Installing a Griptec supercharger pulley on a 2020 Shelby GT500
The release of the 2020 Shelby GT500 was one of the most highly anticipated we’ve seen in our 15 years of business. We were all waiting on the edges of our seats waiting on numbers to be released while Ford teased us with puzzle pieces, drawing it out and adding to the excitement. Ford announced the cars would be making 760hp and performance enthusiasts were stoked.
Now that cars are landing in driveways, it was time to see what the numbers really were and, most importantly, starting to mod them. Lund Racing was one of the first to receive their car and wasted no time getting their 2020 Shelby GT500 on the dyno. Bone stock, the car put down 691rwhp & 581rwtq. The numbers held up to Ford’s claim with a less than 11% loss from the crank to the wheels.
What’s the first mod most GT500 owners have done in the past? Yep, a smaller supercharger pulley. Our friends over at Griptec began the engineering process on a new pulley a few months back and we were excited to be the ones to offer it to our customer. We were able to get our hands on a few of the first pulleys sent out, as well as their special installation tool, and get it to both Lund Racing and Palm Beach Dyno for some installations & testing.
While we are a little far away to hop over to Lund Racing for the first installation, we are nearby Palm Beach Dyno & RareFab so we headed over to document the install on one of their customers’ Shelby GT500s. Will from RareFab completed the installation while Ken B. Of Palm Beach Dyno set up the custom tuning.
The 2020 Shelby GT500 presented an interesting task for pulley installation. The GT500 comes equipped with an inverted TVS (it’s upside down), foregoing the traditional ‘snout’ as we’ve seen on previous year GT500s. The shaft is enclosed in a casing below the blower and the pulley is located behind the thermostat housing.
What’s that mean? It means the coolant needs to be fully (or at least partially) drained to remove the left (passenger) side of the thermostat housing and give access to the supercharger pulley. On the first car the pulley was installed on, Will at RareFab decided to drain the coolant completely, which required removal of the front bumper. (This also allowed him to look around and check out the various cooler cores & location of the intercooler pump, etc.)
However, this step is not necessary. On the 2nd 2020 GT500, Will used a small pump to drain the coolant from the thermostat housing & lines only, since that is all that needs to be removed.
Once the coolant is drained and the coolant reservoir and intake are removed, you will need to remove 3 bolts holding the housing together.
NOTE: Will ziptied the passenger side line out of the way for easier accessibility.
After removal of the housing and taking the thermostat out we got to see the 2020 Shelby GT500 thermostat, which is a new dual-hot side thermostat design. Ford tells us this is for higher coolant flow and cooling capacity.
With the thermostat housing out of the way, you now have access to the supercharger pulley. The pulley & shaft assembly is held in place with 4 bolts, which are easily removed. Once the bolts are removed, you will need to use a little bit of force to remove the shaft assembly from the blower housing. It will slide out in 1 piece.
Like all supercharger pulley setups, you will need a special tool to remove & install the pulleys. Fortunately Griptec not only manufactured the pulley & hub but also made a special tool & socket setup which is available to purchase with the pulley.
The retainer on the bottom of the shaft assembly will need to be removed. You will then seat the shaft into the special tool, which locks the shaft in place so that the pulley can be removed. If the tool is not used, you risk damage to the shaft.
Once the shaft is seated in the lockout tool, you will remove the plastic cap cover that is on the stock pulley.
Once removed, use the included socket to unscrew the stock pulley from the shaft.
If your Griptec pulley is still attached to the hub, you will want to separate them at this time.
Place some red Loctite onto the shaft threads & install the Griptec supercharger pulley hub using a 22mm 12point socket. You will want to torque this down to 65 ft/lbs.
Next, use a drop of blue Loctite on the 8 small titanium (yep, TITANIUM) bolts and use them to install the pulley ring onto the hub with a T30 Torx bit. You will want to torque these to 60 inch/lbs.
Congrats, your pulley is now installed onto the shaft and you are ready for reassembly. Be sure to take a moment and check out the awesome technology packed into the Griptec pulley’s belt surface. (Click here to read more about Griptec pulleys)
Before inserting the shaft assembly back into the blower, you will need to do a couple of things. The shaft is sealed onto the blower from Ford using anaerobic sealer. You will want to be sure and scrape all of the remnants off of both the blower housing as well as the shaft. This not only insures a good seal when reinstalling the shaft but also will prevent any misalignment (and then blower damage) from not sealing evenly.
Once the remnants are removed, apply new anaerobic sealant (aka anaerobic gasket maker) around the shaft.
Insert the shaft & pulley assembly back into the blower & use the 4 bolts removed previously to re-attach.
You will then need to install & wrap the serpentine belt (sizes needed are below).
2.850" Pulley - 70.23" K080702HD
2.750" Pulley - 70.23" K080702HD
2.650" Pulley - 69.88" K080700HD
2.500" Pulley - 69.38" K080694HD
Once the belt is in place, you can now replace the thermostat and use the 3 OEM bolts to reattach the thermostat housing. Next, replace the coolant reservoir tank and reinstall the intake. Refill the coolant & you are ready for tuning and running the car with some extra boost.
Once Will finished installing the pulley, it was time to weigh the car. Ford rates the 2020 Shelby GT500 curb weight as 4225. However, when we weighed Steven N.'s GT500 it came in at exactly 4100lbs, with a pretty even weight distribution.
After the install & weigh-in, the car went next door to Palm Beach Dyno to be strapped down on the dyno and get some custom tuning by Ken Bjonnes. The car used for testing was a 2020 Shelby GT500 belonging to Steven N., aka @iconicgt500 on Instagram. With a 2.75” pulley on 93 octane the car made 765rwhp and 618rwtq at 14psi (stock is 12psi). Unfortunately we did not have a stock baseline to compare to, but going off of Lund Racing’s baseline it’s about a 75rwhp gain which is a nice number considering it was only 2psi and the general rule is roughly 20hp/1psi. After, Ken switched the car over to E85 and made over 800rwhp.
Not interested in dyno numbers and prefer to see what it does at the track? Steven took the Iconic Silver GT500 out to Palm Beach International Raceway to test out the combo and ran a 10.17 @ 139mph with a 1.6 60'. Awesome times!!
Lund Racing also did some testing with the Griptec supercharger pulley, installing a 2.65” pulley on their 2020 Shelby GT500 along with a set of our Lethal Performance Race Pipes, Injector Dynamics ID1050x injectors and some E85. Their car made 902rwhp and 711 rwtq, a 211rwhp GAIN.
The Griptec supercharger pulley for the 2020 Shelby GT500 is available in a 2.85”, 2.75”, 2.65” or 2.50” size and can be purchased as a complete kit with the pulley tool & socket needed for installation.
We also offer the pulley as a complete power package with custom tuning from Lund Racing or Palm Beach Dyno, a Gates HD belt, spark plugs, injectors & optional Lethal Performance Race Pipes.
Click here to check out the Lund Racing power package.
Click here to check out the Palm Beach Dyno power package.
Stay tuned for more product features & updates for the 2020 Shelby GT500 here at Lethal Performance (including that Whipple Superchargers 3.8L we’ve been teasing…).