Hi, Sorry if this is in the wrong section its my fist fourm post. First off, I’d like to start by saying I installed the game around start of November and have been hooked since ! I love the sim and this is purely constructive to help it continue to improve and I hope it won’t cause any offence. Anyway, I’d like to provide some feedback on the R32 GTR, specifically regarding the excessive understeer compared to what Ive encountered with my own car. Im fairly sure it’s mainly down to the way the Attesa has been implemented. Or to be honest didn’t feel like it has been implemented. But I’ll get to that in a sec I own an R32 and regularly track it and compete in the NI sprint championship along with the occasional hillclimb which allows me to directly compare the in-game car with real on-track experience. Infact after some time in the game earlier I took it out for a quick blast to compare them back to back. While yes its still road legal, Its 690hp and fully rose jointed, solid frame bushes etc. Ohlins dampers 10kg and 8kg springs. 888rs So its not that far off a Group A car (upper camber arms on grpA are different) So yes they are front heavy, but the real car is far more neutral than the way it presents in raceroom at the moment. In reality, it responds really well to trail braking. The front loads up nicely and the car will rotate on entry without actually needing much steering input. In Raceroom its nearly the opposite. The front end is stubborn, it refuses to rotate on entry even with with trail braking. Like Coasting, trail braking, gentle or aggressive steering input, going extreme with roll bars and setup, doesn't matter it just doesn't want to rotate no matter what I try. Anyway. I think it’s all down to the ATTESA and front diff. Apologies if you already know all this by the way. One of other differences in the group A and production car was the front diff. Open for production. Grp A had a “1. 5 way" LSD, as in its fully open when not under load. ( Ive drove one with a nismo 1.5 diff fitted and the only time you feel it is on corner exit) Then ATTESA is an active AWD system, 90% of the time it’s sending 100% of the torque to the rear. But depending on signals form the wheel speed sensors and a G sensor an ECU would work out how much torque to send to front. That means on corner entry the car is basically RWD, and only if the rear wants to step out it will then divert some power to the front, but even then it’s usually only 20-30% but it helps pull you out of the slide without needing to counter steer much. Again with the LSD in the front, on entry it’s open as no torque is being sent to the front. In Raceroom, the AWD behaviour feels closer to a constant or prematurely engaged front drive, leading to it pushing and reducing rotation. I’m not suggesting the car should be oversteery or forgiving for one second, but rather that its natural ability to rotate and work with weight transfer is totally different compared to the real thing. Now it’s maybe not an easy fix as no game has ever got ATTESA right. But surely something could be done to help bring the general handling closer. Again I’m only posting this because I genuinely love the car and I adore the game Ive been hooked since installing and would love to see it represented as accurately as possible in Raceroom. Thanks for your time for reading this and for the continued development of the sim. ❤️
Yeah, that's a good point. Raceroom's GT-R is not a Group A (despite its appearance and liveries), but a Group N.
Again that shouldn’t have any major bearing on handling behaviour. Less powerful and heavier than the group A. But ATTESA functionality is identical between them. And If anything then that furthers my point. As the group N is closer to the road car which I’m comparing it too.
@JMGTR32 me again. We already spoke briefly on discord about RR Mx5 races, R32s and RX7s. Really appreciate that you've taken the time to write out what you have. I'm always interested in improving how any of our cars behave and the R32 is probably one of the cars I'm least happy with at the moment, so thanks for getting involved. I didn't have a whole lot to base our car on from period. Homologation documents obviously exist but they outline what the car's systems are but not how they were used. I think that our differential/torque split is set up very differently to how you describe so it's no surprise if it behaves quite differently. There's also the Super HICAS steering system detailed which may be possible to implement. The only immediate detail I'd question is what '1.5 diff means' in terms of locking numbers. If you ask Kaaz, Cusco, OS Giken they all say something different and/or that it means a different thing for each car. Getting to the bottom of exactly what locking % each diff uses would be the first step I think.
Hiya Alex A 1.5 way diff is a generic kinda term for a LSD that acts as an open diff when there’s no torque applied to it during deceleration or coasting. Will lock up and act the same as an LSD during acceleration There’s some info here for the nismo front diff https://www.nismo.co.jp/products/web_catalogue/lsd/front_lsd_skyline_gt-r.html 8 plates on each side and Initial torque is 29.4nm Pressure ring cam angle is 45° on the drive side and 1° on the coast side You could contact Ricwood motorsport in the UK if you wanted more detailed info, they’ve built a few to group A spec and run alot of them in historic championships. The rear feels fine in the game but there will be info on that site for it too I can’t find anything relating to the front diff in the FIA homologation papers about it either other than a reinforced casing, which doubles as the engine sump which will have been modified anyway and it doesn’t mention any other than it’s reinforced. https://historicdb.fia.com/sites/de...001/homologation_form_number_5405_group_a.pdf Regards the torque split 90% of the time all of it is going to the rear. There’s very little info from Nissan on it (in English). I do know it would start to engage when there was more than 5% difference between the front and rear wheel speeds but unsure on G force data. However this graph is will give you some idea. It’s a more aggressive map for the ATTESA from an after market company.
@Alex Hodgkinson Hiya man, Just curious if any updates or any other info you may need or I can help with ? I totally understand if not I'm sure you're up to your eyes busy. Thanks
Yes we are pretty busy to say the least! I'm amassing a collection of things to action and I much prefer to go over everything carefully rather than just throw some numbers at it. I think the biggest questions I have now are about the spring/damper setup. Not sure how well it's done there at the moment and how accurate it is. Do you have any info?
Spring rates already available to it in the setup menu look ok actually. Dampers im not sure on, I havent been able to find any info. Ill keep digging and ask around see what I can get
Have you got any pictures of the wishbones you could share so I can check the accuracy of some calculations I've done?
Hiya, I can get them yea, want front and rear ? I can get some off my own car or I can find some ready available ones online. There are photos on pages 16, 36-38 of the FIA document https://historicdb.fia.com/sites/de...001/homologation_form_number_5405_group_a.pdf Theres some good info, photos and videos in this article too https://www.gtrusablog.com/2020/05/nothing-came-close-group-bnr32.html Thats a group a setup mostly assembled.