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Porsche Club AutoX - Saturday, Aug 30th

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Patrick View Drop Down
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Post Options Post Options   Quote Patrick Quote  Post ReplyReply Direct Link To This Post Posted: 02 September 2014 at 3:58pm

Originally posted by AllanJ AllanJ wrote:

Hey Patrick,

I know you want to learn so that's why the peanut gallery spoke up.  Kudos to you.

Wow, lots there to take in! Let me come back tonight after I've had a chance to digest it all. Thanks Al.

 

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karnak View Drop Down
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Post Options Post Options   Quote karnak Quote  Post ReplyReply Direct Link To This Post Posted: 02 September 2014 at 4:36pm
Here are a couple more links to some runs but please turn down your speakers...

https://www.youtube.com/watch?v=e9awv5Ww2lc

https://www.youtube.com/watch?v=9Le1Fjb-ofQ


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Post Options Post Options   Quote AllanJ Quote  Post ReplyReply Direct Link To This Post Posted: 02 September 2014 at 5:09pm
No problem.

This is all general "performance" driving knowledge that
I've been mentioning to Gary over time but it still takes
a while for everything to gel in your head. It took me a
while!

One more example from when I was there last time:

Rich drove the 914 and felt it understeered. He couldn't
get it to turn in without plowing. Gary felt the same
way. I was a bit surprised because I thought the car was
fairly balanced.

So I adjusted the shocks to move the balance a bit so the
front had more grip (and the rear had less grip).

When I drove the car at lunch, the car sucked! It was
oversteering horribly in linked turns. So I undid my
change and put the car back the way it was.

What was going on between me and Rich? Rich asked me how
I got the car to turn in nicely when all he dealt with
was understeer.

I'll go back to my previous post about weight transfer
and grip levels front to rear.

When Rich drives the car, he has a tendency to get all
the braking done in a straight line before the turn, and
then gets off the brakes quite quickly and is back on the
gas. So what's going to happen is he enters the turn
either neutral weight or even rear-weighted. What are the
tires doing? You will have less than desired grip up
front and with a light front end (on a mid-engined car),
you will often get understeer. Not much weight on those
front tires and it's hard to turn.

What do I do? I "trailbrake" into the turn. I'll dive
into a turn, braking fairly late. By the time I'm ready
to begin my turn, I'm still going too fast to make the
turn without sliding, so I need to keep applying the
brakes. Applying the brakes moves the weight to the
front, giving more pressure to the front tires, giving
them more grip. No understeer for me and the car is
rotating just fine! But as I increase the steering input,
I'm taking away from my overall grip levels because the
car needs tire grip to turn. So as I feed in more
steering, I'm REDUCING the brake level.

Simplified summary of tire grip distribution:

Braking in a straight line: 100%
Turning: 0%

Starting turn with 10% steering
90% braking

Getting into turn with 25% steering
75% braking

Mid-turn 50% steering:
50% braking

Max turn angle 100%
0% braking - completely off brakes now because I'm using
all my potential grip to turn

Time to accelerate out of the turn, reverse of the above

Unwind wheel to 90% turn level:
10% gas

Unwind wheel to 50% steering
50% gas

Out of turn at 0% steering input
100% gas

That kind of thing.

For Gary's car, I'd rather it be set up the way I drive
it because I believe (and so does every car manufacturer
that sells cars in countries that have lawyers) an
understeering car is safer. You don't want to make an
emergency maneuver on the highway to avoid some debris
and end up in a spin! Also, if you have to make an
emergency turn to avoid something, chances are you'll
instinctively lift off the throttle or get on the brakes
and then turn the wheel - an understeering car responds
perfectly to this situation.

One other thing: when I first autocrossed my GT3 I was
understeering everywhere because I drove it wrong. I was
overslowing for a turn and then back on the gas at the
start of a turn, when I wanted to rotate the car. It's
very hard to turn a 911 when only 1/3 of the overall
weight is at the front and you are artificially making
that be even less because you're on the gas at turn
entry. So I'd be plowing through cones all the time. Race
like crazy to the next turn - and mow down more cones. It
was brutal. It wasn't until I understood weight transfer
and how it affects grip levels that I finally drove the
car better.

Weight transfer is key. Understand how that works and how
it affects grip levels and you're well on your way.


Edited by AllanJ
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AllanJ View Drop Down
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Post Options Post Options   Quote AllanJ Quote  Post ReplyReply Direct Link To This Post Posted: 02 September 2014 at 5:13pm
Originally posted by karnak karnak wrote:

Here are a couple more links to some runs
but please turn down your speakers...
https://www.youtube.com/watch?
v=e9awv5Ww2lchttps://www.youtube.com/watch?v=9Le1Fjb-ofQ


Cool!

My ears are bleeding and I feel sea-sick, but cool!

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karnak View Drop Down
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Post Options Post Options   Quote karnak Quote  Post ReplyReply Direct Link To This Post Posted: 02 September 2014 at 7:53pm

ya.. sorry about the noise. I promise I will work on that


Rich was keenly interested in how I was driving and carefully watched what I was doing. when it was his turn, he performed maneuvers with the car I did not seem were do-able. by the end of the day, I had applied some bits here and there. he drove it well.
the mid engine design car (Fieros, etc..), I believe can be set up well but the driver is indeed the biggest variable. we all need to get out there and apply what we know and be observant.

we had old American muscle, all wheel drive, and even an old Volvo there, all swaying to those cones in their own ways. they all were impressive in their own ways. (and if you are still reading this and it does not sound like Bla, Bla, Bla.. then please consider coming to the next event. all these words can be boiled down to some simple things that will help anybody drive more soundly) it is fun stuff!

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Post Options Post Options   Quote AllanJ Quote  Post ReplyReply Direct Link To This Post Posted: 02 September 2014 at 8:14pm
Originally posted by karnak karnak wrote:

...when it was {Rich's} turn, he performed
maneuvers with the car I did not seem were do-able. by
the end of the day, I had applied some bits here and
there. he drove it well.

Rich is a great driver. He has great balance when it
comes to drifting too. I suck by comparison. lol!

Originally posted by karnak karnak wrote:

...(and if you are still reading this and
it does not sound like Bla, Bla, Bla.. then please
consider coming to the next event. all these words can be
boiled down to some simple things that will help anybody
drive more soundly) it is fun stuff!

Indeed! The other key benefit is that the average
speed of autocross is about 60km/h so the car control
skills you learn here are directly applicable to city
street driving. Skills you learn here can save your
bacon!
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Post Options Post Options   Quote Patrick Quote  Post ReplyReply Direct Link To This Post Posted: 04 September 2014 at 1:27pm

Originally posted by AllanJ AllanJ wrote:

The other key benefit is that the average speed of autocross is about 60km/h...

...which is why the BCCC autocross a few weeks ago was rather invigorating when we were entering the stop box at 115 km/h!

Al, you've gone over a ton of helpful stuff. Thanks so much.  I often wish there was a way of having a sweeper set up at a track and then just do that one sweeper over and over and over again until it feels just right. The UBCSCC Autocross 101 which I've taken a couple of times sort of does that, but I'd love to find an abandoned parking lot somewhere out the middle of nowhere and just turn up there with a number of cones. I think that's what it'll take for all this information to actually sink in.

Gary commented that Rich seems to plays tricks with his feet while driving the course. He uses his left foot to brake so as to reserve his right foot for GO duty. Is there some value to learning this technique, or is there a danger of over-complicating things?

One thing I haven't mentioned during any of this discussion of my handling issues is the fact that I've never had the wheels properly aligned on my Formula at a shop.  You may now wonder.. "What the heck!" Keep in mind that Colby and I did a rough alignment (to the best of our ability), but the reason why I didn't take it to a shop is that I wanted to finalize my choice of suspension components first. Among other things (ball joints/struts/shocks/zero-lash end links/sway bar poly bushings) I put lowering springs in, which are a heck of a lot better the factory springs, but as I've mentioned previously, I'm not 100% satisfied with them. Call me thifty/cheap/frugal, but I didn't want to be spending $100+ for alignment more times than necessary. Once I decide for sure what I want to stick with, I'll take the car to a shop and have everything set to specs. That just might improve the handling.



Edited by Patrick
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Post Options Post Options   Quote AllanJ Quote  Post ReplyReply Direct Link To This Post Posted: 04 September 2014 at 7:46pm
There is a way to have you do a sweeper over and over
again, but it'll cost you a lot of money to book the
track.

I do have about 20 cones....

Re: left foot braking: IMHO, don't bother. It's a skill
that takes a long time to learn properly. Over the years
of driving you have done, you have developed a super
sensitive touch to your right foot when on the gas and
brakes. Your left foot just goes in/out on the clutch.
The time it takes to develop a sensitive left foot can be
quite long.

Some modern cars like mine (2004), don't respond well to
left foot braking. You can go on the brakes for about a
second or two before the fuel is cut off. So trying to
use both pedals for any length of time won't work on a
newer car.

Kids who grow up racing carts learn left foot braking at
a young age and can carry that skill to race cars and do
extremely well. They will be faster than an old fart like
me or you. So I don't know. I haven't bothered to
learn it but thinking about it more, you may want to play
with it if you're curious. Try it when you drive to work,
but with nobody close behind you. lol!

That pro autox guy I mentioned a while back said that if
an experienced autox driver tried to learn left foot
braking, expect to be slow for a full year before seeing
any benefit. This is also with a much longer racing
season that you are currently running now (and tons of
practice on the street).

Yes, getting alignments can be costly. Make some
decisions and get it sorted, man!
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Post Options Post Options   Quote Capt Fiero Quote  Post ReplyReply Direct Link To This Post Posted: 05 September 2014 at 1:49pm
I have kept quite in these autocross threads, but thought this to be slightly funny. If you grew up driving in the 60's/70's or just had older cars in the 80s you probably got experience with left foot braking when you came to a stop on a cold day. Fighting to keep that carb'ed car from stalling at stop lights. One foot slightly on the gas and left food modulating the brake as you came to a stop.

      I also read on another autocross group of some of the problems with left foot braking, can be loss of engine vacuum. If your right foot never comes off the gas, especially in turbo cars, (yes even with boost check valves) you may not close the throttle enough for the engine to make enough vacuum to replenish the brake boosters vacuum supply. Then losing your brakes. IIRC a number of years ago there was a woman in a Corvette at the Boundary Bay area lost control of her car and lost braking, either went into the crowd or staging area, I can't completely remember the details.   

So just a few things to think about when it comes to left foot braking.
Capt Fiero
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Eight Fifty Seven GT V8 5spd.
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Post Options Post Options   Quote Rich Sandor Quote  Post ReplyReply Direct Link To This Post Posted: 05 September 2014 at 4:26pm
Quote Gary commented that Rich seems to plays tricks
with his feet while driving the course. He uses his
left foot to brake so as to reserve his right foot for
GO duty. Is there some value to learning this
technique, or is there a danger of over-complicating
things?


The hardest part for me was remembering to go back to
normal braking when entering the stop box. Otherwise
your left foot is committed to the brakes and there's
no way to clutch in... = stall!

It takes time to learn, for sure, and for ME, it is
faster. However I have seen data for GT drivers in the
same car, getting the same times with and without
LFB.. however I'm not sure either was going as fast as
humanly possible. The advantage is multiplied on a
course with more corners (like autox) and not as
noticeable on a course with few corners. However, I
still think LFB has the potential to be faster.

It's undeniably advantageous on older cars with big
turbo lag..

I mostly wanted to weigh in because on the previous
autocross I was bitching about Gary's 9146
understeering, but I didn't have the problem this time
around. I noticed Al mention that perhaps I wasn't
trail-braking.. the thing I realized is that I *was*
trail-braking, but I was starting too late and
carrying too much speed.. the car just wouldn't turn
in.

This time I was braking earlier and smoother and that
let me carry more momentum into the corners.
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Post Options Post Options   Quote Patrick Quote  Post ReplyReply Direct Link To This Post Posted: 06 September 2014 at 12:40pm

Originally posted by AllanJ AllanJ wrote:

I do have about 20 cones....

Gary and I will keep our eyes open for a large abandoned paved area.  I'm sure Colby would be delighted to suggest some locations as well, but Saskatchewan is a bit far to go for autocross practice.

 

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Post Options Post Options   Quote Patrick Quote  Post ReplyReply Direct Link To This Post Posted: 06 September 2014 at 12:48pm

Originally posted by Rich Sandor Rich Sandor wrote:

The hardest part for me was remembering to go back to normal braking when entering the stop box. Otherwise your left foot is committed to the brakes and there's no way to clutch in... = stall!

...

Hey Rich, welcome to our little corner of the automotive universe.

I don't recall seeing you doing the left foot braking when driving my Fiero during course setup/testing. Were you doing it, and I simply missed it, or is left foot braking something you only do in cars you're familar with?



Edited by Patrick
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Post Options Post Options   Quote Rich Sandor Quote  Post ReplyReply Direct Link To This Post Posted: 06 September 2014 at 7:32pm
I was doing it in the Fiero. I LFB in any car that I'm
racing. (no need in street car..)

And the newer cars respond quite well to it - as long as
you're not trying to overlap too much throttle w/ gas. I
LFB in the new corvettes and 911s and it doesn't upset
the computers at all.

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Post Options Post Options   Quote Patrick Quote  Post ReplyReply Direct Link To This Post Posted: 07 September 2014 at 1:21pm

Originally posted by Rich Sandor Rich Sandor wrote:

I was doing it in the Fiero. I LFB in any car that I'm racing.

You're smooth Rich, very smooth... I didn't even notice.  Of course, when you were piloting the Fiero while we were testing the course, it's no surprise that I wasn't staring into the driver's side footwell. I was more interested in where we were headed.

I'm curious about trying out this left foot braking now. I'll see whether an old dog can learn a new trick.

 

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Post Options Post Options   Quote karnak Quote  Post ReplyReply Direct Link To This Post Posted: 08 September 2014 at 9:42pm
Welcome Rich!
as you can see, your run made the best video for quality, although not your fastest run by far, but does show a nice line and driving skill. i enjoyed watching the car go around.

i really had a great time!

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Post Options Post Options   Quote AllanJ Quote  Post ReplyReply Direct Link To This Post Posted: 20 September 2014 at 8:43pm
Hi Rich!

Thanks for jumping in. I was going from a combo of an
obviously foggy memory when you drove a different time
with me in the car and then some theories.

I forget how long it takes to cut the fuel in my car
if you are braking. Didn't seem that long when I tried
it. I trailbrake a lot but then again, I'm also used
to longer turns at a racetrack right now so my sense
of timing is probably biased towards that, and not the
shorter turns in autox.

Patrick, keep us posted on what you do. I'm always
curious.

Cheers,
Allan
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