BGB Motorsports

Folks,

We just hit our 10th day on track with the 991. To date, she only has wheel studs, lug nuts and the new Guard Transmission LSD that we are developing for PDK track duty.

Thus far, the 991 has attended:
Palm Beach International
Daytona International Speedway
Watkins Glen
Barber Motorsports Park
Road Atlanta

My notes are as follows:

1.) 16,000 hard street miles and nearly 10 days on track and she needed pads/rotors on all 4 corners, a bath and a wipe-down.
2.) The Michelins are by far and away the stickiest street tire I have ever run on. I retired the OEM tires at 8000 miles when i hit two nails in one day.
3.) Trying to run a 19" wheel/tire package seems to change the car's balance and drivability ESPECIALLY if the front wheel track reduces from the wheel/tire swap.
4.) Minor issues: horn stopped working, wind buffeting, grinding 2nd gear from tje MECOSA shifting setup and no more washer fluid delivery. Furthermore, it left the boss stranded at Starbucks and wouldn't start - I had to unplug the battery and clear codes and then she started fine - this also happened to me once on a "spirited" test drive where the car just shut off on me in mid-drift.
5.) This car is plenty of car for anyone that is waiting patiently for a GT3 that wants a 7-speed manual.
6.) The next step is to install the Power Kit heads BUT given that the car is totally stock without headers, ECU and air filters, i'm hesitant to do that before we bolt-on more power.
7.) I can't praise the car's ability to do dual duty more if i tried; we can fit 2 sets of "normal people" luggage, drive 475 miles down the higway on a tank and run the car into the ground for 2 days and then do it all over again.
8.) On track the 991 turns-in like a Cayman, yet comes off the corner with all of the beauty of the 911 rear suspension. We really do love this new car!

This really is an amazing car for track duty and every day driving. More to report when the car's homologation into Grand-Am gets completed this month and then we can start campaigning it.

John

John's 991

John, excellent info, and thanks! The dual nature of the 991S is one of the things I love most about it as well. Comfy and quiet on the way to the track, even getting decent gas mileage (28mpg +-) and with the push of Sport + and wing up buttons, it transforms into a really nice track car (mileage drops to 10mpg or less).

I need to replace my tires but it seems that there is a national shortage of the Michelin PSS, so am in a quandary as to what to do.

SB

Can you please provide more info on brake pads you use? if stock pads, please post your impressions of them and whether you used high temp fluid.... ie do they fade or stay consistent throughout a 20-30 minute track session, wear rate, etc.
The info is much appreciated.

SB

One more thing... Please share your track alignment specs. Thanks!

SM_ATL

I am far from being a track expert, but here's some personal feedback (I have taken my first 991 for about 18 days to the track and the new one for 6 days. Tracks: Road A, Barber, AMP & Little Tally).

My brakes did not last that long. Pads were gone and rotors warped after a very hot session at Barber last Summer. I have installed 15" Brembo GT's (front and rear) and it is a very worthy investment. Have had the car running at 100% for an hour on Road A with zero fading. Pay attention to get the right pads from Brembo though. I had one set of 'street and light DE' pads and the front pads were gone in 3 track days.

Totally agree on the Michelin PSS. Best Street/Performance tire available. Better than the stock Pirelli's.

I am running 19" with R888's for the track and I did not notice any significant change in the car balance. No change of front track with the appropriate offset.

Also lost my horn on my 2012.5 991 Has not happened yet on the 2013 model...
Wind buffeting is a major gripe. Let's hope the GT3 mirrors will fix the issue and that we will be able to retrofit them on our 991S

The 991S is for sure as fast as any 997 GT3. The 991 GT3 will be a lot more car, but short off the usual 'Godzilla' GTR's, there aren't many cars on the track that you can not keep up with in a 991S.

Overall, I am totally on the same page regarding track experience . If only there were more options for bucket seats (when are we going to get the bucket seats that are available for the ROW??? I am running 997 GT2 seats for the track) and roll bars! (but bbi does a good one for the 991).

I heard from someone who was tuning his 991 that he was working on getting more camber for the front wheels and was designing camber plates. He said he could not get enough camber with the stock setup for the front wheels but that the rear wheels were OK. Not sure it would be wise in my case since I have PDCC and I do not know how its calibration would work if the alignment is different from stock

BGB Motorsports

Hi Folks,

I'm on the road so I will see if I can respond to all of the inquiries:

1.) OE pads and rotors were okay as long as you didn't leave a customer alone in the car for 35 minutes. These pads/discs went nuclear but this was at Palm Beach Int. in August so it could not have been any hotter.
2.) The warped front rotors were a result of that day at PBIR. As soon as Pagid comes out with something for this car, we will order it but it's a few weeks out. I talked to Pagid last week. I slammed new OE pads/discs on at Atlanta because i didn't want to bother. Front/rear pads were at half-life and rear rotor life was really really good. Rear pad life is equal to the front pad life given the effects of the PSM for wheel-spin control at corner exit.
3.) While most people won't admit this, a lot of the front 997.2 stuff will bolt onto the 991 suspension. Traditional 2-piece front lower control arms will work up front. The toe link lengths however look different and the front sway bar mounting is different than that of the 997.2. You will have to cobble 997.2 bits up front until someone makes true 991 2-piece bits but it's not outside of the realm of possibility.
4.) The street pad, rotor, tire fade on the car is as expected for street OEM parts. The car did very well at Road Atlanta but I was abusing it. I tell all of our customers NOT to go on track without some sort of brake ducting/deflection. The 991 is no different for when you live in the southeast U.S.
5.) I too was disappointed to find no offering for bucket seats. The sport seats are nice but every single person here will agree that the bucket seats are awesome for dual purpose/dual duty cars.
6.) I have found zero wrong with the factory alignment but i haven't visited any tracks with long corners or banking. Watkins Glen will probably require more front camber. Obviously more camber will be better up front and in the rear, eccentrics give good range of motion. Up front where more camber is always necessary, you can make use of existing 2-piece arms if you measure up everything perfectly. Given how neutral the car was from the factory and given how decent the tire wear is, it could stand some additional front camber but there's nothing in the camber/toe department that I am doing to this car over my 997.2 and 987.2 setup knowledge. I guess to put it bluntly, the alignment will become less crucial given how positive the car is on turn-in and how well it tracks down to the apex of any slow or fast corners. Whether it a Cayman or a 997 on the track I usually run 1 more degree of camber in the front than the rear and the front gets toe out while the rear gets toe-in @ 1-2mm per side.

For those of you that like a middle of the road setup, 2.25FR/2.0R seems to keep a lot of weekend warriors happy in the camber department.

BGB Motorsports

how about when you put race gas in the car during a D/E and you leave the track and for the 1st half of a fuel load it says "252 miles to empty" and then for the 2nd half it says "350" and when you fill up again it says "475miles to Empty" and you're like WTH?!??!

Our shop really hopes that the GT3's having PDK only will increase 991 S business for those that want a manual offering that can hang at the track.

John's 991

LOL, welll i have not put race gas in the car, so have not had that experience. But I regularly have the low fuel warning lights go off with about 6 gallons left in the tank when on the track. I discussed it with the dealer who told me that the float was at the bottom of the tank with 6 gallons left, so the computer took over and probably got confused by the fuel sloshing around. Seemed a but curious, but i just feel it filled up a little more often.

SB

Thanks much for the invaluable info, to both BGB and SM_ATL

John, Can you please clarify a couple of things.... Thanks

If I understood you correctly, you are saying that 997.2 GT3 front lower control arms will work for 991S? If so, why are you saying to use 997.2 bits until true 991 adjustable control arms come out.. Any downsides to using 997.2 GT3 control arms?

[/QUOTE]

Also, do you know what stock camber/toe/castor settings are on 991S sport PASM are? Thanks

LotF

I think there is a market for a manual 911 S hooligan to take on the PDK GT3.

Gearing is the GT3 advantage. Weight is the GT3 disadvantage.

Improve the 911 S gearing. Remove weight from the 911 S.

BGB Motorsports

Also, do you know what stock camber/toe/castor settings are on 991S sport PASM are? Thanks[/QUOTE]

I didn't want to come right out and have you guys go trying to bolt parts to the thing because i know that the toe links needed some adjustment to get back there, the front subframe would fit the same dimension front bar but the bushing locating collars would need to be moved, etc. etc. etc. Let us screw with the car some more to see what works and doesn't but my plan is to wait patiently for the GT3 parts that will be available from your dealership or from Porsche Motorsport. We are forced to track the car with the existing rubber bushings until something from the people that wrote the original book comes out. Hopefully in the years to come things from our current vendors will be available on the aftermarket front or even from the dealership.

Having said all of this, I don't mind putting the car on the pad and maxing out the existing eccentric adjustments to see what's available to all of us from a camber, toe spectrum. If you are curious about the factory alignment settings, I have them and can post them for you later today from the shop. If memory serves me correctly, the control arms will bolt in but I didn't re-align the car after so I can't answer whether or not you would achieve your desired toe settings if you put longer arms on at the bottom on the front.

Thanks.

SB

Thank you again. It would be great if you could post factory alignment ranges!

BGB Motorsports

Sorry, I had to do a quick cut/paste. Later I can scan in my notes because I had to convert the degree amounts to millimeters. I'm not advanced enough to work in deg/radians yet until after I stop having dreams that I can't pass trig and have to repeat it during the summer!

____________________________________________________

Adjustment values for suspension alignment

Vehicle height Information
The following values relate to the empty weight, i.e. full fuel tank/fluid reservoirs, vehicle with tools, but without driver or additional weights!

They list 4 specific alignment types based on the 0mm, 10mm and 20mm lowered amounts on the PASM cars shown belowL

Standard

PASM ± 0 mm
(I-no. 477)

PASM - 10 mm
(I-no. 475)
(I-no. 352)

PASM Sport
- 20 mm
(I-no. 030)
(I-no. 031)

Front-axle height (control values)
19-inch wheels
135 mm +/- 10 mm
135 mm +/- 10 mm
125 mm +/- 10 mm
115 mm +/- 10 mm
20-inch wheels
140 mm +/- 10 mm
140 mm +/- 10 mm
130 mm +/- 10 mm
120 mm +/- 10 mm

From road contact surface to measuring point on cross member/bulkhead -arrows-

Quick check: Distance from wing (lower edge) to centre of wheel
390 +/- 10 mm
390 +/- 10 mm
380 mm +/- 10 mm
370 +/- 10 mm

Measuring point for front-axle height
Vehicle height for all C2/C2S worldwide

Standard

PASM ± 0 mm
(I-no. 477)

PASM - 10 mm
(I-no. 475)
(I-no. 352)

PASM Sport
- 20 mm
(I-no. 030)
(I-no. 031)

Rear-axle height (control values)

19-inch wheels
147 mm +/- 10 mm
147 mm +/- 10 mm
137 mm +/- 10 mm
127 mm +/- 10 mm

20-inch wheels
149 mm +/- 10 mm
149 mm +/- 10 mm
139 mm +/- 10 mm
129 mm +/- 10 mm

From road contact surface to outer rear-axle cross member (outer area close to underbody panelling) -arrows-

Quick check: Distance from wing (lower edge) to centre of wheel
398 +/- 10 mm
398 +/- 10 mm
388 mm +/- 10 mm
378 +/- 10 mm

Permitted transverse inclination of the vehicle: Max. difference in height, left to right = 5 mm

Max. wheel-load difference, right to left, on front and rear axle = 20 kg


Measuring point for rear-axle height

Wheel alignment values
WARNING


The following values relate to the empty weight, i.e. full fuel tank, vehicle with tools but without driver or additional weights.
The toe-difference angle value and castor value are influenced by the vehicle height. For this reason the measured result must be evaluated accordingly. No action is necessary in the case of small deviations from the required value (toe difference angle and caster) as long as the value to the right and left is almost the same.

Wheel alignment values for all C2/C2S worldwide

Standard

PASM ± 0 mm
(I-no. 477)

PASM -10 mm
(I-no. 475)
(I-no. 352)

PASM Sport
-20 mm
(I-no. 030)
(I-no. 031)


Front axle

Toe unpressed (total)
+ 2' ± 5'
+ 2' ± 5'
+ 2' ± 5'
+2' ± 5'

Toe difference angle at 20° lock
- 1° 10' ± 30'
- 1° 10' ± 30'
- 1° 10' ± 30'
- 1° 10' ± 30'

Camber (with wheels in straight-ahead position)
- 10' ± 15'
- 35' ± 15'
- 35' ± 15'
- 1° ± 15'

Max. difference, left to right
20'
20'
20'
20'

Caster
8° +30'/-45'
8° +30'/-45'
8° 10' +30'/-45'
8° 20' +30'/-45'

Max. difference, left to right
40'
40'
40'
40'

Rear axle

Toe per wheel
+ 10' ± 5'
+ 10' ± 5'
+ 10' ± 5'
+ 10' ± 5'

Max. difference, left to right
10'
10'
10'
10'

Camber
- 1° 30' ± 15'
- 1° 30' ± 15'
- 1° 30' ± 15'
- 1° 40' ± 15'

Max. difference, left to right
20'
20'
20'
20'

SB

Thanks much.

Interesting.... for PASM sport the front camber at -1 (+ - 0.25), and the rear at -1.67 (+ - 0.25). I bet once you get the front camber more negative than the rear, the balance will improve.

Also interesting that the total front toe in is very slight 0.066 degrees, with 0.1 toe out still considered within the spec. The rear toe is pretty heavy at 20% (10% per side).

Any suspension experts wanna chime in?

BGB Motorsports

I would assume that the factory found a way to keep the car well balanced in the corners and can therefore run more or less static toe front/rear. who knows? Maybe it's another attempt to increase fuel economy by reducing road resistance, lightening the car and making it more aerodynamic by reducing it's height without reducing the cabin room. The rear dog bones were re-designed for camber/toe change and maybe that's why the static settings are different.

Having less camber up front and more in the rear seems like the Boxster/Cayman setup but given that
it's not a strut suspension in the rear of the 991, they have revised the static settings because they probably found something in the re-design of the rear suspension.