Major Track Faults of the 370

memorylasts

Not applicable for the topic

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somewhat-journal-thingy

cossie1600

The turn is too short, you need a continue radius

Guard Dad

Some thoughts on the clutch pedal issue. I don't know if this has been resolved or not but the clutch pedal sticking to the floor was a common problem on certain types of muscle car clutches in the 60's. These clutches would essentially go "over center" when fully released and the G forces generated within the clutch at high revs pinned the clutch in the released position. One solution was to install a travel limiter to prevent the over center condition. Unfortunately such a simple solution doesn't seem to apply in this case.

Since my Z is an A7 I can't confirm my theory but I'll put it out for discussion anyway. Many clutch systems have an assist spring on the clutch pedal assembly, if the Z has such a spring we may have a possible answer to the mystery. The assist spring assembly is typically laid out to push the pedal to the floor in the second half of its travel and lift the pedal off the floor in the first half of travel. In this environment if the clutch fluid were to boil the pedal would stick to the floor when depressed. So addressing the overheating clutch fluid might solve the problem.

travisjb

looks like a fun track! even CCW, you'd get fuel starvation through 6-5 etc... i think you're going to have to carry 3/4 or more of a tank from now on at that track

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2009 370Z #104
*For Sale*

Mike

I have found out today that fuel starvation isn't a problem at Road Atlanta while it's raining heavily.

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NISSAN: 75 280Z / 86 300ZX GLL /87 Sentra SE / 03 350Z / 23 Z
Porsche: 93 968 / 23 Macan GTS / 93 968

travisjb

hahaha!!!

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2009 370Z #104
*For Sale*

Mike

but the slick surfaces exaggerate handling weakness and I think I am in serious need of some more front downforce. The front was really light, causing me to slip and slide quite a bit. It didn't feel so bad to me or the instructor in the car, even though he could tell I was driving on the edge, but two other instructors told him we were sliding all over the place. I couldn't keep up with the modern Bimmers and Audis, but I was slightly faster than the two C6s.

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NISSAN: 75 280Z / 86 300ZX GLL /87 Sentra SE / 03 350Z / 23 Z
Porsche: 93 968 / 23 Macan GTS / 93 968

daisuke149

functional splitter/canards? or a big fat lump of metal bolted to the front

travisjb

some clarification... front was losing traction at low speeds, high speeds, or both? during hard transitions or high-g but lower-rate transitions? during braking or stable front-rear load?

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2009 370Z #104
*For Sale*

Mike

plenty of tread,Yoko AD-08s. Mostly coming out of turns going uphill, low speeds on wet track while accelerating. Fronts would lose grip first, then the whole car would slip a bit. Just seems odd that I couldn't corner as fast as a 330i.

I've never experienced this problem in the dry, I think that if I pushed it harder on the dry than I do, it would happen there too, its just the wet track amplified everything.

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NISSAN: 75 280Z / 86 300ZX GLL /87 Sentra SE / 03 350Z / 23 Z
Porsche: 93 968 / 23 Macan GTS / 93 968

spearfish25

Time to buy a second wing and mount it on the hood. Who cares if our cars aren't FWD? It just looks cool.

On a more serious note, could the front tires have been hydroplaning? How much tread do you have left up there?

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2013 Cadillac V-Wagon, RIP Z

travisjb

process of elimination...

sounds like not a tire issue... can't remember what width you run front and rear... I'm running a square setup, so obviously I get more relative front traction than most setups... assuming yours are not overly staggered and that your front tires were in as good condition as the rears... if so, we can rule out the tires themselves... that is, unless you have something weird going on with tire pressures

didn't occur during braking, so those are out

we can rule out the rear diff

so that leaves setup or driver

on driver... this is a low speed (mechanical grip) corner... you're an experienced driver, so I'm sure you're all over this, but have you tried different ways of entering and exiting that corner? wet tracks = slower in, later apex, more gradual acceleration... and of course when you accelerate you will be transferring weight off the fronts and onto the rears, which brings me to setup

on setup... thing #1 is to disconnect the sway bars in *hard* rain... an old racer trick someone shared with me that tends to alleviate a lot of the twitchiness in the chassis on a wet track...

also, can't remember which coilovers you have... how much adjustability do you have? what are the spring rates you are running front and rear? if you are having this issue of understeer in dry weather as well (you said it was amplified in rain), especially on an uphill exit (where the front *should* have LOADS of traction), then you might think about going up 2K in rear spring rate and before then even try adding some compression (bound) stiffness the rear dampers... and/or maybe take out a few clicks of compression stiffness in front... I always have to remind myself, one change at a time

finally, post up your caster/camber/toe settings on front and rear, if you like and we can comment on those and how they might be playing in... only if that's helpful

others more knowledgeable than me can expand on what might be going on with your setup... also, read these

Effect of Suspension Changes - trackHQ.com - Track Day HPDE W2W Club Racing Time Attack Motorsport Forum
Front anti-roll bar stiffness and understeer? - Corner-Carvers Forums

And final question... please tell us what your tire temps are if you are collecting those (inner, middle, outer) and if there are any obvious wear patterns on the front tires

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2009 370Z #104
*For Sale*

Mike

Tires are 255/295 when I run streets. I thought about the rear sway, but today is gonna dry up. I'm running tein monoflex, but I'm unsure of the rates. Have all shocks set at middle of adjustment range

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NISSAN: 75 280Z / 86 300ZX GLL /87 Sentra SE / 03 350Z / 23 Z
Porsche: 93 968 / 23 Macan GTS / 93 968

travisjb

if you need a quick fix for today...

-2 psi from front tires ***
+2 clicks of compression rear suspension
-2 clicks of compression front suspension

Make sure you have EXACTLY the same suspension settings left and right... count the clicks with precision

Personally, I think you're not running enough front tire... Try using 275/295 next time... or 275/305

If the track is dry, you could also try adding in 1 stop of firmness to rear sway, if you're not there already

*** PSI needs to be evaluated based upon pyrometer readings front and rear... see if you can borrow one from someone at the track and take readings immediately after a session - then come back here and post

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2009 370Z #104
*For Sale*

ChrisSlicks

I would agree with Travis's analysis, you have a very larger stagger at 40mm and that differential is going to be amplified in the wet as you find the limit of traction much sooner.

In the wet I run the shocks well towards the soft side. I think you'll find that in the wet that the stock suspension setup is pretty good and you should try and emulate it as close as possible to enhance feel. The extra bit of body roll is actually very useful in the wet in that it enhances weight transfer and traction.

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