I know you're being facetious Marty, but for everyone else...

The context of the problems have a HUGE impact on the answers that need to be given... I'd argue that it is of greater importance than the parts on the car. You can mod any car all you want, but without the driving skill set, you'll still have problems.

 

To tell you the truth I was fishing for those answers myself in my original questions. Seeing how they were answered would have given so insight.

 

I agree with the assessment on the 350Z, when I'm taking corners at anything greater than 95mph, it seems to wallow, and I can't seem to get around the school bus as well as I can with my 94 Nissan Sentra. I'm looking for answers.

 

The T2 springs really help this. It allows another 10MPH around T8 at thunderhill as well as the bus stop and Riverside at Buttonwillow. I believe the next limit to the loose rear is lift over 90MPH in the rear.

 

How do the T2 springs handle School Buses?? In a school zone.

 

Tein Driving Spec Type Flex Control Master Coilover system set at 3/4 stiffest setting (4's) and lowered 2 inches. Creates negative camber, maybe too much? anyone encounter this?

Hotchkis sport sway bar kit. Front is in hole #2 position - 48% stiffer than stock, Rear is in hole #1 - 80% stiffer than stock. Should I increase the front to offset the stiffer rear sway bar?

Stock diff 3.51 rear end. Every corner (minimum RPM'S are 4,000 - 55mph) exits under speed.

Rear end is a little greasy, oversteer at this point, looking for a little less and the car does push wide.

I track very hard. 911's, Z06's and M3's have slight if any advantage in turns, not straights. I pinch the throttle carefully as too much throttle and the turbo 400 RWHP causes more oversteer. I've gotten used to it.

Maybe someone has come up with the best adjustment holes for the front and rear Hotchkis sway bar. Ideas?

Camber bars, can and do they help or just another thing to spend money. i don't care if the tires wear on the inside, isn't that the point?

I'm interested in answers from those that track hard and they'e taken the time to invest in real solutions themselves. Trial and error. No offense to you others that drive hard in the street, but tracking 14 turns on a 2 mile track at high speeds with 400 RWHP requires 6 point harnesses and real attention. no turns under REAL speed are allowed if you want decent lap times and competition. I'm looking for suggestions that take real time away on my laps.

I've done track in open wheel, and NASCAR too so what do they have that I can add to the 350Z for better cornering? Will frame stiffening devices, GTSPEC, help a lot or only a little?

Taking turns on tight track 90's and 180's at 95 MPH is simply not possible and school busses aren't on the track, let's stay focused. If you track then share your ideas, if you don't then pay attention because what we do here will save you a lot of money out there.

 

Lots of stuff , downforce ( splitter & APR wing) more camber they Z seems to like over -2 , stiffen the sways up. Get wider tires and the list goes on and on. Chassis bracing will also add stability.

 

Greyson:
Firstly, you have some very excellent high performance mods on your car, a fine foundation for tracking.
Secondly, yes there are definitely some things you can do to improve the cornering grip on the car.

My comments are based on what I can glean from the following bit from your post:

"Rear end is a little greasy, oversteer at this point, looking for a little less and the car does push wide.

I track very hard. 911's, Z06's and M3's have slight if any advantage in turns, not straights. I pinch the throttle carefully as too much throttle and the turbo 400 RWHP causes more oversteer. I've gotten used to it".

This suggests to me that while the power of the car easily induces a throttle on oversteer condition on corner exit, which is quite typical in the heavy, short wheelbase Z with turbo FI, the "push" is from a basic handling bias to understeer, and that is also typical. This potentially confusing conundrum is forcing you to a slower corner entry, and especially mid corner, velocity. The beastie power of the turbo rockets you down the straight with those other great cars you mention running with, your BBK lets you carry that speed deep into corner entry, but then you may fight the car into the corner entry because it just frustratingly will not take the entry as fast as the other cars. Some of this may be driving technique, overloading the front grip of the tire/suspension set up, you "push" into and through the turn, then as you hammer the throttle on exit you get tail waggle. You may also get the weight transfer "porpoise" effect as you are nose "heavy" and "pushing" in the turn, then as you come towards/through apex and get back on the gas the weight shifts backwards, you lose some grip in front if you are still under some steering lock, and you break traction in the rear with all the hp you have, and you get to slipping all over the place! (Is this what is happening as you replay it in your mind? I know that it has to me!)

The low aspect ratio front tires in 19" are possibly contributing to this, as well as increasing the amount of unsprung weight, and so, you might consider trading those 19's away for a good set of lightweight 18's that will still clear your big brake kit. Some 275/35/18's would be a good choice for rubber up there in a DOT-R like Nitto NT-01 or Toyo RA-1 or 888. (nothing wrong with the rubber you have, they are excellent, and priced so too!) The slightly bigger 10mm width, and teeny additional flex room in the sidewall, will help imho to keep that front tread working, and not letting go after the lesser flex on those skinny 30's give way and start sliding like a skateboard. Sidewall stiffness is a tricky thing. Wider is not always better in tires, if you get TOO stiff/narrow a sidewall and it starts letting go of its grip. While a 45 aspect on the rubber is definitely too much up front for the track, I think that 35 is about as low as you want to go on the fronts....30 is probably ok in the back, but not lower than that.

Adjustable front upper control arms are a BIG help in getting grip up front, and you may want to go to -3 degrees up there for a twisty track.

Rear adjustable camber links, also highly desireable. You slammed the car down, the setting is not optimal.

Strut tower braces are very desireable. The body is flexing and I certainly found on my G, which is longer and even more prone to flex than the Z, that the front brace, (and the six point roll bar) had significant positive handling benefits to my car. We have several dynamics associated with cornering stress on corner entry, at the level of the contact through the tire we have sidewall distortion/rollover; at the damper/spring level we have the inertial compression and roll; and in the chassis we have flex/twist. As you have already addressed some of the chassis flex with your anti sway bars, you now have other supplemental approaches that will give you real returns. Those include the strut tower braces....but you can also look into an underbody ladder brace, a roll bar with six points of attachment (and that may allow you to dispense with a ladder brace), and urethane bushings(they can squeak like a mouse sometimes, but they do compress less and reduce that "slop" in weight transfer).

Finally, a sound limited slip differential will help to get the power down on corner exit, and as long as you are around 400rwhp or less, a street friendly torsen type lsd, like the Quaife, is worth investigating. A less costly and highly effective clutch type, such as Nismo, is also good, but you have to adjust your street driving to make it civil in parking garages and short 90 degree turns at street corners.

Hope that helps a bit. Good luck, have fun.

PS: If you want to see it gobble up Z06 and M3 and RX-7 TT, check the link below at Reno Fernley for video. That is a "handling" track with 32+ turns in four miles, and some giddyup straights that the FI 350Z/G35 just love. The vid starts with a pass of a vette after hauling it down from behind in the front straight.

Ed

 

You don't need to roll the front fenders to put 275s on the front. They will fit. 275/40/17 on 17x10 FN01R-Cs fit perfect. Of course this was on stock suspension.

 

The 17's will not clear his StopTech kit if he is running the bigger rotors. Since he has 400rwhp he needs that extra large rotor to manage the heat and reduce brake fade.

 

275/35/18's 17's wil not clear the 6 piston stop tech's

chassis stiffeners?
rear link stiffeners?
front suspension stiffeners?
adjustable control arms front and rear?
The LSD I'm willing to keep stock so I can drive it daily.
Stiffen up the sway bars which come stock with polypropelene bushings to which settings?

Can anyone confirm or contradict the effectiveness of EAGLE 1's suggestions. They seem like sound ideas to me.

 

The Quaife lsd is civilized for daily driving, a very unique design and highly effective. You will not get the snap-crackle-pop herky jerk like you get with a mechanical clutch type lsd. Worth researching. But it is an expensive component, so read up and drive a car with one if you can arrange it before you buy. It will truly help with your power on phase as you go through corner exit/acceleration, and try to keep the back end hooked up.

C'mon folks, throw in some thoughts for our comrade here.

Grayson, is my description of what you are experiencing in handling challenge accurate, or is the syndrome different...and if it is different, can you add more description to help the rest of us out here to diagnose the handling challenge and help you better?

 

My 2 cent's,

1, 2 & 3. IMO not worth the investment given how and where they mount, it's something you need more imput on then just owner reviews. If they are really a benefit, how are they leveraging the forces to pull change off? IMO, you would be far better of if that's the area you want to chase to look at how and where Grand Am teams prep their car's for added stiffness.

4. If you don't have aftermarket camber adjustblity, you will want to have it so you can set camber based on tire pyrometer temp spreads.

5. DO NOT KEEP THE OEM VLSD. It is not a proactive system, it must allow wheel slip to occur before it makes a weak attempt to stop the offending wheel. It has a limited amout of torque it can resist before the fluid is simply sheared past. Have to say, I need to do this one myself. When I do I will go with the Cusco RS. Might be be sensicle, but I don't want the Quaife (I would if it could adjust it's percentage of torque transfer and I'll be the first to admit I just might be thinking too much at this one).

6. Poly bushings in the sway's won't add a lot as the oem bushings aren't that bad (Energy Suspension refused to make products for us because of how they viewed the oem parts). You should invest in adjustable sway's so you can fine tune the car's at the limit behavior to suit you. Some will argue to leverage the highest possible amount of bar force that you can, over and above oem levels. If your testing takes you their, so be it, not a path my testing has taken me however. Nismo does offer replacement bushings throughout the suspension. Teams like 350EVO discovered that the car's oem suspension bushings have a lot of deflection that can effect geometry, which is why they used to offer a sperical bushing kit, the Nismo parts are the only one's avaliable that I am aware of.

7. (adding this one). Are you certain that your coilovers are delivering the spring rates and more importantly the damper characteristics that bring you the best times. You can always pull the dampers and send them to http://www.naake.com for a shock dyno and unbiased opinion about how they may or may not be a plus. Tein does have shop services, Naake can make recommendation's that Tein might be able to revalve to. And sending them out for the second opinion does not cost much at all.

I know that Performance Shock in Sonoma will do ride along evaluation's for free, not southern Cal, but just a thought.

 

Eagle1 your cornering description is accurate, It pushes more than I want it too and I am not getting the acceleration out of the apex with this car like others I've driven, (perhaps due to too much power at spool-up creating the oversteer issue at complete exit points, perhaps its at the car limits created by nissan?).

Don't get me wrong, i enjoy the h!!! out of my tracking right now but I know there are others like me that are in the same spot. Like all speed freaks, I'm interested in more if its out there. You seem to run your car hot as well so your insight helps.

I plan on pursuing some of the ideas presented here as they certainly make sense and are not terribly expensive and don't appear to take me the other way - (making things worse!). Maybe some direction from some actual non-road, track only, 350Z racing crew experts may settle some issues. Any out there?

All of us can benefit from this discussion as I only hope it informs others of what not to waste money on that which adds little reward to cornering

 

Have you tried changing you line to match the cars new power delivery? With the power you are putting down, you probably need to use the line of power cars like vettes and such. This also means changhing your braking points, turn ins, and apexes.

It's really hard to tell without more information about what lines you are taking now and how the car feels throughout the braking turning and exit.

 

Marty is right, it is real tough to diagnose without actually getting the feel of driving the car. Even video or right side riding is tough; one needs to have the controls in their hands. But we are narrowing in.

As mentioned above, it is the Nismo bushing set to look into. I used them and the difference is positive.

The strut tower braces are not expensive and easy to install. I don't know anyone that has put them in that regrets it or believes it did not improve stiffness and handling of the car.

Do you have a roll bar installed?

 

I would think the simplest answer to your problems for under-steer would be to get rid of that huge stagger. either make it less like 285's in the back and 275's upfront or get rid of it all together. I personally run 275X18's all around and the car is very neutral. and from your setup your power over steer is a product of too stiff of a sway bar in the back compared to the front. Im from the school of thought that you need some play in suspensions components we are not driving go karts and track driving involves a host of road surfaces which can adversely effect a setup that is made to be driven on glass and nothing else. Off camber turns and transitions can unsettle a car with too stiff of a suspension setup.

Hammad

 

Looks like alot of great info, I have never took a school at 90, so can't help you there. What year Z?

 

Sakred 275 x 18 x ?? 40's or 35's

I think the 18's will clear my stop tech 6 pistons, any confirmation on that?

I do think the 265 and 305/30/19's are probably too stiff of a sidewall so I plan on some 18 inch 40 series, maybe 285's or 275's. Sakred, what offset are you running on your 18's. 30mm offsets on my 19's work fine. Also any good looking 18's that anyone has seen will help as well as pictures and where you got them. Are we talking nitto r compounds or what tire are you using and lastly, are you running them at the track or on the street?

I plan on adding the GT SPEC stiffeners as well as adjustable camber bars. I also plan on stiffening the front more to offset the rear.

Good direction by some of you. once these questions I just asked get answered I will get it done and share my results. Ferrari Club is sponsoring an event at the Gingerman in South Haven after this coming weekend which I am invited to so hopefully the equipment will be on it by then. At least some of it!

 

i agree with sakred about the tires. if you are having push at entry, you may want to decrease the width difference between front and rear. Also i would look at your spring rates. I dont know what the Flex's rates are on 350s but i know they are considered soft coilovers in the 240sx crowd. I have had good success with the Tanabe Pro 7 coilovers that have 12kg/mm rates. I also run with a stiffer rear damper setting to create more understear allowing for earlier application of power on the exit.

Just a few more things to think about