Gran Turismo 7 Physics

[xMAXIx79]

How much power do you need to spin a stock Mazda Roadster in GT7 (in 3rd gear!)? What do you think?

And what is that supposed to tell us now? How good are you at putting a car in an uncontrolled unstable state?
You slam on the brakes and yank the steering to the right, immediately after that with a few hundred kilos on the rear axle you give full throttle, all with a chassis that is NOT designed for such loads and where the wheel geometry of the front and rear axles are not designed for it .

Shouldn't that be an example of good or bad physics or just that you can "rape" any car?

 

[Phaceless_Ph]

I took the ZL1 to a track I drove in real life (not with the Camaro) and I was constantly getting within 1 second of the fastest lap time recorded on fastestlap.com. People are not carrying speed like the are suppose to around corners and getting taken off guard because they don't know how much throttle they are applying. I even catch myself mashing beyond 50% throttle around corners, which you are not suppose to do in may cases. A lot of cornering requires you to hold about 25% throttle and modulate it while carrying the speed around corners. Also, what I love about this game that you can't do in GTS is teeter at the edge of grip and it is fairly natural to capture any type of oversteer. In the end, everyone is getting taken off guard with throttle application. It makes sense as your body has no natural feedback to communicate to you. Maybe they need to place more vibration through the wheel for better communication.

I've been lucky enough to drive Porsche 993s, 996s and 997s in anger in real life . . . that is not how they handle in real life, Polyphony simply went for the harsh stereotype.

 

[///M3]

How much power do you need to spin a stock Mazda Roadster in GT7 (in 3rd gear!)? What do you think?

It’s not power that is the problem it’s the weight loading.

If you watch the replay you can see the inside rear is fully unloaded along with the inside front.

When you start applying any power at that point only one wheel is getting the drive which is trying to move the weight back but it can only move to the outside rear which is asking a lot of one tyre to drive a 1 tonne car.

A 1 tonne car that has all of its mass centfrugally pushing away from the corner so technically that 1 tonne car is actually heavier because of the +1g lateral load.

Edit: not in front of GT at the moment but does that MX5 have an LSD, it doesn’t look like it?

 

[RaceFace85]

It’s not power that is the problem it’s the weight loading.

If you watch the replay you can see the inside rear is fully unloaded along with the inside front.

When you start applying any power at that point only one wheel is getting the drive which is trying to move the weight back but it can only move to the outside rear which is asking a lot of one tyre to drive a 1 tonne car.

A 1 tonne car that has all of its mass centfrugally pushing away from the corner so technically that 1 tonne car is actually heavier because of the +1g lateral load.

The inside wheel isn't really needed for stability because most of the load is on the outside wheels. This isn't possible in real life with this few power and soooooo much smoke.

 

[///M3]

The inside wheel isn't really needed for stability because most of the load is on the outside wheels. This isn't possible in real life with this few power and soooooo much smoke.

The inside rear is needed for drive, what you see there is the exact reason LSDs were invented to shuffle the torque to the wheel(s) with most traction.

You can spin any car regardless of power.

I used to spin my fixed rear axle pro kart all the time on slicks, the margins for control and balance are universal it’s that the balance required is appropriate to speed and mass.

 

[BolverkGTM]

How much power do you need to spin a stock Mazda Roadster in GT7 (in 3rd gear!)? What do you think?

I'd be able to help you better on this with an interior view, but in 3rd, you're using more engine torque. Torque is what breaks rear traction often. Also your corner entry is extremely stiff. Very unsettled.

Also since I believe in putting my money where my mouth is, here you go. I show the same corner twice in this video. One slower way to do it, one faster way to do it, but the point still stands. Your entry is the beginning of the problem.

 

[RaceFace85]

I'd be able to help you better on this with an interior view, but in 3rd, you're using more engine torque. Torque is what breaks rear traction often. Also your corner entry is extremely stiff. Very unsettled.

Also since I believe in putting my money where my mouth is, here you go. I show the same corner twice in this video. One slower way to do it, one faster way to do it, but the point still stands. Your entry is the beginning of the problem.

We are talking about 90 Nm torque in 3rd gear!

 

[///M3]

We are talking about 90 Nm torque in 3rd gear!

Your talking about over 1 tonne of mass moving at 30mph with the grip spread across 2 contact patches smaller than a sheet of A4 paper.

And without an LSD the torque is reduced because of the loss of traction, it’s not “torquing” against anything at that point.

Edit to add:

Torque is the shoving force, once there is no traction there is no torque.

 

[RaceFace85]

Your talking about over 1 tonne of mass moving at 30mph with the grip spread across 2 contact patches smaller than a sheet of A4 paper.

And without an LSD the torque is reduced because of the loss of traction, it’s not “torquing” against anything at that point.

Edit to add:

Torque is the shoving force, once there is no traction there is no torque.

And you really think that this would happen in real life?

 

[///M3]

And you really think that this would happen in real life?

Absolutely does happen every day in real life, chuck a car aggressively at most speeds and the weight and gravity/momentum take over.

 

[BolverkGTM]

We are talking about 90 Nm torque in 3rd gear!

Yeah?

And you really think that this would happen in real life?

On a scale of 1 to 10....how badly do I want to prove a point? Very much so.

 

[RaceFace85]

Absolutely does happen every day in real life, chuck a car aggressively at most speeds and the weight and gravity/momentum take over.

And you mean this serious or are you joking?

 

[///M3]

Some of these are damp tracks but it’s just the adhesion that drops to about 0.9g but the physics are the same wet or dry, just the limit to break traction reduces proportionally. Some are dry and some are even FWD

 

[///M3]

And you mean this serious or are you joking?

I mean seriously, if you just smash the throttle on a car with high steering angle, fully loaded up and in 3rd gear where it will come in to the torque range of the engine very quickly. Yes I am being serious.

 

[///M3]

MX5 - 3rd gear watch from 2:36



I know this circuit I’ve done it several times on my Fireblade

 

[RaceFace85]

Some of these are damp tracks but it’s just the adhesion that drops to about 0.9g but the physics are the same wet or dry, just the limit to break traction reduces proportionally. Some are dry and some are even RWD

What is wrong with his Honda? Did you also see his crash on the Nordschleife?

MX5 - 3rd gear watch from 2:36



I know this circuit I’ve done it several times on my Fireblade

This looks very familiar in a chicane.
You can not compare a hairpin turn with a chicane with hard load transfer. I also don't think that the car was so much downtuned how I did in GT7.

 

[BolverkGTM]

MX5 - 3rd gear watch from 2:36

Oh man, I felt that.... Sad stuff. Glad nobody got hurt.

What is wrong with his Honda? Did you also see his crash on the Nordschleife?

Couldn't say for sure without telemetry data. Seemed like something very minor and related to track surface. Could have been tires, could have been this or that... Could have just been plain user error. Stuff like that happens a lot, but it costs a lot of money IRL. 😟

 

[///M3]

What you will notice differs quite a lot in real life is the cars typically slow quicker as the weight stabilises and the wheels rotate bringing much more grip, it most race games you’ll notice low speed spins aren’t just looping it 180 degrees which is what you’d expect to happen at slower speed hairpins or high steering angle corners.

The technique in most RWD cars is actually to power through the spin, you spin but just loop it.

At speed it’s different because the momentum is that much higher so can continue to overcome the tyre traction for longer, plus people panic brake making the problem worse.

 

[Lord Protector]

I made the mistake of getting a Porsche 997 from the used cars lot when I finally had the money to get a powerful car of my choice and tune it. I drive it with a Thrustmaster wheel without any driving aids besides ABS and even with extensive tuning, experimenting with the aero, brake and LSD balance and making rear suspension soft, its only like 75% reliable, 25% of the time it will kill me in one of the corners without a warning.

It will snap-oversteer every now and then in long corners without the slightest hint that I'm slipping and now I'm only coasting through the fast long corners. It just happens like BANG and I smash into the barriers, without any forewarning, no tire squeal, no sense of the rear losing control. I also have a tuned ~770PP Viper and it does the same thing, especially in the last corner of the High Speed Ring or at Willow Springs the long right hander leading into the two hairpins and the last long right hander before the straight.
Shifting aero balance to the rear with max rear downforce I get the same thing, it simply allows me to go a little faster before it snaps.
I can do a sub 7 minute lap on the Nordschleife with the 770PP Viper on racing hards but do I have to coast a lot through corners, it definitely robs me of at least 5 seconds.

I have experience with GT4, GT5, GT6, Assetto Corsa and many Rally sims and none of those games have this snap-oversteer.

It does not ruin the game for me but it definitely slows me down on lap times, and that's really unfortunate.

I know it sucks, but try TC1 and even ASM tends to help. It works more like a torque vectoring system, rather than a stability system. I think you might enjoy driving a bit more like that.

 

[RaceFace85]

MX5 - 3rd gear watch from 2:36



I know this circuit I’ve done it several times on my Fireblade

Oh man, I felt that.... Sad stuff. Glad nobody got hurt.

Couldn't say for sure without telemetry data. Seemed like something very minor and related to track surface. Could have been tires, could have been this or that... Could have just been plain user error. Stuff like that happens a lot, but it costs a lot of money IRL. 😟

You could be right. This was really not looking normal.

 

[///M3]

Last one, but again the first spin MX5 3rd gear low speed and moderately tight corner.

 

[xMAXIx79]

Last one, but again the first spin MX5 3rd gear low speed and moderately tight corner.

Don't try so hard, he's just trying to find and create evidence that the implementation of the driving physics in the game is totally broken. And no matter what you put in, he'll think it's wrong and keep saying it's implemented very poorly in the game.

I also think it's really more complex to drive, but that's what appeals to me.

 

[pedrocor]

The B-6 license test at Suzuka with the Fairlady/370Z is just broken. It's not like we are trying to go full throttle or something, he even loose grip totally on the left corner entry, just by effect of weight transfer. And not even on road tires.
Immediately after that, the GR-86 at Mountain Trail should be horrifying. But no, you get some understeer if you have too much entry speed and quite manageable oversteer that you can relate to too quick inputs on steering or too much throttle.
The Porsche 911 (964) mission on High Speed Ring is the opposite, that car should be an handful by every means, as any 911 prior to 993, due to too much weight in the rear. But you can be quite aggressive, by GT7 RWD physics standards.
The most uncomfortable part was racing at Blue Moon with the Camaro Z28 and loosing it at turn 2 which shouldn't happen on that enormous banking.
In general I found this rear unbalance manageable to some degree when you start tuning the cars, to minimize weight transfer and taking some toe. Of course, that doesn't help at all in license tests and missions.

 

[RaceFace85]

Last one, but again the first spin MX5 3rd gear low speed and moderately tight corner.

This was a typical S-corner spin what happens pretty often.

 

[///M3]

This was a typical S-corner spin what happens pretty often.

I know I said cars spin all the time…

Weight is transferring rapidly it destabilises the suspension etc.

 

[NikNakTobasco]

This makes perfect sense but IMO the game does a poor job communicating this to you through the force feedback.

This is the real problem I think.

this problem has always existed and will never go away unless you invest in better hardware

I’ve already given Fanatec more money than my actual car is worth. The game just needs some minor tweaks and it’ll be golden.

 

[traind]

If you drive with ASM off and Traction control on 3 you can spin the car bro.. only thing helping not spinning the car is ASM… also have you used TC on GTS?? It’s terrible it would just kick on for anything… this is not the case with GT7! You can drive the TC on and still get the end out… In ACC you had to have The TC on, the thing was you didn’t want to utilize it all the time.. this is the same sensation I get in GT7.

Have you tested your assertion? Because I have tested mine, using a controller. I admit I was exaggerating my statement, yes you can still spin the car with TC on low but TC really shuts down the oversteer much more than ASM. I just tested it again to be sure. Perhaps different cars react differently?

I took the 2019 ZR1 to Brands Hatch in the dry and ran a lap with no aids, then with ASM only, then with TC 1 only. Then with TC 5. No aids is bordering on ridiculous, lol. ASM only will still spin easily but it helps take the edge off. TC1 only had way more intervention than ASM only. Yes, I could spin it with TC 1 only but it took significantly more effort with than with ASM only. TC 5 shuts things down almost completely... I only did one corner with this on, lol.

Try the back to back test and tell me your results. Make sure one test is a high torque RWD street car on sport tires and let's compare.

 

[RaceFace85]

I know I said cars spin all the time…

Weight is transferring rapidly it destabilises the suspension etc.

I just can say you that I drifted a RX-8 in a roundabout and this is very hard to start a drift. It's so hard when you just drive with full throttle in the roundabout. You will be forced to go off the throttle because of the strong understeering. You also need to initiate the drift with a fast movement of the steering wheel. When it drifts it is very easy to control. In GT7 it's very hard not to spin out.

 

[///M3]

I just can say you that I drifted a RX-8 in a roundabout and this is very hard to start a drift. It's so hard when you just drive with full throttle in the roundabout. You will be forced to go off the throttle because of the strong understeering. You also need to initiate the drift with a fast movement of the steering wheel. When it drifts it is very easy to control. In GT7 it's very hard not to spin out.

Ok.

 

[RaceFace85]

Ok.

Looks like that the curb is pretty slippery.