VDC off I almost crashed!!
 

I have a quaife diff and a TT setup

The other night, I tried a WOT pull for the first time with VDC off.

In the middle of the 3rd gear pull the car violently and suddenly spun to the right and then to the left before I made it come to a halt. It scared the **** out of me!

Why did that happen? I have Pilot Super sports 275/35 on the rears and I was going in a straight line under WOT, then around the 4000RPM mark it almost felt like someone grabbed my steering wheel and threw it to the right and then to the left!! There was no gradual loss of control sliding etc, it just happend so suddenly out of nowhere.

Anyone else experience this before?

Bro, your car lost traction. The rear was coming around. I will keep the rest of my comments to myself.

Yeah but I didnt know it would throw me around like that, like it happend really quickly. There was no gradual loss or indication at all, it was farked!

Do i need bigger tyres, and or just turn down the boost?

Wider tires help, more rubber helps, better suspension helps, boost DOESN'T help. This is why a lot of people don't care for TT. When it boosts, it BOOSTS and you very well are going to lose traction. Gotta learn how to feather the gas and control it.

Before doing a pull, try heating the tires. That helps too

Well I am removing the EBC this week. It was throwing me upto 14psi from 8 psi even switched off. That is prolly the cause of the huge traction loss.

I just hope it doesnt spin out of control like that again.

I do have alot of suspension mode aswell

You hit full boost and the tires broke loose. That's not a bug, it's a feature. Fix your right foot, not the car.

As he and everyone else said: You have to crawl before you can walk. Throttle control will do you wonders instead of just burying the pedal and hoping for the best. Hope this was a learning experience.

Yep, once in my 1985 trans am NA V8 305, not much HP but i had upgraded gears in the diff, once both wheels loose traction you're so ******. Between gear changes is most dangerous, also small changes in steering will throw power off to one side and if both wheels dont have traction at that moment you're ******, you're much safer with open diff. you need to take the car to the track to practice WOT pulls so you know what the car will do.

you mean running out of talent?

no.. I prefer to drive within my abilities...

fixes for this issue:

a. throttle control
b. more time learning the cars power....gradually.
c. wider tires
d. stickier tires

It's just a and b. A TT Z will blow the tires off at will. Throttle control can quite literally save your life. Hell, didn't some other guy just wad up a boosted Z because he didn't respect the right pedal? These cars are a lot of fun with 500whp, but respect the power AT ALL TIMES or leave the road backwards.

100%

i had mine accidentally kick out a bit with just 325whp and 305 RE-11 last week when there was a bit of water in an uphill turn lol

but 7 years with the car i know it very well and control it.

You may have a suspension and/or traction nanny problem but I suspect that the other posters are correct - you just need more practice. You're trying to control a lot of HP in a light car with a short wheelbase. :driving:

You can and should do mechanical upgrades to your rear suspension but as it has been said over and over you got to learn how control the loud pedal. You also got to pay attention to whether or or not your tires are up to temperature and what type of road surface you are on. Driving a boosted car requires constant situational awareness. Even on the track I have found myself looking In the wrong direction because I thought my tires were up to temp and I got into the throttle and just as you stated...without warning I was looking the other way.

When you learn how to handle the power your vdc will be a hindrance and quite frankly dangerous to you at speed, but for now it is your friend until you get more seat time and experience.

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lol honestly that's why i crashed my car. i felt the exact same thing you did except i lost traction completely and it spun out.

im in the process of currently swapping all aftermarket parts + motor to a new Z i bought

I don’t know anything about your build but I can pretty much guess what happen. At 4K rpms your turbo(s) spooled up and you got hit with 450/500 ft-lbs of torque all at once. That’s going to bust the tires loose every time.

The solution is there isn’t one. Follow the rest of the advice and take time to learn the car.

Just recognized the screen name. You’re the one with the boost controller issue. If you truly saw 15psi then you probably got another 100+ ft-lbs of torque. You need to get that fixed or you’ll be looking by at a new block.

This too. Even when you've had the car for years and it's become totally predictable, sometimes a tire will hit a patch of something and you have a Code Brown moment.

Not to mention weight transfer. You hit a crest in the road under power and the rear gets light, hang on.

A >500whp Z is a constant lesson in applied physics with expensive penalties.

Curious if shouldn't the ecutek traction control help with this? Not saying it will stop driver error but give a little more chance for recovery time?

Ah, this sounded like fun. I need something like this to happen to get my adrenaline up. Not to worry, I am working on it. :)

Oh, it's going to happen (especially with your build), and it definitely get's your adrenaline up. But, I'm sure you already knew that. :rofl2:

Yeah thats rite.

I looked at the logs after this happend to me that night and there was a massive hike in RPM from 3500 onwards. It felt like it jumped to 4500 instantly after 3500. Probably when that boost spike occured. All good I am getting the EBC removed and hopefully that will knock back down my max boost.

And yeah OK everyone is saying I have to learn to drive it better, feather into the pedal etc. But I am suppose to be taking WOT logs here for my remote tuning, I thought it has to be pelted down the whole time, no babying for the tuning purpose?

You’re tuner should be giving you specific instructions for those data points (i.e. 3rd gear roll-on 3k-redline, etc). Is your tuner familiar with boosted VQs?

The quick jump in rpms you are referring to is when you lost traction. I’m surprised you didn’t redline it.

That’s why street tuning a TT Z for WOT scares the **** out of me. Do that stuff on the dyno and handle the part throttle drive ability stuff on the street.


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:iagree:Or at least on a track.

I bought the Z through a local dealer from another dealer and had to wait for delivery. In the week I waited, the dealer gave me a loaner Z that had essentially bald tires. One moderate throttle application mid-turn and I was slideways back and forth within inches of the curb multiple times. Without prior experience I would have had no shot at recovering, and it was still unexpected and scary as $hit. While I made sure to let the dealership have a piece of my mind for giving me a sports car with tires with 3/32" tread remaining, it was definitely a lesson that was reinforced hard: respect the powah.

With improper throttle application, a boosted Z can easily make brand new, warmed-up, performance tires act like they are bald :twocents:

As I understand it, if you are tracking the car, you may want to go further and get a cutoff switch for the yaw sensor.

The factory VDC button turns the ECU nanny down, but not completely off. Disabling the yaw sensor deactivates even more nanny functions.

(and I went and double-checked this time :) )

Dude - this is what happens with an excess of torque and a shortage of ability.

Do yourself a favour and leave VDC on

This and if you are using Ecutek your tuner should be able to add over boost protection. Mine is set at 15 psi and will immediately retard my power and drop revs to 5000 rpms. I have had my Z over boost on more than one occasion due to a waste gate issue and never had it cause me to loose traction.

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You start with 2 buckets. A full bucket of luck and a empty bucket of experience. When the bucket of luck is empty. You hope the buck of experience is full. If not. You're in deep dodo.

Seb is my tuner. He said he has setup failsafes on my tune.

Not sure if you read my last post, but for remote tuning purposes I have to have VDC off, or it skews the logs.

Seb recommends the Greddy Profec, can't he help you set it up?

Interesting.
I'm supercharged with 450whp and 364ft/lbs which comes on a lot earlier with the Si impeller upgrade I recently had done. I have the Cusco 1.5RS LSD which uses a clutch plate system rather than helical gears like the Quaife LSD has.
When the same situation has happened to me with VDC off and I've applied to much power in a straight line and I break traction, typically the back end of the car kicks out to the left and occasionally to the right. As soon as this happens I back right off the throttle and the rear of the car instantly kicks back to being straight again. The rear has never gone from left to right or visa versa and approaching a complete spin out.
I wonder if the Cusco clutch type as opposed to a helical gear type LSD assists with this? :driving:
Maybe I lifted off quicker...

Oh well since your tuner who isn't there and doesn't know you from a bar of soap asked you to do a WOT pull with VDC off, you should probably listen to him without thinking if it's a good idea....

the very fact you're asking "hey my car suddenly went sideways and I almost crashed, what gives?" on a forum means you are in over your head.

Your SC setup doesn’t have the same torque curve as a turbo. It’s not even close. When the turbo spools up you literally get 250/300 extra ft-lbs in an instant.

Jwick is rite. I am around the 840nm (620 ft•lb) engine torque according to my Ecutek logs, which is probably more closer to 620nm (450ft•lb) wheel torque @3500RPM

Well my tuner is one of the best for this platform if not the best. And after I told him what happend he updated with another tune for me to try, possibly one with better traction control? Not sure, havent tried it yet.

:iagree:

Seb is the man!

My original tune before I swapped exhausts was 500whp and 480wtq. Trust me the difference in just 40wtq is very noticeable when you get it all at once.

Everyone always boasts about HP but it’s torque, and when and how it comes on, that matters.

Yeap, Seb can tune that part of it. I sure he made some adjustments for that.