Full uphill acceleration. Is the 911 known to lose front steering traction/feel ?

[sugarwood]

When my friend test drove my 911, he experienced a front end loss off traction at speed, especially in passing on an upward incline, a feeling of "liftoff".
He said it felt like the back was squatting and the front wasn't grabbing as it should because of the weight.
Naturally, he let off the throttle, but was left disappointed that the car appeared to not be able to handle strong acceleration.
My friend has driven 100's of cars, yet the 911's front lightness struck the fear of God into him, unlike any other car ever has.

Is this limited to full bore acceleration while going uphill?
I have read tons on Pelican about liftoff oversteer, but almost zero on front end lightness during WOT.
Is this normal dynamic for a 911, or is my suspension needing an overhaul ?

[Oh Haha]

The 911s do experience the front end getting "light" at higher speeds. This is due to the rear weight bias.

Do you have a front end spoiler?

[Tremelune]

With enough power...they all do that...

[sugarwood]

Yes, I have both the front spoiler under the valance and rear tail.

So, this is a known thing, yet it doesn't seem to be discussed anywhere. Is it just an obvious thing?
My friend has driven 100's of cars, yet the 911's front lightness struck the fear of God into him.

I searched and found zero threads with the title containing "front light" or "front lightness"!
A Google search did turn up this link:

The Porsche 911: the car that shouldn

Apart from the rock hard ride it’s the front not the back that’s the problem. The great Georg Kacher was absolutely right when he said not long ago in Car magazine that the 911 suffered from poor directional stability at speed. And the front goes scarily light under full bore acceleration. But that just highlights the real mystery of the 911. With no weight on the front, how come turn in is so fantastic?

[Tremelune]

I mean. I've never experienced anything that your friend is describing. Not on a bone stock '87 coupe with no spoilers, nor a 2500-pound widebody with a 3.6 and monster spoilers. That you've never experienced it yourself is also telling. Sounds like he'd prefer a Cayman.

[Bill Verburg]

Originally Posted by sugarwood

When my friend test drove my 911, he experienced a front end loss off traction at speed, especially in passing on an upward incline, a feeling of "liftoff".
He said it felt like the back was squatting and the front wasn't grabbing as it should because of the weight.

Naturally, he let off the throttle, but was left disappointed that the car appeared to not be able to handle strong acceleration.
Is this limited to full bore acceleration while going uphill?

I have read tons on Pelican about liftoff oversteer, but almost zero on front end lightness during WOT.
Is this normal sensation for a 911, or is my suspension needing an overhaul ?

Your friend needs to participate in a few DE's

A basic tool in any car control is throttle and brake usage

In any car, when you are on the throttle the front is unweighted and the rear is more weighted, this results in less front grip and more rear grip

when on the brakes the opposite happens

these 2 tools can be used to change the direction of the cars motion

Basic car control, on the brakes into the turn, when new only in a straight line as you gain skill and confidence increasing trail braking, this gives the front more grip and the car turns in better, on the gas when the apex is approaching, there is a lag even in a n/a car and most of the steering is done to accelerate out of the turn.

In a hill you accelerate into the bottom part, this endows the car w/ a lot of grip at both ends and allows steering and acceleration on the hill, before the crest you will be on the gas and hopefully pointed in the right direction as the front end unloads first and won't steer well at all, the rear unloads second and hopefully doesn't have a lot of self steering dialed in when it re weights.

[Oh Haha]

I know we discussed this but couldn't find the thread.

Somebody will be able to offer more insight than I..

My SC has been at speeds above 120MPH and felt rock solid. I have the front spoiler and factory "turbo" tail.

[rkeele]

your friend must never have driven a 80's or 90's Corvete talk about front end lifting with that long hood you can't even see the road ahead of you when you stand on it, scary with power steering and all, I'm shure you can get used to it though, My 911 race car has been over 140 and is rock solid at those speeds with spoilers

[B85]

Originally Posted by Bill Verburg

Your friend needs to participate in a few DE's

A basic tool in any car control is throttle and brake usage

In any car, when you are on the throttle the front is unweighted and the rear is more weighted, this results in less front grip and more rear grip

when on the brakes the opposite happens

these 2 tools can be used to change the direction of the cars motion

Basic car control, on the brakes into the turn, when new only in a straight line as you gain skill and confidence increasing trail braking, this gives the front more grip and the car turns in better, on the gas when the apex is approaching, there is a lag even in a n/a car and most of the steering is done to accelerate out of the turn.

In a hill you accelerate into the bottom part, this endows the car w/ a lot of grip at both ends and allows steering and acceleration on the hill, before the crest you will be on the gas and hopefully pointed in the right direction as the front end unloads first and won't steer well at all, the rear unloads second and hopefully doesn't have a lot of self steering dialed in when it re weights.

Bill are you a "Rally Driver" ? "hopefully pointed in the right direction " Just kidding. But very good points.

[DRACO A5OG]

Not for nothing, but how are your shocks, original or upgraded?

I recently swapped mine and boy what a difference.

[NYNick]

I think there's something wrong with your car. I'd check your suspension.
I've had the fear of God struck into me as well while driving a 911, but it was never the front end that did it!

[porsche930dude]

could have been just that particular road surface and youre tires not getting along. do you run race tires or maybe theyre just very old? they can be unpredicatable

[Bill Verburg]

Originally Posted by B85

Bill are you a "Rally Driver" ? "hopefully pointed in the right direction " Just kidding. But very good points.

No, but I do this particular hill hundreds of times a year....
and seen more than one car in the trees because they weren't aimed in the right direction

not my car, but you get the idea....

[Noah930]

Assuming your suspension is in proper tune, I don't know if it's the "car appeared to not be able to handle strong acceleration" as much as it is your friend not being used to the slightly different feel of a rear-engined car. Certainly there are laws of physics involved in comparing a car with about 60% of its static weight over the rear wheels compared to the typical front-engined car with >50% of its weight over the front wheels. But while that will affect steering feel, in the end vehicle dynamics are vehicle dynamics. The laws of physics apply the same regardless--it's just a matter of adapting from one car to another. Fear of God may be a bit strong of a reaction IMO. Maybe your friend is just unused to the unfiltered feel of a non-power steering, rear-engined 911, compared to all the front-engined cars he's used to driving.

[VFR750]

Bill is right about cresting hills. Plus, if you've ever piloted a sportbike, you'd know you better be pointed in the right direction.

It would seem your friend is sensing something wrong, which you may have gotten accustomed to. Your shocks and bushings might be worn out. Alignment? I think you should at least consider he's found an issue.

[Bill Douglas]

Yes cresting hills maybe. There is a hill I do my Italian tune-ups on and it's steep. Steeper than you guys will have driven on, and I hit 6,00rpm in second gear then do a hard right. No understeer or feelings of lightness.

[fanaudical]

I second the request for a suspension check.

I've done a fair amount of full-throttle up a hill at various speeds with no discernible change in steering feel. (Maybe I just don't have enough power to make a difference?)

[Dantilla]

With the big-engine, light weight longhood, it was pretty normal that when at full throttle, the car was going straight ahead, no matter where the front tires were pointing, even with Hoosier R-compound tires.

That's why 911s are steered so much with the throttle. Just balancing oversteer and understeer.

[DanielDudley]

So do check out the front end and the rear bushes. When checking out the suspension, you should have about a one inch rake from front to back to help stability at speed. Tired rear shocks, and bad engine or transmission mounts can also make a 911 feel unsettled.

But I think Bill nailed it.

[wayner]

I agree with Dantilla.

...and most people who describe lift throttle oversteer are actually experiencing a rapid re-gain in front traction after under-steering through a corner.

Really, just imaging pushing the front end all the way through a fast corner, approaching a slower corner or decreasing radius, and then suddenly weighting the under-steering front end suddenly giving it maximum tractions...around you go. There is all that weight back there ego help with the spin, but the sudden front end traction when you lift is the real culprit.

These cars are much better on the brakes (able to use more rear brake bias) and much better off the corners (incredible dig-out-of-a-hole traction in the rear) that most cars. The trade off is on throttle understeer. Early cars were even worse/better.

Thats why they say if you can drive a 911 well, you can drive anything well (but not necessary the opposite).

This video from one of the other Pelicanites should be required viewing (and listening to) before attempting to drive a 911 at speed.
https://www.youtube.com/watch?feature=player_embedded&v=H2k1i6HcEQU

Here are some of the masters at work. (At the point where we think we are out of traction, that is where they start going fast).

Watch the wheel, particularly in the last video...but they all do it.
https://www.youtube.com/watch?v=EokoS6R_6c8

https://www.youtube.com/watch?v=CvDD8V9Liq8

https://grrc.goodwood.com/members-meeting-73/drive-early-porsche-911-around-goodwood#JChIIXEbFZqHoK1X.97