Physics Update: GT2RS GT3, GT4

Discussion in 'News & Announcements' started by Alex Hodgkinson, Dec 10, 2019.

  1. Alex Hodgkinson

    Alex Hodgkinson Sector3 Developer

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    Before anything, the #1 rule here is that old setups will not work with any updated cars. Trying to use these setups will result in a very poor handling car. They must be deleted!

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    The Porsche GT2RS Clubsport is the first car built especially for the new GT2 category. Consider that it's not related or even comparable to the old category it's shares a name with. The intention behind this series is to create cars which are less reliant on downforce, have more power and and are easier and/or more enjoyable for gentleman drivers to handle.

    The engine is an absolute weapon: 3.8L twin-turbo flat-6 (of course) kicking out around 700hp and a whopping 750nm of torque. It harks back to what Porsche was all about from the 70s until the late 90s. Earlier versions of power plants like this were fitted to the back of the 935, 936, 956, 962, WSC-95 and 911GT1, just to name a few. Amazingly this engine is almost identical to the power plant found in the road car. As is the gearbox, which explains why there's one extra gear high up which you'll probably never use. 7th is a sort of Autobahn cruising gear for the road car, and it's fitted to the Clubsport too.

    The way the chassis is put together is closer to the GT3 Cup than the GT3-R. It's also very stiffly sprung, just like the Cup Porsche. I believe the reasoning is that the suspension, with it's struts front and rear doesn't allow for as much control of camber during body roll, so that is limited by running stiff springs.


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    Amazingly it's already been two full years since the last complete update of the GT3 class. The last attempt was something we could be really proud of, and proved unanimously popular. So this overhaul was approached with caution and has been a long time in the making having been started back at the start of summer 2018.

    With the most recent cars, the underbody aero (diffuser) plays an increasingly important part in the car's downforce. The higher the rear ride height relative to the front, the more you will increase total downforce, but also drag. Going too high can cause the diffuser to stall however and downforce generation will drop off drastically, so do some experimenting. The rear wing is there mainly to trim aero balance.

    Motorsport traction control and ABS are used throughout, and have both seen a lot of development on our side. Gone are the days when switching traction control off is a must to turn fast lap times. Now you can tune it to help hold a desired amount of slip when on the throttle, without the aggressive cut it's had until now. ABS is an absolute must for fast lap times. The main benefit is that you can brake hard and deep into the turn without any risk of locking a wheel. That'll really help to rotate the car and enable you to carry more speed right to the apex.


    Porsche GT3-R (2019)

    While vising the Nurburgring in April for the Volkswagen ID.R I was lucky enough to be introduced by Romain Dumas to one of the very first of these at an early season VLN race. I'd already been supplied with information and data but to see first hand the new parts and compare it to the old one it shared a Manthey Racing garage with was quite something.
    Downforce is increased, most of it from a larger diffuser, but drag is relatively unchanged so it's a more efficient car aerodynamically. The mirrors are designed especially to channel air around the rear of the car, both to increase downforce and decrease drag.
    Following the general trend of GT3 more is better, so both power, torque and weight are increased. This is all about making better use of the tyres, and the success of heavier cars has proved it's a successful strategy. Until 2019 the GT3R has always been the lightest car in GT3.
    The biggest revelation however comes in the front suspension. It's the first "production based" racing Porsche to use double wishbones up front. This brings it in line with what's used on the GTE racer, and is something which no road-going 911 has ever featured in 56 years. What does it mean? Camber and dive control is much improved meaning braking, tyre optimisation and wear all take a step forward. You'll find that the front end just sticks better.

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    The GT4 series takes track day cars and goes racing with them. Intended as the first step on the endurance racing ladder, a lot of drivers use this series to learn the ropes before moving on to faster machinery. Downforce is moderate but enough to be a factor, tyres are not far off what are used in GT3, and braking systems are fairly close to that class too.
    Motorsport traction control and ABS are used throughout, and have both seen a lot of development on our side. Gone are the days when switching traction control off is a must to turn fast lap times. Now you can tune it to help hold a desired amount of slip when on the throttle, without the aggressive cut it's had until now. ABS is an absolute must for fast lap times. The main benefit is that you can brake hard and deep into the turn without any risk of locking a wheel. That'll really help to rotate the car and enable you to carry more speed right to the apex.
    Gearboxes are homologated, ratios not changeable, and almost always identical to the road car. Hence you will find that, just like the Porsche GT2 Clubsport, some gears are of little use when racing.
    Damper adjustment is also restricted to just low speed, with high speed settings blocked off.

    BMW M4

    Before joining Sector 3, I worked full time as a race circuit instructor. I was fortunate enough to become a regular for BMW on their M events which run at circuits in the UK over the summer. While I didn't drive any M4 GT4s (they weren't on sale yet) I did clock up thousands of kilometres in track-prepared M4s with roll cages, slicks and wings. So from the start I had a very clear vision of where to go with this. Add in the wonderful help of @Will Tregurtha and hoards of data from some very helpful race teams, the development of this has had a lot going for it.

    It's the heaviest and most powerful of our GT4s. The weight is up front and quite high, but that can be used to your advantage by managing weight transfer with the pedals. Mastering the art of trail braking will really pay off, and smooth throttle application is a must to keep the rear end in check.

    There's a small underbody diffuser, so downforce levels can be tuned by adjusting ride height. A higher rear end will give greater overall downforce, but also increase drag.

    Porsche Cayman 718 Clubsport


    Building on the previous generation 981 Cayman, this car has more of everything; Power, torque, downforce, and also weight. Compared to the 981, the engine's power curve is quite different; it all happens at much higher revs here, but down low in the revs there's actually a bit less pull. So make sure you're using the gears efficiently.
    In terms of chassis, it does handle really similarly to the previous generation at low speeds, but the added downforce thanks to a revised wing and underbody diffuser make quite a difference in the fast bits. Just like the M4, you can tune the total downforce level by adjusting ride heights. If you want more top speed, lower the rear ride height so the car sits flatter, but you will loose out on overall downforce.
     
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    Last edited: Dec 11, 2019
  2. Eric Rowland

    Eric Rowland Well-Known Member

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    Have all the GT4 cars been updated to the latest physics and not just the aforementioned BMW and Cayman?
     
  3. Thomas Jansen

    Thomas Jansen Sector3 Developer Beta tester

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    Yep, all of them!
     
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  4. memoNo1

    memoNo1 Active Member

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    Good evening everyone.
    I originally come from rF2.
    I was curious about the big update.
    I have tested it with the DTM92 and what can I say?
    I just bought the Premium Pack! Great job folks! Keep it up!
    Now i give the NoS and the GT4 a check:cool:.
    Hopefully you will also license the remaining GT4s.
    Does every GT4 and DTM92 have its own physics?

    Best regards.
     
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  5. CrimsonEminence

    CrimsonEminence Active Member

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    When you bought the premium, then you've got the Touring Classics...i can recommend the R32 Skyline on Falkenberg...Grassroots Racing AWD feeling (i'm just making up words here :D ). Every car has its own physics. You will notice, when changing between M4 GT4 and Cayman GT4 and you also will notice between DTM 190 Evo and the DTM Audi...a lot! ;D
     
  6. fireballr18

    fireballr18 Well-Known Member

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    Welcome!
    Enjoy the package. R3E is on a fantastic way for some time. GT4 are fantastic, I prefer it over the GT3 as there is less downforce, thus way more to do behind the wheel :)
     
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  7. Frontkratzer

    Frontkratzer Active Member

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    Absolutely right. I started out driving the big cars permanently, but found the most fun in driving GT4's now, especially after the December update. :)
     
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  8. majuh

    majuh Well-Known Member

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    What exactly does that mean? With the Corvette C7 GT3-R right now, it feels like you can always set the rear wing to the maximum angle since it doesn't affect the top speed and brings more stability to the rear instead.