Crazy Eddie

Any shot you have pictures of the brake duct circumcision?
I am amazed it's that close
Thx in advance

orthojoe

The car seemed to push just a touch more than before. My tire wear looks no better, so I'm thinking of going back to the middle settings again. Or maybe leaving the rear on full stiff.

I swapped my wheels left to right after my first track day since I went back to Thill again to even out the biased right right wear. This is what one front tire looks like after 2 track days (10 sessions total)



And the other front tire:

orthojoe

Returned to Thunderhill this past Saturday. This time it was the 5 mile course with the bypassed config on the west side. I've never run this config before, so I'm not sure what is a good lap time, but the well driven 991 GT3s were running 3:11-12 and I was able to get a 3:14. My theoretical best was 3:12 based on best sector times. However, it's tough to get a great lap with such a long course. So many turns, so many chances to screw up. It's easier to get a fast lap on the old 3 mile course! LOL. Respect to those that are running fast times at the ring. That has to be incredibly tough!

I'm loving this car even more each time I take it out. I didn't even think about hopping in my GT3 as it sat in front of me. I ran the GT4 the entire day.

Here is the video of my best lap:

usctrojanGT3

Joe, are you going to get stiffer swift springs? Even with -3.2 of front camber my outside fronts were getting roasted. The stiffer springs have solved that issue. I run full soft front and full stiff rear on the sway bars and the car understeers ever so slightly (not a bad thing though).

Beantown Kman

It appears to be getting more and more clear that the oem spring rates are just too soft for serious track duty. Everybody is chasing understeer and excessive front tire wear with more and more negative camber. But that doesn't appear to be working.

Martin, I think you've commented on this previously but would you mind telling us again how the stiffer springs on your car affected ride quality on the street? Are you driving your car on the street?? I would think 450/550 would be quite stiff for a street car but not quite bone jarring. Are you happy with how your car handles now? Have you changed the ride height?

Quack

Some superb driving there. Bravo!

mrd_spy

thing is it's a road car which can do a track day or 2 for fun, I see it nothing more than that.

If you want to track like a nutter you buy a Radical RXC Spyder

Spending $1.5k a track day trying to punt a road car round a track seems crazy imo but hay it's cheaper than racing I guess.

orthojoe

I think I'm going to have to at this point. Can you tell us what spring rates you are running?

TRAKCAR

Porsche has set up the cars differently, softer it seems.

In the RS is works very good as long as on track you run full stiff rear and suspension hard..
But in the GT4 it seems to be unable to stop the front tires from cording. As opposed the rear outers cording on the RS..

Because under steer in GT4, you can't get the bar stiff enough in front.

So springs seem needed..

MarcD147

Are you running the suspension (button) on regular or stiff?

zmon

I dont know what i am doing wrong, but all i have done is dial 2.75 camber up front and 2.5 in the rear, bars as they come from factory and i am not chewing the outer front tire at all...

I am not running like a sissy at all. ask some of the PCA patomac crew

Bill Lehman

Regarding spring rates, I ran the "Spec Boxster" set-up on my 987.1 which was PSS9s with 450# F and 500# R. This was O.K. on the street but the dampers needed to be run nearly full stiff. I switched to MCS 2-Way remote dampers and 500# F and 600# R. This actually was a little better because the dampers could be set to match the springs. With the non-adjustable damper on the GT4 I think significantly stiffer springs could have issues. There's probably an opportunity for some after market stiffer anti-roll bars. My GT4 should be in port soon. I'll be running data and tracking tire temps and see what we can find out.

orthojoe

Stiff/sport

So it seems...

It may have to do with the track you run. Thunderhill is particularly brutal on the right side tire's outer edges. It could be that I'm over driving the car, but I don't think I am. If anyone watching the video thinks otherwise, I'd be interested to hear.

Actually, the GT4 DOES have adjustable/PASM dampers. I think you are confusing it with the boxster spyder, which doesn't.

Does anyone know what the OEM spring rates are?

Beantown Kman

Joe, someone in this thread mentioned 257F and 457R. https://rennlist.com/forums/gt4/9266...r7-on-gt4.html

mrd_spy

GT4 seems to under steer worst on the limit than my Cayman R even with Rear ARB on full stiff !