crispenigl

Hi Folks,

Check out my video from my SY 997 gt3
http://video.google.com/videoplay?do...35374965&hl=en

I was getting a lot of understeer at this point of the day (this was the last session) and I think I took much air pressure out of the front tires, I was about 35 lbs hot and 42 in the rears.

I think MPSCs want higher pressures (in the front). I had bled a lot of air out earlier in the day.

I was also experiencing the rear stepping out under 50% WOT at the exits of corners. It came right back in, but it was still unsettling.

This was my third time out on the track with my GT3 and I am still learning a lot.

Please ignore that chat/banter at the start of the video I like taking passengers around on the track. This guy fingers were firmly attached to the seat handle.

Greg

GT3 Nut

That would create oversteer not understeer.

997gt3north

- are you running the street or track alignment setup?

- based on my 1 track day in the gt3, i could feel the rear being more slippery when I let the rear tempts get to 39psi than when they only got to 36psi so it is probable (not certain) that your 42psi was causing a more active rearend than you desired - try mid to high 30s next time in the rear

- may also want to try adding wing to the rear to see if this helps at all

- I did not notice the rear stepping out at "half throttle" (and this was at a cold day at limerock) so I suspect that the track lignment + 36/37psi hot rears + full wing makes some difference

- I would agree with understeer, my front suspension was only at -1.7 camber, which will be fixed today to -2- but as this is a 911 everything that I have read is that it comes with having the engine in the rear - I found that a little lift off throttle at turn in or trailing the brakes to set the nose makes a HUGE difference - once this is done, my goal is to work on the setup to then figure out how to make the car as neutral as possible - I suspect softening the rearend by one hole on the swaybar may make the car more tame (faster? but may give more confidence)

NJ-GT

That 997S is very fast. That car was pulling away so easy from the 997 GT3 on the straights...

TTRob

That's the second "on track" 997GT3 video showing a 997S maintaining distance on the straights. I know different drivers, difference in speed coming out of the turns, etc., but what's going on? The GT3 should be able to reel in a 997S... not rip up its ***, but surely gain on it.

mitch236

Let me chime is a little even though I haven't seen the video yet. According to Michelin the true MPSC's on the 911 platform should be run at 32f/36r hot. So you had too much air in both the front and rear. I start with 25/28 cold and with air temps in the mid 70's I can achieve the proper hot pressures. Speaking of pressures, either get a high quality guage or test your's against someone's to see if it is accurate.

As far as understeer goes, the 997 GT-3 has much less out of the box than the 996 had. Most intermediate drivers complain of understeer when the real issue is poor technique. I'm not critisizing you (that's why I didn't watch the video first, I wanted to make broad statements not directed at anyone). Most drivers that I have taught will finish their braking too abruptly causing the car's weight to shift rearward too quickly. At the same moment they begin the turn in. That means you are asking the front tires to do more work at a time when there is not enough weight up front. That is one of the major advantages to trail braking. You want to turn in while maintaining enough weight on the front for grip.

Everyone who intends to track their GT-3 should have an alignment. Most of these cars are in need of a proper alignment anyway. I wouldn't get the dealer to do it, I would find a reputable race shop and have a discussion about how you drive and let them do the alignment.

frayed

You can't conclude anything about the 997S vs. the GT3 from videos like this. I routinely tore up or at least caught Z06s Vipers and occasional Fcar in solo run groups in my 240 hp E36 M3. Just as the E36 M3 passed the GT3 in the video does not mean its a better performing car.

However, the 997 S with its bigger motor does have a fat mid range tq curve. Helps coming out of slow corners if you are down in the rev range.

gmoney99

Looked liked the GT3 was being driven well under the limits, as Greg mentioned it was his third time out so any other cars performance on the vid can't directly be compared. Its not easy wringing out every ounce of performance out of this car.

mjb

Very true. Such a big range of driver skills and desire (or capability) to push hard at most track events, especially in the lower run groups. The driver had a passenger so he may have been taking it easy...or he's not very experienced. Who knows.
It did sound however that he could have been on the gas much earlier in many turns which could account for some of it if the 997S had higher corner exit speeds.
Don't think a properly driven GT3 would be pulled by a stock 997S under any circumstances.

Likemystoppie?

How much does it cost to run on the trace at Willow? From my estimation (my only experience is racing my RC51 around a track) is that he's driving was on the conservative/safe side. A more experienced driver, who's aggressive would be able to produce different results. Nothing more cockpit time on the track can't fix. - that and pushing the limits of car and driver.

grussell

I have run the track alignment in my 997GT3 with the stock 19" Cups and the factory sway bar settings. It is very balanced with some oversteer and very little understeer when driven properly. I find 32 - 34 front and 36 - 38 hot works best. If you have not done the track alignment, you need to.