Nismo-Z

I had 3 off-track excursions this weekend when the ABS kicked in under heavy straight line braking. I've had many similar ABS events over the last several years but have been able to recover before going off. Most noticeable this year is the back-end wanting to come around on occasions under heavy straight line braking. Tires are Pilot Super Sports, pads are Hawk DTC-60 front and rear.

Thoughts on what to fix? Softer rear pads, stickier tires, replace sub-frame bushings?

PP08HR

iTrader: (2)

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terrasmak

iTrader: (8)

What tire sizes front and rear are you running ? Sizes can and will screw with ABS

Next, suspension. How much camber and what spring rates. Mine has gotten worse with stiffer springs and moar camber.

Last, track surface. Braking bumps, they can and will cause braking issues. Turn 2 at Streets of Will is hell on my ABS system , same with turn 1 at LVMS


Btw, you may be experiencing what is know as Ice Mode, cruise over to the track section and look around.

guitman32

iTrader: (15)

Tire sizes will definitely contribute but id say upgrade to a stickier tire to match the pad compound eg rs3/re71 etc before you try and correct the balance. From your experience it sounds like you are ready.

Nismo-Z

It's a bone stock 2008 350Z Nismo. Only mods are adjustable upper A-Arms and 2 1/2 inch brake duct hose blowing on the back side of the rotor, slightly into the hat. Tire size is stock, 245/40ZR-18 front and 265/35ZR-19. I bought the car new in 2008 and have been tracking it ever since with just about 100 track days to date. Camber is about 3.2 degrees front, zero toe and 1.7 rear.

Track surface could be a factor, but Mt Tremblant where I was this weekend is fairly smooth. Watkins Glen is not to bad either. Palmer Mass is new pavement.

My AIM Sole data shows fairly smooth wheel speed deceleration under braking in the rear. but an occasional erratic saw-tooth in the fronts with as much as an 8 MPH difference between RF and LF. Maybe this is the ABS kicking in

guitman32

iTrader: (15)

Id imagine that is definitely your abs. Seems like a combination of track front camber, street tires, and track pads. You would benefit from upping front grip by squaring your setup and moving to a stickier tire compound. If for some reason you dont want to go square just adding a better tire would help alleviate the issue.

thekinn

iTrader: (18)

Lots of theories floating around.. I tried a couple and ended up wrecking. Repaired car, removed ABS. ABS is no longer an issue.

Nismo-Z

Any thoughts on the saw-tooth front wheel speed? ABS?

guitman32

iTrader: (15)

I know you want to hear it from other people, but yes that is your abs.

With your amount of experience surely youve heard of the concept of threshold braking. Or do you still brake into abs every corner? If that is how you drive, im surprised your abs module has lasted that long.

You need more front grip.

guitman32

iTrader: (15)

Or just remove it completely as thekinn alluded to, but then you will definitely have to change how you brake. The system is not perfect, and as you are discovering there are a lot of variables that affect how abs on our platform manifests itself.

Nismo-Z

I'm going to try more grip first. Long overdue. I should have been on R compounds several years ago. I have the tire trailer and hitch ready to go. Going to go with a square setup.

I threshold brake, of course, but usually don't give it a quick wack as this usually gets me into the ABS. I generally go easy at first, building full pressure deeper into the corner. Where I get into ABS trouble is a hard late brake, if I'm carrying too much speed into the corner or I'm taking a late point by, diving in hard to wrap around the apex. It's always under straight line braking though.

I do feel like braking can be an advantage with my Z as I frequently close in on other cars under braking.

Nismo-Z

About to order new rubber. BFG's g-Force R1 tire, size 275/35R18 a good choice? Square setup? Need wheel spacers? What about rims? ENKEI PF01 or maybe RPF1? Whats size?

guitman32

iTrader: (15)

You do have a lot of experience, but since you've never driven on R-comps it may be wise to run a set of RS3 or RE71 before going to R-comp territory. And Im normally not one of those "stay on street tires for as long as possible" kind of instructors.

They will teach you about how to manage the different phases of heat cycling a sticky tire goes through on your typical track day, session after session. And they will be much more forgiving if you still have ABS issues. There is a lot to learn about driving on r-comps, more than just learning to handle the additional grip.

So yes go square, get wheels that fit so you dont need spacers, Enkei makes good wheels. Go at least 10.5 wheel width all around.