BMW vs Porsche supersprint at Sydney Motor Sport Park

[donR]

Just did the inaugral BMW vs Porsche supersprint at Sydney Motor Sport Park SMSP GP circuit which was a bit washed out but some good times and a dry track in the morning. A big turnout with 50 or so Porsches including some classics and as many BMWs. 

The fastest Porsche and car of the morning was some sort of GT3 which posted a 1.34.73, followed by a modified GT2 which did a 1.35.31. The fastest GT3 RSs looked to have been around the 1.39 mark and there was a 996 GT3 which did a 1.41.61. 

Nice to see some of these exotic cars on the track and some very good drivers out there. 

I had a bit of fun chasing a F80 M3 which ended in a spectacular spin out of turn 1 which catches a lot of people out. Not the most forgiving corner particularly for the bigger BMWs:

 

 

[Peter M]

donR,

Just a couple of questions if you don't mind:

What tyres are you running?

What's the difference in lap time between running auto and manual shift modes?

Great timing in capturing the wayward BM at 2.18!

 

Thanks!

[1q2w3e4r]

That's a worry going off there.   Though watching his prior lap, some of the lines were interesting...

[MFX]

What is the lap timer you were using and was that also the telemetry that was overlaid in the video?

[donR]

1 hour ago, Peter M said:

donR,

Just a couple of questions if you don't mind:

What tyres are you running?

What's the difference in lap time between running auto and manual shift modes?

Great timing in capturing the wayward BM at 2.18!

 

Thanks!

Thanks and no worries. I'm running Trofeo R and the BMW was also running semi-slicks - maybe Nakang AR1s or something like that. 

I'm told manual shifting does not lead to faster times compared with auto mode, although perhaps a pro racer or instructor would be a bit faster in manual mode and with PSM turned off. 

I do try a few manual down shifts depending on the corner but I find the PDK is generally faster and better than me and I can focus more on the lines and braking as it is a difficult circuit to master so I couldn't say for sure which is faster.

I did try manual shifts at Wakefield and the times were very similar, maybe only a few tenths slower than with auto shifts. I was surprised as I am not the best at manual shifts despite my last car being manual stick! I think with practice both manual and auto times would be near identical, the PDK is that good. Perhaps worth a manual shift down to second on the last two corners before the straight, might be another tenth in it.

53 minutes ago, MFX said:

What is the lap timer you were using and was that also the telemetry that was overlaid in the video?

The lap timer is the Porsche Track Precision Ap that comes with Sports Chrono. It is sometimes a bit buggy and I have to import and sync the video from my GoPro manually which can be tedious, but the metrics are useful but not always precisely timed due to I think perhaps a relatively low sampling rate of Ap. It is nice though how it displays current time on the PCM display so you know how your lap is going. The ap will also export VBO data to things like circuit tools but I'm yet to understand how to use it properly and/or get a good driver in the car so I can compare my brake points, etc. 

[333pg333]

Whoa!! That guy in the BMW was stupid lucky!! Almost all people that come off on the outside of T1 slide, grab a handful of opposite lock, spear across the track and hit the inside wall at hard angle...and then flip over a few times. He should have bought a few lottery tickets on the way home...after he swapped his pants!

[donR]

37 minutes ago, 333pg333 said:

Whoa!! That guy in the BMW was stupid lucky!! Almost all people that come off on the outside of T1 slide, grab a handful of opposite lock, spear across the track and hit the inside wall at hard angle...and then flip over a few times. He should have bought a few lottery tickets on the way home...after he swapped his pants!

Yes I've heard of people coming to grief there. I actually did a similar thing once on coldish tyres and too firmer suspension but being a cayman and small my call pretty much spun 360 around straight on the inside near the wall and kept going. Scary stuff though and I can see in a bigger and/or less balanced car you could easily hit the wall as the M3 guy did to some extent. 

[AndrewM]

Found it interesting that you were completely off the accelerator around the corners leaving the car completely unloaded....

[donR]

5 hours ago, AndrewM said:

Found it interesting that you were completely off the accelerator around the corners leaving the car completely unloaded....

 Thanks Andrew, I think maybe with the Caymans they are so well balanced that you can roll a bit more. However, always open to suggestions to improve lap times. 

I hope I have improved a little bit since that vid from last year. Here is my latest lap on Cup 2s. Let me know what you think.

 

[LeeM]

 That looked a lot tidier to me...especially around Corporate Hill left hander 👍

[donR]

Thanks, I've made some minor suspension adjustments also and the car seems to be holding in a lot better on fast sweepers without oversteer. I'm hoping some stickier rubber will improve things further but has been good to get a final benchmark time on Cup 2s. 

[AndrewM]

Looks cleaner to me too! If it were me, would try and smooth out the steering input a little, but having said that, you probably do faster lap times than I do.... 😄

 

 

[LeeM]

 Do you, or have you tried left foot braking at all? 

 I can't do it very well in my manual air cooled, yet I do it in any auto I drive. When I've driven a tiptronic 911, I find it definitely assists with smoother braking and transition from the throttle pedal, and also being able to accelerate earlier whilst covering the brake pedal.

 I'm really struggling here to actually explain why it's much better, and many people struggle to change to left foot braking (those who have been successful swear by it now), yet as I raced go karts for coupla 3 years it became natural to me in a car.

 When I raced bikes, I was a second or two (a.k.a an eternity) from a very successful rider, and he told me even if I changed my riding style to knock off a 10th of a second per corner per lap, that's a second or more just there, and also to "Slow down to go fast". It was bloody good advice, and although I never beat him, I could stay with him for a lot longer, and my riding was nowhere near as manic as I used to be.

 I've only ever done 6 laps in a Formula Holden open wheeler where 4 wheels are concerned on a track, yet it's the same as on a bike with it being such a long and arduous process trying to find a 10th here, 10th there, then trying to set up the car(bike) to lower your lap times. You have to try different things that put you outside of your comfort zone to reduce your times.

 I don't profess to being a trackday driving coach guru...very far from it, and you obviously have half an idea with what you're doing, yet from hundreds of laps over 20 odd years on bikes, the best advice I have received and can offer here, is to break the track down into single corners or sections and concentrate on improving them one at a time. 

 

[donR]

I can left foot brake and I have tried it on very windy circuits where there is frequent on throttle - off throttle brake, back on, etc., like what we call Amaroo/South circuit at SMSP. However, my feel on the left brake is definitely not as good as my right so I don't use it much and end up going back to mainly right, but I should try it again one day. It is easy to practice on the street when going slow but not too good on the track when you are going fast. 

On the GP circuit shown above, before the last apex I do a light left foot brake as it should be straight on the gas if you are straight lining that last apex to carry the speed down the long straight. Although I'm still working on it!

I know alot of the sim guys left foot brake on the track as well and on the rare occassions I use a sim I usually left foot brake as there is no feel anyway! I think if you get used to left foot braking it has got to be marginally faster, especially on some corners. I wouldn't be surprised if a lot of the F1 guys are left foot braking? Certainly rally guys are doing it.

[LeeM]

50 minutes ago, donR said:

I wouldn't be surprised if a lot of the F1 guys are left foot braking? 

 They do, as they only have 2 pedals as far as I'm aware. Clutch is on the steering wheel 👍

 Yeah it's tricky to modulate the brake pedal at speed, as I reckon it's more of a mental thing you need to get used to to push the pedal harder. Just gotta practise I s'pose 👍

[Raven]

1 hour ago, LeeM said:

 They do, as they only have 2 pedals as far as I'm aware. Clutch is on the steering wheel 👍

 Yeah it's tricky to modulate the brake pedal at speed, as I reckon it's more of a mental thing you need to get used to to push the pedal harder. Just gotta practise I s'pose 👍

I left foot brake in my Formula 1000 you only use the clutch to start and stop once you are underway no clutch need sequential box....

It is a very easy and natural thing to do in a Formula car 

 

[edgy]

On 23/09/2022 at 21:11, donR said:

Here is my latest lap on Cup 2s.

Hey @donR Pretty sure I see your name on the PCNSW SS results!

Can I ask, how are you finding the Cup 2's?  I have been running them this year too, but coming from R comps, I am finding myself a little frustrated with them, I find the temp/pressures temperamental, or perhaps that is the constant rain we are getting on each club round?  In any case, unless it is fully dry I find myself being very reserved with them...

With A050's I'd have the confidence to push by the end of the out lap, Cup 2's perhaps on lap 2 or 3?? I am throwing that all out the window if there is damp or traffic and it shows in my times (vs dry sessions).. 

cheers

 

[donR]

48 minutes ago, edgy said:

Hey @donR Pretty sure I see your name on the PCNSW SS results!

Can I ask, how are you finding the Cup 2's?  I have been running them this year too, but coming from R comps, I am finding myself a little frustrated with them, I find the temp/pressures temperamental, or perhaps that is the constant rain we are getting on each club round?  In any case, unless it is fully dry I find myself being very reserved with them...

With A050's I'd have the confidence to push by the end of the out lap, Cup 2's perhaps on lap 2 or 3?? I am throwing that all out the window if there is damp or traffic and it shows in my times (vs dry sessions).. 

cheers

 

Relatively speaking I don't think Cup 2s are a particularly fast tyre and you need to drive a perfect lap to lay down a good time, but they are a good dual purpose tyre and warm up pretty quick so you shouldn't get caught out. I was using Trofeo R previously and they were definitely faster than the Cup 2s but not as good in the wet, but still ok, and as you mention with the rain all R-spec tyres are affected. In dry performance I think it is much like this from slowest to fastest:
Cup 2 < A052, Trofeo R, RE-71RS < A050, Z221, DZ03G < Cup 2R (limited laps)

So all of these tyres will be 1 to 2 sec or more faster than Cup 2 and maybe if you are used to A050s it is harder to drive a slower tyre fast, in that you need to be closer to the slip angle. 

With the A050s I can't say I've tried them but I just bought a set of 18" forged Koya's with A050s so I am looking forward to seeing how much faster they are once we get some good weather! Certainly the A050 and the Z221s and DZ03G are meant to be the fastest tyres. Z221s are best value but the rear diameter is a little small for my Cayman.

By the way Pete in his M2 CS was running on A050s the other night and he was consistently posting the fastest times in the wet until it dried up a bit. From what I've heard the A050 is still quite good in the wet if you can get it warmed up enough and on high downforce cars. 

[mc968cs]

Cup 2 are great for ‘drive to track fun days’ but compared to true r on track are compromised for 997 996 chassis use.  (They seem bloody good on 991).  I also thought they heat cycled out.  
Ie proper r spec better for track, not as good on road use ….bit noisy, not quite as good in wet though that last points debatable too. 

trofeo r in 19” were extremely similar to a050 medium in 18” on my 997 gt3. Trofeo wider too.  The 305 rear, is really a good lower profile 320. Put 245 on front and bang out times.  But that’s 997 sizes. 

So for 996 I don’t think anything really tops the medium ao50, but I’m about a season out of date so may be a new r spec that’s better. 

[donR]

I agree proper R spec tyres are very noisey for anything other than their designed track use. Straight grooved Cup 2s and Trofeo Rs, and other similar straight grooved tyres are a lot quieter and good for road use. I've read Cup 2 connect are also marginally faster than older Cup 2s, but then there is the N vs K vs ... spec that can also lead to performance variations.  

My reading suggests Trofeo Rs are on par with the similar design A051s so I would have thought the A050s in medium would be a little faster. I also found that Trofeo Rs took a little longer to warm up in the cold in comparison to Cup 2s but that's expected. Anyway, if I can't beat my Cup 2 and Trofeo R times with A050s I'll eat my words.

I guess wheel size, profile, width and vehicle type can also account for some differences. I understand the smaller 18" wheels with the 35 profile R-spec tyres should also give a little bit of "free" torque over the larger 20" wheels with 30/35 profile tyres, so that might also account for some time. I also thought the A050s looked like they run a little wide when mounted, but that's subjective. 

[edgy]

14 hours ago, mc968cs said:

Cup 2 are great for ‘drive to track fun days’ but compared to true r on track are compromised for 997 996 chassis use.  (They seem bloody good on 991).

Have to say I agree with this statement, I think they are a great dual purpose, but neither great for track or road... your remarks on how they fare on a 991 platform is what I think skews me! I am benchmarking a lot of what those guys are doing and have probably set my expectations too high for the tyre on the older platform! 

14 hours ago, mc968cs said:

I also thought they heat cycled out.  

Me too, at first I wasn't sure what was up, as my times were down significantly within the same week (one private session, one PCNSW event) pulling the data from the Aim unit showed corner speeds down significantly across the board, and lat G... so definitely seemed like they had cycled out, others I pit with running them mentioned 4 solid track days as an average for them to be at their optimal... I am past that. 

20 hours ago, donR said:

So all of these tyres will be 1 to 2 sec or more faster than Cup 2 and maybe if you are used to A050s it is harder to drive a slower tyre fast, in that you need to be closer to the slip angle.

Definitely agree with this! 

 

20 hours ago, donR said:

With the A050s I can't say I've tried them but I just bought a set of 18" forged Koya's with A050s so I am looking forward to seeing how much faster they are once we get some good weather!

I'd imagine the 1-2 sec ballpark! But as you say, the weather has to play ball with us, and this Sunday is looking like another Porsche Motor Yacht Club outing....

[donR]

Had a great opportunity to test out the A050s in both wet, damp and relatively dry conditions and compare with some other caymans on Cup 2 and RE 71-RS R compound tyres. Thought I'd start a seperate thread here so as to not detract from the spinning BMW 😅