Track forum general chit chat

[nicknaz]

Originally Posted by CanAutM3

Fine tuning a chassis is a complex science, easier to screw up than to improve upon.

1000% agree.

Props to the members doing their own test and tune and experimentation

[SYT_Shadow]

Originally Posted by nicknaz

I’ve seen members post about switching out from 1 set of full coilovers to another, and presumably they would keep right height similar after corner balancing, and keep the alignment the same as a first pass.

And didn’t you have a base m4 and now CS? Is there a spring rate difference but not ride height difference there?

Edit; nyg, I have some spare channels in the logger of my SM. If you send over some infrared sensors and a baller jrz coilovers setup, I’ll keep the ride height the same between the “spec” competition suspension and the jrz and we can test and tune and get to the bottom of this

No real reason to. Call Bimmerworld, there is zero doubt about it.

The cause I proposed may be incorrect, however, the effect is undoubted.


Aaaaand I'm traveling in Denver this week but I got a pic from home, my four sets of Bimmerworld flow forged wheels have arrived!!!!! YAY!!!!

[MyFragileHalogen]

Originally Posted by nicknaz

Thanks for the good wishes. It’s fun and I wish I got into it sooner. But even cheap w2w adds up. Lol.

I do think you should re read that article I posted ( the whole point of which is that you shouldn’t be on throttle that early)

I don’t know about some of the Miata advice your giving man.... I’d still want to hit the apex markers, and should be carrying so much more entry speed that you need to wait until apex go back to throttle (this is specifically what I’m working on. My “feel” of a good entry speed is from 3500lb street tires car still, and it’s now got to be 2200lb competition tires car) , and wouldn’t early apex

It’s really not that different tracking SM and F8x, in my opinion. It’s just that the momentum spec car exposes any technique gaps in a pretty brutally honest fashion. (Eg you come in last)

Well, I guess a key difference is my maintenance and tire bills per hour of seat time are a lot lower, and if there’s an off or mechanical it’s a lot cheaper (eg $500 Gearbox and $2k used engine with 20k miles)

Sorry that I dumped the whole thing without taking time digesting your point and articulating mine. I do respect your knowledge and experience and I am sure you are a lot more involved with the serious Miata thing.

I did enjoy thinking about the idea. It's wild! It would be closer working one for an early apexing, momentum preserving Miata on shorter corners. Maybe some drivers with real good control can pull the circus on some other longer corners. Still there would be many situations need throttle to maintain/control car's pitch or throttle steer.

M4 and Miata lines have to be vastly different. M4 needs late apex on most of corners except short connecting ones because it's traction limited upon track out (and it's a lot more important to rotate and get out of corner ASAP). However, Miata can go full throttle with a lot more steering angle and hence taking the same line as M4 is totally wasteful; it can carry a lot more speed by taking earlier apex. Taking early apex and carrying more speed so that it's effectively traction limited upon exit would be more optimal.

The 'not hitting apex' theory is what I wanted to experiment after driving M4 again but have not validated on Miata, but you still can enjoy thinking about it. It's like a kart line- making line wider to carry more speed. I think at some corners (not all corners) it may work. Well precisely not completely like kart line because Miata can still accelerate better than that.. but there will be an optimal line in between.

Having all that said, I would still want to get on full throttle as early as possible. I'd recommend watching our chief driver (LOL) Joerg Weidinger's M4 GTS driving while paying attention to sound how early he's on the throttle and where car is pointed to with respect to apex and exit when he's on throttle. Also looking at steering at the moment shows how much rate of rotation he's getting.

But yeah, I am always learning and willing to be enlightened anytime.

[CanAutM3]

Originally Posted by MyFragileHalogen

Sorry that I dumped the whole thing without taking time digesting your point and articulating mine. I do respect your knowledge and experience and I am sure you are a lot more involved with the serious Miata thing.

I did enjoy thinking about the idea. It's wild! It would be closer working one for an early apexing, momentum preserving Miata on shorter corners. Maybe some drivers with real good control can pull the circus on some other longer corners. Still there would be many situations need throttle to maintain/control car's pitch or throttle steer.

M4 and Miata lines have to be vastly different. M4 needs late apex on most of corners except short connecting ones because it's traction limited upon track out (and it's a lot more important to rotate and get out of corner ASAP). However, Miata can go full throttle with a lot more steering angle and hence taking the same line as M4 is totally wasteful; it can carry a lot more speed by taking earlier apex. Taking early apex and carrying more speed so that it's effectively traction limited upon exit would be more optimal.

The 'not hitting apex' theory is what I wanted to experiment after driving M4 again but have not validated on Miata, but you still can enjoy thinking about it. It's like a kart line- making line wider to carry more speed. I think at some corners (not all corners) it may work. Well precisely not completely like kart line because Miata can still accelerate better than that.. but there will be an optimal line in between.

Having all that said, I would still want to get on full throttle as early as possible. I'd recommend watching our chief driver (LOL) Joerg Weidinger's M4 GTS driving while paying attention to sound how early he's on the throttle and where car is pointed to with respect to apex and exit when he's on throttle. Also looking at steering at the moment shows how much rate of rotation he's getting.

But yeah, I am always learning and willing to be enlightened anytime.

I guess it all depends how we define the "apex". For me, the apex is not a fixed point on a given corner, it varies depending on which line the driver elects to drive around said corner.

To be fast around a corner, you need to decelerate all the way to the apex and accelerate from there (unless the entry speed is insufficient due to the track layout). That "maintenance throttle from turn-in to apex" taught at HPDE events is complete BS. Watch any pro-driver video with telemetry and it is very obvious. It's important to note that one can also be partially on the throttle to balance the car and use throttle steer and still be decelerating on the way to the apex. The earlier you apex, the earlier you can be on the throttle. Late apex is safe, early apex is fast. And yes, it is possible to early apex with the F8X, you use the power to induce more rear lateral slip and generate rotation on track out. It takes finesse and lots of balls to do though, but it's tons of fun.

[MyFragileHalogen]

Originally Posted by CanAutM3

I guess it all depends how we define the "apex". For me, the apex is not a fixed point on a given corner, it varies depending on which line the driver elects to drive around a specific corner.

To be fast around a corner, you need to decelerate all the way to the apex and accelerate from there (unless the entry speed is insufficient due to the track layout). That "maintenance throttle from turn-in to apex" taught at HPDE events is complete BS. Watch any pro-driver video with telemetry and it is very obvious. It's important to note that one can also be partially on the throttle to balance the car and use throttle steer and still be decelerating on the way to the apex. The earlier you apex, the earlier you can be on the throttle. Late apex is safe, early apex is fast. And yes, it is possible to early apex with the F8X, you use the power to induce more rear slip and generate rotation on track out. It takes finesse and lots of balls to do though, but it's tons of fun.

Yes apex changes. I get that idea and happenings that occurs from braking as late as possible- that we all try to do. Places such as double apex (with a fake apex), sweepers and long hugging corners and such are where I can't just hold on brakes all the way to the length. Pro driving videos show definitely shows less maintenance throttle however there are places they still do it although it may be shorter than what non-pro drivers do.

[nicknaz]

Originally Posted by CanAutM3

it is possible to early apex with the F8X, you use the power to induce more rear slip and generate rotation on track out. It takes finesse and lots of balls to do though, but it's tons of fun.

What you described is something I would really really want to work up to doing in my 911.

I find it a bit intimidating with how fast the rear rotates in those conditions, plus timing when there will be boost is tricky for me still.

There are so many more costs and consequences that I find myself super hesitant to experiment and I stick with slower entry and using the corner exit grip to power out (aka noob tactics)

[Lappy]

Quick question for you guys. Im starting to mess with the car and got it out of stock autox class. In stock class I went through a wide range of tires on the stock wheels.

Fronts: 265/35/19, 275/35/19, 285/35/19 (these rubbed front and rear fender liners at times and required a 7mm spacer)
Rears 275/35/19, 285/35/19, 305/30/19 no issues with either set up.

Now that I moved on to a different route, that includes lowering the car and camber plate along with 19x10 square wheels, I see no reason why a 305/30/19 can't fit up front and just run 305 square. Anybody here ever try a 305 front tire? I'm thinking if I get the offset to about 17-18, it should have no problem with clearance, and the fact that a 305/30 is shorter than a 285/35, there should be no fender liner contact in the front or rear of the front wheel well.

[NYG]

305 is not an easy fit in the front of the f8x AFAIK

[CanAutM3]

Originally Posted by Lappy

Quick question for you guys. Im starting to mess with the car and got it out of stock autox class. In stock class I went through a wide range of tires on the stock wheels.

Fronts: 265/35/19, 275/35/19, 285/35/19 (these rubbed front and rear fender liners at times and required a 7mm spacer)
Rears 275/35/19, 285/35/19, 305/30/19 no issues with either set up.

Now that I moved on to a different route, that includes lowering the car and camber plate along with 19x10 square wheels, I see no reason why a 305/30/19 can't fit up front and just run 305 square. Anybody here ever try a 305 front tire? I'm thinking if I get the offset to about 17-18, it should have no problem with clearance, and the fact that a 305/30 is shorter than a 285/35, there should be no fender liner contact in the front or rear of the front wheel well.

From what I gather, it is difficult to fit 305 in front without having to roll the fenders to avoid rubbing.

I would love to run a 305 square setup, I am just not ready to alter my car that much .

[Lappy]

Originally Posted by CanAutM3

From what I gather, it is difficult to fit 305 in front without having to roll the fenders to avoid rubbing.

I would love to run a 305 square setup, I am just not ready to alter my car that much .

I have 305s laying around. I'll report back, based off what I see, it really should not be hard with 3 degrees.

[F3IGHTY]

Originally Posted by Lappy

I have 305s laying around. I'll report back, based off what I see, it really should not be hard with 3 degrees.

Good luck, been there with 315/30-18’s. Ran the car for a few hundred miles and slowly ate away the liners. Running 295/30-18 on an 11” wheel now and it’s perfect. Lots of geometry changes in my situation but even with stock arms I think 295 is the sweet spot.

[MRV99]

Originally Posted by CanAutM3

I guess it all depends how we define the "apex". For me, the apex is not a fixed point on a given corner, it varies depending on which line the driver elects to drive around a specific corner.

To be fast around a corner, you need to decelerate all the way to the apex and accelerate from there (unless the entry speed is insufficient due to the track layout). That "maintenance throttle from turn-in to apex" taught at HPDE events is complete BS. Watch any pro-driver video with telemetry and it is very obvious. It's important to note that one can also be partially on the throttle to balance the car and use throttle steer and still be decelerating on the way to the apex. The earlier you apex, the earlier you can be on the throttle. Late apex is safe, early apex is fast. And yes, it is possible to early apex with the F8X, you use the power to induce more rear slip and generate rotation on track out. It takes finesse and lots of balls to do though, but it's tons of fun.

I can attest that I was using maintenance throttle pre apex and was seriously hindering my lap times. I had an instructor which has 30k laps in various racing series ride with me in one of the sessions and confirmed my "known issues" and talked me through correcting them. I was too hard on the brakes, too early which cause me to slow down too much which I turn caused me to use maintenance throttle. After 30 min session of constant braking reminders, feedback and advice, I finally gained the feeling and confidence. My lap times at Road America dropped 5 seconds because of it. I gained about 10mph on each straight away because of it.

[MyFragileHalogen]

Basic but just wanted to clarify the terminology, early vs late apex thing. Ignore the 'fastest line' marker- it all depends on type of car and type/distance of next corner.

[dth656]

Originally Posted by MRV99

I can attest that I was using maintenance throttle pre apex and was seriously hindering my lap times. I had an instructor which has 30k laps in various racing series ride with me in one of the sessions and confirmed my "known issues" and talked me through correcting them. I was too hard on the brakes, too early which cause me to slow down too much which I turn caused me to use maintenance throttle. After 30 min session of constant braking reminders, feedback and advice, I finally gained the feeling and confidence. My lap times at Road America dropped 5 seconds because of it. I gained about 10mph on each straight away because of it.

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)

[MRV99]

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)

It is tough to explain because he was talking specifically about what I was doing at the time. It focused on being smooth with the brake coming in the braking zone and letting off to carry more speed adding some trail braking. I knew what I needed to do it was just having that person there to give me some feedback and information while it was happening. Then it was taking that info and trying to duplicate it in the next sessions.

Unfortunately there is no silver bullet to fix it because every driver does things a bit different. Take the best drivers and that all approach it a bit differently

[MaynardZed]

Originally Posted by MRV99

It is tough to explain because he was talking specifically about what I was doing at the time. It focused on being smooth with the brake coming in the braking zone and letting off to carry more speed adding some trail braking. I knew what I needed to do it was just having that person there to give me some feedback and information while it was happening. Then it was taking that info and trying to duplicate it in the next sessions.

Unfortunately there is no silver bullet to fix it because every driver does things a bit different. Take the best drivers and that all approach it a bit differently

Bingo. You don’t mash the brakes. More finesse and lots of seat time to perfect. Use the brakes to begin rotating the car, then the tire’s slip angle (scrubbing) will naturally help slow the car as you approach the apex. The rear may release a little, but as you add some throttle back in, it will settle. Plus you’ll have the benefit of the car already being rotated more towards corner exit.

In other words: Use your brakes less for slowing you down and more for turning the car. Your lap times will improve dramatically.

[CanAutM3]

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)

It seems like what you are being taught is the "basic" HPDE approach. It is safe and gets beginner to be smooth. It is however not the fast way around a corner. As I posted earlier, the fast way around a corner is to decelerate all the way to the apex as you are tightening the arc and then accelerate from the apex on as you increase the arc.

Proper braking technique and transition to throttle while coordinating steering input is the key here. A common mistake I see is students being light on the brakes early in the braking zone and then relying on added brake force to adjust the entry speed. There are two fundamental reasons why this is bad. First, by applying light pressure on the brakes they heat up and you then need to rely on hot brakes to slow you down more. This is a killer for brake endurance and life. Second, as you turn-in, you want to be applying less braking, not more. The trick is to be hard on the brakes right at the start of the braking zone, application needs remain smooth (i.e. squeeze, don't stomp on the brakes) but you need to be at maximum brake force right at the onset of the braking zone. You then adjust your entry speed by progressively releasing the brakes. This allows for a very smooth transition into turn-in and allows for seamless trail braking all the way to the apex if needed, plus you do most of the hard braking using cooler brakes fresh from barreling down the straight. The more steering input you give, the less brake force has to be applied. It is a balancing act up to the point where you get the car pointing in the right direction, you then get on the throttle to settle the rear managing deceleration down to the apex. You then get on the throttle more to start accelerating again at the apex while unwinding the steering wheel.

[jmg]

This thread makes me want to leave work early.

[MyFragileHalogen]

I really appreciate the thing that nicknaz brought up, "carrying so much speed into a turn so that you can't get on throttle even by apex." Although I would still imagine it (my lowly opinion ) as a Miata-like thing in order to maximize momentum (perhaps would be scary to even hit the apex) as it does not gain much by maximizing track out acceleration like M4, the continuing discussions with y'all made me think about the mid-corner phase in a way I didn't.

One way to look at how to minimize the mid-corner phase (between end of braking and full throttle, which I incorrectly labeled as "maintenance throttle" that caused confusion- sorry I never heard that term in that way before), I have to avoid the traction circle hanging near maximum x point (thinking as x-horizontal and y-vertical axis, as shown in attached screenshot from Pobst's GT4 video) as much as possible. So looking at these pro drivers' traction circles around the mid-corner shows how they handle it; such as how quick they are on full throttle after end of braking, except a long corner. But even at a longer corner (like that turn of Laguna in the screenshot) Pobst might be handling the mid-corner phase a bit different than I do a longer corner. So much fun!

Oh, also seeing how much he spends on braking while wheel is turned (traction circle in diagonal direction, he stays there for a while at few corners) implies how late he starts braking and fast he enters the corner.

[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.

[CanAutM3]

Originally Posted by MyFragileHalogen

I really appreciate the thing that nicknaz brought up, "carrying so much speed into a turn so that you can't get on throttle even by apex." Although I would still imagine it (my lowly opinion ) as a Miata-like thing in order to maximize momentum (perhaps would be scary to even hit the apex) as it does not gain much by maximizing track out acceleration like M4, the continuing discussions with y'all made me think about the mid-corner phase in a way I didn't.

One way to look at how to minimize the mid-corner phase (between end of braking and full throttle, which I incorrectly labeled as "maintenance throttle" that caused confusion- sorry I never heard that term in that way before), I have to avoid the traction circle hanging near maximum x point (thinking as x-horizontal and y-vertical axis, as shown in attached screenshot from Pobst's GT4 video) as much as possible. So looking at these pro drivers' traction circles around the mid-corner shows how they handle it; such as how quick they are on full throttle after end of braking, except a long corner. But even at a longer corner (like that turn of Laguna in the screenshot) Pobst might be handling the mid-corner phase a bit different than I do a longer corner. So much fun!

Oh, also seeing how much he spends on braking while wheel is turned (traction circle in diagonal direction, he stays there for a while at few corners) implies how late he starts braking and fast he enters the corner.

What you want to be doing for optimal cornering is ride, progressively and constantly, the rim of that friction circle from turn-in to apex to track out.

[MyFragileHalogen]

Originally Posted by CanAutM3

What you want to be doing for optimal cornering is ride, progressively and constantly, the rim of that friction circle from turn-in to apex to track out.

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.

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