10-13-2019, 03:35 PM | #67 | |
Lieutenant Colonel
824
Rep 1,584
Posts |
Quote:
When I first got my F80, I was surprised by how easily the stock custom Pilot Super Sports would break traction, how overly stretched they seemed to be, etc. so I experimented with a few different sets of 20” and 19” tires on my 666M and 437M stock wheels. I gained a ton more performance, I can launch incredibly quickly, put power down coming out of corners much better than before, etc. but I also feel like a lot of the car’s ‘magic’ has been lost in this pursuit. Before, in fully stock form, the car felt tremendously agile, front to rear grip balance seemed to be very neutral and yet easily adjustable mid-corner, the body weight felt very well controlled up until the limits of grip. Now, the suspension & tire sidewalls feel softer at the higher cornering limits, and the damping is less impressive because you end up going that bit more quickly, etc. I’m of the opinion that sometimes the choices made during engineering of certain cars that set super, super quick laptimes are also the same things that make them a little less fun to drive when the stop watch is not involved. |
|
Appreciate
5
|
10-13-2019, 03:57 PM | #68 | ||
Ring Leader of G8X Haters
25083
Rep 8,762
Posts |
Quote:
__________________
Current Garage: 2022 Mercedes-Benz S 580 / 2023 Genesis GV70 2.5T / 2007 Mercedes-Benz E 350 / 1999 Mazda MX-5 Miata
Retired: '95 E36 325i 5MT / '04 E46 330i 6MT / '05 E83 X3 3.0i / '11 E90 335xi / '17 G30 540i / '19 F87 M2C 6MT / '19 MB CLS 53 / '20 MB GLC 300 |
||
Appreciate
0
|
10-13-2019, 04:20 PM | #69 | |
Captain
2532
Rep 825
Posts |
Quote:
Good sir, Remonster, can you talk more about precisely what changes you tried out on your tires? It's almost time for me to swap out new tires on my M2C, and was considering going from the stock MPSS 245/35/19 fronts and 265/35/19 rears to MPS4 in 265/30/19 fronts and 295/30/19 rears. Figured the wider set up would give me greater traction, higher performance, etc., but by the same token, I LOVE how the M2C currently drives, I really couldn't care less about true performance as I don't track and the M2C is just my fun DD, so definitely don't want to do anything that might kill the "magic." For me, the #1 priority is fun, and the car is awesomely fun at the moment. You think making a switch like that might kill some of the fun? |
|
10-13-2019, 05:27 PM | #70 | |
.
16300
Rep 8,395
Posts |
Quote:
Soon to be... The Ultimate Self-Driving Machine ‼️
__________________
///
|
|
Appreciate
0
|
10-13-2019, 05:46 PM | #71 | ||
Lieutenant Colonel
629
Rep 1,755
Posts |
Quote:
Driving yourself in 20 years might be a novelty.
__________________
18? Camaro 2SS 1LE
16' M3 MG Ext. /SO Int. (DCT, Ohlin R/T, 19" wheels) 15' Audi S4 13' Audi TTRS (APR stage 1, MSS springs) 09' C6 Z06 08' M3 Interlagos Blue: 6sp, Tech. |
||
Appreciate
1
///M TOWN16300.00 |
10-13-2019, 09:57 PM | #72 | |
Lieutenant Colonel
2485
Rep 1,602
Posts |
Quote:
Yup. This is a very important thing to keep in mind. The thing is, no matter how bad I want them to, F1 scouts are not going to show up to my local track day to consider me for a job. I am quite literally at one for six billion in terms of "human beings who care if I run a 2:16 instead of a 2:18 at my local track day" Since accepting the universe's (totally unfair) apathy towards my driving talent, I've gone with the philosophy of favoring the subjectively more fun driving experience ten times out of ten. |
|
Appreciate
2
cptobvious2531.50 BlkSVT388.50 |
10-14-2019, 03:22 AM | #73 |
Major General
7334
Rep 7,295
Posts |
I'm fine with people saying they want fun over the best absolute time. I'd agree, but sometimes we have to come to terms with the fact that BMW makes cars that are compromises by design. I mean, if fun and feel on track are your only benchmarks, I'm not sure BMW is competitive in that regard either. BMW makes dual purpose cars, with the possible exception of the M4 GTS. I doubt they would ever be as fun on a track as a Lotus.
M cars start life as the chassis for base series vehicles, so it's going to be tough to compete with purpose-built platforms. It used to be that the BMW base chassis was a lot better than the competition, but everyone else has improved. Still probably the best dual-purpose cars for the money, but let us be objective here. |
Appreciate
3
|
10-14-2019, 05:18 AM | #74 | |
Brigadier General
2721
Rep 3,334
Posts |
Quote:
If you want a bit more width and a slight bit more grip, PS4S (*not* the PS4) 255/35-19 and 275/35-19 are perfect fits for 9" and 10" wheels.
__________________
Current Stable:
2024 G20 M340i Melbourne Red/Cognac 2019 F87 M2 Competition 6MT, LBB, slicktop, exec pkg 2007 E91 328i Silver, slushbox, Eibach fr/E93 M3 rear sway bars, ARC-8 |
|
Appreciate
1
cptobvious2531.50 |
10-14-2019, 07:14 AM | #75 | |
Brigadier General
3663
Rep 3,422
Posts |
Quote:
Funny because just about every enthusiast group outside of our own sees and appreciates M cars for what they are. I used to load up and drive south for track days in my modified E90. Hit winter weather trying to escape more often than not, so my car was coated in salt and grime. I'd arrive to Sebring, Homestead, PBIR looking homeless with a trip's worth of gear, equipment, 4 track wheels, etc. Often approached by Vette, 911, R8 owners inquiring about my mods, then they'd spot my northern plates, ask my story. Shared all of the above and that it's my wife's part-time daily driver, family road trip car back home. None of them thought the M3 sucked because it couldn't match the Z06's on slicks... And yes, even the most extreme iteration of an M car is still going to feel like a highly modified GT car. The starting platform is the starting platform. I've driven a 458 and my M4 GTS back to back on-road. Clearly, two fundamentally different types of cars.
__________________
M4 GTS, GT3, C63 S | E90 M3s, E39 M5
|
|
Appreciate
5
|
10-14-2019, 09:20 AM | #76 | |
Lieutenant Colonel
1996
Rep 1,759
Posts |
Quote:
Then some people don't like the RE-71R for daily so really depends on your usage |
|
Appreciate
1
cptobvious2531.50 |
10-14-2019, 11:48 AM | #78 | ||
Lieutenant Colonel
798
Rep 1,736
Posts
Drives: 2019 BMW 540i xDrive
Join Date: Nov 2018
Location: NYC
|
Quote:
|
||
Appreciate
1
Moflow2484.50 |
10-14-2019, 12:00 PM | #79 | |
Lieutenant Colonel
824
Rep 1,584
Posts |
Quote:
In your case, it looks like PS4S is 0.2" wider front and rear than PSS at the tread so you should be very happy with the upgrade if you stick to the same 245/35 front and 265/35 rear. I would not recommend moving up to the 265 & 295 setup, the car will feel totally different to what you're used to and not in a good way IMO. |
|
Appreciate
2
cptobvious2531.50 clee1982797.50 |
10-15-2019, 07:52 AM | #80 | |
Major General
2750
Rep 6,759
Posts |
Quote:
So it's not crazy tight and technical like Shenandoah but I think it's a good mix of challenges thrown at a car. C&D picked it over other tracks because of that. You should try it.
__________________
2018 F80 Santorini 2019 Z4 3.0i 2022 X2 M35i |
|
Appreciate
1
Moflow2484.50 |
10-15-2019, 04:36 PM | #81 | |
Major General
2750
Rep 6,759
Posts |
Quote:
2. To your point about putting the power down, it doesn't seem to me the F80 had a problem with that in heavy track use, it's always been the front lacking for grip in my experience. That's why everyone runs 275 with camber plates at the front and wish they could run more. My rear tires are having a walk in the park on track, compared to the fronts... 3. Anecdotal but in my opinion they did get it right in the CS. C&D should have tested the CS. But you're right, the F8x suspension is too soft for the track. Still despite this, with good tires and brake pads I run very similar times as the Camaro SS and Mustangs 350 in my run groups. Don't get hung up on a couple of seconds difference in amateur tests. There is such variability in it, that the reality of what is happening at track events (where most everyone runs equal performance brakes and tires) is very different.
__________________
2018 F80 Santorini 2019 Z4 3.0i 2022 X2 M35i |
|
Appreciate
0
|
10-16-2019, 07:08 AM | #82 | |
HALA MADRID!
938
Rep 2,879
Posts |
Quote:
why is that? I went 295/30r19 rears (MP4S), and the car drives absolutely phenomenal! Kept the 245/35 front size. The car can put the power down much better, there is more grip on the corners specially coming out of the apex, and in highway/city driving there is literally ZERO after effects. Car feels more planted and more secure to me. Not to mention the amazing aesthetic upgrade. Car looks like a true M car now, and very aggressive looking. the ONLY downside I can point to thus far, in a very small way, is that there is a hint more of hydroplaning when there is heavy rain, in these south florida afternoon thunderstorms. Nothing huge but it's slightly noticeable.
__________________
F87 M2 Competition, Sunset Orange, Exc, DCT. **SOLD** F80 M3 Mineral Grey/Sakir Orange, Exc, DCT... ED 6/2015 **SOLD**E90 M3, Interlagos Blue / M individual two-tone, ZCP, ZP2, ZCV, DCT, ED. |
|
Appreciate
0
|
10-16-2019, 12:05 PM | #83 | |
Lieutenant Colonel
3354
Rep 1,823
Posts |
Quote:
So if you like coming out of corners a bit sideways and power slides this setup will make it difficult to oversteer. If you drive 6 or 7/10 you likely will never notice. Last edited by 5.M0NSTER; 10-16-2019 at 12:27 PM.. |
|
Appreciate
1
clee1982797.50 |
10-16-2019, 03:29 PM | #84 | |
HALA MADRID!
938
Rep 2,879
Posts |
Quote:
Twice I've been on the track in this car, one in OEM tires, and once in this setup....same track (PBIR), similar conditions (clear, 80's temps, et al), and there is significant improvement in overall handling specially in the tighter corners of the track. On the back corner prior to the long straight away, where you want to take the apex as fast and aggressive as you can to get a good roll into the straight away, the difference was absolutely noticeable...IN A GOOD WAY! no understeer whatsoever, and much more planted. This myth of understeer on the larger rears on this chassis (and on the F80), is absolutely false. I will take videos next time I go in a few weeks. Similar effects where felt in my older F80 M3, and you can see it here (295 rears on the F80):
__________________
F87 M2 Competition, Sunset Orange, Exc, DCT. **SOLD** F80 M3 Mineral Grey/Sakir Orange, Exc, DCT... ED 6/2015 **SOLD**E90 M3, Interlagos Blue / M individual two-tone, ZCP, ZP2, ZCV, DCT, ED. |
|
Appreciate
0
|
10-17-2019, 02:33 AM | #85 | |
Lieutenant Colonel
3354
Rep 1,823
Posts |
Quote:
By which governing principles of physics do you think increasing mechanical grip in the rear but not in the front results in same over/under-steer balance as before? What you describe on corner exit makes perfect sense. More traction in the rear helps put the power down on corner exit. Plus eLSD sends more torque to the outside wheel to add yaw torque and rotation out of a corner combating understeer. The flip side of this (and there is a flip side as for every action there IS an equal but opposite reaction) is when increasing steering off throttle and on brakes. Front wheels by definition will lose grip and begin to understeer before the rear lose grip. This doesn't have to be terminal understeer (since you increased traction in the back by max of 11%) it can manifest in you needing to increase steering from 90 deg wheel angle to 105 deg for example, and this you most likely don't notice. But it’s there. Because Physics. So I misspoke when I said the difference would be clear as day because ~11% difference is not discernible to an average driver. Next time you're on a small roundabout, take it pretty hard, let the car settle at 0.7g lateral acceleration or so, and slowly add throttle while increasing steering input. You will get understeer sooner with your setup than in stock tire configuration. Guaranteed. Because Physics. If you were able to instrument your car and measure speed, yaw, lateral acceleration, steering wheel angle and side slip the difference will be quite clear. Your "feel" doesn't have the objectivity of instrumentation data. P.S. I work on electronic stability control systems. Algorithms and tuning. This is sort of my daily work both in theory and practice.
__________________
2017 BMW M2 German Spec
6MT, Driver's Package --> SOLD 2018 Camaro SS 1LE. Because race car! "Redline a day keeps the mechanics away" Last edited by 5.M0NSTER; 10-17-2019 at 07:18 AM.. |
|
Appreciate
7
|
10-17-2019, 08:48 AM | #86 | |
Major
175
Rep 1,040
Posts |
Agreed 100%. Would be good to know why BMW is avoiding proper testing of this particular automobile. I am pretty sure C/D and other have asked for it by now.
Quote:
|
|
Appreciate
0
|
10-17-2019, 12:32 PM | #87 | |
HALA MADRID!
938
Rep 2,879
Posts |
Quote:
Yes, there will absolutely be more "forced" understeer on the front wheel due to the higher grip on the rears, per se..... and again, as you pointed out, the difference is NOT noticeable by average driver or track enthusiasts. I'm sure professional drivers and BMW M-Testers will definitely see this effect, but to me and the vast majority of the folks in this forum, this will not be noticeable. On the flip side, the effects of the better grip on the rear, to these same "average" drivers and track enthusiasts will be MORE noticeable and with a better overall driving dynamics.... in my very humble opinion. To me, the net-v-net benefit of the better grip, the more planted nature on hard corners, and the more aggressive stance.... vs..... the slight increase in hydroplaning and the slight increase (~11% at worst case as you stated ) in front understeer at full push, is more than beneficial to me. ps- If anyone likes drifting more, or likes the tossability nature of this car as is, then yes, going wider tires - specially 295/30, is not for you
__________________
F87 M2 Competition, Sunset Orange, Exc, DCT. **SOLD** F80 M3 Mineral Grey/Sakir Orange, Exc, DCT... ED 6/2015 **SOLD**E90 M3, Interlagos Blue / M individual two-tone, ZCP, ZP2, ZCV, DCT, ED. |
|
Appreciate
1
5.M0NSTER3353.50 |
10-17-2019, 01:31 PM | #88 | |
Lieutenant Colonel
3354
Rep 1,823
Posts |
Quote:
And you bring up a good point. Depending on how you drive there is an advantage to higher stagger like you describe. Most people can control understeer a lot easier than oversteer. All you have to do is lift and/or apply a little brake to transfer more weight forward. It can even be faster on the track because it can give you more confidence to get on the throttle harder and stay on the throttle. If you turn in just a bit early and get on the gas sooner you can maximize a setup with more stagger on track without feeling the understeer. I like oversteer, but it can be nerve wracking and typically not the fastest around the track. In my opinion M2 with the factory stagger has the perfect balance for how I drive. I like braking very late and diving into the corners late and hard, and manage slip with throttle and steering. I was doing hot laps at Nurburgring over the summer and lost grip mid corner in Hatzenbach series of corners. But thanks to the balance both front and rear let go simultaneously, and the car slid out towards the outside of the track. I did nothing, kept all my inputs constant. Fraction of the second later I felt the grip come back and I added a bit more steering to get back on the racing line. I thought this was very telling about a balanced nature of the car. I tracked a heavily modified 2014 Mustang GT before this, and that car was very tail happy. It helped me sharpen my senses to recognize and control oversteer to a point of near pre-cognition. I had full suspension so there was no understeer (unless I did something stupid), and with R comp tires it became very snappy. Huge grip, and then instantly no grip. The M2 is much more approachable and transitions slower. I find myself having to slow down my responses because the car has such a balanced and progressive nature. But we all drive different and enjoy different characteristics of the car. Glad you found your perfect setup Keep tracking it, it's quite rewarding. And driver mod is the best mod money can buy!
__________________
2017 BMW M2 German Spec
6MT, Driver's Package --> SOLD 2018 Camaro SS 1LE. Because race car! "Redline a day keeps the mechanics away" Last edited by 5.M0NSTER; 10-17-2019 at 02:27 PM.. |
|
Appreciate
2
cptobvious2531.50 ssabripo937.50 |
Post Reply |
Bookmarks |
|
|