Petevb

I christened the GT4 properly at the autocross yesterday:

Huge turnout with the Golden Gate PCA region on the old Alameda Naval Air Station runway. We managed nine runs each despite 120 drivers, though I could have used even more as the GT4 does take some getting used to. We got some very quick competition including another GT4, a couple 991 GT3s and the usual fully prepped race cars. The GT4 compared exceedingly well out of the box.

My car started stock including alignment and tire pressures, and I ended up being the quickest car out there on street tires- some guys on Hoosiers and slicks were ahead of me, but not by as much as I'd have expected. Top Porsche was a prepped 991 GT3 on Hoosier A7s driven by a 2x Porsche Parade champion- the car's being tested and tuned for nationals. It ended up 1.5 seconds ahead of my best scratch time, closer than I'd expected given that the tires alone are worth over a second.

The MPSC2s are not ideal for that surface and didn't fully get to temperature, but the car was sticky regardless. I adjusted the rear swaybar to full stiff to dial out some push, and with that turn-in is phenomenal- I was hitting apex cones all morning turning in too quickly. Gearing is exactly wrong for autocross as expected: 1st was slightly too short to hold through the tight stuff, 2nd too tall to be fully on boil or wind out. I'm more convinced than ever this was intentional, because without the handicap it'd scare GT3s.

The car's incredibly easy to drive- it covers all manner of mistakes. My first run was within a second of my best, surprising given my unfamiliarity and rustiness. You can get very aggressive on both brakes and turn in and the car refuses to get upset.

I do have two criticisms that for me make the car less than a 10 on the autocross, though they are driver and style dependent so not everyone will agree.

First, the car rewards tidy. The GT4 (unlike a 911) is simply slower when the back starts moving under power. This is an issue because I personally love cars that reward exuberance and powersides- in a 911 this is often the fast way around. Those that agree will be a bit disappointed in the GT4, for those that don't it will be a non-issue.

Second, and partly connected to the above, the car is almost too easy. It doesn't challenge quite enough, feeling somewhat under-powered for its chassis. It's quick, but it's far less involving and easier than other cars turning similar times. Again some will like easy and see this as a feature.

I'd personally love to drop 2nd by 10+ mph, add a little power and throw some Hoosiers on. I suspect so equipped it'd go from a very good car to a real weapon capable of going toe to toe with anything that shows up, and it'd up the challenge factor to boot.

Another white GT4 with a partially stripped interior was on hand as well in the morning. He didn't adjust swaybars, complained of push and ended up ~3 seconds behind me. My car was plenty neutral without going full soft in front- no question you can easily dial out understeer. There was also 991 GT3 with MPSCs behind me, but that was driver not car.

My last run is below. You can see I'm leaving something on the table in the slalom and in some of the quickest bits, so there's a little to be gained in the driver as well. Overall 8 out of 10 on the AX out of the box, with a full point of the mark down coming from the tall gearing.

neanicu

Thanks for the report Pete. Nice driving.

consolidated

Great report. Good to hear low-medium speed understeer is easy to adjust out without going to full-full on the bars. Having race SPB for a few years, yes, midengined Porsches are faster with their wheels somewhat lined up, without big slip angles, or dramatic rotation like a 911. But it's a fun challenge, driving tidy to be quick and not having to throw or hustle it.

4ng crcs

driving the old 911's on the ice...

vantage

Thanks Pete. My first "track" experiences were autox and I think there is a lot to be learned from it, but I hated spending the entire day to get < 10 minutes of driving time.

Da Hapa

Nice driving.

Archimedes

Forgive me if this is a stupid question, but I've never attended an autocross. Are most autocross layouts that fast of a set up? I'm not sure why, but I thought AX was a lot tighter with more tight turns. Is that not typically the case?

Petevb

There's something to that...
That's pretty typical around here, but it depends on where you run. Usually our courses are longer, almost 2x as long as that one, and peak speeds are similar but we might have one or two hairpins thrown in where you drop down to maybe 35 mph. National SCCA events are also big and often quite a bit faster again, and they rarely have hairpins so average speed stays up. You can ask around to figure out how quick your local groups usually are, I do enjoy the faster ones more.

switchface

Thanks for sharing Pete. When you say the MPSC2s weren't ideal, is that because the airstrip had what looks like a coating on it, or simply because they can't get up to proper operating temps at auto-x?

Interesting seeing an auto-x track on a runway, its dead flat! For comparison, at Qualcomm, half of the track is usually slightly uphill and the other half is slightly downhill. Combine the crappy surface condition (that loves to eat Michellins) and the off-camber sections, you really need to watch your throttle.

Here is a comparison video from my old 987.1 on street tires:
https://vimeo.com/86569325

Maverick1

Car sounds amazing.

MarcD147

was wondering if you can use it compare runs...

Petevb

I've run MPSC2s on my BMW 1M before, and they seemed very surface dependent. On some surfaces they were less grippy and would build heat slowly, on others they stuck like glue and would be tacky half way through the first run.

This surface is in between, but the run was short and the wait between runs long, so the tires never really got up to their optimum. I only built 2 psi of pressure on the right side, a good indicator that they were not really working. I suspect ideally I would have softened the front bar instead of stiffened the back to deal with the low grip.
I did get it but haven't set up to use it yet- to much going on first time out. I'll try and set it up for next time...

FergusH

Great video!

Was the track layout faster because it was used for a beginner's class on Saturday? I was one of those beginners and I was wondering if the track was faster (and easier?) than a regular autocross track. Not that it felt easy to me - as my spinning and cone munching would attest to! - but it wasn't quite as twisty as I'd thought it might have been.

Jooyoung99

That is impressive! Not just the car, but the driver as well.

Petevb

It was a little shorter than normal to help beginners, but I wouldn't say faster...
Thanks very much.