I have it from a reliable source that leaving VDC on with an operating FI unit (SC or turbo) can lead to detonation when the VDC kicks in to cut out engine power. By cutting fuel to cylinders 1 and 2, an immediate lean situation can occur. It was recommended to me, therefore, that I keep VDC off, especially when driving hard--not just to gain total control over what the engine does, but also to prevent this kind of detonation. Has anyone else heard about this? I'm getting a Vortech SC installed in my G35 and am worried about driving with the VDC on most of the time (a major safety improvement). I don't want to save my life while at the same time killing my engine. But, it's when driving hard that the VDC is most needed.

 

I know who your reliable source is. I got the same advice.. Hope you like the Vortech. Glad your asking the question however..

 

All I have to say is... HAHAHAHAHA! The only problem with VDC and FI is when you are trying to punch it. The VDC thinks the car is slipping and cuts the power. For everyday driving VDC is perfectly okay. Now if you are driving the car hard, you want to turn VDC off so you don't get a slip light and bog the engine down. Not because you are worried about detonation.

 

I think the issue is the way VDC cuts the power--by choking off fuel to cylinders 1 and 2. It doesn't stop the spark plugs from firing. Sorry to have caused you that attack of mirth.

 

I should add to my response: as far as I know (which may not be very far).

 

VDC is highly overrated IMO.....You should not bother leaving it on unless the weather or driving conditions are such that even if you are driving conservatively there is a chance that the car may need to cut power in a quick and dirty to maybe avoid losing control.

All that to say is even without FI - it's hard on the car to drive it hard knowing the VDC will constantly flick on - If you're driving it hard intentionally, you should turn VDC off.

'nuff said...

 

Please forgive me for disagreeing with you. VDC is one of the most important safety advances since ABS. When one is not intentionally driving hard on a track, it's there for situations you least expect--sudden avoidance maneuvers, patch of oil or ice, etc., etc. VDC can prevent loss of control and even a rollover. All the Infinitis and the Z car are among a very few makes that offer it standard. VDC is a sophisticated computerized system that can react and modulate power to each individual wheel in a manner that is impossible without it--even for an expert driver.

New York Times had a column on it about 2-3 weeks ago. The automotive editor said that VDC and side head-protection airbags have been shown to be life-savers that no other existing safety device can match. He said that he would never buy a car for himself or any family member without these two items. This is the first part of the article (it's now archived and costs money to retrieve entirely):

NEW YORK TIMES
BUSINESS/FINANCIAL DESK | November 16, 2004, Tuesday

The 2 New 'Must Haves' of Auto Safety; Experts Enthusiastic About Stability Control and Special Side Air Bags

By DANNY HAKIM (NYT) 1298 words
Late Edition - Final , Section C , Page 1 , Column 4

DISPLAYING FIRST 50 OF 1298 WORDS - Many car shoppers count cup-holders, check legroom and carefully consider color. ... Top auto experts, however, say there are two important must-have safety features on their own shopping lists side air bags specifically designed to protect a person's head, and electronic stability control, which helps drivers regain control of...

 

What about seat belts?

 

The VDC doesnt cut fuel....it closes the throttle plate.
So no chance of fuel starvation.

 

from the service manual it appears to say it does cut fuel but also as you stated the TP..

the manual decribes the TCS and then in the VDC section mentions that in addition to the TCS, VDC does x,y,z