useridchallenged

I've not really seen anyone mention this - perhaps there's a reason?

My application is that I want to change my daily driver to B16 dampers, DSC, and set at SPASM ride height for autocross, but I don't want to install a front-axle lift (FAL) for steep driveways.

I'd rather spend FAL dollars on an RSS Stage 2 suspension upgrade or similar. For daily driving, it would be nice to soften the ride a bit for potholes, and I know the DSC can help with this. I drive 8-11k miles per year (175K miles on my 2005 C2 that I've driven for 19 out of its 20 years), and autocross a few times per year when I can. I'm okay not winning trophies, so long as I keep improving my skills and times. And as a DD, I need the backseat for kids and "stuff", so no track (prefer a roll bar for that).

Rather than shell out $5k for a front-axle kit, why not go to a 1" larger diameter street tire which increases the ride height by 11-12 mm, while dropping down to GTS SPASM ride height with race tires?

For example:

Street = 295/35/19 rear + 235/40/19 front (+11mm ride height)
AutoX = 294/30/19 rear + 235/35/19 front (factory)

Cons

• Limited tire selection for street (Michelin Pilot S4S is an option with the example above, more options with 18s)
• Extra rubber fills out the wheel well (might actually look okay?)
• Taller sidewalls will soften the handling a bit - but this is only for street driving, nowhere near the limit
• Need two wheel sets for street and auto-x (extra cost for rims, if you don't already have a race set, which I do)
• Alignment will be compromised between street and race for DD use and auto-x use

Pros

• No change in alignment IF the wheel offset and tire width are unchanged between street and race wheels
• Taller sidewalls will soften the potholes a bit and be kinder on rims
• No need for a second car and second garage bay for a dedicated track car (I've thought about it)

I'd love a stable with a DD, track and auto-x car, but that's not going to happen. So my goal is a DD that has some GT3-ish handling qualities, but will be an incredible DD at the same time.

Tell me why this is a good or bad idea? Has anyone done or considered this?

Frank 993 C4S

Sounds pretty complicated to just deal with steep driveways.
- If you are running taller front tires, you will likely also need the GT3 turn stops, otherwise you could be rubbing against your wheel liners when turning your front wheels
- If you insist on a separate set of tires/wheels, I would run 18 in wheels for Auto-x because you have better race tire availability as you progress

Sporty

"(175K miles on my 2005 C2 that I've driven for 19 out of its 20 years)" that's good to hear assuming original motor - no borescoring nor IMS issues?

Sorry can't advise on your wheel/tire set up other then say I have stock 18" size on my Eibach lowered C2 (Michelins SS) and have a pretty steep driveway. As long as I take it on an angle, no problem, and it rides great and I typically don't have any issues on the road, of course being observant as possible. I do not autocross or track my car, btw.

ThunderRolls

You are overthinking. Adaptation is what you have to acknowledge.

voiceprint1

I recommend a used boxster or cayman, you can really get the most out of the mid engine setup on autocross, unless you are a superb driver, or have a much more track focused 911 (GT3, Turbo s, RS)

useridchallenged

A Cayman would definitely be great for autocross. Alas, the back seat of the 911 fits my life and family needs, and garage limitations. I'm leaning toward the "more track focused 911" as you suggest - thank you!

useridchallenged

Yeah, I think you're right.

I just need to simplify my goal and live with the consequences.

That said, thanks to your comment and @Frank 993 C4S, I'm leaning toward building a 997.1 "GT3 Touring-ish" suspension with GT3 height. Sofas for comfort, no roll bar for family-friendly functionality, no wing to attract young racers or law enforcement. Should still be more than bitchin' fun every day.

I think the 19s look better on a street car, but the reality is that 18s provide more tire options as @Frank 993 C4S pointed out, and the slightly taller sidewalls on 18s will be more street friendly.

Form follows function.

useridchallenged

IMS failure in 2009. 110K miles on then new crate motor that Porsche paid for. No borescoring (yet), but seems inevitable at some point as I head to 200K miles and beyond. I'm not too worried about the bore scoring - just a good reason to rebuild and improve my modest 3.6L.

How low did you go relative to the stock C2 ride height (i.e. PASM -10mm, SPASM -20mm, GT3 -30mm, or other?). What size tires are you running on your 18s? This is the real world daily driver information I'm looking for!

useridchallenged

You are so right! I totally missed the obvious fender clipping. And turn stops are not exactly ideal for auto-x.

I've been resisting the 18s from an aesthetics perspective, but the issue of more 18" tire options is very real. Besides, the taller side walls on the 18" DD wheels will soften up the daily drive just a bit. And more tire width up front would marginally reduce understeer.

Just how wide a tire can you get in the front wheel well and still maintain full lock-to-lock without clipping? 245? 255?