Project
Monaro gets an electronic Turbo 700 able to handle 450 hp
at the treads.
Last
issue Project Monaro
dipped into the 12s, with street tyres aboard, but shortly
afterwards the auto cried enough., the box has done umteen
passes on the dyno as well as a lot of full power drag passes,
with so much extra power on tap the internals had become
seriously fried so Daniel, from Chipmaster, decided it was
time to make the box match the engine in the grunt department
and to cover the planned future upgrades
Next
issue we will bring you coverage of Daniel’s lock up torque
converter test as he will be testing a couple of high stall
converters against the standard piece in the Monaro as the
quest for lower ETs continues. The head and cam upgrade
and the eventual step up to a supercharger will follow.
Brute
Strength.
The
General’s electronic Turbo 700 automatic transmission has
been lurking inside US cars for years and has also been
behind the engines of thousands of Commodores since the
VR days. As there are so many of these transmissions
out there, Perth Street Car decided to see what it took
to beef one up so that it could comfortably handle 450 hp.
While we were at it we decided to make it shift harder and
throw in a high stall torque converter to transform it into
a true street/strip auto. Graeme Stone, Stone Racing
Transmissions, has built many hundreds of Turbo 700s and
he was happy to guide us through the steps required to build
a tough one.
The
following photographs show the steps involved in building
bulletproof 4L60E auto.
0021
The
standard band compared to the heavy duty Alto Red wide band.
This is used to strengthen the hold on 2nd and
4th gears.
0023
A
standard sun gear shell (left) compared to a Brute sun gear
shell. The main difference is the radius around the
spline support – many standard shells break at this point.
0024
A
race 3rd and 4th gear clutch kit is
used comprising 9 frictions and stronger Kolene steels.
The standard (fried) set is on the right and has only 5
frictions. This is another known problem area with
the 4L60E, a lack of clutch pressure and surface area burns
out top gear and overdrive. The load release springs
are not used in the beefed box.
0026
A
high performance pressure regulator (right) is used to boost
line pressure throughout the box, which makes more pressure
available to apply bands and clutch packs.
0027
The
billet servo (right) applies the band for 2nd
and 4th gear. The larger surface area of
the servo means greater force is applied to the band giving
it more torque handling ability. Pictured in the centre
is a Corvette servo.
0030
Graeme
has drilled the reverse drum (left) to allow extra cooling
to the band. The holes also allow oil inside the drum
to be released – reducing the amount of drag from the reverse
clutch pack when forward gears are selected.
0032
Note
the position of the oil holes match the location of the
grooves in the band.
0035
On
the left is a TCI 3000 rpm high stall compared to the huge
standard torque converter.
0037
The
empty housing secured in Graeme’s trick jig.
0039
Looking
inside the case, the piston that engages low gear has been
installed.
0040
Low
gear clutches and steels are installed on the piston.
0042
Graeme
measures the clutch clearance – this is critical.
0047
The
heavy duty Brute shell is slotted in above the low gear
clutch.
0052
Annulus
and planetary gears are fitted above the Brute shell.
These gears provide the different ratios for 1st
and 2nd gears.
0054
The
output shaft is installed, this engages the planetary gear
set.
0055
3rd
and 4th clutch packs and sprag are assembled
inside the clutch drum.
0057
The
clutch drum is lowered into the housing and sits above the
planetaries.
0060
The
reverse clutch drum is assembled.
0061
Installation
of the reverse clutch drum.
0063
The
wide Alto Red band fits around the reverse clutch drum.
0064
The
billet servo locates on the side of the casing and its pin
engages the wide band installed in the previous step.
0066
Graeme
measures the band clearance with a dial indicator.
The clearance must be exact to prevent drag or slippage
of the band.
0067
A
new bush and seal are installed in the front pump.
Although this is a near new gearbox a new seal is good insurance
against an annoying potential leak at a later date.
0068
After
several internal modifications, the rebuilt front pump is
assembled.
0070
The
front pump is fitted into the casing.
0071
End
float in the drivetrain is also critical. Graeme ensures
that it is set between 15 and 36-thou.
0072
Before
the valve body is fitted, air pressure is used to check
the operation of all clutch packs, the servo and the front
pump.
0085
The
transfer plate sits between the housing and the valve body.
It is modified for improved gear shifts.
0089
Graeme
adjusts the force solenoid in the valve body for increased
line pressure.
This
makes gear shifts faster and clutch packs bite harder.
0090
After
modification, the valve body is fitted to the casing.
The valve body in the 4L60E is controlled by electronic
solenoids which activate gear changes.
0091
The
valve body, filter and all wiring has been installed.
All that is missing is the sump.
0094
The
finished product: including a high stall lock-up converter.
Let’s go Racing!
When
the new transmission was installed in the Monaro, Daniel
had to modify the computer to allow for the increased line
pressure, which made each gear shift harder. Through
the software, he was able to tailor the gear change points
and feel to suit his requirements both in power and economy
modes. In this case those requirements included blazing
the tyres all the way through top gear!
The
finished Turbo 700 is now capable of handling 450 hp at
the wheels. It has all the right ingredients for a
tough street and strip car. Commodore owners now have
a viable alternative to installing a manual gearbox or reverting
to older style Turbo 350 or 400 gearboxes. Graeme
can also make further strengthening modifications for nitrous
or supercharged cars that produce up to 650hp – now that’s
a tough tranny!
Sorry
no pics as we have been unable to obtain the original PSC
photos
Click
here for Part 4
Source:
Chipmaster.
9452-0213.
