Negative 'G'

[GriffoVRS]

There is a particular country road near me that when you drive along it you go over 'hump' where the car goes a bit 'light'.

The peculiar thing is that immediately after going over the hump there is a distinct loss of power for a second or so as if the fuelling is briefly restricted, and then everything is back to normal.

This never used to happen with my PD vRS, and I am surprised that this would happen with a fuel injected car.

Anyone else experienced this?

[vRSLen]

That will be the anti flight relay

[darrenw]

Loss of power = front wheels off ground??

Could be the ASR kicking in?

[PowerMalc]

Don'nt worry. What you lose in performance you'll gain in 'Air Miles'

[GriffoVRS]

Loss of power = front wheels off ground??

Could be the ASR kicking in?

Not going fast enough for this to happen. No indication on the dash.

There are some shorter bumps further down the road where you don't notice this effect, so I guess it only happens over a more sustained 'hump',

[Anthony 1]

It does sound as though ASR or something might be reducing power if it feels that he wheels are spinning. I shut off the power my self when cresting or just before the crest at the brow. If I am breaking hard for a hump back, I hold the brake until the crest so as to compress the suspension then as I crest I release the brake allowing the suspension to recoil. This keeps the wheels in contact with the road and makes the car less likely to go airborne and so one can lay down the power again earlier.

[oilburninnut]

never heard of him,does he play similar stuff to tenacious d?

[dan_the_v8man]

does this explain your loss of power?

[sworrall]

i always get this when dong some neg g on downward corners coming home from the alwen. I always assumed it was the ESP thinking I was going off the road. Neg G not good on the nether regions too!

[GriffoVRS]

Probably a better description is 'cresting' a hill, at around 60 mph.

The car is definitely not taking off or the wheels spinning, but does get a bit 'light' over the brow. Interesting to note that someone else has experienced something similar with a CR vRS.

As I say no lights on the dash, but when I get a chance I will have to drive it with the ESP off to see if it still happens.

[dan_the_v8man]

what happens if you do it with the ESP switched off?

[fireftrm]

Mine does this too, definitley with the wheels on the ground. I thought I was imagining it! As we are trained to accelerate on the down lip of humps (gigs the car in) it is even more pronounced when on a response drive. The humo doesn't have to be very sharp and there is no way that the ESP should be affecting it, no slipping, loss of traction in anyway indeed. It is just like a loss of power, or even braking, but why would the ESP be involved, I can't see why? HAving said that I can't see what else either. I was wondering if hill start was in any way involved, according to the handbook HHC is part of ESP yet I have never felt mine operating on slopes (I had it demonstrated at a nearby set of lights when I had an L&K on trial), is the HHC really there in all ESP systems and if so is mine somehow working in descents but not ascents?

[GriffoVRS]

what happens if you do it with the ESP switched off?

Tried it with the ESP switched off today, and had exactly the same effect!

It appears to be nothing to worry about, just a bit odd.

[AndyK11]

Tried it with the ESP switched off today, and had exactly the same effect!

It appears to be nothing to worry about, just a bit odd.

I get exactly this on my drive to work down a slight dip after a crest. Mine's a FL vRS CR too.

I don't have to be going particuarly fast either... feels like I've just lifted off the throttle when I haven't.

Very odd, but as you say doesn't seem to be anything to worry about.

[dan_the_v8man]

Potentially it could be if you were giving it some beans into a corner

Where are you from Andy if you dont mind me asking? Its really got me thinking this one

[Namaso]

Interesting!, I have a Limited edition VRs with the CR engine and have experienced exactly the same loss of power when driving over a dip, but not all dips. Also someone mentioned about the hill assist. Not sure whether this is fitted to mine but certainly doesn't work. I have full esp fitted. Will talk to my dealer tomorrow

[gilesk]

I see your Octavia and raise you a focus

[AndyK11]

Potentially it could be if you were giving it some beans into a corner

Where are you from Andy if you dont mind me asking? Its really got me thinking this one

I'm from near Dorking but this particular stretch of road is on the A323 near Farnborough.

I tried it again last night... steady 50mph, car goes slightly light over the brow of the hill, but it's actually when the negative-g kicks in going down the following dip that the power is 'cut'.

All very strange... :wonder:

[Browny_37]

I see your Octavia and raise you a focus

Impressive!

[fireftrm]

It is very odd and it has affected my response drives, at times. Anyone also know about the hill hold and ESP issue, is it part of the system or not????????

[fireftrm]

Just bumping to the top of the list as I would like help over the negative g issue and whether hill hold is standard as part of ESP - help, please?!

[GriffoVRS]

Just bumping to the top of the list as I would like help over the negative g issue and whether hill hold is standard as part of ESP - help, please?!

Don't think that I have a hill hold fiunction on my manual vRS. I also get this effect with the ESP switched off.

[prolfe]

it happens on mine 2010 cr vrs manual. I'm gonna speak to the stealer about it

[fireftrm]

What about hill hold? in the manual it shows it as an intrinsic part of ESP yet I think it is only on certain models?

The negative G issue is annoying, almost feels like a brake application :S

Edited 17 February, 2010 by fireftrm

[GriffoVRS]

it happens on mine 2010 cr vrs manual. I'm gonna speak to the stealer about it

I'd be amazed if they can provide an answer; but if they do let us know.

Came down the road in question today, and there is a significant cut in the power, though it recovers after a second or so. I have driven this road 100's of times in all types of cars, including a PD vRS, and have never had this effect before.