Precision Industries Vigilante Torque Converter Install and Test - Converting For Lower E.T.S - Pontiac Tech
Installing And Drag Testing A Vigilante Torque Converter On An '06 GTO Street Car
From the May, 2008 issue of High Performance Pontiac
By Randall D. Allen
Photography by Randall D. Allen
We all like to go faster, but the path to lower e.t.'s isn't always through engine upgrades. There's performance to be found in the remainder of the drivetrain as well. Adding a higher-rpm stall torque converter to the 4L60-E or 4L65-E automatic transmission behind your GTO's LS1 or LS2 powerplant will improve acceleration, providing that the stall speed is properly matched to the engine output and torque characteristics. Another advantage is the stealth nature of a converter upgrade. No one will know about it except for you. In fact, it will be very difficult to detect-even by the dealer-which is a major plus if your GTO is still under warranty. This can't be said for more obvious underhood mods.
The torque converter, which is a hydrodynamic fluid coupling device, links the engine and transmission and acts as a torque multiplier during the stall and acceleration phases. Providing your GTO with the optimum stall speed will result in the best performance.
As the fluid is pumped through the converter, there are energy losses, however, leading to a coupling efficiency that in the past could never achieve 100 percent. With the advent of the lock-up torque converter, the industry was forever changed. Lock-up converters by nature add a clutch that physically links the pump and turbine, effectively changing the converter into a purely mechanical coupling upon lock-up.
This is a benefit to those installing a higher-stall speed converter when using the overdrive transmission because at highway speed with overdrive, cruise rpm will be lower than stall rpm. There would normally be slippage, which increases heat and reduces reliability, however, the lock-up feature has eliminated the slippage so now you can run a higher-stall speed converter to improve torque multiplication (performance) off the line and still cruise in overdrive at low rpm without worry.
Choosing a converter upgrade is generally determined by matching the converter stall speed to the engine's powerband, vehicle weight and rear gear, among other factors. According to Terry Hendrick, of Precision Industries, "Stall speed is determined by the engine's peak torque and is the rpm at which the converter will hold the engine speed and not allow further increase. Since many times when you rev the engine against the brakes the torque will overcome braking power and the car will start to push through them before stall speed is reached, hobbyists commonly use flash speed to discuss converters; that is the engine rpm at which the car begins to move forward when the gas pedal is depressed on launch.
"The real trick is to produce a torque converter that's strong enough to handle increased stall speed and still lock up efficiently. For owners of late-model F-bodies and GTOs, the factory torque converters stall between 1,500-1,800 rpm, depending on power. In general, for the majority of street applications, our Vigilante series of lock-up converters with a stall speed of between 2,800-3,200 are recommended."
Precision Industries developed the Vigilante line of converters from a clean sheet of paper and they contain state-of-the-art features including a specially designed and heat-treated 4130 alloy machined impeller hub, along with a heat-treated 4142 alloy turbine hub.
Precision Industries was the first aftermarket torque converter manufacturer to design, develop and manufacture multi-disc torque converters. In addition to carrying an industry-leading written unconditional two-year warranty, each converter is eligible for one free stall adjustment within two years of the date of purchase.
Unique features include a...
Unique features include a one-piece billet mounting cover and a billet clutch surface that provides an enlarged clutch contact area, and specially designed damper and clutch linings.
The Precision Industries Vigilante...
The Precision Industries Vigilante series of torque converters for the LS1- and LS2-equipped GTOs are 9.5- to 10.5-inch lock-up style units that can be ordered with stalls between 2,400 and 6,500 rpm. After consulting with RPM and Vigilante, a 9.5-inch, 3,200-rpm stall converter (PN LS2-3200, $765) was sourced.
Installation of the converter...
Installation of the converter begins by disconnecting the negative battery terminal and placing the trans in neutral. After getting the car in the air, the front skid plate was pulled off by removing the four 13mm bolts retaining it.
The two 13mm bolts that attach...
The two 13mm bolts that attach the catalytic converters to the headpipe on each side were removed, followed by the two 13mm bolts that join each pipe to the factory after-cat exhaust at the junction of the muffler and dual exhaust pipes. The two separate exhaust sections were then removed and stored for reinstallation later.
Electrical connectors were...
Electrical connectors were disconnected for each of the two front and rear O2 sensors because the exhaust system needed to be taken out to provide enough clearance to remove the transmission.
An 18mm socket-and-wrench...
An 18mm socket-and-wrench combination was used to remove the three nuts and bolts to separate the driveshaft-mounting flange from the rear pinion yoke flange. The front driveshaft yoke was left in the transmission to prevent fluid from escaping out of the rear seal.
The shift linkage was rem...
The shift linkage was removed.
Next, the four 16mm bolts...
Next, the four 16mm bolts holding the transmission crossmember were extricated.
At the front of the transmission...
At the front of the transmission on the passenger side, the two engine starter bolts were liberated with a 13mm socket. Gently allowing the starter to rest on the steering rack, the single 10mm bolt that holds the transmission dustcover was then taken out.
At the back driver-side of...
At the back driver-side of the bellhousing, the inspection cover was snapped off and a prybar was employed to rotate the flywheel until each of the three torque converter bolts was visible through the transmission dustcover. Then they were removed with an 18mm socket wrench.
Since the plan was to upgrade...
Since the plan was to upgrade the transmission with Amsoil synthetic ATF, the pan was dropped by backing out the 16 13mm bolts with an impact wrench. In addition to reducing the weight of the transmission assembly when removed, it's a good idea to do a trans service at this point, anyway.
Follow along as we go though the removal of the factory unit and install a Vigilante torque converter into an '06 GTO owned by Bob Cook of Allen, Texas. In addition, a quality transmission cooler from Hayden and Amsoil's synthetic ATF will be added to ensure that the fluid in the transmission remains cool under the most demanding conditions. Labor will be put into the capable hands of Real Performance Motorsports (RPM) of Lewisville, Texas, and technician Manuel Bejar. Once installation is complete, it's off to the dragstrip to find out if the Vigilante converter can live up to its reputation as one of the best bang-for-your-buck performance modifications for late-model GM vehicles.
Drag testing was conducted before and after the installation of the Vigilante torque converter on back-to-back weekends. Baseline testing of the stock torque converter was conducted at the Texas Motorplex in Ennis, Texas, a quarter-mile racing facility. Testing of the Vigilante torque converter had to be conducted at North Star Dragway in Denton, Texas, an eighth-mile racing venue.
Although both tracks are located within 60 miles of each other, NHRA conversion factors were applied in order to compensate for differences in elevation, temperature, humidity and barometric pressure. The conversion factor for Ennis was 0.9744, while North Star Dragway calculated out to 0.9835.
|Facility:||Texas Motorplex||North Star Dragway|
|Humidity:||54 percent||46 percent|
|Conversion Factor:||0.9744 e.t.||0.9835 e.t.|
|Configuration–Best||60-ft|| 330-ft||1/8 ET||1/8 MPH|
|Stock Converter||2.00||5.56||8.45||85.64 |
|Stock Converter ||8.23|
|Configuration–Average||60-ft|| 330-ft||1/8 ET||1/8 MPH|
|Stock Converter||2.02||5.58||8.48|| 85.34|
|Stock Converter ||8.26|
Tools And Supplies Loctite Metric Sockets and Wrenches Prybar Torque Wrench Tubing Cutter
After installing a 3,200-rpm stall Vigilante torque converter, this '06 GTO took yet another leap forward from a performance standpoint. According to Bob Cook, "The car gained almost two-and-a-half-tenths in the eighth-mile and averaged over two-tenths even when the engine was heat soaked. The converted bests are a bit misleading since the baseline established at Ennis was done as part of the Texas Muscle Car Challenge Series and there was ample time for the engine and transmission to cool down before each pass. Nonetheless, with a prior best of 13.08 in the quarter-mile (uncorrected), the Goat should now easily achieve consistent 12.80s in the quarter. After reviewing the results, the 60-ft. times were significantly improved with a tenth-and-a-half increase.
"As expected, once a performance torque converter was installed, the Mickey Thompson ET Street radials (HPP, Oct. '07, "Hookin' up a Goat (and a Bird) on a Budget") responded and hooked without any evidence of wheel spin. From a normal driving perspective, you really can't tell that there is a high-performance converter installed. Part-throttle acceleration and overdrive lock-up on the highway have been unaffected. Any additional heat that the higher-stall converter may generate has been more than compensated for with the addition of the transmission cooler and AMSOIL synthetic ATF."
The Vigilante converter operates much like an OE unit until the throttle is mashed and it flashes higher, instantly propelling the LS2 engine into the power band. Although the Vigilante torque converter is not the cheapest performance modification out there, it's a very good bang-for-your-buck. If you're in the market to take your automatic-equipped late-model GTO or Firebird to the next level, consider giving Precision Industries a call and let them custom-build a converter for you in a flash!
After lowering the pan, the...
After lowering the pan, the gasket was carefully pulled off of the transmission case. Other than a minor amount of normal clutch residue on the pan magnet, the fluid was clean and fresh smelling. No visible metallic particles were observed that would indicate imminent failure.
Before removing the bellhousing,...
Before removing the bellhousing, a few minor items were attended to. The pan was reinstalled with a few bolts and the transmission TCM harness was unplugged, along with the remaining electrical connectors. A C-clip that retains the transmission lines was removed and they were pushed out of the way. Using the transmission jack with a safety tie-down ensured that the unit would stay stable when lowered.
A flex socket and a long extension...
A flex socket and a long extension are extremely helpful to remove four of the eight 13mm transmission-attaching bolts that are at the top of the bellhousing.
After verifying that all electrical...
After verifying that all electrical connectors were disconnected and that nothing would encumber the removal, technician Manuel Bejar wiggled the transmission back an inch or so, allowing him access to use a prybar to gently pry on the bellhousing in a back and forth motion until the two block-mounted dowel pins were cleared (one on each side of transmission at approximately 3 and 9 o'clock).
Once the transmission was...
Once the transmission was lowered, the torque converter was rotated counter-clockwise to disengage it from the trans-mission input shaft, then it was removed. Before inspecting the torque converter and emptying it to determine if any metallic shavings were evident, Manuel carefully inspected the input shaft of the transmission and the flexplate for chips or stress cracks. Since all of the components, including the fluid residing in the stock converter, looked fresh, the Vigilante converter was ready to take center stage.
The Vigilante is more colorful,...
The Vigilante is more colorful, but more importantly, measures in at 9.5 inches in diameter versus the stocker's 300mm diameter (11.8 inches).
Manuel wiped off the input...
Manuel wiped off the input shaft of the transmission and then poured a 1/2-quart of the AMSOIL ATF into the converter. After verifying that the lithium grease pre-applied by Precision Industries was liberally coating the converter hub, the unit was slipped onto the transmission shaft and then rotated clock-wise until it fully engaged (normally three audible clicks, as the converter rotates into position).
The transmission was then...
The transmission was then lifted back up. After ensuring that there were no burs or rust in the back of the crank, the greased nose of the converter was slid into it as the trans was moved forward, firmly engaging the dowel pins with the bellhousing as well. The bellhousing bolts were then reinstalled and torqued evenly to 37 lb-ft. After removing the trans jack, the converter lugs and flexplate bolt-holes were aligned and checked for 1/8- to 1/16-inch clearance between the flexplate and lug surfaces to ensure the converter was properly engaged with the crank and the transmission. The supplied bolts were liberally coated with Red Loctite, installed and torqued evenly to 44 lb-ft. All components previously removed, including the starter, exhaust, driveshaft and electrical connectors, were reinstalled with the exception of the front skid plate.
A Hayden Automotive Rapid-Cool...
A Hayden Automotive Rapid-Cool transmission cooler (PN 679, $119.06) features an advanced plate and fin design and 3/8-inch push-on fittings. It measures 3/4x11-3/8x11 inches and comes with a 3/8-inch hose, and all of the various fittings and installation notes. Although not mandatory, according to Vigilante, a trans-cooler, especially in the warmer regions of the country, will go a long way to ensure that the fluid stays cool.
To install the transmission...
To install the transmission cooler, the shield covering the lower front valance was removed via four push-pin-style GM fasteners. Once it was out, there was just enough access to begin determining where the transmission cooler would be mounted. Since the installation area is so tight, hobbyists may want to consider removing the front bumper cover.
In order to get sufficient...
In order to get sufficient space to mount the cooler, the factory power steering cooler lines were disconnected and the fluid was drained. After determining a mounting location, the supplied 3/8-inch lines were attached and the cooler was mounted against the radiator and retained with four of the push-through style fasteners.
Due to the hot climate of...
Due to the hot climate of Dallas, it was determined that the cooler would be run as a stand-alone instead of augmenting the radiator. To complete the installation, the trans' hard lines going into the radiator were cut using a tubing cutter. The rubber lines attached to the cooler were cut to length and routed to the hard lines. A small section of rubber hose was then used to form a closed loop on the radiator itself to seal it up.
Tie-wraps were utilized to...
Tie-wraps were utilized to keep the cooler lines out of the way before everything was buttoned up. Back at the trans, using a new GM pan gasket, the pan was reinstalled and the bolts torqued. One final check was made under the car. Grease and wax remover took care of any residual transmission fluid on the exhaust and underside.
AMSOIL Universal Synthetic...
AMSOIL Universal Synthetic ATF was sourced (Case-PN ATF01, $110.40 Quart-PN ATFQT $9.30) for this project. In addition to being a fully synthetic ATF that exceeds the GM Dexron III specifications, the fluid will resist thermal and oxidation degradation and ensure a cooler-running transmission. According to Ed Newman of AMSOIL, "with overdrive transmissions like the GM 4L65-E, we typically see significant transmission temperature drops and rate the fluid to 50,000 miles under extreme conditions." So confident were we in the AMSOIL ATF that the power steering cooler was filled with the fluid as well. After the final checks and some break-in miles, it was off to the dragstrip.