How fast is the GT86 on track?

[Griever423]

Originally Posted by CSG Mike

The new 5.0 is a really forgiving platform... you can do all sorts of stupid stuff with the power and recover. The Mustang's wheelbase is long, giving it a large moment of yaw inertia, so it's much easier to recover than one of the twins. Also, you have enough power available to just spin both rear tires if needed, whereas the twins can't really do that.

Interesting. The BRZ will be the first momentum car I've driven on a road course. Before the mustang it was an 06' STi which is a different experience altogether. I'm eager to see later in the season when it's not 105 degrees here in Texas what she's capable of.

[CSG Mike]

Originally Posted by Griever423

Interesting. The BRZ will be the first momentum car I've driven on a road course. Before the mustang it was an 06' STi which is a different experience altogether. I'm eager to see later in the season when it's not 105 degrees here in Texas what she's capable of.

The thing that everyone struggles with most, is that the car has enough power to spin one inside rear tire, which is enough to induce a spin, but not enough power to spin both tires, which makes it easier to recover.

[celica73]

Originally Posted by Griever423

Interesting. The BRZ will be the first momentum car I've driven on a road course. Before the mustang it was an 06' STi which is a different experience altogether. I'm eager to see later in the season when it's not 105 degrees here in Texas what she's capable of.

Um, every car is a momentum car.

[Sleepless]

Originally Posted by celica73

Um, every car is a momentum car.

While people have different definitions, I like the definitions that says a momentum car has more grip than power and thus requires a line through that maximizes corner speed, while a car that has more power than grip will gives up some corner speed to make the corner a bit sharper, and get on the power ASAP.

So, a momentum car has to optimize its grip, while a non-momentum car has to optimize its power.

[Kronos]

Originally Posted by Sleepless

While people have different definitions, I like the definitions that says a momentum car has more grip than power and thus requires a line through that maximizes corner speed, while a car that has more power than grip will gives up some corner speed to make the corner a bit sharper, and get on the power ASAP.



So, a momentum car has to optimize its grip, while a non-momentum car has to optimize its power.

Took the words right out of my mouth. You just beat me to the post 👍

[troek]

Thats a lesson ive learned and seems to work for me at least. I spent so much time playing gran turismo with high hp cars that when i went to the track in real life i found my self taking turns sharper so i could have a straiter exit so i could lay on the throttle but after getting passed in turns by toyota vitzs i started taking a more sweeping line and even though i had to roll onto power more slowly, i dropped as much as 1 second on some sections.

[celica73]

Originally Posted by Sleepless

While people have different definitions, I like the definitions that says a momentum car has more grip than power and thus requires a line through that maximizes corner speed, while a car that has more power than grip will gives up some corner speed to make the corner a bit sharper, and get on the power ASAP.

So, a momentum car has to optimize its grip, while a non-momentum car has to optimize its power.

troek gets it.

A high horsepower car that slows to 65 mph for a turn is somehow faster than the same high HP car that takes the turn at 70 mph. That never computes.

Anyone who uses that definition is probably using it as a crutch. You described the "easy" line (or the novice line). That line uses a traction "oval" rather than the full traction circle. It's hard to use all the available grip, even harder when there is a lot of power on tap.

Here's a riddle.

How long does it take a Corvette to accelerate from 65 mph to 70 mph? How much distance is covered?

How long does it take the same Corvette to accelerate from 70 mph to 70 mph? How much distance is covered?

Which Corvette got to 70 mph faster, and in the shortest possible distance?



On a slower, tighter turn (take turns 1-2 at VIR as an example) the "HP" line would have me brake deeper in a straight line, and take a later apex, then I get to romp on the throttle, and in doing so, I stay 15-20 feet from proper track out.

The "momentum" line has me trailbraking to the apex, then rolling onto the throttle at apex and being mostly full throttle at track out (and it's a nice drop off into the clay if you overshoot). In both cases I've started to apply throttle at the apex.

In case #1 I am going slower when I get on the throttle, and I have to cover more ground at the slowest speed.

in case #2 I'm already moving faster, I'm still applying throttle (at the same time) and I don't need to travel as far at my minimum velocity. Sounds like a win to me!

If you get out of HPDE and into racing, the HP line will also result in you getting passed on the inside. Every. Single. Time.

[Kronos]

Let see if I can clear up this misunderstanding in different trains of thought. I definitely see where you are coming from and your points ares valid. Obviously you want to take a high horsepower car or any car around the corner with the most momentum possible.

People like to refer to the GT 86 as a momentum car because subjectively speaking it's chassis could easily handle more power. The chassis is better than the tires and engine that it comes with . Therefore you need to use the chassis as the cars crutch as it's not going to be blasting out of corners. The chassis of this car is it's defining feature. Not the engine and not anything else really. And the term "momentum car" is simply referring to that.

That's how I look at it at least

But I do agree, if you want to be fast on the track, every car should be a momentum car

[CSG Mike]

All of the points above are valid. You have to balance momentum line with power line, based on the amount of grip and power a given car has.

The question is, are you going for a lap time or racing? If you're racing, are you using a fast lap line to catch up to the person ahead of you or run away from the one behind you, or are you taking a defensive line to prevent a pass?

That'll affect line as well.

[Sleepless]

Originally Posted by celica73

troek gets it.

I believe is was agreeing that there is a difference between HP and momentum cars. So, agreed, he "gets it".

Originally Posted by celica73

A high horsepower car that slows to 65 mph for a turn is somehow faster than the same high HP car that takes the turn at 70 mph. That never computes.

For me, it does compute just fine. However, first we need to break down the corner into entry and exit phases. There is no "make a corner at a certain speed"; one does not take a corner at a constant speed. Entry includes trail braking, therefore the speed is decreasing. The exit phase consists of accelerating, thus the speed is increasing.

The fast way through the corner in a high HP car is to give up a bit at mid corner (still using the full friction circle) in order to tighten the corner to shorten it and get to full power sooner. Effectively, the apex is later than on with a momentum car.

It works. I have a Palatov D2 which has 430HP and weighs 1900lbs so it is a great example of an HP car compared to the BRZ. I tried many lines in that car and compared to the BRZ, a later apex is faster.

Originally Posted by celica73

If you get out of HPDE and into racing, the HP line will also result in you getting passed on the inside. Every. Single. Time.

True, but then a defensive line is neither of the two lines I described since both keep you to the outside of the turn at corner entry. If there isn't anyone in the mirrors or are qualifying, then a defensive line is not the fastest, regardless of the type of car.

[DarkSunrise]

Some good reading on this subject from a professional race car driver:

Another thing to bear in mind is whether your car is low, or high, on horsepower. If you have a car like a Miata or Subaru BRZ, where the power is relatively low compared to its handling performance, you must focus on maintaining momentum through the turn. Simply, the car does not have enough power to turn on its axis and go. So we must focus on rolling speed into and through the corner so we don't rely as much on acceleration out of the turn. If you are in a high-powered, lower grip car then we must do the opposite. Our key advantage is our high power, so focus on that. Brake late, turn the car aggressively and quickly and get back to power early and hard. We lose a touch of time mid corner but maximize our entry and exit, knowing our car can pull that lower mid corner speed due to its big engine.

An example of this is the driving styles between an IndyCar and a Grand-Am sports car. Yes, IndyCar has high horsepower but it has a massive amount of grip, too. In fact, the power-to-grip ratio is stacked more heavily on the side of grip. So we maximize our mid corner speed and keep up our momentum. The Grand-Am car is low grip in relation to its power. So we are aggressive and focus on turning the car and relying on its big V8 to overcome its grip deficiency.

http://jalopnik.com/5932661/how-to-a...eel-drive-cars

[Element Tuning]

I think this illustrates how capable the FRS/BRZ chassis really is. I had this car no more than a couple days and this is the first time I ever had it on track. This is a Time Attack race and all cars are prepped track cars on slicks, suspensions, plus race brakes, and well my FRS is totally stock except I tossed on my STi race wheels and tires (very heavy).

[ame="https://www.youtube.com/watch?v=ZxAkNUQ24Pk"]Element Tuning FRS/BRZ Whelen USTT 2012 NJ - YouTube[/ame]

I would say the chassis is more capable than most drivers are able to extract. With mods the car actually becomes easier to drive. Even on stock with just tires I was able to carry more corner speed than the type of track prepped cars the OP mentions.

This type of track is the FRS/BRZs home turf! Tracks with tight turns before a long straight will put a frown on your face however. LOL!

Thanks,
Phil Grabow

[glamcem]

Originally Posted by Element Tuning

I think this illustrates how capable the FRS/BRZ chassis really is. I had this car no more than a couple days and this is the first time I ever had it on track. This is a Time Attack race and all cars are prepped track cars on slicks, suspensions, plus race brakes, and well my FRS is totally stock except I tossed on my STi race wheels and tires (very heavy).

I would say the chassis is more capable than most drivers are able to extract. With mods the car actually becomes easier to drive. Even on stock with just tires I was able to carry more corner speed than the type of track prepped cars the OP mentions.

This type of track is the FRS/BRZs home turf! Tracks with tight turns before a long straight will put a frown on your face however. LOL!

Thanks,
Phil Grabow

smooth driving .. I am pretty sure that also contributes (by a big margin) to being able to keep up with the big dogs

[CSG Mike]

Originally Posted by Element Tuning

I think this illustrates how capable the FRS/BRZ chassis really is. I had this car no more than a couple days and this is the first time I ever had it on track. This is a Time Attack race and all cars are prepped track cars on slicks, suspensions, plus race brakes, and well my FRS is totally stock except I tossed on my STi race wheels and tires (very heavy).

I would say the chassis is more capable than most drivers are able to extract. With mods the car actually becomes easier to drive. Even on stock with just tires I was able to carry more corner speed than the type of track prepped cars the OP mentions.

This type of track is the FRS/BRZs home turf! Tracks with tight turns before a long straight will put a frown on your face however. LOL!

Thanks,
Phil Grabow

Not everyone has your driver mod...