370Z Track Build Potential? - Compete with 911 GT3
 

What are your thoughts on building a 370Z Track car that could compete with a Porsche 911 GT3?

I have been tracking a 370Z since 2014 and ever so slowly modifying my Base Sport with the goal at some point to be primarily a track car.

While my performance modification journey has really just begun...my ultimate question is...do you think the Z has the "mod potential" to run similar lap times as a $130K Porsche GT3?

My primary Track is NCM in Ky...where I am currently running lap times of 2:29.xx. GT3 drivers with similar track experience are running lap times of 2.19.xx. As such, looking to trim 10s off lap times with performance mods.

Thoughts / Experiences?

What generation GT3?

For the Z, are you staying NA? Street trim or gutted interior?

Referring to late model GT3...i.e 2015+

For the Z, looking for potential in "street-able trim"...meaning decent seats, all interior, roll-bar, harnesses, weekend driver.

Power-train....ideally NA, but would entertain FI....but concerned about reliability and heat on track.

Guessing you haven’t seen Kels yet. To answer your question how much time, money, and dedication are you will to pour into your Z.

Keeping it NA you would need to push the motor to the absolute limits and run at least 15:1 compression to make the power

Since I am looking to see what the potential is...I hadn't really considered any time period or financial boundaries. But since you asked, and we should keep it within reason, I would say:

Time - 2 to 5 Years
Budget - 10 to $20K

Here is what started my thinking....
- I paid 31K for a new 2014 Z,
- invested 10K in mods so far (not all performance),
- I could buy $130K Car....or build one one far cheaper that can compete with advanced class stock cars (Porsche, Corvettes, GTR's)
- If someone owns a $130K Porsche GT3...they expect it to perform at a certain level...but when they come across a 370Z that can hang with or beat a high end car...then that get's attention.

It's doable. N/A, you need a motor like Sasha. FI, stage 2.5 TT like Spooler's. Seq tranny. $20,000 coil overs. Gut the car. And lots of face time with the windshield. Better yet. Just buy a GT3. Because you will be in the same area money wise.

Sasha and Shamu's Z's will run with them. Neither one is streetable.

The most expensive part of the equation is addressing the power deficit. To reliably extract enough power to hang with 991 GT3’s lap after lap after lap, your budget isn’t enough for NA, probably too tight for FI.

I always aim at a “lowly” 996 GT3, that’s more fair to my beloved Z lol.

4 wheel steering, PDK, brakes that don’t quit, 9k rev limit motor...come on, that’s a little too much for our car to go up against.

😂, try 5-10x that amount. Unless you’re doing all the tuning and building yourself. Nothing wrong with dreaming

You will end spending that much money as advanced class stock cars. Not to mention the amount of things you will be breaking and the time on the track needed to test out parts. So you’re tiny budget will be soaked up in no time. I know because I’m well past your budget and even with a great driver I couldn’t come close to running with a gt3

They do have the potential to run with a GT3, money is going to be the problem. Dry sump and Bryant racing crank will be a must for reliability. The engine is where all the money will be spent. OS Giken Diff, 10k in suspension parts, Diff cooler, Proper Clutch, Built engine with dry sump. Don't forget all the track days to get the time in the seat. The GT3's are track ready. Jump in them and go. All the development has been done.

Horsepower: 475 hp
Curb weight: 3,153 lbs
For starters is what your trying to beat. Just the HP alone will put you at 10k. If you don't care about your well being or the cars you might get some where in the ball park of your goal for 20k. You can shop around for lots of used parts and refinish them and get safety equipment that just expired to save costs. You really still need at least another 10 to 20k doing slot of work yourself and searching for cheap used parts. And in the end you'll have a painful, loud, sweat box, that needs constant maintenance. While they have an OEM car.


Oh and you'll need a tow vehicle and trailer, so really no you need like 5 to 10 times that budget as stated before.

Well stated. Took Sasha only 12 years.

At this guy's budget of 20k....no chance for the reasons stated above

There is a reason the gt3 costs as much as it does

i think the best course is to make your car track worthy and safe, with reliable, easy and cost effective power from bolt ons

A good intake, exhaust, RFHC or test pipes (or if u got the elbow grease, headers), and a tune from a reputable shop

Cage or harness bar, race seat, helmet
High quality fluids everywhere
oil cooling
dedicated track pads
2 pc rotors all around
brake ducting
track tires (200 tw or stickier) and lightweight wheels
the best coilovers you can afford
SPL adjustable everything
hotchkis front sway, optional rear

thats a safe build, there are blueprints and options for this, nothing exotic needed

then you just invest as much SEAT time as you can and max out your skill
once you are at the point where track instructors can't get any more out of your car

then you decide if you wanna drop the $10k plus needed for a turbo and install, and a complete gutting of your interior to cut weight, including replacing stuff with carbon fiber everywhere
plus aero parts like a front splitter and adjustable wing

basically go up to the point where stuff is reasonably reversible and then max out your skill

for $130k, what other car can you even buy off the lot that's gonna beat a GT3 thats remotely streetable? some variant of a corvette, used maybe?

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.

As far as benchmarking the gt3, imo, the only choice for lsd is the os giken. And all clutch based lsds should run a diff cooler if pushed hard.

As far as helical gear lsds go, I still stand by it not being necessary to run a diff cooler, just change the fluid regularly and you’ll be gtg.

I’m a big believer in keeping stuff as low maintenance and simple as possible wherever possible, less stuff to break and ruin your day.

I will add one caveat to the above however, regarding the wavetrac, since it has carbon fiber plates in it and is a little bit of a hybrid type diff, a cooler might be helpful there, but for a traditional gear lsd like a torsen or quaife, I still say not necessary.

Wavetrac's do wear out. Heard one clunking on a YouTube video, guy said it was done. LOL

Didn't rusty's setup add something like $1000+ to the cost of the diff?(assuming not everyone can win a diff cooler at Z days)

If I had to pay for it. It's grand.

Ha, I’ve always suspected the marketing/hype was a bit too good to be true. If wavetracs wear out, then imo, that completely defeats the point of getting one, the big selling point to a gear type diff like a torsen is that it’ll outlast the car and require zero maintenance or rebuilds.

If you have to occasionally rebuild the wavetrac, better off just stepping up to a better performing clutch type diff like the osg from the get go.

My OS Giken LSD was good for at least 3 seconds for me.
+ some aero and your planned mods should put ya within striking distance with r compounds. Going to be hard to keep up with them on power. I'd think if you did every bolt on possible you could be with a 996 or 997.

Are we talking about a GT3 street car as it rolls out of the factory (street tires, etc)? Honestly, I would be surprised if it turned a faster lap time on just about any track than my TT3 car on Hoosiers. A pro driver on some of the highest speed tracks might be able to put up a time I can't match....but I'm not sure (maybe something like Road America). I think I was about 2-3 seconds faster Summit than a 991.2 with Mike Skeen driving a few years ago, but I could be wrong.

In the Carrera Cup series down under, 991.2 GT3's are running 1m34s at PI GP Circuit. These are slightly de-tuned from Stephane Ratel Series GT3's (which is the GT3 RS).

In a race event at the same circuit a few weeks ago, a road spec GT3, lightened and with a cage and 5 year old Pirelli slicks driven by a 62 year old amateur driver ran a 1m42s lap.

Which are you comparing to ?

At best, even the most highly modified Z34 with a 500+hp engine is not going to compete against a GT3RS (or a proper SRO GT3) without a shed-load of enhancements (1100kg weight, flat floor, splitter, wing etc)

Pardon me. Updates

BGTV8....I was initially looking to compare to a stock 991.2 (2015) GT3. I will be content to compete with the 996 or 997 to be honest. Again, I just want to be able to run confidently in the Advance Group and not be passed non-stop.

Appears that an a Diff Upgrade is very high on everyone's list to gain lap times. Will definitely begin researching this as my next major mod following my planned Ohlin Coil-overs this winter.

Spec-Jay...A 3 sec gain from Diff sounds like a pretty big move. Is there anything special to your setup that enabled that type of gain...or do you think I could experience similar results on a track that I currently run 2:29.xx?