orthojoe

Trofeo R: 28F/29R hot
MPSC2: 32F/34R hot, but others have said lower is better

Why is it better than the Mobil 1? How do you know that it's definitively better?

ipse dixit

At least for the factory-fill Mobile 1, it's street-based, not race-based Mobile 1, which lacks certain additives, esp. zinc and phosphorus levels for film strength. Greater degradation at high operating engine temps. OEM oil fills (i.e. street-based) are more for emissions, than endurance and performance.

Also, Motul 300v is ester-based and does not breakdown until over 500 degrees F.

Of course, my mechanic also told me to use Motul 300v.

orthojoe

^ thanks!

Manifold

I continue to be baffled by the varying experiences and opinions of credible people regarding the camber. My own approach has been to keep the car as close to factory setup as possible, and since there are some reports of that working well for the track, I'm thinking that trying the 1.5 cambers may be worth a shot. Plus, as noted previously, the Sport Cup 2 tires have different compounds across the width, so optimum grip may mean more wear towards the outside shoulder (ie, contact patch may be good across the width, but faster wear of softer rubber may make it look like more camber is needed).

Regarding the cup cars, while many suspension components may be similar, my understanding is that cup cars run much higher spring rates, and have lower ride height and generally different suspension geometry and alignment. And using slicks likely also makes a big difference as far as optimal camber.

orthojoe

Higher spring rates would lend to needing less negative camber rather than more, no?
Yes, slicks need more negative camber, but not a difference of 3.5 degrees (-1.5 vs -4.0). One degree (-3.0- vs -4.0) would be more likely, no?

I just can't buy into -1.5 camber as being ideal for the track.

Manifold

My inexpert sense is that all of these factors interact as a system, so looking at camber in isolation from the other factors may not work. For example, when I mentioned to the pro racer that I changed my cambers from -1.5 to -2.0 and left everything else the same, his first comment was that the camber change would affect roll centers, something which I hadn't thought about - and only barely understand!

mooty

get a base aligement, say factory recommended.
track it.
use pyrometer measure across tread, based on reading, adj camber.
while each tire and suspension system may have some preference of camber, it also depends on how u drive.

Manifold

Good idea on tire temps, though I wonder if different compounds across the width might heat up differently?

Rob VN

Orthojoe,

Could you do me a favor and post the part numbers of the stock brake pads?

Also FWIW the GT4 alignment calls for -1.5 degree camber at all corners.

Regards,

Rob

Clark-ApexPerformance

Rob

front stock p/n 99135194781
rear stock p/n 99135294880

pfc front p/n 7721.11.17.44 - http://www.apexperformance.net/prod-2559.htm

pfc rear p/n 7727.11.18.44 -http://www.apexperformance.net/prod-2558.htm


ferodo front p/n fcp4464w - http://www.apexperformance.net/prod-2768.htm

ferodo rear p/n fcp4465w - http://www.apexperformance.net/prod-2769.htm

hope this helps.

Clark

Rob VN

Thanks Clark

Rob

facefixr

i was able to get the video and data out of the app with a mac app called reflector2 ($15) and you can all see how crappy the data recording and sound are....lots of chop and loss of signal for a second or two. The complete loss and gap at the end of each lap is horrible. How can Porsche put something like this out? Any word on a fix?

facefixr

Another. I must say you dont hear the sound breaking up on the app itself but the lock up of the data happens at least twice a lap for 1-2 seconds.

mooty

i dont understand your meaning.

1. if u mean a single tire with diff compound inside to outside, then look for manufacturer's guidance of temp range.

2 if u mean michelin compound is different than pirelli for example, you are right and they will heat up differently. and depending how **** you are, it will change car set up. most race cars are aligned to run a specific tire of a specific size. for example, the car on my avatar runs on yoko advan slicks. and that's what i run exclusively. never on nitto or michelin slicks. b/c the camber setup changes a lot as i change rubber.

but tire temp will really help you dial it in.
hope this helps.

if you really wnat to be picking, bring a tech.
as you come off track, the take temp and change alignent on the spot. that's how my alignment was determined

9972RS

I think the iphone track app functions similarly to Harry's lap timer. You'll need an external GPS to get better data. vbox sport, maybe?