fc-racer

I think Viperbob is rubbing off on me, I can't leave well enough alone. I dropped the car off at Weissach while I head out to cold Calgary for a business trip. So far, the list is pretty short, but this is what's on the agenda:

- Replace airbag wheel with Momo Runner (same as the one I had in my 964 Turbo using the factory airbag testbox so no airbag light)
- Price out 996 Turbo wheels (is there any issue with running a 295/30 rear instead of the 285/30?)
- Price out various suspension options (I am looking at RUF, RUF adjustable, PSS9 and JIC)
- Replace factory bypass valves with Forge metal valves
- Mild stereo upgrade (new head, speakers, amplifer)

Other than that, it's just basic clean up stuff, replace some missing trim pieces here and there and that's about it.

For suspension, I am waiting on prices for the RUF parts and have obtained pricing and information on the PSS9 and JIC parts. I am going to go back to a rubber top mount, I can't handle the harshness of the metal bearings in the camber plates and monoball rear mounts. While I will be tracking this car, it is still my primary transportation and I don't want a harsh ride, stiff is ok, harsh is not.

Does anyone run a track pad on the street? The car came with a set of Ferodo DS3000's. They were amazing, but made horrible screeching noises. When I replaced them with factory pads, I noted that they were not installed with anti-vibration shims. If I were to put the shims in and the DS3000's back, do you think it would be reasonably quiet? I am ok with the occasional scream, but not when mothers drop their children everytime I come to a light.

I wanted to say thanks to all the folks that have helped me in sourcing parts, cars, information, etc. over the past few months as I've looked for a 993 Turbo. Also, big thanks to Asgar at www.weissach.com for being a true enthusiast and always being helpful.

Thanks,
Farzaan

forklift

I run Pagid Orange on the street and some people in traffic act like Anthony Perkins is behind them.

viperbob

Farzaan,

The 996TT wheels look great on a 993TT. I have them on and love them. They angular shape of the 996TT wheel contrasts the round lines of the 993TT beautifully. Another guy here locally just bought a 993TT and one of his first upgrades (after PSS9s) was to get a set of the 996TT wheels. Also, I run 235s/315s on these wheels with no rubbing issues.

I was also thinking of going with the Momo Runner. Please take some pics when you return. I would love to see them...

You are starting down a dangerous path already.... Good job...

mkhn

That's me vBob's referring to. My second mod was getting the 996 wheels. I am currently running 235's up front and 295's in the rear. I've got the Michelin Pilot Sport2(ala GT3). When I bought the wheels about a month ago from Wheel Enhancements, the PS2's were not available in 315, but I was told that its just matter of time before they have those.

Bob, at full turn lock, I actually think my 235's are rubbing the inner part of the wheel in the fender. It doesn't really bother me as I am barely ever in full lock. I can feel the vibration through the steering wheel that seems to be tire rubbing, but thats as far as I've looked into it. I'll actually stick an arm up into the wheel well this weekend to make sure.

911/Q45

I think the vibration you mention is just the front differential ratcheting, I've always gotten that with mine and have stock wheel and tire sizes.

Doug Driver

Further to Farzaan's question about wheel sizes - aside from the rubbing issues, are there any problems upsetting the all wheel drive balance by running the 295/30 in back instead of the stock 285/30 with the 225/40 up front?

Farzaan - as an aside, I used to really enjoy your racing posts on the 951 site several years ago when I had a 951.

GT9111

What's the definitive advantage of replacing stock bypass valves with Forge metal valves? Is Forge the name brand of the aftermarket valves or is it a description of the manufacturing process?

PorschePhD

There are no side effects other than good. The factory valves have a tendency to spilt the rubber diaphram. This leaves the risk of sending it down the inlet pipe to the turbo and through the compressor. The compressor wheel is toast at that point. The factory Bosch valve is plastic halves with a rubber diaphragm and spring sandwiched in them. The later version or version we use is an all billet version that is a CNC billet plunger. No risk of anything coming down the pike. Very common issue often over looked because of the pain of accessibility to the CBVs.

viperbob

Doug,

As long as you stay with tires in the front and rear that are close to the same overall diameter you will be fine. These also vary quite a bit my the individual tire manufacturers even with the same theoretically sized tires.

GT9111 - What you are referring to are the divertor valves. The stock ones are plastic, and the aftermarket replacement ones are forged aluminum.

Steve - At least the valves are a little easier to get to in a 993 vs a 996....

fc-racer

I don't think there will be any problem. If you look at the diameters between the two, the difference is minimal:

285/30R18 = 285mm (est. tread width) * 30% (aspect ratio of sidewall) = 85.5mm (this is your sidewall height)

85.5mm + (18" * 25.4) + 85.5mm = 628.2mm

295/30R18 = 295mm * 30% = 88.5mm
88.5mm + 457.2mm + 88.5mm = 634.2mm

The difference is only 6mm and when you consider that the difference between new and worn tread depth is usually around 6mm on each side (top and bottom when you measure diameter) for a total of 12mm difference in diameter, the 295's should be no problem at all.

Hope I did those calculations right!

As an aside, I bought a set of 996TT hollows today and will be installed hopefully today. They were on a 996TT for around 12k km and have Pirello Pzero's on them.

Thanks, I hope to add many stories here as well

ca993twin

You may want to check-out tirerack.com, as they have a chart showing revs/mile for various tires. As viperbob mentioned, there is quite a large difference with different manufacturers even with the same size "spec". The above computation will get you to a ballpark, but there is too much variation to trust that.

fc-racer

Bob, here is a pic of the Runner in my C2T, similar interior:



The thing I really like about the Runner is that it looks factory because it has the OEM looking horn pad. Also, it's 360mm instead of the 350mm. I find 350mm too small for daily street use, it feels aftermarket if it's that small. The 360mm feels like something that Porsche would offer as an option.

I get the car back tomorrow with some small changes made and a set of 996 Turbo wheels