, on a scale of 1 - 10...

Track driving - 1.

Drift driving to break traction? Maybe 4-5. Not tracked for a while......but shouldn't guy be banned/black flagged from open trackdays in Sepang?

 

[reardriven]

Re: Trackers, on a scale of 1 - 10...

1. I will brake hard about 2 secs maybe, come off the brakes and feed in the lock but not with such speed as you describe.

2. Part throttle. Not flat out. Cos my car does not generate downforce like race cars.


Questions

T7/8 - need to clip both apexes or just "miss" both??? If I clip the first I miss the second, unless i brake in-between which i suppose is wrong.

T12 - any advice? looks daunting before you approach but is really easier by the feel when going through it

..with 1 being completely wrong, and 10 being completely correct, how do the following score in your opinion, assuming the aim is to drive the car well, and drive the track well:

1) T4 Sepang, you are supposed to brake hard a couple hundred millsec just before turn entry. The steering wheel input for this turn entry is supposed to be from 0 to ~170 degrees of steering wheel input in under a couple hundred millisec - nearly a step input

2) T5 and T6 of Sepang being described as "flat out acceleration corners".

The car in this case in a typical showroom stock road car, ~1.5 tons, street tires, ~220hp, RWD.

Just curious as to what most trackers think of the above.. thanks.

 

[Shaun]

Re: Trackers, on a scale of 1 - 10...

Thanks all of you for giving your views. Waiting to hear from a few more before explaining the reason I asked heheh

==

Reardriven mate, your questions have some long answers and will get another thread of their own sometime soon while this topic runs its course. In the meantime here's a screengrab of some some basic parameterization of T7 and T8 from back in 2009 and based on 2007 imagery lol. It is the first step of the process which was for inputs to simulation for a race team. As only the basic geometries are shown at this stage, he answer is not contained in the screengrab, but one area shows clearly why nearly all classes of car face tradeoffs at T7 and T8, especially road cars. Can you see which dimension specifically? The driven solutions are different too depending on a few variables. More later ok? I want to finish this topic first. Hope you don't mind man.

The scale is shown and the 44+, 47+ figures are diameter, not radius, and of the driven line, not the track inside boundary. These and the, 5.8 figure have to be scaled (top left first image) to get real distance. To keep things simpler, vehicle track width is assumed 0, which makes the tradeoff appear very slightly larger than it really is versus say a typical road car track width of around 1.8m on a 16m circuit width.

and here's a closer view

 

[harold996tt]

Re: Trackers, on a scale of 1 - 10...

Point One:

Add extra weight to the front just before turn with the heavy brake application just before turn in to get additional grip on the front before getting an acute angle... so u are suggesting "pivoting the car around turn 4" with a slight possible break in traction in the rear wheels- although the rear may not even break with a 220bhp car. Could mean more speed into the turn and less time off the gas... I would say maybe.... 5 to be neutral. But never driven a 220bhp rear drive so really hard to gauge (covering my ass here for a stupid answer).

Point Two:

Only 220bhp and a pretty heavy car... may be able to go close to full throttle. But in my cars zero chance of that. I am always part throttle all the way till I see the straight away line part way through 6.

Now dazzle me with your biometric lines and pretty pictures data man.... And on June 28 I want the answer for those turns and all other turns in a 540bhp 4wd mid engine car!!!

 

[reardriven]

Re: Trackers, on a scale of 1 - 10...

Very technical Shaun. Sorry I catch no ball.

I found out that if I turn in early for T7 like what you traced in the diagram, I am unable to go all the way to the left side of the track (where 5.80 is printed) but instead go on a "shallower parabola" (is that the right word? dang i'm geometrically challenged)..if not my T8 feels "unnatural". hee

 

[MachoMan]

Re: Trackers, on a scale of 1 - 10...

1) I think with a 1.5 ton car on street tyres, braking that late into a corner (off-throttle I assume) with massive and quick steering inputs will have a high chance of oversteer at corner entry. From my experience, I get better laptimes by avoiding late braking and get the car settled nicely before turning in. So I'll give 2/10.

2) Depends whether he goes flat out right from entry. Or lift off slightly, turn in, then flat out. Maybe a tail heavy car may benefit with more throttle on. But either way, a showroom stock car on street tyres going flat out through T5-6 is too exciting for my liking. I have only seen formula cars on full slicks do that. 3/10.

Maybe shaun has some answers that is contrary to our general opinions? Surprise us :shock:

T7-T8. I tried a few ways to tackle them. And I find that missing the T7 apex slightly (maybe 0.5-1m) and clipping T8 apex gives me better exit speed for T8 and thua reap the benefits in the long stretch before T9. But then I only have about 8 track day experience at Sepang

Let's let Shaun finish this topic before we continue on T7-T8. I'm curious if my line works too.

 

[MachoMan]

Re: Trackers, on a scale of 1 - 10...

Actually, come to think of it.. I have seen someone drive in a style quite similar to the two points Shaun raised. But maybe not so extreme though... But similiar... :thinking:

 

[powersteer]

Re: Trackers, on a scale of 1 - 10...

1) T4 Sepang, you are supposed to brake hard a couple hundred millsec just before turn entry. The steering wheel input for this turn entry is supposed to be from 0 to ~170 degrees of steering wheel input in under a couple hundred millisec - nearly a step input

hmm, I've not driven in Sepang often enough to qualify a proper comment ... so pardon me if I'm wrong.

Do you mean this:

or this:

 

[Racebred]

Re: Trackers, on a scale of 1 - 10...

ahah.... are we allowed to take the patented secret line for turn 4, if no one is watching? You easily save half a second. hehehe

 

[Shaun]

Re: Trackers, on a scale of 1 - 10...

Actually, come to think of it.. I have seen someone drive in a style quite similar to the two points Shaun raised. But maybe not so extreme though... But similiar... :thinking:

Pudgy Malay fella? Big brand instructor? I have some videos of him at Sepang..

 

[TripleM]

Re: Trackers, on a scale of 1 - 10...

1. Scale 1
For me, hard braking into braking zone in straight line and by the time steering is ready for turn in, ease off the brake pressure n let the car roll
Steering angle is never 170 deg. That will only happen if u go wide and miss the apex .

2. Assuming in 3-4 gears into T5 at entry speed of say conservatively at 120kmh and then flat out carrying the speed to T6? That's got to be a freak car to be able to do that, which is F1 cars only.
But if u r crusing at 6 gears into T5 and then tap the brake lightly w/o dropping gears n WOT then yeah u can WOT coz the throttle input is probably useless to generate the acceleration. ...hehehe...

 

[racingminds]

Re: Trackers, on a scale of 1 - 10...

Hmmmmm.......

 

[Shaun]

Re: Trackers, on a scale of 1 - 10...

Now dazzle me with your biometric lines and pretty pictures data man.... And on June 28 I want the answer for those turns and all other turns in a 540bhp 4wd mid engine car!!!

Do you mean geometric?
It'll be a miracle if 28th June really does happen mate lol

Hmmmmm.......

Jyoji, yes? What does the knowing wink signify? haha

===

Shawn, input?

Jack and Simon, thanks!

 

[powersteer]

Re: Trackers, on a scale of 1 - 10...

2. Assuming in 3-4 gears into T5 at entry speed of say conservatively at 120kmh and then flat out carrying the speed to T6? That's got to be a freak car to be able to do that, which is F1 cars only.
But if u r crusing at 6 gears into T5 and then tap the brake lightly w/o dropping gears n WOT then yeah u can WOT coz the throttle input is probably useless to generate the acceleration. ...hehehe...

i think my road car shd be able to take T5-6 flat too.
.
.
.
.
.
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in 1st and 2nd gears only.

 

[racingminds]

Re: Trackers, on a scale of 1 - 10...

lol nothing~~dropping by to say hi since I'll prolly be on the forums here more now. Returning to Sepang this saturday too after a 1year+ hiatus.

 

[Shaun]

Re: Trackers, on a scale of 1 - 10...

lol nothing~~dropping by to say hi since I'll prolly be on the forums here more now. Returning to Sepang this saturday too after a 1year+ hiatus.

Cool, I'll be up there Fri and Sat.. see ya

Time to beat in an E46 M3 on semis is around 2:36 set by some pretty modified E46 M3s and a a couple CSLs, CSL should be 34s though.. maybe even high 33s. Stockish Z4M (brakes, wheels) on semis also floating around 35, 36.

 

[totoseow]

Re: Trackers, on a scale of 1 - 10...

ahah.... are we allowed to take the patented secret line for turn 4, if no one is watching? You easily save half a second. hehehe

that wheel line inside curb dun work la.