I was torn about where to post this, but I think this is the most appropriate place with all the experience here.

My 07 G was recently TT’d by GTM to almost 470WHp. After this week, it will also have a VB upgrade. The car is also a 5AT with 20x285 tires in back.

One day, I’m going to want to try it, so I’ve been searching here and talking to others trying to learn the best way to launch at the track. All my past cars were MT and nowhere near this HP level. I’ve also never driven on a track either. Obviously putting it in DS with VDC off then flooring it will probably not do anymore.

So my question to you FI straight line gurus … is it actually better to leave the VDC on in a FI car? Or better to go with VDC off and practice a lot to learn when to apply throttle? If it’s better with VDC off, can anyone with similar power levels tell me how they are doing it so I don’t have to start from scratch? I don’t want to break the car and ruin all the hard work Sam put into this thing. TIA.

 

VDC off and change your wheels, you have no sidewall on your tires to grip

 

I know the tires aren't optimized for best 1/4 mile times, I just wanted to see what the car can do in full street trim. I'd like to know what what others have already learned ... so I minimize tire waste with excessive practicing and risk breaking something. What would happen if I tried this with VDC on?

 

I've learned that each track is different, each lane is different. If you get on right after an 900hp muscle car that just left an *** streak of rubber down the track your going to slip and slide everywhere.

Over and above, warm your tires up before you line up, also deflate 5-10lbs of pressure from your rear tires to help with the flex/grip. With an automatic you'll probably have to feather the pedal a little from 1st to 2nd to get the car to grip, after that its going to be ***** to the walls.

 

you never want vdc on w/ FI except in the rain....

 

Well VDC helps keep my car straight in gears 1 and 2, so... I usually leave it on all the time for daily driving. It's hard to control traction with a high stall torque converter in lower gears - you've got 2x torque multiplication and boost hits hard at the same time - rpms rise too quickly and street tires won't hold. Very hard to modulate power on the launch because it's such a steep power curve. I need to get speed dependent boost control set up. (Running PS2 summer tires, 295R18). I can alternate between rolling slowly and spinning - it's comical.

Did you get the GTM-5AT upgrade? If you have the high stall converter, good luck launching with street tires!

 

Yes, as everyone said...Having VDC on while you are on the track can be bad. Find a set of 18" wheels. When I first started tracking I picked up a relatively cheap set from Wheeldude.com, The Nismo knock-offs. And they did fine when I first started going.

And start off with a 200 tread wear tire or something not too sticky. Helps you learn a lot about how far you can push your car and once you start getting better slap on some stickier ones.

http://www.wheeldude.com/catalog/pro...oducts_id=5608

Good luck man.

 

Interesting ... everyone writes to avoid the water using street tires w/ or w/o FI. So in your opinion, you don't think traction will be a problem going from 2-3?

 

Any time the car take over..= bad....you should have full control. VDC cuts the throttle as well when you stomp on it..that = bad too. Even when you turn it off, its still not comletely off. VDC caused me to almost completley lose control of the car in the twisties from its compensation that it was trying to apply. It may be beneficial in spirited street driving but not for track use. You need to wire a switch in line to the power for the yaw sensor located behind the hand brake..03's its the purple wire in the harness at that location. That shuts it all off. That = good.

 

VDC always needs to be off at the dragstrip. In my 6MT car, I cant go WOT in 1-3rd with it on or it cuts me back, same goes for 1-3 shifts.

Your going to have to peddle the car as best you can and see what you can do, good luck.

CROM-VDC only interfers even when off when throttle AND brake is applied at the same time-like when doing brunouts. Ive NEVER had it screw me up when off and driving hard, you cant apply both gas and brake at the same time. 98% of people shouldnt turn off VDC on the street in the twisties, as much as we all like to believe we are hot $hit, we arent. I drove at ZdayZ keeping up with the fast guys with VDC on, nobody could believe it.

 

Stock converter, just a shift kit.

 

Sounds like the consensus is DS mode, VDC off, and watch the 1-2 shift. The rest is practice to see how much throttle I can put in before it gives.

 

I had the same power levels as you in my 5AT. Its a waste of time to go down the track at those levels without DR'S or slicks. Invest in some DR's or slicks and turn the VDC off. Its much more fun that way

 

So with DRs or slicks, it's just mash and go with VDC off?

And if you had to do it with street tires, what would you suggest for best results?

 

One time, I accidently left my VDC/TCS on and I hit 17.5sec! VDC/TCS bad.. Turn that thing off... Nissan's TCS isn't as advanced as Benz's.. ETS or something... My friend with E55amg leaves the ETS on and hits high 11s/ low 12s...

 

1st question.... (and you can manually shift without tire spin)
2nd question.... Just leave it in full auto mode. Try it with the VDC off and see what happens. Its no fun to pedal a car and at your power levels thats what your going to do on street tires unless you drive like a granny