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Fighting understeer - looking for ideas

Old 11-08-2018, 01:21 AM
  #46  
951and944S
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Originally Posted by yoramw View Post
Looking on multiple options to continue improving my lap time:

Car related:
1. I have VEMS and fuel delivery upgrade waiting in the closet for install
2. I received an Audi V8 LSD (torsen) for little money and I hope to swap my open diff with it (I did it for a friend with an NA already so I know what needs to be done other than the trans oil cooler).
3. Continue to stiffen the rear (currently with 350lb, 8 clicks dialed in the coil overs)
4. Swap wheels for wider and larger 17"

#1 & #3 are easy
#2 & #4 doable, but will take more time

Driver related:
1. Watch my videos over and over... (doing it already)
2. Get more time with an instructor on the track
3. Get some driving simulator lessons - we have a top notch simulator instructor here and I am quite a numbers guy, so the telemetry I get there is also quite helpful

Obviously I can't do all for the two races I have in the coming weeks, so I want to zoom in two or three items first.
What would you recommended?

Thanks so much for your help so far.
Don't bother fine tuning any further the suspension until you decide on the diff, it'd be counterproductive to retune again.

17", depending on tire, you can probably get away with without changing too much the circumference, I know in Hoosier R7, there is a 17" that's no different than the 16" we run, 18", not so close. In treaded tires like appear to be on your car, no idea.

Is this door to door actual racing or time attack..?

T
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Old 11-08-2018, 10:38 AM
  #47  
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Thanks for the tips.
Yes, it is threaded semi slicks type tyre (Currently Hankook RS-3 Z222. The Toyo R888r I think are grippier were not available)

It is a Time Attack style competition... Too scared to take on real head on race at this point.
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Old 11-08-2018, 04:17 PM
  #48  
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Originally Posted by yoramw View Post
Thanks for the tips.
Yes, it is threaded semi slicks type tyre (Currently Hankook RS-3 Z222. The Toyo R888r I think are grippier were not available)

It is a Time Attack style competition... Too scared to take on real head on race at this point.
Ashamed, since your one biggest gain aside from you having a driving epiphany is going to be tire.

As Patrick alluded, your tires have finite grip, think of it, whatever tire you have as 100% grip.

If you are using 40% of the tire's grip in braking, you only have 60% to use for cornering.

Through time and experience, you can continue a percentage braking whilst still turning to use as close to 100% of grip at all times, either braking, acceleration or turning.

The drivers that can keep a car at the highest percentage level of traction will be fastest in a same given car.

Smooth is fastest but these tracks (vids you have shown so far) are very busy.

Are you left foot braking....? That's one way to gain time by cutting down on that transition and also creatively adding grip to the front end.

T
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Old 11-09-2018, 05:29 PM
  #49  
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I am not left foot braking at this point. I will give it try...
A side from the time it takes to move the right foot between the two pedals, is scenario that requires braking and accelerating at the same time (I can think of rev matching while downshifting, but there I need the left foot for the clutch)
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Old 11-09-2018, 10:11 PM
  #50  
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Originally Posted by yoramw View Post
I am not left foot braking at this point. I will give it try...
A side from the time it takes to move the right foot between the two pedals, is scenario that requires braking and accelerating at the same time (I can think of rev matching while downshifting, but there I need the left foot for the clutch)
You are transferring weight to the front axle when you brake, it's an obvious progression to left foot brake.

T
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Old 11-12-2018, 07:41 PM
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LFB is something you need to practice first. I found that it was easiest to learn the modulation with an Automatic car. Your Left leg/foot soon learns to stop jabbing at the brake pedal and you flying through the windscreen lol.
You don't do it while shifting gears. It's best used for long sweeping corners where you stay in one gear. When you enter the corner you can dab the brake with left foot which brings the nose down and allows you to hit the apex without having to back off or apply more steering wheel lock.
With practice you can enter the corner at higher speed and sort of swoop through it maintaining speed. Therefore higher exit speed. Win - Win.
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Old 11-12-2018, 08:09 PM
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This makes total sense to me. Thanks a lot!
Funny, but I have already started practicing LFB on my automatic daily car last week...
I will be back at the track on Thursday and I will see if I can already gain something from it or if I need more practice even for a minimal gain.
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Old 11-15-2018, 05:25 AM
  #53  
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Not sure if you've ever driven a GoKart but they have 2 pedals which you obviously operate left foot left pedal (brake) - right foot right pedal (accelerator). It doesn't take long to get used to in an Auto car.
That's all l drive at the moment and I would lfb probably 80% of the time. Use both pedals at the same time a lot. Sure, it wears out pads sooner but on a track car you won't even notice it because you won't lfb much.
It's generally more just a tap to bring nose down than full hard cadence braking. You also have to learn to heel and toe comfortably too if you're not already.
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Old 11-18-2018, 07:12 PM
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I found this question of left-foot braking, which was never mentioned in any of the several track driving classes I've attended, intriguing, so I did some googling, and found both proponents and detractors of the method. This is the most balanced article I found, and it support's Patrick's view of when it should and shouldn't be used:

http://www.racershq.com/intro10/

I've been practicing it in our road cars, and don't find it to be unnatural at all - anxious to try it out at my next track session.

Last edited by Cloud9...68; 11-18-2018 at 08:52 PM.
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Old 11-18-2018, 08:19 PM
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There is a section of our local track (not NOLA) know as "the peanut" that I drive flat on the throttle 4th/3rd gears just slowing and steering/rotating with brakes.

Time saving (mentioned in article) is a legit enough reason but imagine an esses switchback set up with 4 cones or barrels that you can make it through at 60mph.

After the exit of the last cone/barrel is long straight.

Enter at 80mph, stay on WOT, modulate enough brake pressure to limit speed to 60mph then just let off brake completely when you are clear since you are already WOT.
Doing the last bit also has effect of transferring weight back to rear for traction on exit.

Another benefit is, you can do your brake pedal tap to set pads while still on WOT when you approach a corner.

T
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Old 11-18-2018, 08:26 PM
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Net is kind of in the way, and there are probably no other know vids I can share because camera is on a more downward view that normal for some reason, but

make this video full screen and you will see examples of everything I am describing.

WOT + brake when close to another car's bumper, setting brake pads, etc., etc.


(This is 8V NA start with 10 SP1 cars and 3-4 SP2 cars behind (except for brief moment he loses lead - main cars in from are SP3 968/944S2/T)

T
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Old 11-20-2018, 02:22 PM
  #57  
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I use left foot braking almost every place where I have to decelerate without downshifting. It allows me to overlap brake and gas so that boost is building as I come off the brakes.

Also helpful for setting the pads against the rotors after knockback or when checking for brakes before entering a high-speed braking zone.
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