TRACK OG's ONLY!!

Jonny · 02-13-2017, 02:36 AM

Hey guys, so I have done a lot of research and PM’ed a couple of guys on this, but what spring rates should I run. I am planning on ordering coilovers soon but I do not know what spring rates to run. While my car is only going to spend 1% of it’s life on the track, I want a really nice street setup that will handle corners as good as any European sports car. I was under the impression that running stiffer front and looser rear would be better but my brother and me had a 2-hour discussion turned argument on suspension. He owns a genesis coupe 3.8 performance model (with Brembos), and we both plan on tracking our cars for the first time this season. My brother main points are that running looser front and stiffer rear is better because:
• Most reputable suspension companies (I.E. swift) run stiffer rear
• Genesis coupes have 3kg front, and 7 kg rear spring rates stock, their suspension was tuned by lotus, which is known world wide for their suspension and are second to none to McLaren. Also a Nissan engineer is know where as reputable as a Lotus engineer
• Sway bars make a difference because it essentially acts as a giant spring thus affecting suspension

My arguments are that:
• Suspension companies run stiffer rears to tune the car to induce under steer instead of over steer, which under steer is generally easier to control and thus safer for the average driver to control
• Most racecars run stiffer fronts than rear. BTW real race cars are RWD not AWD
• The gentlemen who won an national autocross trophy (sorry bro but I forgot your username) runs 20 kg front and 16 kg rear if I remember correctly
• Many different factors come into play such as tire size and suspension settings
So my planned settings are
• 275/35R18 front and 295/35R18 rear (almost a square set up, the difference tire width is very minimal)
• A Hotchkis front sway bar and stock rear
• Slight toe-in
• 2 degrees of camber all round
• Lowered 2 inches in the front and .75 inches in the rear on BC coilovers with swift springs and rubber top mounts

There is a tire engineer for continental tires that comes into my work and pretty much talks about stuff I can’t really see making a difference suspension wise. He also drives a Lexus, not exactly a race car. But I have noticed that people who are successful in autocross run stiffer fronts than in the rear. I am genuinely confused on this subject so I ask for all the members with experience on the track to chime in, thanks.

OptionZero · 02-13-2017, 03:26 AM

Man there's alot there, and most of it is wrong.

If your car is going to be 99% daily driver, why are you gearing your plans for "track driving"? It also sounds like you're spending alot of time bench racing in your head with lots of assumptions (wrong assumptions, to boot)

First, if you're driving for the first time on a track, all this suspension tuning ******** doesn't matter. Get your *** in the seat, strap on a helmet, and just drive the damn car. Nothing you do to the suspension will matter as much as the education of actual track time.

There's SOME stuff you should do, like changing your fluids and pads, adding an oil cooler, and making sure you have some decent rubber, but this is primarily for your safety and for the protection of your car. But other than that, "performance mods" are worthless when you have literally no track experience. You aren't racing for time anyways, you're driving for fun and to learn.

Stiffer rear bar = relatively more grip in front = less understeer, so i don't know what the heck you were talking about with stiffer rear bar inducing understeer. Stiffer rear bar will induce more oversteer. There are also limits to sway bars do, and you need to understand what function they serve. They control weight transfer/roll side to side by connecting the two sides if your suspension; stiffer overall is better to a point, but you also have to manage your spring/shock settings. Super duper stiff sway bars made of the fanciest material might not be such a good idea if you hit a curb blasting around some corner; all of a sudden your car is upset and you're dead. There is such a thing as too stiff a sway bar (that's probably not the case here, just saying).

The Z *is* set up with understeer in front for "safety", and thats why the track guys are slapping on 285 and larger tires up front and going for a more square set up. Broadly speaking, more front tire = more front grip = less understeer. Track guys here are also getting bigger rear sway bars to get that rear end to turn.

Those settings look fine, but tire compound is just as important as size. If you're going 18's, its gonna look like crap on the street (way to small for a Z) but for the track there will be plenty of tire options. Are you running a dedicate track wheel set up with a diff wheel set up for street? Are you running the same set of tires on both track and street? This would matter if you were driving to actually go fast, since the best track tires are not good street tires (duh?)

But again, since you are a complete notice, you just want some summer tires and call it a day, No need for Pilot Sport Cups or anything

Also - i have no idea who this tire engineer from Continental was, but it's extremely . . . shortsighted? immature? presumptuous? of you to write him off because he drives a Lexus instead of a "race car" to work. You know what Lexus's are good for? Driving to work. You know what race cars aren't good for? Driving to work. Do you think F1 race car drivers drive F1 race cars home, to drop their kids off from school, and to dinner? Nah. He could be a scrub poser. Or he could be an actual tire engineer and car enthusiast with some Cayman GT4 in his garage next to his Lexus, fully capable of smoking your ****. Can't judge a dude based on what he rolls as a daily. Maybe you should also listen more closely to what he's talking about instead of writing off what he says as "stuff that won't make a difference" based on your . . . not that extensive knowledge.

Halfkiddio · 02-13-2017, 11:47 AM

Alright. Lets start at the top of your list, since that is the easiest.

*What spring rates you run depends on what the motion ratio equation comes up with for a given chassis, and what corner weights you have (I know it can also depend on aero loads as well as a couple other things, but I'm simplifying here for noob reasons).

*Nobody here cares about the Genesis coupes, and what they run for spring rates will not apply at all to a 370. Ignore everything he has to say about this.

*You are partially correct about sway bars, except that they relate to roll stiffness for the most part.

Alright. Your arguments:
*Again, what spring rates you have depend on the chassis, as well as the suspension design.

*This might be true, but it also is car dependent. And any drive type can be a racecar. You just need to know how to drive them.

*If you're doing track days, completely ignore what autocross guys use for spring rates. For the majority, they need something that lets them change directions extremely fast, while controlling body movement in a short amount of time. You don't see these types of loads on a road course.

*Your tire sizing isn't bad, but the 275/295 split is somewhat. The height difference is pretty signifigant, and can throw the VDC system for a loop. That can be worked around, but the base issues will still be there.

*You're right on the money with sway bar choices, and I will be ordering my Hotchkis this week. (Pro Tip: Amazon has the Hotchkis for $208 shipped.)

*I prefer zero toe front and rear, but that suits my driving style. This is an area that has a bunch of conflicting answers, so I will just say try different settings and see what you like.

*camber is good, although you will need SPL upper control arms to actually adjust anything in the front. You might need more depending on what tires you are going to run.

*Ride height is also something you figure out what works for you and your setup. Personally, I won't be going much more than 2 inches front and rear, as I prefer how the car handles with very little rake.

And in reference to your comment about the Continental engineer, I will refer you to OptionZero's statement. You never know what he has sitting in his garage, or his experience levels. Never assume.

In closing, I will say that seat time trumps all things above for a novice. Once you learn how the car reacts when it's stock, you know what to change so the car better suits your driving style.

synolimit · 02-13-2017, 12:43 PM

Call an engineer at Stance, Fortune Auto etc. Spring rate calculators can be used to determine this as every single component of a system adds to it, aero, type of tire (slick, DOT etc) etc. they'll give you the best advice.

2011 Nismo#91 · 02-13-2017, 01:33 PM

If this is going to be your first time on the track do not worry about your suspension, it is very capable of doing what is needed. Your experience will be what is holding the car back and not the suspension. Most importantly don't even think about what your friend is doing, you're going to have more than enough to think about on the track then what they are doing, just focus on you. If you want to improve your car and spend a few hundred dollars get a few of these books, Autocross to Win (DGs Autocross Secrets) - Further Reading. They will benefit you more at this point then any suspension mods.

I have done a few track days and suspension is the very last mods on my list. and even now I don't think it's needed except for the front sway bar. I feel my money would be better spent on more track days and replacing wear and tear items from said track days then any more upgrades.

But if you really want to spend some money to make you go fast getting some race seats that are comfortable with a safe harness bar and 6 point harness and Hans will make you much faster because you won't be sliding around so much or holding on the wheel for dear life. And it will cost about the same in the end as a good complete suspension setup.

Jhill · 02-13-2017, 01:40 PM

Not going to go through the list as everyone has already basically explained the same thing.

As far as spring rates go then there truly isn't one "perfect" rate. Even within all the coilover they use different rates, suspension is subjective and what is right for you may be trash for someone else. When it really comes down to fractions of second they switch spring rates per course as well, a rougher course runs a softer spring and vice versa. I imagine weather plays a role too, can't have stiff as a rock suspension on a wet surface or all you'll do is slide.

If your looking for a good compromise suspension any of the fortune, bc, stance or powertrix (what I chose) will work good and all can reach relatively the same rates (since general rule is + / - 2k without a revalve. Although I guess if you start a little firmer like stance/powertrix 12/10 then you can drop to bc 10/8 or jump up to 14/12 whereas bc you can drop to 8/6 but that's actually softer in rear than oem and same as oem in front and can only reach stance/powertrix starting rates of 12/10.

And as mentioned above you can not compare rates one car to another as the leverage ratios are not the same for example your genesis may use a inboard spring with a very long control arm in the rear with a McPherson strut front (I don't know the genesis so just making it up). Now take a guess where most of the weight of the car will be up front with the engine or in the back with just a diff? Hopefully you guess up front, so then how is it possible for the front to a 4K lighter spring and still support the front? Leverage rate.

AlWakRa · 02-13-2017, 04:48 PM

Quote:

Originally Posted by Halfkiddio

In closing, I will say that seat time trumps all things above for a novice. Once you learn how the car reacts when it's stock, you know what to change so the car better suits your driving style.

I would say stick to this advise, you will not regret it, learn the car handling characteristics, you don't need to upgrade until you get more seat time in track. Last track day I went in my DD (stock charger SRT), there was a Mclaren, which naturally should smoke me, but the novice driver in it couldn't have better times than me, even Toyobaru twins that has good drivers was faster than him, and our track isn't crowded, so we can get some hot laps.

You have a choice of becoming better driver first, or make your car hard to drive at your level.

Quote:

Originally Posted by Jonny

• Lowered 2 inches in the front and .75 inches in the rear on BC coilovers with swift springs and rubber top mounts

Search for Lift-off oversteer, and you will know why you should avoid a higher stance at back side (specially without aero). It got my attention as I just experienced it before two days

Eagle · 02-13-2017, 07:29 PM

Quote:

Originally Posted by OptionZero

Man there's alot there, and most of it is wrong.

If your car is going to be 99% daily driver, why are you gearing your plans for "track driving"? It also sounds like you're spending alot of time bench racing in your head with lots of assumptions (wrong assumptions, to boot)

First, if you're driving for the first time on a track, all this suspension tuning ******** doesn't matter. Get your *** in the seat, strap on a helmet, and just drive the damn car. Nothing you do to the suspension will matter as much as the education of actual track time.

There's SOME stuff you should do, like changing your fluids and pads, adding an oil cooler, and making sure you have some decent rubber, but this is primarily for your safety and for the protection of your car. But other than that, "performance mods" are worthless when you have literally no track experience. You aren't racing for time anyways, you're driving for fun and to learn.

Stiffer rear bar = relatively more grip in front = less understeer, so i don't know what the heck you were talking about with stiffer rear bar inducing understeer. Stiffer rear bar will induce more oversteer. There are also limits to sway bars do, and you need to understand what function they serve. They control weight transfer/roll side to side by connecting the two sides if your suspension; stiffer overall is better to a point, but you also have to manage your spring/shock settings. Super duper stiff sway bars made of the fanciest material might not be such a good idea if you hit a curb blasting around some corner; all of a sudden your car is upset and you're dead. There is such a thing as too stiff a sway bar (that's probably not the case here, just saying).

The Z *is* set up with understeer in front for "safety", and thats why the track guys are slapping on 285 and larger tires up front and going for a more square set up. Broadly speaking, more front tire = more front grip = less understeer. Track guys here are also getting bigger rear sway bars to get that rear end to turn.

Those settings look fine, but tire compound is just as important as size. If you're going 18's, its gonna look like crap on the street (way to small for a Z) but for the track there will be plenty of tire options. Are you running a dedicate track wheel set up with a diff wheel set up for street? Are you running the same set of tires on both track and street? This would matter if you were driving to actually go fast, since the best track tires are not good street tires (duh?)

But again, since you are a complete notice, you just want some summer tires and call it a day, No need for Pilot Sport Cups or anything

Also - i have no idea who this tire engineer from Continental was, but it's extremely . . . shortsighted? immature? presumptuous? of you to write him off because he drives a Lexus instead of a "race car" to work. You know what Lexus's are good for? Driving to work. You know what race cars aren't good for? Driving to work. Do you think F1 race car drivers drive F1 race cars home, to drop their kids off from school, and to dinner? Nah. He could be a scrub poser. Or he could be an actual tire engineer and car enthusiast with some Cayman GT4 in his garage next to his Lexus, fully capable of smoking your ****. Can't judge a dude based on what he rolls as a daily. Maybe you should also listen more closely to what he's talking about instead of writing off what he says as "stuff that won't make a difference" based on your . . . not that extensive knowledge.

Minor correction to what was said here...everything else makes sense. 18's looking crappy on a Z is totally subjective though (I love my 18x10 VMR 810's).

Although this sounds counter intuitive, 370z's need the stiffest swaybar possible in the front and least stiff/no sway bar whatsoever in the rear. This has been confirmed by several sources here, Doran Racing (campaigned the 370z in the Grand AM/IMSA Continental Tire Series), BJ Zacharias(user: Dwnshift), former Nissan GT Academy Winner and Driver for Doran/Nissan (Steven Doherty), users: ClintFocus, martin82, GS1388, myself and a few others are running this setup and it works well.

My understanding is that this is done because of the suspension geometry of the Z34, it's just different than most other FR cars. I don't know the exact science behind it, but my theory is that what happens is a big sway up front neutralizes the roll by keeping those front wheels planted when loading up the suspension on turn in and under deceleration.

Reducing the stiffness in the rear allows the body to roll and probably keeps wight transfer more progressive...perhaps the Z34 is stiff enough in the rear as it is? Feedback from guys running stiff rear sways is that the car oversteers hard and becomes a handful.

My recommendation is to run the stock setup first see how it feels...get a front sway bar or a front and rear pair (i recommend Hotchkis). Try it with the front bar on the car, then try it with the rear.

Hope this helps.

Jhill · 02-14-2017, 12:14 AM

Quote:

Originally Posted by Eagle

Minor correction to what was said here...everything else makes sense. 18's looking crappy on a Z is totally subjective though (I love my 18x10 VMR 810's).

Although this sounds counter intuitive, 370z's need the stiffest swaybar possible in the front and least stiff/no sway bar whatsoever in the rear. This has been confirmed by several sources here, Doran Racing (campaigned the 370z in the Grand AM/IMSA Continental Tire Series), BJ Zacharias(user: Dwnshift), former Nissan GT Academy Winner and Driver for Doran/Nissan (Steven Doherty), users: ClintFocus, martin82, GS1388, myself and a few others are running this setup and it works well.

My understanding is that this is done because of the suspension geometry of the Z34, it's just different than most other FR cars. I don't know the exact science behind it, but my theory is that what happens is a big sway up front neutralizes the roll by keeping those front wheels planted when loading up the suspension on turn in and under deceleration.

Reducing the stiffness in the rear allows the body to roll and probably keeps wight transfer more progressive...perhaps the Z34 is stiff enough in the rear as it is? Feedback from guys running stiff rear sways is that the car oversteers hard and becomes a handful.

My recommendation is to run the stock setup first see how it feels...get a front sway bar or a front and rear pair (i recommend Hotchkis). Try it with the front bar on the car, then try it with the rear.

Hope this helps.

I see this a lot too and find it odd as I still feel the car understeers with two bars, however it is a ton better and like it a lot but I am not super fast (still new). I also think it depends a lot on your total setup including alignment. a super stiff front bar will not allow roll as you say which can be good for racing purpose with an aggressive camber angle but if running more a street/track angle then you will eliminate the - camber gain through the SLA suspension and could potentially hurt performance, also if not running slicks you can overpower the tires etc. My opinion from what I have heard is I would compromise somewhere in the middle, I chose stillen but I have heard the eibachs are very good too.

and yes I would say try stock first, then bars and last coilovers. Bars alone made a huge difference and made the car much more neutral right away.

and yes poster above lift off oversteer is scary as hell lol but I kind of got used to it in old car as that is how you can cut the turn in FWD which actually seems more tail happy than my Z, but it is a slide for live feel and thankfully have not had it happen in the Z.

Xhilr8n! · 02-14-2017, 01:21 AM

Put your money into the loose nut behind the wheel

Jonny · 02-14-2017, 02:40 AM

Thank you everyone for their reply's. BTW I already did my brakes and brake fluid. I have Hawk HPS and Stoptech STR-660. I guess I should have said that in the beginning.

As far as the Continental engineer he honestly came on as a little cocky and kinda gave me a smirk when I told him I drive a 370z. He may or may not have a track car in the garage, but I do know that he has a degree and I don't (yet). So unwillingly I accept that he may know what he is talking about. It is going to be my first track event in late spring and I do not want to make a complete fool out of myself. I'm OK with being a partial fool, but not a complete one

BuddyH · 02-14-2017, 08:53 AM

When it comes down to it, everyone has their own ideas and I say take it all with a grain of salt. It is your car and you ultimately have to choose what's right for you. Personally, the list I always recommend for people I talk to is Safety, tires, brakes and an oil cooler. You've already flushed your brake fluid, so I'll skip that.

Buying a good helmet is the first thing I always suggest. No point in go-fast mods if you hurt yourself on a mistake (which will happen eventually). Eventually if you find you take to the sport, then a good seat does wonders to any track car, as well as a harness. A good seat and harness that keeps you planted has been proven to help lap times.

Next I'd go with tires. Everything everyone does to their cars performance wise, means nothing if you have bad tires. No matter how fast you are, how big your brake kit is, how expensive your coils are, it all comes down to those 4 points of contact. So make sure you don't cheap out, and buy good, new tires.

Lastly, I would get an oil cooler. I would suggest a 34 row with a thermostatic plate. No point in going smaller as long as you use the thermo plate. The oil in our Zs run very hot on track days, whether it's cold or hot, so unless you want to "embarrass" yourself hitting limp mode mid track session and having to let it cool off for 15 minutes or so till it's good to go again, I'd get one.

Other than that, I hope you take to the sport and make sure you post up the results from your first race. Good luck. Also, it never hurts to message a motor sports team with a 370Z. Most of the time, they have no problems answering any questions.

Jhill · 02-14-2017, 11:39 AM

Quote:

Originally Posted by BuddyH

When it comes down to it, everyone has their own ideas and I say take it all with a grain of salt. It is your car and you ultimately have to choose what's right for you. Personally, the list I always recommend for people I talk to is Safety, tires, brakes and an oil cooler. You've already flushed your brake fluid, so I'll skip that.

Buying a good helmet is the first thing I always suggest. No point in go-fast mods if you hurt yourself on a mistake (which will happen eventually). Eventually if you find you take to the sport, then a good seat does wonders to any track car, as well as a harness. A good seat and harness that keeps you planted has been proven to help lap times.

Next I'd go with tires. Everything everyone does to their cars performance wise, means nothing if you have bad tires. No matter how fast you are, how big your brake kit is, how expensive your coils are, it all comes down to those 4 points of contact. So make sure you don't cheap out, and buy good, new tires.

Lastly, I would get an oil cooler. I would suggest a 34 row with a thermostatic plate. No point in going smaller as long as you use the thermo plate. The oil in our Zs run very hot on track days, whether it's cold or hot, so unless you want to "embarrass" yourself hitting limp mode mid track session and having to let it cool off for 15 minutes or so till it's good to go again, I'd get one.

Other than that, I hope you take to the sport and make sure you post up the results from your first race. Good luck. Also, it never hurts to message a motor sports team with a 370Z. Most of the time, they have no problems answering any questions.

Best answer here, although maybe I wouldn't put helmet as second thing since rentals are cheap it would take quiet a few track days before justifying owning my own helmet. I do plan to get my own but not right away, I would put the oil cooler in top of the list as to hit limp mode after spending $$$ on a track day would be completely crappy.

Rusty · 02-14-2017, 02:12 PM

The more time you have behind the wheel. The better you will get. Once you get more experience. Then you can start mapping out what changes you may feel you need. You already did the brakes. If you have a manual, insulate the clutch line down by the exhaust manifold. Get a 34 row oil cooler too. Good tires is a must. Once you start doing trackdays. It becomes a deep rabbit hole.

Get your own helmet. Sometimes there are not any rentals available. Also, you don't want someone else's head lice.

AlWakRa · 02-14-2017, 04:26 PM

Quote:

Originally Posted by Jhill

and yes poster above lift off oversteer is scary as hell lol but I kind of got used to it in old car as that is how you can cut the turn in FWD which actually seems more tail happy than my Z, but it is a slide for live feel and thankfully have not had it happen in the Z.

My rear is higher than front by roughly 15mm, empty trunk, half petrol tank, and whiteline swaybar on medium setting (I know it is not best setting, but was eager to try new coilovers) I was managing it until the tires became hot and viola

It is a horrible experience and could be worse, tbh I was reckless (noting that I was over 85 mph when it happened) Thankfully no injuries or scratches, only small dents on the Volks to remind me of it, never owned a FWD car, only time tracked a fwd was on Nurburgring and I didn't push the limit. Wouldn't like OP to be in the same situation if he got coilovers before his first track day.

And since OP has SS lines and upgraded pads I agree with most people who suggested an oil cooler, it is a must. Tires in good condition also a must but I think he needs to feel the limit of the car in his first run on track, so against having Extreme performance tires. He shouldn't focus on posting fast laptimes, they will come automatically with more seat time

.

02-13-2017, 02:36 AM	#1 (permalink)
Jonny Base Member Join Date: Aug 2015 Location: Chi-raq Posts: 67 Drives: 12' 370Z Rep Power: 10	TRACK OG's ONLY!! Hey guys, so I have done a lot of research and PM’ed a couple of guys on this, but what spring rates should I run. I am planning on ordering coilovers soon but I do not know what spring rates to run. While my car is only going to spend 1% of it’s life on the track, I want a really nice street setup that will handle corners as good as any European sports car. I was under the impression that running stiffer front and looser rear would be better but my brother and me had a 2-hour discussion turned argument on suspension. He owns a genesis coupe 3.8 performance model (with Brembos), and we both plan on tracking our cars for the first time this season. My brother main points are that running looser front and stiffer rear is better because: • Most reputable suspension companies (I.E. swift) run stiffer rear • Genesis coupes have 3kg front, and 7 kg rear spring rates stock, their suspension was tuned by lotus, which is known world wide for their suspension and are second to none to McLaren. Also a Nissan engineer is know where as reputable as a Lotus engineer • Sway bars make a difference because it essentially acts as a giant spring thus affecting suspension My arguments are that: • Suspension companies run stiffer rears to tune the car to induce under steer instead of over steer, which under steer is generally easier to control and thus safer for the average driver to control • Most racecars run stiffer fronts than rear. BTW real race cars are RWD not AWD • The gentlemen who won an national autocross trophy (sorry bro but I forgot your username) runs 20 kg front and 16 kg rear if I remember correctly • Many different factors come into play such as tire size and suspension settings So my planned settings are • 275/35R18 front and 295/35R18 rear (almost a square set up, the difference tire width is very minimal) • A Hotchkis front sway bar and stock rear • Slight toe-in • 2 degrees of camber all round • Lowered 2 inches in the front and .75 inches in the rear on BC coilovers with swift springs and rubber top mounts There is a tire engineer for continental tires that comes into my work and pretty much talks about stuff I can’t really see making a difference suspension wise. He also drives a Lexus, not exactly a race car. But I have noticed that people who are successful in autocross run stiffer fronts than in the rear. I am genuinely confused on this subject so I ask for all the members with experience on the track to chime in, thanks.

02-13-2017, 03:26 AM	#2 (permalink)
OptionZero A True Z Fanatic Join Date: Apr 2011 Location: Sacramento Posts: 3,235 Drives: 15 370Z Nismo 6MT Rep Power: 214100	Man there's alot there, and most of it is wrong. If your car is going to be 99% daily driver, why are you gearing your plans for "track driving"? It also sounds like you're spending alot of time bench racing in your head with lots of assumptions (wrong assumptions, to boot) First, if you're driving for the first time on a track, all this suspension tuning ****** doesn't matter. Get your * in the seat, strap on a helmet, and just drive the damn car. Nothing you do to the suspension will matter as much as the education of actual track time. There's SOME stuff you should do, like changing your fluids and pads, adding an oil cooler, and making sure you have some decent rubber, but this is primarily for your safety and for the protection of your car. But other than that, "performance mods" are worthless when you have literally no track experience. You aren't racing for time anyways, you're driving for fun and to learn. Stiffer rear bar = relatively more grip in front = less understeer, so i don't know what the heck you were talking about with stiffer rear bar inducing understeer. Stiffer rear bar will induce more oversteer. There are also limits to sway bars do, and you need to understand what function they serve. They control weight transfer/roll side to side by connecting the two sides if your suspension; stiffer overall is better to a point, but you also have to manage your spring/shock settings. Super duper stiff sway bars made of the fanciest material might not be such a good idea if you hit a curb blasting around some corner; all of a sudden your car is upset and you're dead. There is such a thing as too stiff a sway bar (that's probably not the case here, just saying). The Z is set up with understeer in front for "safety", and thats why the track guys are slapping on 285 and larger tires up front and going for a more square set up. Broadly speaking, more front tire = more front grip = less understeer. Track guys here are also getting bigger rear sway bars to get that rear end to turn. Those settings look fine, but tire compound is just as important as size. If you're going 18's, its gonna look like crap on the street (way to small for a Z) but for the track there will be plenty of tire options. Are you running a dedicate track wheel set up with a diff wheel set up for street? Are you running the same set of tires on both track and street? This would matter if you were driving to actually go fast, since the best track tires are not good street tires (duh?) But again, since you are a complete notice, you just want some summer tires and call it a day, No need for Pilot Sport Cups or anything Also - i have no idea who this tire engineer from Continental was, but it's extremely . . . shortsighted? immature? presumptuous? of you to write him off because he drives a Lexus instead of a "race car" to work. You know what Lexus's are good for? Driving to work. You know what race cars aren't good for? Driving to work. Do you think F1 race car drivers drive F1 race cars home, to drop their kids off from school, and to dinner? Nah. He could be a scrub poser. Or he could be an actual tire engineer and car enthusiast with some Cayman GT4 in his garage next to his Lexus, fully capable of smoking your ***. Can't judge a dude based on what he rolls as a daily. Maybe you should also listen more closely to what he's talking about instead of writing off what he says as "stuff that won't make a difference" based on your . . . not that extensive knowledge. AlWakRa, Eagle, 2011 Nismo#91 and 12 others like this. __________________ OptionZero Build Thread Last edited by OptionZero; 02-13-2017 at 03:36 AM.*

02-13-2017, 11:47 AM	#3 (permalink)
Halfkiddio Enthusiast Member Join Date: Jan 2015 Location: Knoxville Age: 30 Posts: 250 Drives: 09 RAE 370Z Rep Power: 10	Alright. Lets start at the top of your list, since that is the easiest. What spring rates you run depends on what the motion ratio equation comes up with for a given chassis, and what corner weights you have (I know it can also depend on aero loads as well as a couple other things, but I'm simplifying here for noob reasons). Nobody here cares about the Genesis coupes, and what they run for spring rates will not apply at all to a 370. Ignore everything he has to say about this. You are partially correct about sway bars, except that they relate to roll stiffness for the most part. Alright. Your arguments: Again, what spring rates you have depend on the chassis, as well as the suspension design. This might be true, but it also is car dependent. And any drive type can be a racecar. You just need to know how to drive them. If you're doing track days, completely ignore what autocross guys use for spring rates. For the majority, they need something that lets them change directions extremely fast, while controlling body movement in a short amount of time. You don't see these types of loads on a road course. Your tire sizing isn't bad, but the 275/295 split is somewhat. The height difference is pretty signifigant, and can throw the VDC system for a loop. That can be worked around, but the base issues will still be there. You're right on the money with sway bar choices, and I will be ordering my Hotchkis this week. (Pro Tip: Amazon has the Hotchkis for $208 shipped.) I prefer zero toe front and rear, but that suits my driving style. This is an area that has a bunch of conflicting answers, so I will just say try different settings and see what you like. camber is good, although you will need SPL upper control arms to actually adjust anything in the front. You might need more depending on what tires you are going to run. Ride height is also something you figure out what works for you and your setup. Personally, I won't be going much more than 2 inches front and rear, as I prefer how the car handles with very little rake. And in reference to your comment about the Continental engineer, I will refer you to OptionZero's statement. You never know what he has sitting in his garage, or his experience levels. Never assume. In closing, I will say that seat time trumps all things above for a novice. Once you learn how the car reacts when it's stock, you know what to change so the car better suits your driving style. AlWakRa, Eagle and Jonny like this. Last edited by Halfkiddio; 02-13-2017 at 11:50 AM.*

02-13-2017, 12:43 PM	#4 (permalink)
synolimit A True Z Fanatic Join Date: May 2013 Location: Columbus, OH Posts: 5,051 Drives: 2013 Silver 370z Rep Power: 3389	Call an engineer at Stance, Fortune Auto etc. Spring rate calculators can be used to determine this as every single component of a system adds to it, aero, type of tire (slick, DOT etc) etc. they'll give you the best advice. Hotrodz, Halfkiddio and Jonny like this. __________________ 13 370z-

02-13-2017, 01:33 PM	#5 (permalink)
2011 Nismo#91 A True Z Fanatic Join Date: Mar 2011 Location: NJ Posts: 2,402 Drives: slowly Rep Power: 40569	If this is going to be your first time on the track do not worry about your suspension, it is very capable of doing what is needed. Your experience will be what is holding the car back and not the suspension. Most importantly don't even think about what your friend is doing, you're going to have more than enough to think about on the track then what they are doing, just focus on you. If you want to improve your car and spend a few hundred dollars get a few of these books, Autocross to Win (DGs Autocross Secrets) - Further Reading. They will benefit you more at this point then any suspension mods. I have done a few track days and suspension is the very last mods on my list. and even now I don't think it's needed except for the front sway bar. I feel my money would be better spent on more track days and replacing wear and tear items from said track days then any more upgrades. But if you really want to spend some money to make you go fast getting some race seats that are comfortable with a safe harness bar and 6 point harness and Hans will make you much faster because you won't be sliding around so much or holding on the wheel for dear life. And it will cost about the same in the end as a good complete suspension setup. AlWakRa, Eagle and Jonny like this. __________________ GTR TT 493Whp/431lbft, Ecutek, Southbend 6puck,Quaife, RPM RollBar 4Point, R888R, JRZ RSPro F(10R/10C) R(10R/6C) 1000f500r inlbs+150inlbs Tender, SPL everywhere.Full Specs

02-13-2017, 01:40 PM	#6 (permalink)
Jhill Track Member Join Date: Mar 2016 Location: San jose Posts: 854 Drives: 2013 370z sport Rep Power: 3384	Not going to go through the list as everyone has already basically explained the same thing. As far as spring rates go then there truly isn't one "perfect" rate. Even within all the coilover they use different rates, suspension is subjective and what is right for you may be trash for someone else. When it really comes down to fractions of second they switch spring rates per course as well, a rougher course runs a softer spring and vice versa. I imagine weather plays a role too, can't have stiff as a rock suspension on a wet surface or all you'll do is slide. If your looking for a good compromise suspension any of the fortune, bc, stance or powertrix (what I chose) will work good and all can reach relatively the same rates (since general rule is + / - 2k without a revalve. Although I guess if you start a little firmer like stance/powertrix 12/10 then you can drop to bc 10/8 or jump up to 14/12 whereas bc you can drop to 8/6 but that's actually softer in rear than oem and same as oem in front and can only reach stance/powertrix starting rates of 12/10. And as mentioned above you can not compare rates one car to another as the leverage ratios are not the same for example your genesis may use a inboard spring with a very long control arm in the rear with a McPherson strut front (I don't know the genesis so just making it up). Now take a guess where most of the weight of the car will be up front with the engine or in the back with just a diff? Hopefully you guess up front, so then how is it possible for the front to a 4K lighter spring and still support the front? Leverage rate. littlejuanito and Jonny like this. Last edited by Jhill; 02-13-2017 at 01:53 PM.

02-14-2017, 01:21 AM	#10 (permalink)
Xhilr8n! Base Member Join Date: Nov 2016 Location: Asheville, NC, USA Posts: 132 Drives: 2016 370Z Nismo Rep Power: 9	Put your money into the loose nut behind the wheel Eagle, 2011 Nismo#91, Rusty and 1 others like this. __________________ Lotus: 1974 Europa, 2005 track Elise, 2011 Evora S DD: 2015 Honda Civic Si, Toyota Tundra TRD PRO 2007 350Z, 2010 370Z 40th, 2016 370Z Nismo, should read XZILR8N!

02-14-2017, 02:40 AM	#11 (permalink)
Jonny Base Member Join Date: Aug 2015 Location: Chi-raq Posts: 67 Drives: 12' 370Z Rep Power: 10	Thank you everyone for their reply's. BTW I already did my brakes and brake fluid. I have Hawk HPS and Stoptech STR-660. I guess I should have said that in the beginning. As far as the Continental engineer he honestly came on as a little cocky and kinda gave me a smirk when I told him I drive a 370z. He may or may not have a track car in the garage, but I do know that he has a degree and I don't (yet). So unwillingly I accept that he may know what he is talking about. It is going to be my first track event in late spring and I do not want to make a complete fool out of myself. I'm OK with being a partial fool, but not a complete one Eagle likes this.

02-14-2017, 08:53 AM	#12 (permalink)
BuddyH Base Member Join Date: Nov 2015 Location: Kansas City Posts: 11 Drives: 09 370Z MB M6 Rep Power: 10	When it comes down to it, everyone has their own ideas and I say take it all with a grain of salt. It is your car and you ultimately have to choose what's right for you. Personally, the list I always recommend for people I talk to is Safety, tires, brakes and an oil cooler. You've already flushed your brake fluid, so I'll skip that. Buying a good helmet is the first thing I always suggest. No point in go-fast mods if you hurt yourself on a mistake (which will happen eventually). Eventually if you find you take to the sport, then a good seat does wonders to any track car, as well as a harness. A good seat and harness that keeps you planted has been proven to help lap times. Next I'd go with tires. Everything everyone does to their cars performance wise, means nothing if you have bad tires. No matter how fast you are, how big your brake kit is, how expensive your coils are, it all comes down to those 4 points of contact. So make sure you don't cheap out, and buy good, new tires. Lastly, I would get an oil cooler. I would suggest a 34 row with a thermostatic plate. No point in going smaller as long as you use the thermo plate. The oil in our Zs run very hot on track days, whether it's cold or hot, so unless you want to "embarrass" yourself hitting limp mode mid track session and having to let it cool off for 15 minutes or so till it's good to go again, I'd get one. Other than that, I hope you take to the sport and make sure you post up the results from your first race. Good luck. Also, it never hurts to message a motor sports team with a 370Z. Most of the time, they have no problems answering any questions. Eagle likes this.

02-14-2017, 02:12 PM	#14 (permalink)
Rusty Ronin Samurai - Assassin Join Date: Dec 2011 Location: Fayettenam,Pennsyltucky Age: 68 Posts: 35,218 Drives: 2011 Nismo GM 6M Rep Power: 2684438	The more time you have behind the wheel. The better you will get. Once you get more experience. Then you can start mapping out what changes you may feel you need. You already did the brakes. If you have a manual, insulate the clutch line down by the exhaust manifold. Get a 34 row oil cooler too. Good tires is a must. Once you start doing trackdays. It becomes a deep rabbit hole. Get your own helmet. Sometimes there are not any rentals available. Also, you don't want someone else's head lice. Eagle, Hotrodz, NorthStyle and 1 others like this. __________________ 浪人 - 殺し屋 "The Difficult Anytime, The Impossible By Appointment Only" http://www.the370z.com/members-370z-...o-journal.html Last edited by Rusty; 02-14-2017 at 02:15 PM.