If lap times are your motivation then you may want to look at a C6 or C7 Corvette. The Z can handle but to get the HP it would probably be cheaper to start with a C6 or C7.

So, my experience is, you can reach 997 GT3 performance with reasonable ride in street.

I am currently there, my car best time 2:20 in the track I participate, this is where most Caymans GT4 and 997 GT3 times.

A stock 991 GT3 should do 2:18-2:17 and 991.2 do 2:15 or less.

So, for myself to get there, I needed to invest in suspension (custom coilovers and full spl arms), OS LSD, OS clutch and flywheel, simple boltons and tune, brake upgrades (pads - rotors), and some other small details like bushing - mounts - cooling. Also, I drive on 200tw tires (Nexen sur4g). I don't know if I am forgotten something, but I have my build with all details.

Everything depends on the track itself, I gain time over other cars in braking and acceleration out of corners. Not a lot to expect in straights.

If I want to enter the territory of 991.1 or 991.2 GT3, I think I will need S2 Cams for better acceleration, full aero (splitter, wing mainly), weight reduction, full slicks. Aero good for 2-3 seconds, and slicks are good for another 2-3 seconds. So, it would be a 2:15 car.

Disclaimer, all estimations without cost, and all depends on the track I attend (Losail International Circuit).

I would agree, a c6 or c7, even a camaro zl1 or shelby gt350, can be a better starting point as they don't lack power, only needs some suspension work, which will make wonders and keep them as fast or faster than gt3s. I think a shelby with camber plates and 200tw tires can come very close to stock gt3.

Forgive me for being the guy to bring up blaspheme, and there are a whole lot of caveats to address in this; a LS swap is an option. For someone who wants a 450-500hp naturally aspirated track setup, it could theoretically be done in a rather street-able way, and likely for less cost than a science experiment naturally aspirated VQ build.

:wtf2:

Just throw an LS in it, the tried and true solution lol!

Can you retain all OEM functions and gauges? I know someone has one running, but I forgot his user name.

Thanks to all for level-setting my expectations. I will set my sights on what is truly achievable.

Overall Objective: run in the advanced group with confidence...and run close to the middle of the pack....so I am not constantly being passed.

I really want to stick with the Z for the foreseeable future. I am not a fan of Corvettes or Camaro's.

Progress thus far:
- SS Brakelines; RB600 Fluid, Carbotech XP10/XP8, Still Brake Ducts
- 25Row Setrab Oil Cooler; Redline PS Fluid; Redline Diff Oil; Red Line MT-85 Trans Oil
- Motordyne Shockwave Exhaust; ...just drop in air filters
- SPL Upper Control Arms with -2.75 Camber, near 0 toe
- Hotchkis Sport Suspension Sway Bars
- Enkei PF07 Race Series Wheels(Square); 200 TW Tires (RE11, SUR4G, and Hankook RS4 next)
- EcuTek RaceROM
- Schroth 4-pt (ASM) Harness; Simpson Hybrid Head and Neck device

Seat time = 24 Track Days; accomplishing ~6 per year

Next Mods planned:
- Ohlin DFV Custom Coil-overs (Ordered from Germany)
- Race Seats and Roll-bar
- Continued Track time...and getting instruction as often as I can.
- ...reading your comments and builds for what follows

Again, thanks for your candid feedback, experience suggestions, and encourage the dialog to continue on this thread for all to benefit.

Need a good LSD and diff cooler.

Around $65k gets you a new zl1 1le, that car out of the box will be competitive with gt3s of any generation. But you’ll be driving a camaro, so there’s that. :ugh2:

Cheap (ish) speed used c6 zo6 and mod that car, much better platform to start with than a 370z.

A new mk III TT RS with stage 1 tune and rear sway bar upgrade, fluid and brake pad upgrades, and front camber plates will match new gt3s in performance. The tune puts the car at a 10.9 sec 1/4 mile at 124 mph and the other small upgrades get you the improved handling and braking. :tup:

A used gtr is also a good option but mods and maintenance and repairs will be more expensive than a vette or tt rs.

You know the best way to get 1 million dollars right? Start with 10 million and take up racing as a hobby. :driving:

Yeap, this will make the biggest improvement to your lap times from the track rats that have installed them earlier on here.

Does a wavetrac need a cooler? I thought their strength was low maintenance

My OS Giken will run over 265F without the diff cooler on during a track session.

They are not as prone to overheating as a clutch diff. OS Giken, Nismo, Cusco, etc...

Diff cooler isn’t maintenance. That refers to having to rebuild the clutch packs in a clutch type lsd like the os giken.

Helical gear type atbd’s (lsds) don’t ever really wear out in theory, and require no special oil additives either and like spooler said, they do tend to run cooler

IMO, for hpde, a diff cooler isn’t necessary with a helical gear lsd, just change the diff fluid more frequently like every other event or twice a year depending on how you drive etc and use top line gear oil like motul or redline.

I am still a bit skeptical about the life expectancy of the carbon plates in the wavetrac never wearing out vs a traditional gear lsd like a torsen. That said, I’ve never heard of one wearing out so realistically it probably isn’t an issue.

Think I might be the only one to have a diff temp gauge here. So we know what temps of the OS Giken is. But we don't know what the other LSD's will produce in temps. But I think they will be close to what the OS Giken produces. Maybe more in temps with a gear LSD. Because you have more gears working the lube. Bearings, ring and pinion, plus the gears inside the diff. In a plate type LSD. You have the bearings, ring and pinion, plus the plate slippage. One shears the lube, the other heats up the lube through friction. On the stock VLSD. Heat is it's enemy. Get them hot, and they fade.

I think for this particular thread, with the yard stick being a GT3, diff cooler is warranted. For myself, part of building one’s version of GT3 involves not worrying about overheating various fluids.