more reason to remove the ABS, check this out

from david dirks
"Here is my in-car video from the Championship race:

http://vimeo.com/50910095

Some highlights:
10:30 Pass #1 by Jeremy, which was not shown in the Speedcasttv coverage.
20:30 Pass attempt by Pete, where we both played chicken late braking into T2. My ABS kicked in and I played in the sandbox for a while...
27:12 ABS kicked in again at the same spot, and I subsequently used a CMC car to slow me down. Pete took advantage of that and passed on the inside. Also not shown in the Speedcasttv coverage."

 

AND his Wavetrac crapped out...went into "open diff mode"...listen to the wheel spin in the tighter corners.

And yes he has a diff cooler

 

What's wrong with the ABS "kicking in"? Is he saying it interfered and didn't work? We can see the late brake at 20:47. It looked like he was trying to finish the pass on that other car and stop Pete from passing. I just don't understand what went wrong except for going in too fast. ? . ?

I hear a slipping clutch (or foot) as well. Listen at 26:32 - 26:39

Happens on mine after a few sessions. This is what I'll try moving forward:

- Fresh fluid for Saturday practice/qual/race and Sunday practice/qual
- Fresh fluid for Sunday race, then hoping for it to last the next Sat P/Q/R and Su P/Q

 

ABS generally causes a lot of understeer.

 

All this talk about ABS is timely.

Was at the track today and had an ABS issue. Of course it happened at the worst place on the track - after 4 into 5a at Mosport. Basically 190kph into a hairpin, with next to no runoff.

Fortunately, I had a passenger and was taking it pretty easy - but that also scared me because the braking was pretty easy and shouldn't have locked up. A relatively easy catch but it spooked me pretty bad. Couldn't figure out why it happened. After getting back to the pits to try figure out the problem i noticed the abs light was on, then I remembered this thread.

The rear lockup was just like when I've pulled the abs fuse, only then I'm ready for it. I've driven that corner over 500 times and the bias has been 100% realiable until now. Didn't get a chance to read the code (my laptop was dead) and the light cleared once I hit the kill switch to try and clear it.

I guess I'll make it part of my pre-flight to check for an abs code but now I wonder if I should go abs delete. Don't really want that kind of unexpected lockup when I'm really on it.

 

Are there more ABS issues on Wavetrac equipped cars? And can ABS engagement overheat the Wavetrac?

 

I think they are two completely separate components, ABS triggering would not have an effect on the differential overheating. I think the topic was simply brought up because that individual had issue with both components on the same day - not because one caused the other.

 

Right now, the "common denominator" is the Mid-Ohio race track itself...many turns, lots of heavy braking, and relitively low average speeds...and a lot of driving sideways based on what I saw on the Web of the NASA Championships...

I tried to find the average lap times for the Spec Zs, I recall they are in the 71-73 MPH range...anybody know for sure?

 

Food for thought:

I have heard some Z racers discussing "lack of vacuum " as a cause for brake failures...i.e., no power boast available after multiple stops...

Comments?

 

I have heard this too and have a request out to my mechanic to see if it is something he can do. I'm a little hesitant to take my novice skills to the task of being the vacuum reservoir guinea pig. If I do get it hooked up I'll definitely share pics and any info I can provide. Until then, I'm going to do my best to just stay out of ABS. If I add a few seconds.. I really don't care- it's just HPDEs for me. I did also replace my hubs, rotors, and pads.. I heard that Pagid pads may have less aggressive initial bite.

The idea came from some threads over on the thethree70z site. It seems that more vacuum reserve can't hurt..

I know there are different theories within this thread, but still think any/all discussion is helpful for improving the 350Z ABS situation.

 

In general ABS systems don't care about available vacuum. The booster is only there to assist the driver with applying pedal pressure. I don't know specifically about the 350Z ABS programming but I've replaced boosters on late model BMWs with dual MC brackets and have seen no negative affects on the ABS systems.

And always remember, fan boy sites tend to exaggerate model issues.

 

Agreed...however one of the alleged symptoms when things go to hell on the track is that the Brake Pedal gets hard...but not braking.

Kinda like when you lose vacuum...

Anyway just thinkin' out loud...

 

Ice mode feels like that, but the fronts are locked up. Since they are locked, it feels like they are doing nothing so you push harder.

 

I have not seen any reports of the front wheel being locked during ice mode...only "no braking" at all...no skid marks or lockup.

I must have missed that condition being reported.

 

That is also the same as i got autocrossing when it went into ICE mode.


From what i understand ICE mode disables ABS because it doesnt know when to do when tires are slipping so easily.

 

Apparently there is Electronic Brake Distribution software as well as ABS on all models that will increase brake fluid pressure to the rear wheels to reduce slippage:

EBD Function


Electronic Brake Distributor is a function that detects subtle slippages between the front and rear wheels during braking, and it improves handling stability by electronically controlling the Brake Fluid Pressure which results in reduced rear wheel slippage.
In case of electrical system break down, the Fail-Safe function is activated, the EBD and ABS becomes inoperative, and the ABS warning lamp and brake (EBD) warning lamp are turned on.
Electrical System Diagnosis by CONSULT-II is available.
Fail-Safe Function
ABS, EBD SYSTEM
In case of electrical problems with the ABS, the ABS warning lamp will turn on. In case of electrical problem with the EBD, Brake (EBD) warning lamp, ABS warning lamp will turn on. Simultaneously, the ABS becomes one of the following conditions of the Fail-Safe function.


For ABS trouble, only the EBD is activated and the condition of the vehicle is the same condition of vehicles without ABS equipment.
For EBD trouble, the EBD and ABS become inoperative, and the condition of the vehicle is the same as the condition of vehicles without ABS, EBD equipment. NOTE: In condition 1 described above, an ABS Self Diagnosis sound may be heard. That is a normal condition because a self diagnosis for "Key Switch ON" and "the First Starting" are being performed.

 

For those not running spacers obviously no part in this type of failure.

I have two sets of oem wheels I use and do run spacers. We have to use the bolt on style spacer here in NZ and the flush fit nuts supplied with my front spacers are simply inadequate and one side came loose. It nackered the front hub and I was able to hear/feel it quite easily.

I biffed the silly little wheel nuts away and now use long open ended nuts.

I agree with other comments that the hubs should be treated as consumable parts especially when doing track days or more.

 

Ice mode or not, my brakes didn't work this past weekend and neither did the gravel trap... got a lot of repairing to do. Pedal had pressure, brakes just didn't work. I lifted and re-applied once or twice during my path to berm. Expected the gravel to stop me and didn't have a back-out plan after that.


I won't be tracking it again until the brake system is re-done.. It will be a while before I get to the braking system, but once I do I'll post up the route I take.

 

Sorry to see that, thekinn, but thanks for posting. It certainly doesn't look like you were overcooking it, and that all of a sudden you just had no brakes at all.

Can you provide some details: tires, pads, how long you had been out in that session, how many sessions you had run earlier, whether there were any warning signals, how the pedal felt, etc.?

Also, what track is that? I don't recognize it.

 

Dam, I need to start mine soon. ABS will be gone on my car.

BTW what size tires, front and rear?