sick, thanks!

 

Back from the annual fall VIR event. Again, as seems like every year, great weather conditions with temps in the low 70s and sunny during the day and cold in the 20s and 30s at night. I actually came back from a 2 week european trip the night before, so I was a bit jet lagged and trying to re-adjust all weekend, which was not helped by the time change that happened on Sunday morning.

The car did great, I have zero complaints. My best laps were in 2:10 range, which is on par with my best laps I set before when I was running slicks, so considering I'm on 200 treadwear tires now, it's not bad. The car would benefit from another corner balance now that the weight distribution has changed, that will be a winter project. Also really need to look into a better intake manifold and maybe a tune to get some more power toward the top end. Do the tunes that UpRev provides raise the rev limiter?

Here's a few open laps from Sunday afternoon

And one more session with some traffic, being chased by the gray 911S, which is my buddy running Hoosier slicks. I didn't check the tire pressures before this session and the tires were starting to overheat towards the end of the session, were at 38 psi hot when I came off.

 

A few pics from the event shot by F&S

 

hey bro. I was just looking at the p4p poly rear hatch windows again and they have a new option for air vents cut into the rear window. I've seen that on a few track cars. WDYT, good idea or bad for a FT track car? probably if it's not in an enclosed trailer you would have to cover it for transport.

 

Interesting find... If you watch my rear view feed you can see how much the rear window is getting pushed or sucked down at speed. Is it an issue?not so far but over time who knows, hairline cracks could start to develop from the repeated stress. Not sure vent holes would help much though, probably would need to add some bracing for real solution. Also, yeay, I don't want to flood the car when it rains in the paddock.

 

I'm almost thinking you could install louvers instead of a rear window and get better ventilation without rain getting in as much

 

here's what it looks like

 

nice, I just got back from VIR last weekend myself. 2:10 is a great lap time. I did notice my plastics 4 performance rear glass was flopping around alot too, it was kinda annoying to be honest. I think im going to install some NACA ducts on it to get more air flow in the car and maybe help keep it from moving around.

 

Starting to collect parts for next season. I've got the Kinetix intake manifold on order along with Hitachi 76mm throttle body and new intake piping. According to my research the stock inside diameters are 70mm for the throttle body and 72mm for the MAF and the rest of the intake. Since I'm not sure when I'll be getting a tune, for now I'm upgrading the tb, which is the choke point of the stock setup, but leaving the rest of the piping at 72mm so the MAF signal is still the same.
I've got a large intake cone leftover from the Audi that's still in good condition, so lll probably use that and build a custom heat shield for it.
Also got the SPL solid subframe mounts to install, a rebuild kit for the front calipers and still have solid engine mounts sitting on my bench.
And I need to redo corner balance, so it'll be a busy winter.

 

sounds like fun. curious if the kinetix maniford is going to help

 

can't wait to see what you do! I enjoy incremental builds. it's incredibly satisfying to watch the small changes produce results.

 

I chose the kinetix intake because I'm most interested into top rpm gains. I'd love to see the advertised 30hp, but I doubt it'll be such a large improvement irl. So far I got the tb and intake piping, including new MAF housing. Not sure if I end up using all these bits or combination of this and OEM bits, we'll see what works best.

 

Hoon, do you know why the Z without aero seems to be a bit unstable at high speeds +110 mph? At VIR i've noticed the back end feels "floaty" on the straights. I know aero can def help it feel more planted, but I'm also thinking is it because of the rubber bushings all back there? In the front I have solid bushings - is the mismatched solid front and OEM rubber rear giving me that feel?

 

Was it only in the straights, like the front straight kink or did you feel it in the uphill esses as well? In my experience, especially when switching to a square setup the rear is way over stiff by default. When I first went to 275s all around I was easily losing rear grip on the front straight kink at speed. Taking out the rear sway bar and in general softening the rear helped. I also added a bit of a rake, the front fenders are at 25" to the ground but rears are 25.5". As far as aero, obviously adding a large wing is a solution but even adding the ducktail spoiler provided some much needed rear grip.

BTW, I still have oem subframe bushings that I'll be replacing with solids this winter. I'll sure that'll help, but I don't feel like the oem bushings are causing any major issues for me.

 

I haven't paid attention in detail, but I notice it on different tracks, not just VIR. As the Z is getting up in speed anywhere +110 mph there is not much confidence in the rear. Apologies for not being able to pinpoint much detail other than it feels "floaty".

When you are softening the rear, what are you spring rates? I do have near OEM spec spring rates (hotchkis springs).

 

The reason I'm asking is that if it feels ok in the esses then it might be an alignment issue. Currently I'm on 7k rear springs in true coilover configuration. I tried 10k springs and it was too stiff. But if you're still using OEM configuration of separate springs and shocks then you'll want springs stiffer then 7k, since they are closer to the center of the car.

 

I felt my Z get pretty unstable in the front, kinda floating around as well above 130, at 145 on the back straight its super sketch. I picked up a 9lives racing wing and splitter, I hope that helps. I also have this horrible vibration in my brakes. I upgraded to the brembo GT 6 pot, hopefully that corrects that, not having confidence in the brakes is scary too. Hoon, you gonna be at VIR in march? I'd like to run some laps with you.

 

I don't believe I have vir plans in March, my first event is likely gonna be at Summit Point at the beginning of March. Which event are you interested in?

 

Almost ready to do some wrenching, need to order more fluids before I bring the car in from storage. In the meantime a sneak peak.

 

nice! really curious how this works out for you. Def. looks cool! I was probably gonna do NASA mid atl VIR event in March