First track day shakedown

wstar

It can sometimes, counter-intuitively. I won't argue the point with you, since it's a ridiculously complicated topic and I'm not a suspension engineer (I don't even play one on TV!), and it's not like I've gone and attempted adding removing every possible combination of settings and stock/aftermarket suspension bits either But there are all kinds of complicated interactions going on even with a simple item like a swaybar.

In the net, I do think a stiffer front bar + adding both caster and camber in the front (I'm at approx -2.5 and 6 now on the SPL camber arms) is the magic ticket on this car for trackday stuff (assuming reasonably-upgraded coilovers and grippy tires), and I don't get any understeer issues to speak of (nor, for that matter, do I get out-of-control twitchy oversteer - I get a nice neutral feeling that's easy to push into controlled oversteer). I think the stiff front bar is part of the equation.

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Arrvaxx

Great post! Thanks!

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synolimit

Man how nice would it be to lower the car and achieve -2.5?! I'm -1.5 now with swift specRs in the front. My coils will be here soon and I might lower a hair more. To bad I can't go lower and get a number I want. $800 SPL arms suck for only needing a few degrees.

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13 370z-

DR_

Then just get the Kinetix arms (I'm selling mine BTW). They are only a little heavier than stock and a lot lighter than the SPL arms.

GSS138

The initial reduction in understeer is most likely due to just reducing the body roll up front. The body roll, especially on softer springs, will induce understeer by throwing the CG towards the outside front wheel. But there should be a point where "too much" bar will yes, cause the outside to again push. But the first problem you are trying to solve with the stiffer bar is killing some body roll.

If the car was close to being balanced then a sway bar is sort of like the trim on an airplane. But when the front is bouncing around like a pogo stick as it does on the OEM suspension, you are dealing with a problem situation, not a fine tuning situation.

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Current Mods: Vorpal Weapon +5.

Zauskycop

Now I'm agreeing. Too much roll will overwhelm the outside tire, and by reducing that roll, you are correct that it will balance the car more. Ideally, you want as little swaybar as possible up front, with the work being done by the springs. For lack of springs, the swaybar is the poor man's substitute.

Years ago I was at a little speaking engagement by Carrol Smith and it really enlightened me to the "common sense" portion of setting up cars. His quote was "Swaybars do all the right things for all the wrong reasons". Basically, the front swaybar is balancing the car by putting load on the inside spring. But the load isn't into the ground, but actually LIFTING the tire, thus reducing the grip on the inside tire...hence the push. Luckily the Z, with its immense front weight, is still able to keep a load on the inside and keep its balance. I used to autocross a MR2 Spyder...and if you have ever seen one of those (or some Porsche vehicles for that matter) with big front bars, seeing them three wheel out of corners is a very common occurence!

Tracy Ramsey

Rusty

I'm running the Hotchkis sway bars (biggest bars out there).The rear on the softest setting. Front camber -2, caster +6, toe zero. Rear camber -1.75, and toe zero. With 275/35-19 front and 325/30-19 rear tires. Fo me, it feels pretty much balanced for my driving level.

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GSS138

Pretty much use the same train of thought, I am also a big Carroll Smith fan.

It always bothers me when I see those damn 3 wheeling pictures lol.

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Current Mods: Vorpal Weapon +5.

synolimit

No caster though. A modded SPC so the nut won't slip might be ok.

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13 370z-

Drew M

So after a couple months of use, would you recommend the car for a fellow instructor?

Zauskycop

I instruct at the Chicago Region PDX program, and I know *I* would! I am still learning some finer points of the car but so far I love it in the 4 track days I have done.

My latest "aha" moment came when I was understeering a bit (Whiteline front sway, stock rear) in steady state corners. Normally it would mean too much speed, or too much steering angle, and I tried both with limited success. So I tried to give more throttle and it worked! Basically I think you are using the on power oversteer that is inherent in the car to balance out the off throttle understeer?

Still have stock suspension underneath, and this may all change when I go to a square setup and put SPL arms on the car, but it was rather enlightening to me using power in the car...quite a change from a 125 hp Spec Miata!!!

Tracy Ramsey

Drew M

Thanks Tracy! Do you feel you can drive the hell out of it like you can the Miata?

It's hard for anything to compare to an SM car. They're phenomenal through the turns and will reward you with a little more straight line speed. I just don't want to drive one everyday. I'm making the change from an ITS RX7. Less power than the Nissan and decent (at best) through the turns. I'm just trying to consolidate everything into 1 car.

Shiru

Drew, my Z is a replacement for a Miata and I raced SM for a brief moment in time.

The Z will be a great track car but its not quite there yet. I'm trying to take baby steps with it to get the balance right but due to work, I haven't gotten as many track days as I would like to test it out. Next one is Grattan mid Sept.

Since my last post I installed a 25row Z1 oil cooler kit. Amazing difference in temps so I think that problem is solved. I was very concerned running at 260 degrees before.

The brakes will still need some attention as I want more cooling. I've got some ideas that'll be mocked up in the next coming weeks. I'll post pics as I get it worked out.

As for handling, the Z is good but not Miata great. The power is there to rotate the tail however there is a definite understeer issue that needs to be worked out. Unlike an SM you can't mash the throttle...a little more dexterity will be needed. I'm going to start with an alignment to get as much camber as stock parts will allow and possibly wider fronts since mechanical grip is always my first step. If that doesn't correct it well enough then I think the adj control arms for more camber.

From the feel of it I don't think heavier sways in the front will help with the Nismo package. Its already got heavy bars and not a lot of roll.

Shamu

Youre going to find the car increasingly frustrating as you start to do the things you think are easy for track work. Understeer is just related to lack of negative camber up front and perhaps toe settings. Also need plenty of tire up front too (nothing less than 285 in my opinion). SPL's adjustable upper arms are decent and allow caster adjustment as well.

If you dont make major changes in springs you will need a big front bar. It helps keep rear end planted annd does help with rollover. Overall just reduces need for so much neg camber. Hocthkis is decent cheap adjustable bar.

Oil temps. be careful your running upper end right now. Id go for biggest cooler you can mount. Also be waware if you go with sticky tires the cars have oil starve issue as well. ...speaking of starve get one of Phunks suel starve kits or you will be doomed to running full tank of gas forever.

Brakes. Be very very cautious. If you are serious track guy and like braking deep the OEM abs system will bite you with Ice mode eventually. First time it happened to me I almost $hit my pants. Had to throw car sideways into turn to slow myself down. Important to now the 370Z is heavily rear brake biased in stock form. You should keep that in mind when making pad choices.

These cars handle far better than any SM I have seen on track. I pass them in turns all the time in the Z. I

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Grant

Shiru

Definitely something I'll need to look into. I hadn't heard of oil starving on these cars as an issue. For this summer I'm sticking with OEM tires but I'll look for better options over the winter while its in storage.

I had "ice mode" happen to me on the street and ya, I nearly messed myself. For the brakes I'm running upgraded pads plus I'm looking at ventilation options for improved cooling. The ABS is a whole different story and as this is still a street driven car, I'll just deal with it.

Well the Z is definitely faster but for tossibility into a corner the properly setup Miata is hard to beat.