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DaveGT3.... I haven't experienced what you describe, nor have my GT3 buddies. In the US, we all have Mk II GT3's which are all still on 4 year warranty. I see that you are in Ireland, ans so may have a Mk I...which may not still be on warranty. If it is on warranty, get thee to a Porsche Service Centre and get their opinion and "register" your complaint so that you have a record of the problem. If not on warranty, I would get as many other opinions as possible from shops, as well as Porsche. Good luck and let us know what you find out.

Hi GT350..... I have no personal experience with those Kumhos on my GT3...but, I do have some personal opinions. As you know, the GT3 is very sensitive to suspension settings, especially alignment and tires. The factory engaged Michelin to develop tires for current 911 models including the GT3 and GT2. The N spec Michelin PS2 and Pilot Sport Cup (in PCar sizes) are a result. My personal experience is only with those two tires on my GT3. The Cup is, of course, track oriented and the PS2 is street (and a little track) oriented. There is a difference in how each feels and handles. You might notice that the rear PS2s in 295/30-18 N2 are Extra Load rated at Load Rating 98. That means they are designed to handle a bigger load at standard pressure than the same sized tire that is not an Extra Load. Several European manufacturers are spec'ing Extra Load tires as original equipment these days. I've seen what happens when a 30 aspect ratio tire loses pressure slowly, or blows out. It is usually destroyed quickly before you can feel the tire going low....and without a spare, you are on a flat bed home. Personally, I feel a little bit better with the Extra Load rating and with the factory's recommendation of that tire. I know that the Michelins are really expensive...but so are your wheels (which can get damaged in a deflation) and your time. Over the last 25 years, I've tried lots of different tires on lots of different cars. I've come to the personal opinion that I get what I pay for in tirres.

Again, I agree completely with Mike. (We must be similar drivers with similar driving preferences). I start Pilot Sport Cups with 26/27 front/rear...and have the same comments about how they feel and how they warm up. Do pressure test them hot after each session....warming afternoons may have you bleeding off more air. AND BE SURE to air them back up to street pressures for the ride home. You won't get track type heat in them driving home and too-low pressures on the street will risk sidewall failure (read: Catastrophic Failure) on a long ride home.

HI Dave....I started with the factory settings of 1 off of full hard on both ends (also reputed to be Roland Kussmaul's recommended settings). I find it a good balance for short, lumpy tracks we have in Colorado. As I gained confidence in me and the car, I decided that a bit more rear grip on bumpy exits would be a good thing, so I softened the rear one more notch (to two off of full hard). For my tastes, this is a good setup. I suspect that the advice you received stems from the line of thought that one unfamiliar with the handling of a 911 is safest starting out with a setup that minimizes the chance of oversteer. If you start there, you will likely feel understeer on turn-in as you get faster. Be ready to experiment and let us know what works for you.

Congrats on the car. I run my car setup like this: Front: ride height 115mm, camber -2.5°, toe 0.05° in per side, sway bar 1 softer than full stiff, pressure 33psi hot Rear: ride height 128mm, camber -2.4°, toe 0.30° in per side, sway bar 2 softer than full stiff, pressure 36psi hot To get -2.5° front camber, you will need to shim the front arms with about 8 to 10mm of factory shims per side. Alternatively, you can rotate the strut tops to the alternate set of mounting holes, but you won't be able to get much less than about -2.7°. New cars are often shipped with front ride height 10mm too high, so you may need to lower the front. Rear height is usually pretty close to 128mm. The softer rear bar helps getting on the power early. However you will suffer from more understeer in slower corners. A bit of trailbraking helps get some rotation. For autocross, a softer front or harder rear helps. Dave.... after two years of fiddling, I support Mike's recommendations completely. You say you will use the GT3 80% on the track. While that alignment will work on the street, it won't be the best for steering stability and tire wear. I can get 3+ alignments done for the price of one rear tire....so, I realign for track and back for the street. I run my car on major road trips too and difference is worth the time and trouble of realigning. BTW, I had a local machinist make some aluminum shims for the front lower arms in 3/8" stock. He patterned them after the factory shims....and, they work just fine.

Factory USA M030 dampers are different parts/numbers from ROW M030 dampers (my experience with '99 C4 and C2). Yes, M030 dampers have different damping rates releative to non-M030. USA M030 dampers ALSO have different shaft lengths (vs ROW M030's) to accomodate the 10mm different spring lengths/ride heights. I ordered and installed the ROW M030 kit on my C4 which was ordered with the USA M030 option. I measured and confirmed the different shaft lengths. Apparently the factory considers it important to match the ride height to damper stroke/location within the damper.

Hi Sean.... In my personal, humble opinion...you will not find a pad that will meet all your criteria. I've tried, unsuccessfully. All pads will create dust. Race pads (Pagid: orange, yellow, black, orange) will have higher coefficients of friction and higher temperature tolerance....and will howl on the street after you cook them on the track. They will dust and wear your rotors a bit more....but They Will Stop You time after time. That's why Porsche uses them on the track. Stock pads are a good compromise of dust/performance for a street car, but, will wear quickly and can fade on the track. It all depends on how hard you need/want to use your brakes. My GT3 came off the track Saturday (short, tight track that really burdens brakes) with smoke coming off the pads (Pagid blacks and oranges), but, they were still stopping me predictably. Next weekend, I'll switch back to factory pads for the street. At the track, you burn a lot of gas and use a lot of brake. That's the way it is. Your brakes are as important as your motor. You will be paying a lot of attention to your brakes and servicing them regularly. It's not hard to swap pads in the process.

Did you have a cell phone with you in the car when you heard the noise?

Beautiful car, KIYO. Congratulations! :clapping:

Hi Ram.... In my personal opinion, there is little to be gained in chipping or re-flashing a naturally aspirated car these days. The factories usually get all they feel they can from their motors without unduly pushing the limits of durability. On a naturally aspirated motor, about the only thing that could make a difference (all else being equal) is the ignition timing. A little more advance often gets a little more torque in low-mid range and a few horsepower at the top...but, with the possibility of "bouncing" off the knock sensor with pre-ignition/pinging depending on the quality of the fuel you can find. The motor will produce the most just short of pre-ignition, but, controlling the ignition advance with the knock sensor/retard process is not the best way to manage the thing. You can reduce the pre-ignition effect with a little more fuel, but, then the O2 feedback loop steps in to bring the mixture back toward stoichiometric (ideal combustion for the cats to deal with). Sure, factories have to make assumptions about the quality of fuel you use, but, they are highly motivated to get all the performance they can out of your motor without introducing engine life-shortening conditions. For what it's worth, a friend had his 993 motor chipped and tuned professionally on a chassis dyno by a Very Well Known race shop. A few months later, as we tore through the empty roads of the American Desert, his motor holed a piston and broke several sets of rings due to pre-ignition. You pays yer money and you takes yer chances.

I believe that all current NA (996's) have an auxiliary air pumps. I'm not sure about the turbos. 996's do not have "pre-catalysts" like a lot of cars are getting these days. Pre-cats are placed close to the exhaust manifold and designed to clean up the extra dirty exhaust that is emitted during cold start due to cold and inefficiently burned gas. They also introduce some amount of extra restriction in the exhaust tracts. 996's do have regular/main cats that introduce very little restriction. To deal with the dirty start-up situation, 996's (including GT3's) have an auxiliary fresh air pump (what your picture is pointing at) controlled by the ECU that injects fresh air into the exhaust system right at the exhaust ports in the heads. You can see the injection ports in the heads if you remove the exhaust manifolds. There are even "reliefs" in the gasket to circulate the fresh air among the ports. The fresh air will mix with the hot, unburned hydrocarbons at cold start and burn them in the exhaust manifolds. It sounds like popping/rattling on start up, especially on a GT3. The ECU runs this until things warm up...usually up to 2 minutes depending on engine temp. This is a Good Thing! The pump is electric and saps no horsepower...and the whole thing is over in a minute or two. Boxsters have pre-cats in their exhaust manifolds and they "look" very restrictive. The 996 "air pump" is nothing like the old "smog pumps" of the '70's.

Joseph.... Here's a quote from my posting answering a similar question about a ROW Mk I GT3: "The Mk I and Mk II street GT3's are know for a metallic rattle on cold start. I believe there are two kinds of rattle. The first is a "low oil pressure" rattle (for a few seconds at most) and the second is a warm-up rattle (for about a minute depending on temps) due to the secondary air injection into the exhaust that is there to speed the warmup of the catalytic converters. It kind of pops/rattles in the exhaust. The second may be unique to the Mk II and/or US cars. We don't have Mk I's in the US. Yours sounds like the first kind of rattle. On my Mk II, the duration of the first kind of rattle is based on how long it has sat without running leading me to conclude it has to do with oil draining out of a chain tensioner or valve lifters." What is happening is that all engines have to run rich on cold start due to insufficient atomization of fuel on cold engine parts. The cold, rich engine burns incompletely and there is unburned hydrocarbons in the exhaust. The secondary air pump puts fresh air into the exhaust near the exhaust ports where it helps burn the stuff in the exhaust which tends to heat up the cats quickly. The duration of the process is controlled by the ECU.

Hi David... Welcome to renntech. The Mk I and Mk II street GT3's are know for a metallic rattle on cold start. I believe there are two kinds of rattle. The first is a "low oil pressure" rattle (for a few seconds at most) and the second is a warm-up rattle (for about a minute depending on temps) due to the secondary air injection into the exhaust that is there to speed the warmup of the catalytic converters. It kind of pops/rattles in the exhaust. The second may be unique to the Mk II and/or US cars. We don't have Mk I's in the US. Yours sounds like the first kind of rattle. On my Mk II, the duration of the first kind of rattle is based on how long it has sat without running leading me to conclude it has to do with oil draining out of a chain tensioner or valve lifters. It's worrying if it is, indeed, only coming from one side of the engine. I suggest you listen to the engine yourself at the back of the car with the lid up while someone else starts it to determine.

"Motorsport Parts" are sometimes orderable through your dealer (I've gotten 'motorsport/cup car' parts like GT3 air scoops, spoilers, etc from my dealer), and sometimes not. If the dealer can't get them, call a race shop like The Racer's Group (707) 935.3999 or Devek (650) 369.3383.

I have used it with no known negative effects in '99 C4, '04 GT3, various Audis.

Welcome, A-Fox...Let us know if we can help. You have one of the most special current Porsches available!

Hi Greig.... Here in the colonies, we only have hands-on experience with the MK II GT3, so this is speculation on my part. I did have a 1999 C4 and the stock exhaust tips were removable at a joint about four inches up the bend from the tip. Get under the rear end and have a look up and see if there is a bolted band clamp holding the tips/L-bend parts on.

Hi Doc..... "Has anyone done this before?".... Yes, it's a logical next step in enjoying your car on the track. Both the tires you show are street legal (DOT in the US), steel belted for normal resistance to street pot holes, etc, have track oriented rubber compounds, and reduced tread depths for minimum tread squirm on the track. With street suspension and alignment, you will wear the outer shoulders of the tires first in enthusiastic cornering.....and you may wish to bias your suspension setup toward more even tire wear on the track....but, it will compromise your street tire wear and handling....it's a compromise you must decide on and live with.

Hi V.... ar38070's advice is correct. Fresh, high temp brake fluid and good track oriented pads are your next step. That will optimize the brakes you have. That being said, though, many have found that the Mk I GT3 can be driven beyond the capabilities of it's front brakes on the track. Porsche addressed this situation when they designed the GT3 Mk II. The Mk II has bigger front rotors (350mm vs 330), bigger 6 pot Brembo calipers with even bigger pads. and, maybe most importantly, vastly better front brake cooling. Air is directed through the fender liners from the front radiators and bigger, lower scoops are attached to the lower front control arms to direct cool air from beneath the car onto the inside of the rotors. Many of the track oriented Mk I's in the UK have had their front brakes updated to Mk II specs. It's a bolt on process. Increasing the cooling air flow would be a big help too. You can email Gert at carnewal.com (info@carnewal.com). He has the upgrade kits and also after market cooling kits.

bnewport.... Your dealer is correct...but, so is Loren. I had a '99 C4. For 40K miles I ran 8"s and 10"s with 225/40-18's and 285/30-18's with no problems. Have a look at the revs per mile for those two sizes of tire for the make/model of tire you expect to get....and, if they are within 2% of each other...you are good to go.

Hmmmm If that is true, I wonder what that might mean for the possibility of a 997 GT3 in the US market......? The 996 GT3 is unavailable WITH a sunroof.

I and a few friends have many miles of experience with BFG T/A KDs on 996s, 986s and a couple project cars. We began using them because of their reputation as "the fastest street tire available". They were designed by BFG to achieve that reputation in the late '90's and they pretty much did that. BUT, they have some drawbacks. Even though they are owned by Michelin, they can't seem to make a consistently round T/A KD. We had many many balancing problems traced usually to an out of round tire. To achieve the handling reputation the T/A KD has a Big Block tread pattern that, when new, is Very Noisy. As they wear, they then get VERY VERY NOISY...but, yeh, they are still fast. As they wear and become closer to slicks they also get very twitchy....especially if they have worn asymmetrically. I finally got rid of my last set early.....the tires became louder than I could stand. And the tread life is only poor to average as are all ultra performance tires for Porsches.

Hi Carmelo.... Most US GT3s were delivered with the Michelin Pilot Sport 2 N2. This tire was developed by Michelin for the GT3 (note the N2 designation) and the rear 295/30-18s are also "Extra Load" rated. This means that the tires are designed to comfortably handle more load at rated max inflation. The PS2 295/30-18 is service rated at 98Y or 1653 lbs, whereas the normal load rating for that size is 94 or 1477 lbs. Given that, and the fact that the PS2 is probably the best all around performance tire that I have tried (IMHO), I would recommend the PS2. Note that there is a rear Pirelli PZero Rosso Asimmetrico that is "Porsche Approved" with an "N" rating, but that tire does not have the XL Load Rating.... and that there IS a PZero Rosso in that size that DOES have the XL rating, but, curiously is NOT Porsche "N" rated. You can do all the research at: http://www.tirerack.com/tires As far as getting the best price...there are cheaper alternatives, but, for our cars, I would not start with price as my first criteria. Personally, I do the research and decide what I want, then ask my local good-guy tire dealer to get them for me for the best possible price....and I bring him lots of business in return.

I have not had nor heard of this particular problem, V. It's a strange one. I would bet, though, that there is a fault code logged implying a fix. I would hope that a dealer would not charge you that much just to run a scan.

Don't forget to have the dealer ckeck the alignment, and the suspension and half shaft on the corner that was hit.