Power Start Feature?

I was reading through some 2007 Shelby GT500 data and saw a reference to the "Power Start Feature". Apparently it allows optimum wheel spin from a standing start on dry pavement, according to the data, which was located under the traction control segment. Are they talking about just switching off the traction control, or is there a performance mode with the Shelby GT500 I am unaware of? It would be interesting if the GT500 had a competition mode similar to what is planned for the 2008 Cobalt Turbo SS. The Cobalt Turbo SS will have a launch control function in the DIC which is designed for closed course performance driving and adjust's chassis controls (including turning off T/C), in controlled driving conditions. The launch control is part of the Cobalt Turbo SS's competition mode and enables consistent acceleration performance, according to the data I read. The 2008 Cobalt Turbo SS will also have a no lift shift alogorithym, so it can be shifted at WOT without lifting the accelerator between shifts, which will result in extremely consistent times, and damage free shifting, especially drag racing. Talk about slick programming. I can see where this will make the Cobalt Turbo SS very competitive in all forms of racing. Of course the Cobalt is a front wheel drive. The down side is it appears as time and technology go forward, less and less driver skill will be required to race cars.


Doc

 

Power Start Feature? Thanks for taking

the time to post. I thought this one was going to go into the archives unanswered.

Can you reference any of the articles or post them? I would appreciate it. I am particularly interested whether or not the articles you mention recommend switching off traction control.

From what I have been able to ascertain from the Ford Performance Info Center, once they were able to reference their own data, after I told them where to locate/find it, is that they (FPIC folks) called it "creative verbiage", which simply meant defeating the traction control, i.e., switching it off.

Pretty much in the stone age compared to the new Cobalt Turbo electronics I mentioned in my post.

Doc

 

Power Start Feature? I did track down

a few articles after searching the web, that define the Power Start feature, which apparently goes back to about 1999 on SVT vehicles. The articles do not however, as far as I can divine, clearly say whether or not the T/C must be enabled or turned off in order for the Power Start feature to activate, and whether Power Start is in sync with T/C, alternates back and forth with T/C under certain conditions, w/o interference with T/C, or whatever.

The common denominator for Power Start to work properly seems to be that in order for the Power Start to allow for an aggressive straight ahead standing start, the vehicle must be on smooth dry surface, and tracking in a straight line.

Doc

 

Power Start Feature? So I guess

since Power Start is apparently part of the T/C system, we then presume T/C needs to be enabled, or could it be part of the T/C system even when not enabled? Still kinda murky whether T/C is required to be enabled to enjoy Power Start. Judging from the underwhelming amount of contributors to this thread, it appears no one, (incuding FPIC from my separate research) is absolutely knowledgeable or familiar with the nuances of the Power Start feature.

It is interesting to note in your article that the tester/drivers were able to improve on their times without using the Power Start.

I'll put this whole thing in quotes as I lost track of the articles found on the web from which the paragraphs were taken from, including yours, this is what I have so far:

"It is my understanding that the traction control is improved to allow burnouts and launches - Worth noting: Traction Control on Mustangs has had the "power start" feature since 1999. This is not new or unique to the 2007 GT500. My 2000 Mustang GT and my 2003 Mach 1 have the power start feature that allow a little tire spin if the accelerometer and ABS systems detect tire spin with "adequate" forward acceleration (such as launching hard at the dragstrip or on dry pavement). However, if not enough (or no) forward acceleration are detected (such as when you're on a slick surface) then the power start feature gives way to traction control setting off the reduction in spark/fuel and brake application as needed to provide forward acceleration."

"TRACTION CONTROL
An all-speed traction control system (TCS) is standard equipment on all the 2001 Ford SVT Mustang Cobras--a hybrid system that is designed to meet the performance needs of SVT Cobra drivers. The system’s "Power Start" feature allows the driver to spin the drive wheels under acceleration, as long as the car tracks straight. If the system senses the vehicle slipping sideways, the traction control system will engage. The system also has a driver-selectable on/off switch. With the TCS activated, when either of the two rear ABS/traction control sensors detects a wheel spinning at a rate higher than its counterpart, the engine management system retards ignition timing and modulates the fuel-air ratio to reduce power to that wheel. If the spinning continues, engine management cuts off one or more cylinders, and the ABS applies braking to the spinning wheel, transferring power to the other drive wheel. The sophisticated system can detect the difference between wheelspin due to acceleration from cornering slippage, based on differences in slip rates at the wheels. The TCS engine management strategies work at all speeds, and the system can apply braking to either rear wheel at speeds up to 62 mph."

"There's more to the SVT Cobra package than just a power rating. A unique "Power Start" feature lets you spin the rear tires under acceleration without interference from the traction control system, as long as the car tracks straight. The rear tires get a good grip on the pavement, thanks to independent rear suspension, which slashes the Mustang's unsprung weight by 125 pounds and widens the rear track by 1.2 inches."

"The Cobra gets standard traction control, a feature now also available across the Mustang lineup. It combines braking and engine control, with engine torque reducing first, followed by cylinder cut-off. If the electronic control unit senses too much undesired wheel slippage, it then kicks in individual braking to regain control, feeding off inputs from all four antilock brake sensors to monitor individual wheel speed to transfer torque to the wheel with a grip. Aware that the typical Cobra aficionado fancies a bit of wheel spin (read: the occasional smoky burnout), not only can the driver manually disable the traction control, but a feature SVT calls Power Start allows for aggressive, straight-ahead dry pavement standing-starts without activating the traction control system."

"What surprised us, however, was the GT500’s loss in the acceleration runs. Its 100-hp advantage should have been enough to leave the Vette in a cloud of rubber dust. The GT500 also has a useful launch-control system that’s part of the standard traction control. To get a nearly perfect hole shot, all you have to do is rev the engine to 3200 rpm, dump the clutch, and floor it. The system automatically modulates engine power to make the driver look like Kenny Bernstein. With it, we hit 60 mph in 4.6 seconds. But we were able to go even quicker without it, thanks to the terrifically tractable engine that makes it easy to keep the tires hooked up. Moreover, the Shelby has a programmable shift light and audible chirp to free your eyes from monitoring the 6000-rpm redline on the tach. Under full human control, we shaved 0.1 second from the 60-mph sprint, lowering it to 4.5 seconds. The quarter-mile required only 12.9 seconds at 112 mph, 150 mph came in 30.3 seconds, and an electronic tether limited top speed to 155 mph."

Doc

 

Power Start Feature? It is listed/acknowledged

in the Ford Dealer literature for the 2007 Shelby GT500, which comprises white pages 33 to 52. On page 47 under All-Speed Traction Control, The last bullet point sentence, "Power Start feature allows optiumum wheel spin from a standing start on dry pavement."

So apparently it does exist, though not real well known, further explained, understood or recognized.


Doc

 

Power Start Feature? Absolutely

correct. Probably the single most important technical feature in the GT500 for those interested in aggressive straight line acceleration, 1/8 mile, 1/4 mile or otherwise.

I remember reading sometime back how long it took and and difficult it was for GM to develop the technology for their T/C system. Lots of complex alogorithym's, I'm sure. Once a good foundation exists, then it is just a matter of adding tweaks like Power Start, or as in the case of the Cobalt Turbo, no lift shift, and launch control.

Doc

 

Continuing Power Start Feature?

If you find anything else pertaining to Power Start as time goes on, how about sticking it on this thread, and maybe some of our fellow Forum folks as well as you and I may be able to profit from a greater indepth knowledge of our GT500's technical performance features. I'll do the same. Like you, I cannot fathom why such a useful performance feature developed for the car seems to be so relatively unknown. Unless those who do know about it keep quiet so as to enjoy a performance advantage.

Doc