Shelby GT500 Project - Part 1 Kenne Bell Install
July 21, 2008 | Installations
by Eric Brooks
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Background
We picked up our White / Blue Stripe GT500 Coupe in April 2007. In factory form, it is a very nice car. Quite possibly the best riding and most comfortable Mustang made. But its performance does not cut it, due to its weight. In factory form, these cars are tanks! The very first modification was a flash tune, which picked the car up a whopping 60 RWHP. In stock form the car managed 407 RWHP (SAE DynoJet). With a tune only, it laid down 470 RWHP. The aftermarket tune (by me) was very conservative, 500 RWHP is attaintable with the stock pulley / blower combo. With nothing more than 275/40/17 Mickey Thompson drag radials, I managed a 12.33 @ 114 MPH. Impressive for a stock car, but still not quite, due to the weight and horrible 60 foot times.
Preface
When we decided that we wanted more power out of our GT500, the call to Kenne Bell was a no brainer. Kenne Bell has been a leader in positive displacement twin screw superchargers for years, but it was not until the factory supercharged 2003 Mustang Cobra was released that Kenne Bell got the recognition they deserve. Before the 03 Cobra, centrifugal blowers ruled the Mustang aftermarket. The 2003 Cobra, with its factory intercooler setup was perfect candidate for a twin screw. After the Kenne Bell 2.2L blowers were released, hundreds of Cobras were sporting over 600 rear wheel horsepower on pump gas, many of which were dipping into the high 10s in the quarter mile, with nothing more than sticky tires. The GT500, with its larger displacement, and better flowing cylinder heads is also a great candidate for a Kenne Bell.
With the release of the GT500, Kenne Bell also released a new, larger more efficient blower – the 2.8 Liter H series blower, with a new Mammoth inlet. This new setup had already laid down 700 rear wheel horsepower on pump gas, and 800 with race gas on Kenne Bell’s DynoJet dyno.
Kenne Bell 2.8H Stage 3
A week after ordering our blower, it had arrived. As with their previous kits, this one was no different. The parts included with the kit were of the highest quality. The kit includes the 2.8H Blower, a huge twin 77mm throttle body, a dual Boost A Pump specifically designed for the GT500’s twin pumps, an assortment of pulleys, a new intake system, Diablosport MAFia, and miscellaneous hardware for the install (bolts, hoses, etc). I must note, the instruction manual included with the GT500 blower is by far the best instruction manual I have seen of any blower kit, including previous KB kits.
The Installation
With all of our new parts unpacked and sorted, we begin the installation.
We start by disconnecting the negative battery terminal. The KB instructions suggest cutting the hood next, but we opted to do this last.
Next we remove the 4 13mm nuts that hold the strut tower brace in place. Since the brace will not be reinstalled (does not fit), store it away. Reinstall the 3 nuts and torque them to 26 ft. lbs.
Disconnect the MAF connector by pulling the red locking tab, and then pull the connector loose.
Here we remove the breather connection from the driver side cam cover. Remove it by pushing the green tab back to unlock the connection, and then it just slides off.
Using a nut driver or 5/16” socket, remove the clamp that holds the factory intake tube to the throttle body.
Remove the vacuum line from the side of the intake tube.
Release the filter box clamps on both sides, and then the entire intake assembly can be removed and stored away. None of it is reused on the Stage 3 kit.
With the intake tubing removed, we can move on to the throttle body and supercharger elbow.
To remove the TPS sensor connector, slide the red locking tab back then depress the lock that was under the red tab and the connector can be removed.
The Throttle Actuator Control connector is just like the MAF connector, pull the red tab back, and squeeze the lock to remove it.
The throttle body has 4 8mm bolts that have to be removed. Once the bolts are out, store them and the throttle body away, as they are not reused.
In this picture you can see the amount of oil that has already started collecting on the inside of the supercharger inlet. This is a common problem on supercharged cars, even factory supercharged.
Before removing the supercharger inlet, the brake boost hose and EVAP hose must be removed. Here you can see the removal of the EVAP hose by depressing the white retainer. The hose then easily pulls off.
The brake booster connection is removed the same way, although it’s a bit tougher to get to.
After removing the 4 8mm bolts from the supercharger inlet, it is easily removed. Store the bolts and inlet away, they are not reused.
The vacuum line on the top of the supercharger bypass is removed.
The vacuum line that connects to the bypass valve is attached to the hose barb seen here. Disconnect it from the barb as shown.
This large rubber 90 degree hose with 3 small vacuum lines coming out of it must be disconnected.
In the upper left hand corner of this image, you can see we have disconnected the EGR connector as well has the double 90 degree rubber elbow. Here we are disconnecting the PCV hose from the passenger side of the blower. The connector is just like the one on the driver side.
Disconnect the other end of the PCV hose from passenger side cam cover.
Here is the supercharger bypass vacuum line. Set it aside for later.
Disconnect the Fuel Rail Pressure Sensor (FRPS) connector by pushing down the locking tab and sliding it off.
Next remove the vacuum line from the FRP sensor by pulling on it.
To remove the fuel injector connectors, push down the tab, and the connector slides off easily. Do this for all 8 injectors.
Next we remove the connector from the Downstream Air Temperature sensor (Not Shown), and then we disconnect the fuel line from the fuel rails. This has got to be the easiest fuel line disconnect ever, as it requires absolutely no tools. I’ve placed a shop towel under the fuel line to catch any fuel that may drip out.
Next remove the 4 8mm bolts from that hold the fuel rail to the lower intake. There are two on each side of the blower. Keep these bolts, they will be reused.
After a bit of rocking back and forth, the rails and injectors are easily removed. Place the rails/injectors on a clean workbench. The fuel line that connects the rails will be modified later in the install.
Remove the two 8mm bolts that hold the coolant tank to the radiator so that you can access the inner belt tensioner. There is enough room to sit the coolant tank to the side while you do this.
Use a 3/8” break bar to release the tension on the belt so that you can remove the belt from the supercharger.
Next in line is to remove the EGR tube. If you have a 1 1/16” open end wrench, it would be a plus, I used an adjustable wrench which fit it perfectly (opened to the max).
There are two 10mm bolts that attach the EGR valve to the backside of the blower. Remove them, and set the EGR valve and gasket to the side for reinstallation on the Kenne Bell blower.
This next step is a bit of a pain to get to. Use a pair of needle nose pliers to squeeze the clamp and push this hose off the barb. Not a lot of room to work here.
Woohoo, its getting exciting now, the blower is almost off. All that is left is removing the ten 13mm bolts that hold the blower to the lower plenum. Hold onto the bolts.
Finally we see some progress. Lift the blower off the lower manifold, and set it to the side.
Here you can see the factory GT500 intercooler. I must add that getting the stock blower off is not nearly as difficult as the 2003 Cobra blower removal.
Here you can see the difference in blower size as well as the inlet itself.
We missed taking a picture of the wire loom retainer removal which is very simple. Here we are removing the two 8mm bolts that hold the shield for this large wiring harness. This harness will be moved slightly to accommodate the larger blower.
Here we have wrapped the harness with a high temperature heat wrap that will protect against 1800 Degrees! Not shown are two zipties to secure the heat wrap (its glued to the harness as well).
Now the reassembly process is under way. These two dowels are glued into place on the lower manifold using KB supplied silicone. Be sure to pay attention to which way you insert these as they are chamfered on the top.
Here you can see a finely machined discharge plate. This comes bolted to the blower. Remove the two M6 hex bit bolts to remove it from the blower.
KB sends an O-ring that fits tightly in the discharge plate. Take your time and work it into the groove. Spraying it with silicone before you install it is not a bad idea. Next, remove the tape from the discharge plate; leave the tape where the bypass goes in place for now (Don’t want to drop any bolts in there).
Here you can see the discharge plate sitting on the lower manifold. It fits snugly, and the chamfered dowels ensure it’s positioned perfectly.
There are a few different sized bolts that are used to mount the discharge plate so double check the manual to make sure you have them in the right place. Snug all the bolts down, but don’t tighten them, they must be torqued. Use a torque wrench to tighten the bolts in a criss-cross pattern. Torque the bolts down to 16 ft. lbs. I called Jim Bell during this step because I was certain this was not tight enough, but it is not a typo. 16 ft. lbs. is correct.
Back to the fuel rails on the workbench… Using a utility knife or a razor like I am using, cut the hose near the barb. Be careful not to cut into the barb.
After working the hose back and forth, it comes off the barb. The factory fuel hose is replaced with a longer piece from KB, because the blower interferes with the stock hose.
The next step is installing the longer hose. It slides over the barb. I expected this to be a tough step, but it is not that bad. Spray the inside of the hose with some silicone and man handle it. Once you have one side done, slide the supplied heat shield (shown) over the fuel hose, and then connect the other rail to the other end of the hose.
*KB has sent a replacement fuel hose out, as there were issues with the original hose supplied with the kit.
Next is a common sense step. Lube the injector O-rings with some of the supplied blower oil. This should always be done when installing injectors in ANY application.
Put the rails and injectors back in place, within the lower manifold, and reinstall the four factory 8mm bolts to secure the rails. Torque them to 53 in. lbs.
Go ahead and plug in each injector connector. Make sure the connection is snug and you hear a click.
You can’t tell much by this picture, but I am inserting a supplied vacuum hose in the same heat shield that covers the fuel line. This line will send boost to the Boost- A-Pump switch. This hose should be routed along the firewall and behind the driver side shock tower.
Next we lube up the O-ring that was installed in the discharge plate earlier, put a little oil around the bottom of the blower too. Use the supplied blower oil. Go ahead and zip tie the fuel line down by the rails as shown. This makes it easier when bolting the blower back on. You can also go ahead and plug the ACT sensor back up as well.
Now its time to drop the blower in place. Sit the blower down towards the front of the discharge plate, because the two slip together. Once the blower is sitting flat on the discharge plate, slide it toward the rear of the car.
Once the blower is in place, you can snug down each bolt but do not tighten. Using a torque wrench, tighten each bolt to 16 ft. lbs. Start in the center, and criss-cross working your way to the edges.
Now that all the blower bolts are tightened to spec, the large hose should be reattached to the back of the blower. Then the EGR valve is reattached using the factory bolts. The bolts should be tightened to 19 ft. lbs. and the nut should be tightened to 29 ft. lbs. We missed getting pictures of these steps because there was not enough room to take a good picture of it.
Kenne Bell sends the bypass valve unassembled. After you put it all together, this is what it should look like installed on the car.
Once the bypass is installed, some of the vacuum lines are modified before reinstallation. You can also go ahead and start plugging stuff back in. All that is left is reinstalling the throttle body, inlet, MAF and DiablosportMAFia. These steps are different depending on what you go back with, as Kenne Bell sells the kit in 3 stages. We are installing a Stage 3 kit, that includes a much larger throttle body, inlet, MAF housing, and air filter assembly.
Shown here is the massive size difference of the stock throttle body vs the Kenne Bell Mammoth!
Here you can see the huge throttle body mounted to the inlet.
Probably the most gut wrenching part of the install is cutting the hood. For this, I enlisted my home boy Pete Taylor, a life long friend to do the deed. He worked for my family’s collision repair shop for at least 20 years. With a die grinder in hand, a small section of the hood’s inner support is removed to clear the blower.
Here is the finished product. The intake ducting is borrowed from a Ford GT.
Once the install was finished and the BAP (Boost a Pump) was wired up, we connected the Kenne Bell supplied SCT XCalibrator and loaded in their street tune. After loading the tune in, we fired up the car to check for any vacuum or fuel leaks. No leaks were found so we took her for a spin. WHOA, the KB really wakes these heavy sleds up BIG TIME. There is no traction to be found in 1st, 2nd, or 3rd gears. The car does not feel really stable during acceleration and 80 MPH+. The rear end sways, we will address this later.
About a week after the install, it was dyno time. After making a few test pulls to check air/fuel, everything looked good, we laid down 675 RWHP, SAE DynoJet corrected numbers. All runs were made at South Georgia Corvette with yours truly working the dyno. The 3″ upper pulley made 15 psi boost throughout the run. Just before redline it touched 17 psi.
This graph shows the power increase over stock (tune only). The only change from run 3 to run 7 was the addition of the Kenne Bell Stage 3 supercharger kit. Overall, I am very impressed by the fit and finish of the Kenne Bell kit, the supplied tune, and the power increase. Now, that we are making 200 more RWHP over a stock + tuned GT500, we have got to set the car up to use this power. Keep any eye open for more upcoming articles on our Shelby GT500 Project.
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