Track forum general chit chat

[CanAutM3]

Originally Posted by MyFragileHalogen

Right sir! How one travels along that rim matters (depth and which place you want to spend most of time) in order to brake late and accelerate out fast. Just getting that circular path doesn't mean much.

Well, there's no "depth" to a rim, so there aren't that many options .

As I posted, you need to ride that friction circle rim progressively and constantly from turn-in to apex to track out. If you are not riding the rim, you are not maximizing grip. You are at maximum forward deceleration (max braking) right up to turn-in, as you release the brake and progressively turn the steering wheel you progressively transfer more and more tire grip from longitudinal to lateral grip. At the apex, the slowest section of the corner, you are at maximum lateral acceleration (max cornering). At that point, you start applying more throttle while unwinding the steering wheel, progressively moving from maximum lateral to maximum longitudinal acceleration at track out.

The reason why it is possible to be at full throttle right at the apex on some corners depending on the car, is that engine power by itself might be insufficient to ride the tire's true friction circle limit, so it becomes a question of balancing the car's speed with the turning radius.

Originally Posted by MyFragileHalogen

One more (realistic) consideration would be speed on that corner and how close walls are. Has to take time on that one.

Where walls a located is irrelevant to what needs to be done for fast laps

[Gomeler]

Originally Posted by MyFragileHalogen

My advice to people who start to learn trail-braking is to pay attention to how weight shifts. First find a safe corner free of walls and try braking about 20-40% (to be safer) and then start smoothly turn the wheel, assuming it's left turn, and feel how weight moves from front end to the right front and then to the right as you release brake pressure. As you turn wheel and weight shifts you can feel suspension being loaded (springs are compressed) to front right side- it's a great feeling as it's loaded and ready for 'action.' From that you can manipulate the vector (direction and amount) of the weight by both brake and steering inputs to see how car reacts and find limits. Eventually it can be done from higher braking pressure, higher speed..and (maybe..) where walls are close.
Key is careful, incremental experiments and feel of and smoothness in weight transfer. Then.. brake pedal from throttle pedal transition should (be smooth enough to) maintain how weight is loaded as before beginning track out of the corner.

If an instructor is not quite happy with your smoothness, most likely you are not smooth enough. Sometimes it may feel like you are doing smooth enough for what you do and they sound like a bit too much (for even their driving pace); but as you get faster and faster, YOU will need that smoothness eventually.

Something else, learn trail braking preferably on an increasing radius turn, and just practice on the same corner over and over again. Having a very forgiving turn makes for a much more pleasant learning experience. You will likely spin the car quite a few times.

Relating to braking, it should ramp quickly to threshold braking limits, and taper towards the apex, or so I was taught. You have to be extremely careful about tapering and lifting off the pedal, if you go from 20% brake to none, you will upset the car and spin if you're already at the grip limit. Luckily with RWD cars you can then just throttle out if you're comfortable enough, but it's slower than running the perfect line. It does give you a nice ego boost when you recover a spin via liberal application of the throttle pedal.

[SYT_Shadow]

Originally Posted by CanAutM3

Where walls a located is irrelevant to what needs to be done for fast laps

you speak the truth hehe

[MyFragileHalogen]

Originally Posted by CanAutM3

Well, there's no "depth" to a rim, so there aren't that many options .

As I posted, you need to ride that friction circle rim progressively and constantly from turn-in to apex to track out. If you are not riding the rim, you are not maximizing grip. You are at maximum forward deceleration (max braking) right up to turn-in, as you release the brake and progressively turn the steering wheel you progressively transfer more and more tire grip from longitudinal to lateral grip. At the apex, the slowest section of the corner, you are at maximum lateral acceleration (max cornering). At that point, you start applying more throttle while unwinding the steering wheel, progressively moving from maximum lateral to maximum longitudinal acceleration at track out.

The reason why it is possible to be at full throttle right at the apex on some corners depending on the car, is that engine power by itself might be insufficient to ride the tire's true friction circle limit, so it becomes a question of balancing the car's speed with the turning radius.

Where walls a located is irrelevant to what needs to be done for fast laps

I might be digging in a little to deep than necessary, or my thought may not be the fastest way, but what I have been trying out is that (for example) in addition to that circular rim I could pull that a bit more outward at a spot as I needed more rotation in a hairpin without throwing car into drift mode. I presume the friction circle is a (an ideal) theoretical concept that could be a bit different in reality depending on cars and corners. Or maybe I was not riding on the true friction circle in which I could have gone on a larger radius circle? I will find that out some day. Except that there may be some special cases, I agree with your explanation- very nicely put as always.

Hey it ain't a video game and walls are scary! Just have to precisely determine worst case scenarios and proceed with more carefully experiment.

[CanAutM3]

Originally Posted by MyFragileHalogen

or my thought may not be the fastest way, but what I have been trying out is that (for example) in addition to that circular rim I could pull that a bit more outward at a spot as I needed more rotation in a hairpin without throwing car into drift mode. I presume the friction circle is a (an ideal) theoretical concept that could be a bit different in reality depending on cars and corners. Or maybe I was not riding on the true friction circle in which I could have gone on a larger radius circle? I will find that out some day. Except that there may be some special cases, I agree with your explanation- very nicely put as always.

Hey it ain't a video game and walls are scary! Just have to precisely determine worst case scenarios and proceed with more carefully experiment.

Originally Posted by MyFragileHalogen

I might be digging in a little to deep than necessary

Digging deep is fun

Originally Posted by MyFragileHalogen

or my thought may not be the fastest way, but what I have been trying out is that (for example) in addition to that circular rim I could pull that a bit more outward at a spot as I needed more rotation in a hairpin without throwing car into drift mode.

By principle, the "rim" of the friction circle is where you are able to get the most lateral force from the tires. From inherent physics, tires need to slip to generate lateral force, which means the tires are slipping laterally as you a "riding the rim".

To be able to get "more rotation", you need to vary the front-to-rear slip ratio of the tires without having to go beyond the friction circle limits.

Originally Posted by MyFragileHalogen

I presume the friction circle is a (an ideal) theoretical concept that could be a bit different in reality depending on cars and corners. Or maybe I was not riding on the true friction circle in which I could have gone on a larger radius circle? I will find that out some day. Except that there may be some special cases, I agree with your explanation- very nicely put as always.

At maximum grip, you are still on the "rim" of the friction circle regardless of the turning radius, what varies is the speed. In fact, the speed varies to the square root of the radius arc.

Disclaimer: in real life, it is not a true "circle" as the maximum grip in each direction varies depending on each individual tire design, but the concept remain valid nonetheless.

[nicknaz]

Originally Posted by dth656

hi---do you mind talking about some of the feedback you rcved? I feel that I'm doing something similar, due to the instruction I have rcved while in the beginner run groups w/ hooked on driving and similar. basically, brake in a straight line, maintenance throttle during turn in and up to the apex, then add throttle as you unwind the steering and track out.

i'm assuming that this is part of the reason my laptimes are so slow (2:24ish at T-hill 3-mile w/ bypass)

Hi, I can share some aim data from my SM if you are interested, and I can ask the faster drivers (eg doing 2:08 in their SM in that configuration) who shared their data with me if I can share with you also.

it wouldn’t be apples to apples obviously but should give you some ideas

Are you at the point where you can use dsc off safely? My $0.02 would be to start there if you are still using mdm.

[nicknaz]

Originally Posted by MyFragileHalogen

I might be digging in a little to deep than necessary, or my thought may not be the fastest way, but what I have been trying out is that (for example) in addition to that circular rim I could pull that a bit more outward at a spot as I needed more rotation in a hairpin without throwing car into drift mode. I presume the friction circle is a (an ideal) theoretical concept that could be a bit different in reality depending on cars and corners. Or maybe I was not riding on the true friction circle in which I could have gone on a larger radius circle? I will find that out some day. Except that there may be some special cases, I agree with your explanation- very nicely put as always.

Hey it ain't a video game and walls are scary! Just have to precisely determine worst case scenarios and proceed with more carefully experiment.

Halogen, I personally think you are making it harder because you’re trying to do it via a theoretical discussion.

If you reviewed the brake pressure, throttle position, lat and long G and car position graphs plus compared vids, between you and a faster driver in your car, you’d get the list to to-Dos immediately (unfortunately, as I have found, it isn’t always possible to do the fixes in the same weekend).

I don’t know where you are located, but look at the fastest people on the lap times list in our sub and coordinate with those guys!!

For example, colatkitty matched randy P’s big willow time (in a borrowed m4 no less...) if he’s in your area, shoot him a PM?

[dth656]

Originally Posted by nicknaz

Hi, I can share some aim data from my SM if you are interested, and I can ask the faster drivers (eg doing 2:08 in their SM in that configuration) who shared their data with me if I can share with you also.

it wouldn’t be apples to apples obviously but should give you some ideas

Are you at the point where you can use dsc off safely? My $0.02 would be to start there if you are still using mdm.

Thanks Canautm3 and others for their input!

Nicknaz, yes that would be great if you don't mind sharing your AIM data (perhaps via video overlay?). I run MDM for the first session or two, then off for the rest of the day as temps and comfort level increase.

[OhioRiderAaron]

All the GT500 reviews just hit. Guess who's not getting much work done now !

[SYT_Shadow]

Originally Posted by OhioRiderAaron

All the GT500 reviews just hit. Guess who's not getting much work done now !

LOL

I've already read one, kind of disappointed.
4200lb. 93k for one with the track package.

How could I track something like that? It makes the GTR seem light.

It's probably still fast as hell due to HP and good chassis, but tracking a 760hp car that weighs 4200lb is going to get very, very expensive.

[OhioRiderAaron]

Originally Posted by SYT_Shadow

LOL

I've already read one, kind of disappointed.
4200lb. 93k for one with the track package.

How could I track something like that? It makes the GTR seem light.

It's probably still fast as hell due to HP and good chassis, but tracking a 760hp car that weighs 4200lb is going to get very, very expensive.

Yeah I'm a bit confused about one review that said it's better than the C8? Well of course it's better the C8's that are available atm, but that's not even a direct competitor IMO.

And wow, didn't realize it was 4200lbs! Yikes.

[F80Speed77]

Speaking of weight... had my 2015 on the scales at an SCCA event this past weekend and was really surprised to see the car come in a few pounds under 3400lbs!?! This was with a little under a half tank of gas and some of the trunk junk removed. It's a DCT car with HK, carbon roof, and dynamic suspension (executive package). Anyone else see anything similar or are our regions scales really far off lol?

[SYT_Shadow]

Originally Posted by F80Speed77

Speaking of weight... had my 2015 on the scales at an SCCA event this past weekend and was really surprised to see the car come in a few pounds under 3400lbs!?! This was with a little under a half tank of gas and some of the trunk junk removed. It's a DCT car with HK, carbon roof, and dynamic suspension (executive package). Anyone else see anything similar or are our regions scales really far off lol?

I weighed my M3 CS with corner scales and a full tank of gas. All original, totally OEM car. 3600lb.

Disappointing as my 2013 E92 M3 also weighed 3600lb in the same conditions

[nicknaz]

Originally Posted by F80Speed77

Speaking of weight... had my 2015 on the scales at an SCCA event this past weekend and was really surprised to see the car come in a few pounds under 3400lbs!?! This was with a little under a half tank of gas and some of the trunk junk removed. It's a DCT car with HK, carbon roof, and dynamic suspension (executive package). Anyone else see anything similar or are our regions scales really far off lol?

https://f80.bimmerpost.com/forums/showthread.php?t=974479

3562lb for no options 6mt f80 with full tank (aka lightest config).

Definitely time for club to recalibrate the scales. IMHO.

[MyFragileHalogen]

Originally Posted by nicknaz

Halogen, I personally think you are making it harder because you’re trying to do it via a theoretical discussion.

If you reviewed the brake pressure, throttle position, lat and long G and car position graphs plus compared vids, between you and a faster driver in your car, you’d get the list to to-Dos immediately (unfortunately, as I have found, it isn’t always possible to do the fixes in the same weekend).

I don’t know where you are located, but look at the fastest people on the lap times list in our sub and coordinate with those guys!!

For example, colatkitty matched randy P’s big willow time (in a borrowed m4 no less...) if he’s in your area, shoot him a PM?

Haha right! It's not easy to precisely describe in words while digesting new views and ideas and also trying to think how I was doing things. I am also just beginning to figure out the fun of all these arts. Nonetheless what you brought is very helpful to think about. This year I just jumped back into M4 and was focusing on matching turn in speed with my MX-5 (which is not bad but yet not quite optimal) and trying to figure out how to accelerate out of corners as soon as possible. While figuring out how soon i could progress to WOT, I was inevitably generating slacks. I need to get better at finding that point without sliding too much or having to wait and carry more speed to kill that slack up to that point while also maximizing braking G at every corners.

No doubt using the aim solo data (as well as getting into racing) would bring really quick improvement...but these might be a bit too stressful for me. and I am poor.

I wish Cal tracks were closer! Laguna Seca is 12h+ away. Some people drive down to Thunderhill which is 8hrs away.

[MyFragileHalogen]

Originally Posted by CanAutM3

Digging deep is fun

By principle, the "rim" of the friction circle is where you are able to get the most lateral force from the tires. From inherent physics, tires need to slip to generate lateral force, which means the tires are slipping laterally as you a "riding the rim".

To be able to get "more rotation", you need to vary the front-to-rear slip ratio of the tires without having to go beyond the friction circle limits.

At maximum grip, you are still on the "rim" of the friction circle regardless of the turning radius, what varies is the speed. In fact, the speed varies to the square root of the radius arc.

Disclaimer: in real life, it is not a true "circle" as the maximum grip in each direction varies depending on each individual tire design, but the concept remain valid nonetheless.

One of my favorite things are the feeling of weight loaded tires/suspension and weight's movement along the... rim, a very useful concept for easy visualization!

[MyFragileHalogen]

Originally Posted by F80Speed77

Speaking of weight... had my 2015 on the scales at an SCCA event this past weekend and was really surprised to see the car come in a few pounds under 3400lbs!?! This was with a little under a half tank of gas and some of the trunk junk removed. It's a DCT car with HK, carbon roof, and dynamic suspension (executive package). Anyone else see anything similar or are our regions scales really far off lol?

Your car is a LEMON!

[nicknaz]

Hi all, just wanted to share that I got my SCCA full comp license this weekend after completing my 7th regional race and a 2hr enduro

I had been working up to this for the last year so I’m really happy about it.

I’m still 6-7% off the pace of the podium winners in SM (eg really slow) and will keep chipping away at that next year.

[F80Speed77]

Originally Posted by MyFragileHalogen

Your car is a LEMON!

Maybe they forgot all the airbags?

[MaynardZed]

Originally Posted by nicknaz

Hi all, just wanted to share that I got my SCCA full comp license this weekend after completing my 7th regional race and a 2hr enduro

I had been working up to this for the last year so I’m really happy about it.

I’m still 6-7% off the pace of the podium winners in SM (eg really slow) and will keep chipping away at that next year.

Congrats! Having faster guys to chase is the quickest way up that learning curve. You'll get there sooner than you think. Good to see SCCA so active up there. Nothing at all from them here in AZ. Just NASA and ProAuto Sports.

I'm hearing SpeedVentures is starting to do more W2W racing? Anyone in SoCal can confirm?

I'm so far out ahead in points for ProAuto Sports, I might not race with them this weekend. Got a bunch of Pontiac parts I should sell at the Pontiac festival instead. Need to save up some dough$$. I really, really want an NP01. I've seen used ones getting down below $50K now. Might be a new fun challenge for me.



Ok, morning ponderings are over...

[Lappy]

Mine on SCCA scales, lightest m4 spec (CCB/19s/6mt/wireless charging/cloth) was 3540 with some crap in it and full on gas, so figure empty, low 3500s, less fuel somewhere in the mid to high 34xx range., a CS rolled up right after me and was heavier lol.

[PrimeBMW]

Originally Posted by nicknaz

Hi all, just wanted to share that I got my SCCA full comp license this weekend after completing my 7th regional race and a 2hr enduro

I had been working up to this for the last year so I’m really happy about it.

I’m still 6-7% off the pace of the podium winners in SM (eg really slow) and will keep chipping away at that next year.

They made you run 7+ races before giving you you full comp license?!!! Silly. As you watch all the veterans bump into each other and crash.