Side by side acceleration & braking test

sucahyo · Nov 14, 2005

Index:
100-0mph time of some car tested by Parnelli Bone
1/24 vs 24/18 part II, no drafting
Stock vs Racing brake
Braking using toe
Braking using camber
Tire effect on weight transfer
Spring rate and ride height effect on FR car acceleration
Spring rate and ride height effect on weight transfer
Stickier tire increase weight transfer
Damper vs Spring effect on weight transfer
Stock vs Racing brake with less smoke
Spring rate and ride height effect on FF car acceleration
Brake bias effect on braking distance
Stock vs racing brake on different tire
Toe effect on turning
TCSC effect on acceleration and braking
CVT vs 5 speed transmission, CVT wins
NA vs Turbo, race test

The First test:
Based on my testing, 1/24 brake bias will stop faster than 24/18 on silvia, but I want to compare it side by side. I just recently found out that you can use the same button for controller 1 and controller 2 in epsxe. So I use the same button for steering, accel and brake for both and test it with GT2 2 player arcade.
For the car I use Silvia spec R Aero 98 ( this is a highly subjective choice

)

The car have engine mods, super soft tire, race brake, full trans mods, no weight mods. 439hp@7000, 1240kg.
The red car have 1/24 brake distribution, the blue car have 24/18.
the test done on RR valey.
I reversing the car to make a better top speed before braking

For some reason, red is slightly faster

Before braking the speed is about the same.

red have slightly faster braking on high speed

The difference became more and more apparent on lower speed

the different is huge below 50kmph when the wheel seems locked

conclusion:
my calculated braking distance from time difference is wrong (too big), but the result is accurate.
we should test the brake setting on every extreme configuration to find out what the optimum brake setting for the car is. For me testing using side by side is slower than time testing (15 minutes).
Testing side by side using another car should give different result, ie. in R34 Vspec will not give such a huge differences in braking.

oops, I forgot to mention, the 1 front /24 rear brake dist win ! and by a very large margin

in case any of you thinking that the brake setting must have been swapped, look at this bigger picture, red car have smoke from rear tire, blue car have smoke from front tire.

Parnelli Bone · Nov 14, 2005

Man, that's so wack. Well like I said, it seems in GT2 the brake controller is merely a device to assist cornering. In real life, cars often have larger front brake rotors and the emphasis is typically on stronger brake settings for cars because rear brakes tend to lock up. Polyphone ignored this in GT2...if I weren't so lazy, I'd test a GT3 Silvia and see what the results are. I'll try & do it tomorrow.

I've been doing lots of GT2 brake testing on various makes & models, and I find that (when the brakes are stock) brakes have little to do with total braking time. When going from 100 to 0 mph, a Jaguar has a shorter braking time (I don't know about distance) than a little kei car or a super-light Tommykaira ZZ-S. I think braking time has to do with weight and possibly tire size. Again and again, the lighter cars (which should stop quicker) take 4.5 to 5.5 seconds to come to a full stop, but heavier ones typically stop in 3.8 to 4.5 seconds...I'll post my data tomorrow, it's interesting.

sucahyo · Nov 14, 2005

Maybe PD use front and rear brake multiplier which is different on each car that incorporate the weight transfer and weight distribution. This way we don't have to think that complicated thing when tuning the brake.
If you set it same, you have neutral braking. If you use weight distribution rule you will double the PD attempt to simulate the real car brake, so it end up overloading the front tire.................

More drag result
from start:

equal power:

2.5 final drive (red) vs 5.5 final drive (blue)

winner: 2.500 final drive

85/130 ride height (red) vs 85/85 ride height (blue)

winner: drag ride height

Scaff · Nov 14, 2005

Good work here guys, and your results would tend to agree with testing I have done in the past with GT braking.

The whole of the GT series treats brake bias in a very basic way and as with all the settings, the effects are very much watered down from real world effects.

You will also notice that GT treats the front tyres as far more important that the rear tyres. Hence the reason locking the fronts has a major effect on braking when compared to locking the rears.

While these trends do appear in later versions of GT, they are not as dominant, but still a pain.

Without trying to be critical I just want to go over a few points here

Parnelli Bone
I've been doing lots of GT2 brake testing on various makes & models, and i find that (when the brakes are stock) brakes have little to do with total braking time.

Which would be correct, if a cars braking system is capable of locking the tyres then the size of brakes will not further reduce a cars stopping distance/time.

Brakes do not stop a car, tyres do.

Its why brake bias is a tool for adjusting braking, you can only use it to optimise the grip offered by the four tyres and ensure they are all doing a equal share of the braking load. However what brake bias can do is result in (if set incorrectly) is an increase in braking distances and instability under braking.

However as I said above, these effects are minimised in the GT series and the effect on the fronts more evident than the rears.

Parnelli Bone
When going from 100 to 0 mph, a Jaguar has a shorter braking time (i don't know about distance) than a little kei car or a super-light Tommykaira ZZ-S. I think braking time has to do with weight and possibly tire size. Again and again, the lighter cars (which should stop quicker) take 4.5 to 5.5 seconds to come to a full stop, but heavier ones typically stop in 3.8 to 4.5 seconds...i'll post my data tomorrow, it's interesting.

A very common misunderstanding, weight does not have a significant effect on braking distances (but it does have a major effect on the size and type of discs and pads you require and how they will be cooled). The amount of weight transfered under braking does have an effect on the physics of braking, but it is a second order effect and car be trimed and controlled by brake bias and ride height (change the ride height and you change the COG and therefore change the amount of weight transfered).

The single component that has the biggest effect on braking (arguably after the driver) are, as you quite rightly observed, the tyres.

The size of the contact patch, type of compound and the slip percentage they are able the reach have the single biggest effect on stopping distances of any componant.

For a lot more on this take a look at the GT4 & Brakes thread (link in my sig), while it is mainly concerned with testing and data from GT4, it does have a lot of info on the physics of braking that may be of interest.

Regards

Scaff

liam2maps · Nov 14, 2005

The previous poster raises the very good point about tyres. Infact the majority of speed in cars is translated into the tyres which have the MOST important role. If your tyres aren't up to scratch they won't do the job. Especially so in racing.

Take F1 for instance, Michelin totally butt****ed Bridgestone this year. Out of the 19 Grand Prixs held Michelin won 18. Bridgestone won only one GP (the controversial USA GP which Michelin runners were told to pit in due to a fault in the tyre WALL contruction that made them prone to the banking at the Indy circuit). What made it all the MORE humiliating is that this year focused on tyre reliability and endurance, which is Bridgestones general advantage.

Michelin is generally a faster more higher performance tyre with Bridgestone offering good strong performance but better endurance.

Back to the topic. If you do further more testing the angle at which the tyre faces the road is also important.

Having said that brake control is also very important and weight does effect braking (more so the handling and the force if there is an impact).

Parnelli Bone · Nov 14, 2005

Scaff
A very common misunderstanding, weight does not have a significant effect on braking distances (but it does have a major effect on the size and type of discs and pads you require and how they will be cooled). The amount of weight transfered under braking does have an effect on the physics of braking, but it is a second order effect and car be trimed and controlled by brake bias and ride height (change the ride height and you change the COG and therefore change the amount of weight transfered).

I was talking about the game, not real-life tests. Also, I am strictly testing cars when they are totally stock, not making any adjustments at all. Check it out:

Brake tests 100 to zero mph. I accelerate to 100 mph, pressing the pause button over and over so that when I reach 100, I use full braking force and no downshifts. All cars tested with this method.

1971 Dodge Charger (3,785 lbs.) 3.613 seconds

1998 Ford Mustang SVT (3,397 lbs.) 3.561 seconds

1990 RUF CTR Ylw. Bird (2,645 lbs.) 3.767 seconds

1991 Mazda AZ-1 (1,587 lbs.) 5.144 seconds

1998 Suzuki Alto Works RS/Z (1,587 pounds) 5.714 seconds

1992 Mitsu Mirage Cyb. (2,336 pounds) 4.0 seconds

1999 Mercedes AMG E55 (3,769 pounds) 3.459 seconds

1998 Nissan Stagea 25t... (3,637 lbs.) 3.525 seconds

1996 Tommykaira ZZ-S (1,477 lbs.) 4.508 seconds

Now, you can make the argument that the Mazda AZ-1 and Suzuki, both which have tires that have a tread width of 155 in real life, take longer to stop partially because of those skinny tires. But what about the Tommykaira? In real life, it has P205/50ZR-15's ...basically high-performance tires with a wide tread width for such a light car. In comparison, the Nissan Stagea, which is 2,400 pounds heavier and has 225 tread-width tires, stops almost a full second less than the Tommy. Are we to assume it's the extra 20 mm of width that causes this?

The Mitsubishi Mirage, a FWD, should have one of the shortest stop times with its 195/55R-15's, yet it ranks below all the heavy RWD and 4WD's. Look at the Dodge Charger. In real life, it had rather narrow tires (haven't got exact dimensions, but trust me...most of the 60's muscle cars had underrated tires), yet it comes to a full stop in only slightly less time than a modern Mustang. And the Charger BEATS a RUF? Yeah rite, in your dreams maybe!

The only car that makes sense here is the Mercedes, if you're going by the tire theory. In real life, it has killer vented disc brakes all around (possibly cross-drilled) and 235/40ZR-18's up front with 265/35ZR-18's in the rear...phat tires all around, and low-profile, to boot.

My point is that (in the game, anyways) braking force and tire patch aren't taken into account the way they should be. My theory is that weight is the determining factor--basically how they programmed the game.

sucahyo · Nov 15, 2005

To help understand it I calculate those car tire size using noquarter excel but only from 1st and 2nd gear.
Order by tire size and time
1996 Tommykaira ZZ-S xxxxxxx 22" tire (1,477 lbs.) 4.508 seconds
1998 Suzuki Alto Works RS/Zxx 22" tire (1,565 lbs.) 5.714 seconds
1992 Mitsu Mirage Cyb. xxxxxx 23" tire (2.292 lbs.) 4.0 seconds
1991 Mazda AZ-1 xxxxxxxxxxxx 23" tire (1,587 lbs.) 5.144 seconds
1999 Mercedes AMG E55 xxxxx 24" tire (3,769 lbs.) 3.459 seconds
1998 Nissan Stagea 25t... xxxx 24" tire (3,637 lbs.) 3.525 seconds
1990 RUF CTR Ylw. Bird xxxxxxx 24" tire (2,645 lbs.) 3.767 seconds
1998 Ford Mustang SVT xxxxxxx 25" tire (3,397 lbs.) 3.561 seconds
1971 Dodge Charger xxxxxxxxxx 25" tire (3,785 lbs.) 3.613 seconds

it seems the car with small tire have slower time.

Parnelli Bone · Nov 15, 2005

sucahyo
To help understand it I calculate those car tire size using noquarter excel but only from 1st and 2nd gear.
Order by tire size and time
1996 Tommykaira ZZ-S xxxxxxx 22" tire (1,477 lbs.) 4.508 seconds
1998 Suzuki Alto Works RS/Zxx 22" tire (1,565 lbs.) 5.714 seconds
1992 Mitsu Mirage Cyb. xxxxxx 23" tire (2.292 lbs.) 4.0 seconds
1991 Mazda AZ-1 xxxxxxxxxxxx 23" tire (1,587 lbs.) 5.144 seconds
1999 Mercedes AMG E55 xxxxx 24" tire (3,769 lbs.) 3.459 seconds
1998 Nissan Stagea 25t... xxxx 24" tire (3,637 lbs.) 3.525 seconds
1990 RUF CTR Ylw. Bird xxxxxxx 24" tire (2,645 lbs.) 3.767 seconds
1998 Ford Mustang SVT xxxxxxx 25" tire (3,397 lbs.) 3.561 seconds
1971 Dodge Charger xxxxxxxxxx 25" tire (3,785 lbs.) 3.613 seconds

it seems the car with small tire have slower time.

Errr....where are you getting those tire width dimensions? The Alto Works and AZ-1 would have tires only 6.1" in width. 155mm ÷ 25.4=6.1". The Tommy would have 8 and 3/4" width tires. I'm confused.

sucahyo · Nov 15, 2005

Parnelli Bone
Errr....where are you getting those tire width dimensions? The Alto Works and AZ-1 would have tires only 6.1" in width. 155mm ÷ 25.4=6.1". The Tommy would have 8 and 3/4" width tires. I'm confused.

Those are tire diameter, I use the derivative of NoQuarter Excel file.
You can also use this attachment, where I color the cell I modify with red.
I fill the 1st, 2nd gear ratio and final drive, drive it using manual, fill the max rpm, notice the 1st gear speed, change the gear to 2nd, notice the speed, I change the tire diameter to make the calculated speed as close as possible with the test.
Even if this calculator might be wrong, but the speed increase based on gear ratio is accurate enough. When I tune the gear, I usually calculate the tire diameter first using 1st gear, then calculate the last gear ratio to the speed I want. I usually endup in 3 mile/sec differences from the real speed.
With this tool, I am thinking to test the myth that rims can increase tire size.

BTW, I just found out that you need to warmup the race brake to make it work optimal. But testing the brake using race brake is unreliable, because I think the brake force is influence by the brake temperature, if you use it rarely (like in test track) the brake force became lower.
Testing the brake using stock brake can give closer time for me.
I found it using Aston Martin V8 Vantage on test track. Using stock brake and no controller, I get the exact same braking time for each half lap. Using race brake get me high time for the first half lap, and varying lower time on the subsequent half lap. I did the braking on each straight, so its twice in a lap.
*edit*
I was wrong, when I test it again it doesn't happen (although the test is a bit different), the same first 2 result is just coincidence.
*edit*

Parnelli Bone · Nov 15, 2005

No, I'm not talking about diameter, I am talking about the width of REAL-LIFE tires. Diameter affects the way a car rides and handles more than it affects braking ability. The width of a tire (the actual area where the tire meets the pavement) affects traction and braking ability on a first-hand basis. I'm not even talking about tire diameter...that's a whole different issue.

In theory (and in real life) a car with a wide tire should have a shorter stopping distance than one with narrow tires...assuming both cars weigh the same, are using the same compound tires, and have the same brake rotors and pads.

A Dodge Charger, and generally most muscle cars from the '60s, should have poor brake ability when compared to a Tommykaira or RUF Porsche partially because of lesser tires as well as lesser technology. I know this first-hand because I used to have a '67 Ford Mustang long ago. That thing could move like the wind, but the brakes were iffy at best.

The fact that, in the game, a Charger stops in less time than an RUF means somebody didn't program braking ability correctly. that is my point. They got acceleration ability a lot more correct than they got braking. Get what I'm saying?

Scaff · Nov 15, 2005

Parnelli Bone
I was talking about the game, not real-life tests. Also, i am strictly testing cars when they are totally stock, not making any adjustments at all. Check it out:

Brake tests 100 to zero mph. I accelerate to 100 mph, pressing the pause button over and over so that when i reach 100, i use full braking force and no downshifts. All cars tested with this method.

1971 Dodge Charger (3,785 lbs.) 3.613 seconds

1998 Ford Mustang SVT (3,397 lbs.) 3.561 seconds

1990 RUF CTR Ylw. Bird (2,645 lbs.) 3.767 seconds

1991 Mazda AZ-1 (1,587 lbs.) 5.144 seconds

1998 Suzuki Alto Works RS/Z (1,587 pounds) 5.714 seconds

1992 Mitsu Mirage Cyb. (2,336 pounds) 4.0 seconds

1999 Mercedes AMG E55 (3,769 pounds) 3.459 seconds

1998 Nissan Stagea 25t... (3,637 lbs.) 3.525 seconds

1996 Tommykaira ZZ-S (1,477 lbs.) 4.508 seconds

I'm sorry if the specifics of my original post was not clear, and you are right I should have made it clear that I was refering to real life braking physics.

However, while the GT series is not 100% acurate to the real world, it does follow the basics, and from my knowledge (I train in this area in the Automotive industry) and testing the results are not totaly out of sync with reality.

Weight and weight transfer are both factors in stopping distances, but they are not as significant (by quite a factor) as tyre compound and contact patch size.

Parnelli Bone
Now, you can make the argument that the Mazda AZ-1 and Suzuki, both which have tires that have a tread width of 155 in real life, take longer to stop partially because of those skinny tires. But waht about the Tommykaira? In real life, it has P205/50ZR-15's ...basically high-performance tires with a wide tread width for such a light car. In comparison, the Nissan Stagea, which is 2,400 pounds heavier and has 225 tread-width tires, stops almost a full second less than the Tommy. Are we to assume it's the extra 20 mm of width that causes this?

An extra 2cm of width on a tyres contact patch is a significant increase, and while in reality the ZZ-S has high-performance tyres in GT if the same type of tyre are fitted to two cars they are going to be of the same compound.

To give a real world example of this, are you aware that a Range Rover has a shorter stopping distance than a Lotus Elise!

Parnelli Bone
The Mitsubishi Mirage, a FWD, should have one of the shortest stop times with its 195/55R-15's, yet it ranks below all the heavy RWD and 4WD's. Look at the Dodge Charger. In real life, it had rather narrow tires (haven't got exact dimensions, but trust me...most of the 60's muscle cars had underrated tires), yet it comes to a full stop in only slightly less time than a modern Mustang. And the Charger BEATS a RUF? Yeah rite, in your dreams maybe!

Once again weight is not the overall factor here, and yes I can see a Charger beating an RUF in terms of stopping. Once again to look at real world comparisons, an RUF CTR 2 stops in 4.89 secs, while a VW Toureg takes 4.52 secs. The original CTR being based on an '80s Porsche had narrow front tyres and by modern Porsche standards narrow rears.

Parnelli Bone
The only car that makes sense here is the Mercedes, if you're going by the tire theory. In real life, it has killer vented disc brakes all around (possibly cross-drilled) and 235/40ZR-18's up front with 265/35ZR-18's in the rear...phat tires all around, and low-profile, to boot.

I would totally agree that the tyres here are the principal reason for the excellent stopping time of the Merc. But, the discs type and size have little to do with single incident stopping times (as long as they are fit for the purpose).

Its another common myth (in the real world) that fitting larger discs and uprated pads will stop a car quicker; as long as the original brakes were up to the task then the uprated items will not stop you quicker. The advatages of uprated brakes are generally found in better initial bite, easier modulation and greater fade resistence.

You can find a lot more info on these subjects and many more in the GT4 & Brakes thread. Of particular interest are the Autocar 0-100-0 tests (youwill find the last four years results), which clearly show that weight is not the most significant real world factor in stopping.

Parnelli Bone
My point is that (in the game, anyways) braking force and tire patch aren't taken into account the way they should be. My theory is that weight is the determining factor--basically how they programmed the game.

I can't agree with this, while the GT series do massively simplfy the physics of braking, I do not believe that they completely ignore them.

Sucahyo's post below indicates that tyre size is a major factor in stopping distance in GT2, my own testing in GT4 also agrees with this.

You can't look at different cars to see how weight affects stopping times, a far better idea would be to test a single car, both stock and then with each stage of weight reduction.

Regards

Scaff

Parnelli Bone · Nov 15, 2005

Well, all I am saying is that I'm going by a theory (and it's just a theory) that whoever was in charge of programming acceleration vs. braking in GT2 spent a lot more time programming the acceleration of a car vs. its braking time. Here's a quote from my website about the Peugeot 306 S16:

"The unmodified car (in the game) gets from 0 to 60mph in 8 seconds, and hits a top speed of 149 down the test track. An interesting note here: I found a website with a VERY long name that tested a real 306 and got a 0-60 time of 8.2, 0-400m in 16.5 (Gran Turismo test yielded 16.454) and 0-1000m in 29.9 (Gran Turismo = 29.647). The real car's top speed of 134 was the only major difference, mostly because in real life, one can't force a car's engine past the red-line much."

I've found several instances in GT2 like this where a real car's acceleration is extremely similar to the game-version car after testing several hundred game cars, sometimes within hundreths of a second. I don't think this attention to detail is carried over to braking.

Now I don't know about a Range Rover vs. an Elise, but no way a Charger will beat a RUF! That ain't happening. If I manage to find some real-life data to support this, I'll surely be back with it.

Perhaps when I was doing my tests, since I'm going from full acceleration to full braking, a lighter car is more prone towards locking wheels? I don't know.

But I see your point, too...in other words, if you take a Charger and brake-test it, give it stage 1 weight and test it again, it should have a longer stopping time by my theory with lesser weight. So I'll be back with my conclusion on that.

Scaff · Nov 16, 2005

Parnelli Bone
Well, all i am saying is that i'm going by a theory (and it's just a theory) that whoever was in charge of programming acceleration vs. braking in GT2 spent alot more time programming the acceleration of a car vs. its braking time. Here's a quote from my website about the Peugeot 306 S16:

"The unmodified car (in the game) gets from 0 to 60mph in 8 seconds, and hits a top speed of 149 down the test track. An interesting note here: I found a website with a VERY long name that tested a real 306 and got a 0-60 time of 8.2, 0-400m in 16.5 (Gran Turismo test yielded 16.454) and 0-1000m in 29.9 (Gran Turismo = 29.647). The real car's top speed of 134 was the only major difference, mostly because in real life, one can't force a car's engine past the red-line much."

I've found several instances in gT2 like this where a real car's acceleration is extremely similar to the game-version car after testing several hundred game cars, sometimes within hundreths of a second. I don't think this attention to detail is carried over to braking.

Now i don't know about a Range Rover vs. an Elise, but no way a Charger will beat a RUF! That ain't happening. If i manage to find some real-life data to support this, i'll surely be back with it.

Perhaps when i was doing my tests, since i'm going from full accelertion to full braking, a lighter car is more prone towards locking wheels? I don't know.

But i see your point, too...in other words, if you take a Charger and brake-test it, give it stage 1 weight and test it again, it should have a longer stopping time by my theory with lesser weight. So i'll be back with my conclusion on that.

Don't get me wrong, I'm not claiming that GT2's stopping times are realistic in terms of matching real life figures.

What I was trying to say (and not vey well, sorry about that) is that while the figures are not realistic, the basic rules appear to be followed.

All the brakeing times you posted are within a range of 2.255 seconds, which is close to the sort of range you can see in real life. This years Autocar 0-100-0 tests was run with 27 cars completing the test, the range of stopping times was 2.52 seconds.

The stopping times also appear from the comparison that they seem to follow the basic rules that would exist in the real world.

Remember, I did not say that weight and weight distribution do not effect braking times, just that they are not the most significant factors. They should not have a huge effect on what is going on.

I look forward to your test results, should be interesting.

BTW with regard to the Charger, remember that the GT series does not take into account the problem of older braking systems and how poor the initial bite could be and how quickly they overheat. Fitted with a modern braking system (which is what GT effectively gives all older cars) and modern rubber and I'm quite sure it could pull up well.

Regards

Scaff

Parnelli Bone · Nov 16, 2005

Ah, you have a point about the Charger. In fact, in the GT User Guide or reference manual (I forget which one) it says something about all cars in the game being affixed with ABS brakes, which of course were not used in the '60s. So that takes care of that.

And I didn't know about the Autozine tests. Muy intersanté.

No test results available now. I'm drunk!

Scaff · Nov 16, 2005

Parnelli Bone
Ah, you have a point about the Charger. In fact, in the GT User Guide or reference manual (i forget which one) it says something about all cars in the game being affixed with ABS brakes, which of course were not used in the 60's. So that takes care of that.

And i didn't know about hte Autozine tests. Muy intersanté.

No test results available now. I'm drunk!

Yep, I may not have been to clear in my post that I was of course talking about a charger in GT, and yes all cars are fitted with ABS in the GT series. Even with high brake force settings the wheels rarely lock, just trigger the ABS.

In regard to weight reduction testing, I have just done some in GT4, its in the GT4 & Brakes thread, just click on the link in my sig.

Not sure why you have concluded that reducing a cars weight would increase stopping distances, they should (if it follows the basics of the real world) be reduced, but not by a significant amount.

Regards

Scaff

Parnelli Bone · Nov 16, 2005

Scaff
Yep, I may not have been to clear in my post that I was of course talking about a charger in GT, and yes all cars are fitted with ABS in the GT series. Even with high brake force settings the wheels rarely lock, just trigger the ABS.

In regard to weight reduction testing, I have just done some in GT4, its in the GT4 & Brakes thread, just click on the link in my sig.

Not sure why you have concluded that reducing a cars weight would increase stopping distances, they should (if it follows the basics of the real world) be reduced, but not by a significant amount.

Regards

Scaff

OKay, it's a THEORY...nothing has been concluded yet. I was going on the theory that in GT2, they didn't take braking into account the way they obviously studied acceleration, power, and speed. I was going on the t-H*e@O%r!Y that weight was the determining factor and I forgot all about the generic ABS system placed into all GT2 cars. Therefore, my original assumption (brakes in the game cars don't mirror real-life). Is still correct. Hence, a Charger could not outbrake a RUF Yellow Bird in real-life. The fact that it does in the game means...ah, I give up, dude.

Anyways, I'm too hungover now for tests, but I'll do them later I promise. I'm always doing tests, man.

And I try and read as little as possible about GT4 to avoid spoilers, but I read the thread you posted. Again, very interesting.

liam2maps · Nov 16, 2005

My post was totally ignored

Scaff · Nov 16, 2005

liam2maps
My post was totally ignored

It wasn't ignored, it just seemed complete in what it was trying to say.

Don't take offence as none was intended.

👍

Parnelli Bone
OKay, it's a THEORY...nothing has been concluded yet. I was going on the tHEORy that in GT2, they didn't take braking into account the way they obviously studied acceleration, power, and speed. I was going on the t-H*e@O%r!Y that weight was the determining factor and i forgot all about the generic ABS system placed into all GT2 cars. Therfore, my original assumption (brakes in the game cars don't mirror real-life). Is still correct. Hence, a Charger could not outbrake a RUF Yellow Bird in real-life. The fact that it does in the game means...ah, i give up, dude.

Anyways, I'm too hungover now for tests, but i'll do them later i promise. I'm always doing tests, man.

And i try and read as little as possible about GT4 to avoid spoilers, but i read the thread you posted. Again, very interesting.

I would agree with you that GT2 brakes 100% mirror real life, but within the limits of the physics engine they appear to follow the basic rules.

A real life brake test with a Charger and Yellowbird, with both original, the Charger would I agree lose. But fitted with modern brakes and tyres (a'la GT2) the results would be a lot closer, hence your results.

I would also agree with you that the GT series has always treated braking as an afterthought in comparison to the other areas of the game. Global ABS, which means locking the wheels is almost impossiable if they are straight, is a major pain and needs sorting out soon.

Hope you're hangover clears up soon, as I look forward to the tests, I oculd do them myself, but I'm just to damn lazy to dig out GT2.

BTW thanks for the feedback on the GT4 & Brakes thread, as you can probably tell its taken up a fair bit of my free time since it started, but it has opened up the subject of braking to a whole new group of people.

Regards

Scaff

Parnelli Bone · Nov 17, 2005

liam2maps
My post was totally ignored

Hey I got a whole website that gets totally ignored!

Seriously, tho, it wasn't ignored, it's just that we agree with you about the roll tires & suspension setup has in braking.

1989therat · Nov 17, 2005

um I hate to bring this up...but the blue silvia was drafting and therefore had less wind resistance which made the deceleration force smaller. Therefore the car will take longer to stop. Could you perhaps retest w/o the car being directly behind the other?

sucahyo · Nov 17, 2005

deleted double post

sucahyo · Nov 17, 2005

liam2maps
My post was totally ignored

No, I am thinking to test the camber and toe effect on braking, but I am still finding the more reliable way to test, because I think the acceleration will be different.

1989therat
um I hate to bring this up...but the blue silvia was drafting and therefore had less wind resistance which made the deceleration force smaller. Therefore the car will take longer to stop. Could you perhaps retest w/o the car being directly behind the other?

You are right, it seems that without drafting the blue stop a bit faster, almost unnoticable on 75mph (after 220mph), but very big on 0mph.

sucahyo · Nov 17, 2005

Stock vs Racing
in GT4, many people already test race brake and stock brake without having a conclusion. Many advised not to use race brake at all because there is no benefit using it.
So this is my GT2 test, red is stock, blue is racing brake.

Using 1/1 brake controller, the result is same:

Not using brake controller, the result is same above 100mph, racing brake faster below 100mph:

my conclusion: use race brake can have benefit in GT2

sucahyo · Nov 17, 2005

Braking using toe
red has 0.0/0.0 toe, blue has +0.2/+0.2 toe

due to non neutral toe on blue, blue have slower speed when almost braking, the speed decrease is the same for both vehicle, but the actual braking distance is different. The toe actually help braking. From disbelieve I check it many times to see if I am doing it wrong, but its not, the toe help braking but reduce acceleration a little.
Next is camber.

sucahyo · Nov 18, 2005

Braking using camber
Red is 6.0/5.0, blue is 0.0/0.0

Huge acceleration differences, small braking differences.

Red is 2.0/1.0, blue is 0.0/0.0

Small acceleration differences, small braking differences.

Camber reduce acceleration and braking.

sucahyo · Nov 18, 2005

Tire effect on weight transfer
Red is super soft, blue is simulation.
Both using 11/24 brake balance.

on the same speed, the red is smoking, the blue doesn't. The red front tire is smoking because its overload, giving red 1/24 will give the front less smoke. The blue will smoke the front tire when using 24/24.
So, different tire need different brake bias.

sucahyo · Nov 18, 2005

Because I don't feel right about this test, I rename this braking test to "effect on acceleration", you can ignore the braking result..
Spring rate effect on acceleration
Red is 2.0/2.0, blue is 20.0/20.0, both using 130/130 ride height and simulation tire.

low spring rate reduce acceleration, but have better braking distance. I prefer hard because the braking differences is not too much compare to acceleration diferences.

Ride height effect on acceleration
Red is 85/85, blue is 130/130. Both using 20/20 spring rate.

The effect is greater than spring rate, low ride height have much slower acceleration but also have a bit faster braking

Drag ride height vs high ride height
Red is 85/130, blue is 130/130

drag have faster acceleration, and little slower braking.

Parnelli Bone · Nov 18, 2005

You are the MAN with all these tests! Research like this is gonna change the way I'll set up my cars here and there. Are you reading, Kazunori? ¬

sucahyo · Nov 19, 2005

I like testing

sucahyo · Nov 19, 2005

Spring rate & ride height effect on weight transfer
I decide to combine this two because I failed to test the difference if using only one suspension change. I use Mine R32.5 because it give no smoke when using 24/1 brake bias, this car has a rare extreme rear bias. Many other car in my garage has extreme front bias, some with neutral bias.
I consider it extreme front bias when the car not smoking using 1/24, meaning using 24/24 will make the front tire smoking, meaning the car has more front brake force. I consider it neutral when the car not smoking using 24/24. I consider it rear bias when the car not smoking using 24/1.
So, using 1/24 brake bias on car that give no smoke using 24/1 will make the rear tire smoke. We can see from the amount of smoke the difference in weight transfer.
White OZ rim: 20.0/20.0 spring rate, 89/89 ride height.
Black Dunlop rim: 2.0/2.0 spring rate, 135/135 ride height.

Black start to smoke from 60 kmph, white start to smoke from 50 kmph. With black gives really deep diving. The amount of smoke also different. Smoke came out because the rear wheel has less traction. The more weight transfered to the front the less traction the rear wheel has.
So, if you change ride height and spring rate, you should at least review you brake balance setting.
And because the car in GT2 by default can have different brake bias, you can't generalize your setting. The easiest thing to do is check the bias using extreme combination to see which tire is smoking.

Note: all my conclusion is from the test, not from real life or theory, so, if I am wrong, please tell me.

Side by side acceleration & braking test

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