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FORDMUSCLE.com

Project GMII back at the track
Fancy footwork knocks off a couple more tenths

Author and driver: Jim Langley

When we last saw our little green project car, Green Machine II had taken to the new T5Z manual transmission like a Shotgun Hemi to nitro-methane! Once the driver (yours truly) actually began to understand how to drive the new-fangled contraption the ET’s dropped by an outstanding 0.589 seconds- from 14.089 seconds on the fist try to a new, gear banging best, of 13.500. While I have been both impressed and very pleased with my daily drivers performance like most racers I want more! Having tasted mid 13’s has only increased my appetite for speed.

The hardcore 5.0 Mustang crowd has been breaking into the 12 second zone on basically stock engines since the introduction of the electronically fuel injected 1987 Mustang GT and LX.

With just the addition of slicks, short belt, gears (usually 4.10’s), removed front sway bar, some weight reduction, good traction and great air these small block wonders could do what very few big block cars of the ‘60’s could do given similar mods.

Our 1992 LX project car is pushing the envelope of stock 5.0L performance. A T5 has replaced the AOD, and 3.73 gears turn the wheels, but the otherwise stock Mustang is well below the mid-13 ET mark.

In the mid to late 80’s, not even the General’s top dog, the Corvette, could do that with 48 more cubic inches! (Ok- the Buick Grand National could but it had a turbo, and you had to up the boost at that.)

The big, flat torque curve and well designed anti-squat rear end combined with a light package made the EFI Mustangs serious over-achievers at the drag strip.

There was one last piece of the performance puzzle needed to go from a 13.00 to a 12.9x- and that was the black art of power shifting. While stick racers have been doing this since the 50’s it was the new 5.0 crowd that took this practice and made it their own. The well-matched ratios and full synchros in the Borg Warner T5 five-speed transmission coupled with a aftermarket short throw shifter allowed the serious speed freaks to shift to the next gear without ever lifting the throttle!

It takes both talent and practice to accomplish this dance smoothly and effectively. But done properly, several tenths can be shaved off your ET with no other changes to the car. Trust us- it really does work- our track results prove it.

Lower ET’s at no cost? Sounds like a deal too good to be true. To be honest- there is a cost, even though it isn’t up front. We here at F/M have seen the detritus left over after a T5 has seen too many missed power shifts more than once. If you plan to powershift, be sure to have a line on used T5's, because sooner or later you will break yours. So with the warning label out of the way, go get those blue suede shoes and we will show you the dance that is power shifting!

Types of shifting
First, let’s talk about three different types of shifting and show the progression from slow and easy to fast and, umm, nope- we won’t go there.

Granny Shifting
When we first learn about the mysteries of the manual transmission and that third little pedal on the left we all heard something like this- “Ok-wiggle the stick and make sure it is in neutral, gently push in the clutch all the way, carefully push the stick into first gear and slowly release the clutch and give it a little gas.” This would result in one of two outcomes- a hard lurch and stall or almost no perceptible forward motion and the sweet odor of burning clutch accompanied by shouts of “Let it out! Let it out!” Once the car actually moved in first you would repeat the process for each successive gear shifting as high as 3000 rpm and letting off the gas between shifts. With practice you could do this smoothly and even quickly, conjuring visions of Dan Gurney blasting down the Mulsanne straight.

Today, we politely call this process Granny shifting- guaranteed to prolong the life of both transmission and clutch and not raise any eyebrows with your local patrol officers.

Speed Shifting
If you are reading this then you assuredly moved on to the next stage, which we call Speed Shifting. Once you had a taste of a couple of stoplight acceleration contests you realized that the time spent between shifts was wasted, especially if you went up against an automatic, or worse, an auto with a shift kit. With each shift your opponent would gain a small advantage. With practice, you can click off really quick speed shifts by slightly lifting off the throttle with your right foot at the same time you stab the clutch with your left foot and slam the stick into the next gear with you right hand (or left, for those Down-Under and other such exotic places.) Now there is very little loss of acceleration between shifts and you can hang with your buddy’s automatic.

Spending some time at the track helps to refine the technique and prepares you for the final stage in shifting evolution- Power Shifting!

Power Shifting
Ever listen a manual car down the race track? You can tell the good drivers from the not so good simply by the sound of the engine at each shift.

The Granny Shifters sound like this- Waaaaaaaaa! -moment of silence- Wuh, Waaaaaaaaa!

The good Speed Shifters sound like this- Waaaaaaa !-tiny delay- Waaaaaaaa! With less rpm drop the engine does not bog down going into the next gear- you might even hear a good Bark! from the rear tires.

The Power Shifters sound like this Waaaaaaa! WHAA! Waaaaaaa! WHAA! Waaaaaa! WHAA! Waaaaa! and bark the tires in all gears (unless on slicks.) The rpms not only don’t drop- they actually go up between shifts since the throttle is wide open the whole time!

How to Powershift

The Power Shift Shuffle goes something like this- the gas pedal goes to the floor and stays there- never lift! Preload the stick by pulling on it before you reach your shift point. At the pivotal moment simultaneously KICK the clutch pedal and slam the stick into the next gear. Time it right and you will see the rpms climb 200 to 500 rpm between gears and feel a strong surge as the next gear engages. I started power shifting only the 3 to 4 shift my last track day of 2001. It is the easiest shift, straight back, with time to prepare mentally while 3rd winds out. I was able to knock off a pair of 13.50 runs that day and go home grinning from ear to ear. It was time to go to the next level and see if I could actually improve on those mid-13’s.


Testing it at the Track
January 19th was finally a dry Saturday- time for Test ‘N Tune. The weather was perfect- mid 40;s, dry and high barometric pressure that gave a corrected altitude of –1500 feet. What a lot of racers call mineshaft air.

Unfortunately you can't powershift through the long staging lines.

The second run started with only a 2.005 60 ft. but with a competitor beside me the length of the track I let it all hang out and kept the pedal welded to the floor. With the tach climbing towards 5500rpm in 1st I gritted my teeth, locked my right knee, pulled on the stick and stabbed the clutch on time- BANG! The rpm’s jumped to 6000rpm briefly and then dropped as the shifter slammed into 2nd. What a rush! GM II leaped ahead as the tires bit-

"I had never felt the car move like that before."

The next two shifts worked just as advertised with a surge of power each time. The ET? How about a 13.61 at 101.5mph? Previous best with a 2.0 60 ft. was a 13.78. Confident in my shifting ability I concentrated on dropping the 60 ft. time. The result was the best ET to date, a 13.39!

The effects of power shifting
Shifting style

60 ft

ET
MPH
speed shift
2.00
13.78
powershift

2.00

13.61

101.5

speed shift

1.91

13.50

102

powershift

1.89

13.39

101.6

   

Previous best- 13.50 at 102 on a 1.91 60 ft. Power shifting shaved a little over one tenth off of that time. Not bad for free!

I did miss 2nd gear trying to powershift on the last run of the day. My timing was off and the shifter stopped short accompanied by a harsh grinding noise. No harm was done. The car has been shifting fine since then.

Next step?
Try some slicks and pull the sway bar. If that 60 ft can drop another solid tenth and a half before the weather warms up GMII just may see a 12 second time slip. And unlike the previous fellows with the lightened, no option 5.0’s this driver will do it in leather seats with power windows, full stereo and sound insulation to insure a comfortable trip down the track. F/M

Powershifting: keep the accelator pedal planted, and stab the clutch while throwing the stick in gear. Refresh your browser to watch it in action!

 

More Project GMII Articles
Testing the Mac Prochamber
12 Seconds and Beyond
Braced For Action
Powershifting! GMII hits new lows!
Bracket Racing Update
Testing the C&L 76mm Mass Air Meter on GM
Introduction to GMI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Powershifting brings our '92 LX to the low 13's.
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