loose control under acceleration?


H

HHGT

Guest
Back in 2004, when I used to go to Bondurant in AZ, Bob's grandson had just started teaching drifting. At the time Bob suggested drifting school to any novice with big HP as a means to understand the dynamics of a vehicle, steer your way out of trouble and avoid calling the insurance company. When my calendar frees up, the next event on my list is drifting school.

Tim are you reading this? I'm still waiting!:biggrin
 

Fubar

Totally ****** Up
Mark II Lifetime
Le Mans 2010 Supporter
Aug 2, 2006
3,979
Dallas, TX
Thanks Fish!

One of my favorites parts about working with Fish is the explanations he brings to the modifications we make on the GT. He works with a few professional race teams. Consequently, I thought he would have a good insight and I know he has a good talent for explaining that information.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,283
Las Vegas, NV
I do not think other cars have so many spin related accidents as compared to total production. I have not heard any issues being discussed on the Lamborghini forum or in speaking with the other Mosler owners.

...

With the airplanes that I fly we call these issues "dark corners". These are areas we stay away from at all costs. But with airplanes we know not to go below a certain well defined speeds, or pull too many G's at a speed, or have the nose pointed down below a certain altitude. It would be nice if there was a definition of the dark corner so I could stay away from it. Hopefully I will test it out at the airport ramp this spring.
...

I have another perspective on this. How many of the other super cars have all the nannies? I'm sure, no, positive, that if the GT had traction control and stability control we wouldn't hear about this as much.

When I drove the Corvettes at Bondurant they wouldn't let us turn them off and admonished us that if the instructor got in the car and they were off he'd slap our p**p**. They told us to be aware when they kicked in to save your butt and their car, and to recognize "you just pushed over the limit" [the dark corner] and to remember to not do that again. Without nannies to save your butt, the only way to really know what the limit is is to find it be experiment. Like I said, I'd really like to find a skid pad. My trip to Bondurant has been canceled for March but I might still try to go down this year, probably fall.

Dark corners are like black holes. You want to get close enough to enjoy the experience but not so close that you fall in :)

I've found this discussion very enlightening.

Edit: My bad for not reading past the replies before responding but MoTeC Magic made some of these same points.

And I'll be the original poster's and Chip's event was the "compression braking" event - the process of letting off the throttle is braking, and with high compression high torque engines can be treacherous. Observe in the video of the Porsche on the righ I posted yesterday he NEVER let off the throttle without a downshift and rev matching blip...
 
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Luke Warmwater

Permanent Vacation
Jul 29, 2009
1,414
Boondocks, Colorado
Back in 2004, when I used to go to Bondurant in AZ, Bob's grandson had just started teaching drifting. At the time Bob suggested drifting school to any novice with big HP as a means to understand the dynamics of a vehicle, steer your way out of trouble and avoid calling the insurance company. When my calendar frees up, the next event on my list is drifting school.

Tim are you reading this? I'm still waiting!:biggrin

That sounds like a great idea. Growing up we lived up about at 9500' above Jamestown in Colorado. My brother and I used to race up and down the dirt fire road that climbed out of Jamestown up a couple thousand feet to the house. Mom & Dad had no idea what we were doing with the family vehicles :) Looking back it was reckless as hell because a miss sliding around those tight bends was going to send you rolling several hundred feet down the side of the mountain. But when you 17 and bulletproof it hardly crossed our minds. The up side is we spent a couple years learning how to drive like dorks and were drifting before it was even called drifting. I've never lost it a car in my life other than taking out a few smaller pines rallying up my driveway a couple years back. After a little scuffed paint and having to walk up the mountain to get the loader to drag it out I was none worse for the wear and was reminded again that if you ride the line you will fall off sooner or later.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,283
Las Vegas, NV
The Ford GT was designed with geometric features to minimize over steer accidents, it has roll under steer built into the suspension geometry, ridiculously small front tires and spring rates that promote under steer. These things push like pigs in almost all situations, Mark McGowan can verify that if you don't believe me.

While looking on the net about under/oversteer on one place it was stated that US designed automobiles are deliberately designed to understeer instead of oversteer. With understeer the front of the car hits the wall, with oversteer you go backwards and chances are your rear end hits the wall. They further concluded that lawyers don't like cars that go around in circles and hit the rear into walls and sue manufacturers when it happens [regardless of whose fault it was.] So you're stuck with understeer.
 

cobra498

GT Owner
Jul 14, 2010
310
Central Ca;ifornia
Thanks Fish!

One of my favorites parts about working with Fish is the explanations he brings to the modifications we make on the GT. He works with a few professional race teams. Consequently, I thought he would have a good insight and I know he has a good talent for explaining that information.

Yes, MoTec Magic makes excellent points about lifting, I neglected to mention that lifting or braking at the wrong time can be as bad or worse than mashing the throttle. Not lifting all the way off no matter what is as difficult to learn as left foot braking with good modulation. It all comes back to throttle control both on and off, braking and steering none of them should be violent. I had a driving instructor many years ago tell me "don't ask the car to do something it does not want to do" good advice to this day.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,283
Las Vegas, NV
That sounds like a great idea. Growing up we lived up about at 9500' above Jamestown in Colorado. My brother and I used to race up and down the dirt fire road that climbed out of Jamestown up a couple thousand feet to the house. Mom & Dad had no idea what we were doing with the family vehicles :) Looking back it was reckless as hell because a miss sliding around those tight bends was going to send you rolling several hundred feet down the side of the mountain. But when you 17 and bulletproof it hardly crossed our minds. The up side is we spent a couple years learning how to drive like dorks and were drifting before it was even called drifting. I've never lost it a car in my life other than taking out a few smaller pines rallying up my driveway a couple years back. After a little scuffed paint and having to walk up the mountain to get the loader to drag it out I was none worse for the wear and was reminded again that if you ride the line you will fall off sooner or later.

So how about Bondurant this fall? I was going to go down in March before the Shelby 50th in Vegas, but I simply don't want to wrestle the weather. A good time in the fall would be the Mon-Tue-Wed before the Barrett Jackson auction in Vegas. It'll be hot in Phoenix then though.

In the advanced class they will let you drive your own car but for the beginner 3 or 4 day class you have to drive theirs (and you get a regional SCCA card if you want). If we could get a big enough group we could probably schedule it still. They are setting their 2012 schedule now though so soon...
 

dbk

Admin
Staff member
Le Mans 2010 Supporter
Jul 30, 2005
15,260
Metro Detroit
I religiously tell people to be careful when they get a GT not because it's particularly any more dangerous than most other sports cars, but because it doesn't have any electronics to save you. Car is deceptively fast and won't interfere if you screw up.

I was a pretty frequent drag racer before I got the GT and I have to say, when I drove the GT stock I thought "Dude, can this thing even spin the tires?" The car has loads of grip and if you nail the throttle from low speed pointed in a straight line, it's not exactly easy to get it out of sorts. That's part of the problem. The GT feels so predictable and under control that you feel invincible until you're not, and by the time you've realized it, you're screwed.

Add power and all bets are off. I drove my car with Goodyears and the pulley/tune/exhaust for about 9,000 miles, and that's about the scariest combo to me. If you mat the throttle in 1st or 2nd in cool weather, forget it. I drove the car with the twin turbos and goodyears for maybe 5-6k miles and that was less scary, but you could feel it haze the tires when boost piled on near the top of third. The TT setup with 1000 rwhp and Bridgestones is significantly less scary to me than 600rwhp from the OEM blower and Goodyears.

I've also never been in another car that changes so much due to weather. If it's 95*, it won't matter what you have done to the car, it's gonna feel slow. I went to the drag strip on a day where there were flurries on the way to the track, and even scared shitless rolling out of the start not hammering the throttle, the car went 133 mph with just the pulley/tune. I definitely feel like if I had ran the car out hard it would have easily gone 135+. On a hot day? I wouldn't be surprised if it lost 8-9 mph from that.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,283
Las Vegas, NV
I would venture a some what educated guess than many of the GT accidents were the result of slight but quick movement of the steering wheel as the car was transistioning a change in balance. Camber change,Too much right foot, too much steering, and slightly delayed reaction time by the driver, leads to that Oh Sh*t moment.

I'll beg to disagree. Maybe some, but I will wager that some are the throttle-lift-off from high RPM or even worse, a badly timed downshift (which is a guarantee of compression braking). Don't ask me how I know. OK, I'll tell anyway. First, when I grew up and in drivers ed we were taught to use engine braking instead of or with the brakes to slow down. I was approaching a turn with the Cobra, downshifted to do the turn, and did a 360 in the road side. Fortunately nothing bad. That is when I wrote a sticky note on the dash: "Transmission Go, Brakes Slow".

Learn and practice heel-toe RPM matching and that isn't a problem, but most people don't even know what it is let alone how to do it. At Bondurant you practice it for 1/2 day... Best 1/2 day of the class. Except for the full day on the Formula Mazdas.
 

HIRISC

GT Owner
Mark II Lifetime
Mar 14, 2007
259
Minneapolis, MN
I have another perspective on this. How many of the other super cars have all the nannies? I'm sure, no, positive, that if the GT had traction control and stability control we wouldn't hear about this as much..

Agreed. Stability control on the FGT would have likely helped reduce quite a few of the street-side incidents.

I didn't spend any time looking this up, but I don't think there were too many 'supercars' that combined >500hp, mid-engined layout and no stability control. Mclaren F1 had no stability control, the Enzo had stability control.

One particular car of similar vintage, the Carrera GT, shares the FGT's layout, high power level (higher hp, lower tq) and no stability control. It did not come equipped with rock-hard Goodyears. No matter, they wreck too. Likewise, the GT2's (no stability, no runflats) didn't get their 'widowmaker' name because they were easy to control (however, rear engine <<< mid engine).

I prefer stability control for street driving. There really isn't a reason to turn it off (there), so I leave mine on in cars so equipped.

Almost a non-issue now as only (mostly) boutique manufacturers don't provide it... If you buy a Mosler or a Noble/Rossion, you know what you're getting into presumably.
 
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Luke Warmwater

Permanent Vacation
Jul 29, 2009
1,414
Boondocks, Colorado
So how about Bondurant this fall? I was going to go down in March before the Shelby 50th in Vegas, but I simply don't want to wrestle the weather. A good time in the fall would be the Mon-Tue-Wed before the Barrett Jackson auction in Vegas. It'll be hot in Phoenix then though.

In the advanced class they will let you drive your own car but for the beginner 3 or 4 day class you have to drive theirs (and you get a regional SCCA card if you want). If we could get a big enough group we could probably schedule it still. They are setting their 2012 schedule now though so soon...

I might be in Tony. I have a couple week long golf vacations planned for 2012 and hoping to run BBOR. If time permits that would be a great learning experience.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,283
Las Vegas, NV
I didn't spend any time looking this up, but I don't think there were too many 'supercars' that combined >500hp, runflats, mid-engined layout and no stability control. Mclaren F1 had no stability control and no runflats, the Enzo had stability control, but not runflats....

I thought Traction Control became mandatory on all cars in the US and I thought it was before the FGT and am curious how they managed to make it without. I recall the big deal about Stability Control becoming mandatory too and the claim that car costs would increase dramatically because of it. Well, SC is basically software controlled use of the ABS system.

I have to admit the stability/traction control on the Bondurant Corvettes was a good feedback and they did help me learn where the edge of the cliff was, but when I go back for advanced since I'm planning on driving the GT one of the days they will be turned off at some point.

Edit: Fixed ABS to Traction Control. Brain got disconnected from fingers :)
 
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Superfly

HERITAGE GT OWNER
Mark II Lifetime
Jun 23, 2008
2,210
Edmonton, Alberta
I thought ABS became mandatory on all cars in the US and I thought it was before the FGT and am curious how they managed to make it without. I recall the big deal about stability control becoming mandatory too and the claim that car costs would increase dramatically because of it. Well, SC is basically software controlled use of the ABS system.

I have to admit the SC/ABS on the Bondurant Corvettes was a good feedback and they did help me learn where the edge of the cliff was, but when I go back for advanced since I'm planning on driving the GT one of the days they will be turned off at some point.

^^^ We DO have ABS, just not Traction Control or Stability Control (at least not beyond an educated right foot.....)
 

TO AWSUM

Ford GT Owner
Mark II Lifetime
Jul 4, 2007
1,512
Niceville FL
Nice discussion. I remember the leasons my dad taught me about letting off the gas at the wrong time when I was 13. I grew up in South Dakota and my dad took me out on the frozen river and taught me how to use speed, throttle control, brake control, steering, shifting to a lower or highter gear, clutch control, etc. to navigate around the patchy snow drifts on the river. He would let me weave around the piles of snow on the ice and of course I spun out many times. Soon, I learned to judge my speed, learned how not to lift my foot off the gas peddle abruptly, and conversly not to stomp on the gas pedal which every knows about, not to stomp on the brake, to let the clutch out slowly and deliberately and not abruptly, and to be SMOOTH in everything I changed. As MOTEC and others have stated it is sometimes counter intuative that you need to continue to apply throttle in a skid and not abruptly take your foot off the gas or even worse apply brakes. When you change something abruptly in a car, you had better be pointing it in a straight line (like a dragster) or the car will become unstable and spin off the road/track (like a dragster). The key, besides knowing the cars grip limits, is to be smooth in applying and unapplying throttle, brakes, steering, gear changes, clutch engagements, etc. BE SMOOTH. These lessons helped me be a better go-cart racer, motorcycle racer, fly aircraft, control high horse power cars and drive on slippery roads. Is knowing or gaining these skills going to keep you from crashing? NO!! There are always unexpected things that happen that you can not recover from, but having these skills can definitely give you the knowledge and skills to avoid many circumstances you find yourself getting too close to. It allows you to recognize that you are approaching your limits quicker. I think that is what is mean by "experienced drivers" - recognizing a problem earlier so you have more time to think about what the correct reaction should be.
 
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GT38

GT Owner
Mark IV Lifetime
Jan 19, 2008
720
Glendale, Arizona
The rainy weather at Rally 5 gave the opportunity to spend more time at the skid pad at VIR. Here's a collection of videos of Ford GT's intentionally spinning. These are 1920x1080 HD videos (i.e., large files), so if you have a slow connection you may need to let them stream ahead for a bit for smoother playback.

"Team Jeff" Boulais in GT38, which had Goodyear slicks on it. Note his comment at 2:20 that it was harder to break loose than the Daytona Coupe (see video of it in my next post). Picture-in-picture showing inside and outside simultaneously starts at 3:40:
[video=vimeo;15877703]http://vimeo.com/15877703[/video]

"JBG" John Glatz:
[video=vimeo;16037969]http://vimeo.com/16037969[/video]

"AZStad" Shane Ettestad in the Joyride GT:
[video=vimeo;16035854]http://vimeo.com/16035854[/video]

And this is just plain nuts:
[video=vimeo;16038663]http://vimeo.com/16038663[/video]
 

GT38

GT Owner
Mark IV Lifetime
Jan 19, 2008
720
Glendale, Arizona
Other cars on the VIR skidpad at Rally 5.

Team Jeff continues the fun in the SPF Daytona coupe - and proves that a Moose will fit in it!
[video=vimeo;15887457]http://vimeo.com/15887457[/video]

Jeff takes the Moose's rental Mustang out:
[video=vimeo;16040951]http://vimeo.com/16040951[/video]

DBK in a Raptor:
[video=vimeo;16041549]http://vimeo.com/16041549[/video]

Tim Cantwell in his Exige:
[video=vimeo;16042567]http://vimeo.com/16042567[/video]

Jeff & Tim in the Daytona:
[video=vimeo;16043483]http://vimeo.com/16043483[/video]
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
^^^ We DO have ABS, just not Traction Control or Stability Control (at least not beyond an educated right foot.....)

Some FGT owners have added Traction Control via Discovery-Automotive, or Motec. A nice mod, but a very involved installation.
 

MoTeC Magic

Spectator
Aug 21, 2009
99
Dallas, TX
Some FGT owners have added Traction Control via Discovery-Automotive, or Motec. A nice mod, but a very involved installation.

Currently working and almost done with the plug and play MoTeC kits with boost by gear control for the Super Charged cars and race grade Traction Control. I'm sure Fubar will update all on his project as we get it finished. His is the first plug and play kit.

Cheers
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
Currently working and almost done with the plug and play MoTeC kits with boost by gear control for the Super Charged cars and race grade Traction Control. I'm sure Fubar will update all on his project as we get it finished. His is the first plug and play kit.

Cheers

How are you handling the instrument cluster? Is the MoTec piggybanked with the stock ECU or is the MoTec driving the stock guages? I look forward to reading more about the project.
 

MoTeC Magic

Spectator
Aug 21, 2009
99
Dallas, TX
Piggybacked over factory ECU. This way gauges, AC, ABS, etc still work.

The system will handle all motor functions... we're also working on DBW throttle for the GT to go with the system. It will be able to prevent compression braking lockups by acting as a throttle damper (what most high hp road race cars have) that will more slowly close the throttle on abrupt lifts.
System will also have multifuel capabilities. We've designed a stock fuel tank replacement that is compatible with gasoline, methanol, and E85. We've integrated a fuel sensor that will sense the ethanol content allowing the vehicle to be a true flex fuel system. Boost by gear, traction control, launch control, nitrous control, antilag for turbo cars, etc.... are some of the bells and whistles being included.

Will be a really nice solution for the GT.... and should make a lot of the higher hp cars much quicker and safer to play around in.

Cheers