GMII back at the track
knocks off a couple more tenths
and driver: Jim Langley
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 ETs 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 13s has only increased my appetite for speed.
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.
just the addition of slicks, short belt, gears (usually 4.10s),
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 60s could do given similar mods.
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.
the mid to late 80s, not even the Generals 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.
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 50s 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 ETs at no cost? Sounds like a deal too good to be true.
To be honest- there is a cost, even though it isnt 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!
First, lets talk about three different types of shifting and show
the progression from slow and easy to fast and, umm, nope- we wont
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.
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 buddys automatic.
Spending some time at the track helps to refine the technique and prepares
you for the final stage in shifting evolution- 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
The Granny Shifters sound like this- Waaaaaaaaa! -moment of silence-
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 dont 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-13s.
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.
you can't powershift through the long staging lines.
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 rpms jumped to 6000rpm briefly and
then dropped as the shifter slammed into 2nd. What a rush! GM II leaped
ahead as the tires bit-
had never felt the car move like that before."
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!
effects of power shifting
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
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 5.0s 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