How-To : Dual-Pass Intercooler Endplate
Here is a list of instructions for installing a Dual-pass Intercooler Endplate. It is highly recommended that you read all instructions before beginning this project. If there is anything you are unclear of, please ask a question. If you still do not understand it, maybe this is not something you should do, as it requires at least some general knowledge of automotive work.
Again, I am NOT responsible for what YOU do to YOUR car.
That being said, here are the following parts you will need :
Dual-pass intercooler endplate (GM Part #88958721 - or there are aftermarket companies that also make these cheaper)
Plenty of extra 3/4" heater hose
Assortment of 3/4" heater hose fittings to include "T" fittings and elbows
Highly recommended :
Option B kit (Crate Engine Depot - Option B Kit - also available in aftermarket locations)
1. Park the car on ramps or jackstands, disconnect the battery.
2. Open hood. Remove the Fuel Rail Cover. Remove the supercharger belt, and begin disconnecting the electrical lines and vacuum hoses that are attached to the supercharger. Disconnect the air intake from the throttle body. The throttle body does not need to be removed from the supercharger (if you know how to unhook it from the wiring harness), however, this would be an opportune time to clean the throttle body.
Disconnecting the Air Intake
3. Double check that you removed all electrical/vacuum lines, and begin to unbolt the supercharger. There are 4 bolts that hold it down. After removing these bolts, you can remove the supercharger. Keep in mind that there are 2 alignment "locater" tabs that sit in the upper left, and lower right holes on the intake manifold to keep the supercharger in place when bolting it down. These tabs can easily come out when removing the supercharger and fall in to the intake manifold opening. Try to make sure this does not happen, as these can be extremely hard to get back out. The best thing to do is remove the tabs and set them aside while you have the intake manifold out.
Unbolting the supercharger
Removing the supercharger
Supercharger removed. Notice the 2 alignment tabs in the upper left/lower right holes
4. Next up is to remove the intake manifold. Begin by removing the MAP sensor and the vacuum hose, and then draining the intercooler system by removing a hose from either side of the stock heat exchanger. Remove the stock filler neck assembly, and the hoses from the stock endplate. Begin removing the bolts to the intake manifold in the correct sequence, starting from the outside and working your way in. There should still be 2 studs that have not been removed yet. Leave these in here for now as you unbolt the hidden 8th bolt.
5. Depending on how agile you are, you may need to remove the alternator to get to the hidden 8th bolt. I've included a picture with the intake manifold already removed to show its location.
6. At this point, (hopefully you have a friend to give you a hand) hold on to the intake manifold and remove the remaining 2 studs. The intake manifold is ready to be removed. Keep in mind that the intake manifold gasket will probably fall as you remove the intake manifold.
Intake manifold removed (note* I left the studs in. Also note that the radiator hose does not have to be removed as is shown in the picture)
7. Set the intake manifold on its side with the endplate on the top. Begin removing the stock endplate by removing the 7 bolts. Remove the endplate.
Stock endplate
8. The intake manifold has 4 "Laminova Cores" which are directional. These need to be re-routed to take advantage of the dual-pass endplate. Very carefully remove the lower 2 cores and switch their location. Make sure to press them in to "lock" their position.
Laminova Core
Locking them in place
9. Assemble the dual-pass endplate if it is not already put together. If it does not come with a new gasket, you may reuse the old one, by carefully lining it up on the intake manifold. Also, make sure there is a green O-ring gasket on the top end of the endplate. If there is not, reuse the old one. Bolt up the dual-pass endplate, torquing the bolts to 89 in/lbs.
10. Now you can replace the intake manifold. Begin by having a friend hold up the intake manifold while you replace the studs (make sure the intake manifold gasket is present!). Leaving it supported by the studs, replace the 8th bolt. Then, starting at the center and working your way out, begin tightening the bolts/nuts to 89in/lbs. Reconnect the MAP sensor and vacuum line.
Intake manifold being installed with dual-pass endplate
11. (note* I have not installed the supercharger yet, as to leave some extra elbow room while routing the hoses) If you are leaving the stock intercooler hoses mostly in place (Option A), then route your hoses following the stock layout, with the addition of the dual-pass endplate's extra nipple. The middle nipple is now your "in". Use a combination of "T" fittings and 90* elbows to complete the system. If you are going with Option B, proceed to step 12.
12a. The Option B kit comes with an additional surge tank, and a bleeder line to help extract air from the intercooler system. Find a good, solid way to mount the tank, making sure it is the highest point in the system. Run your hoses according to the following diagram (note that there is an additional heat exchanger in the diagram)
12b. There should be a 1/4" air bleed line in the kit. To install this, place the small orifice in the end of the line. Look at the top of the stock heat exchanger, to a small screwed on fitting. Using the fittings in the kit, connect the 1/4" line to the hole on the stock heat exchanger. Connect the other end of the line to the surge tank.
13. After all your hoses have been routed, make sure to double check that they are routed correctly. Tighten down all hose clamps. Reinstall the supercharger, throttle body and air intake assembly. Reconnect all vacuum hoses and electrical harnesses. Plug in your battery, and start the car.
14. The last thing to do is to make sure your intercooler pump is working, as these commonly go bad. If this is not working, hit it with a hammer as a temporary fix, but replace it soon. Congratulations, you are done!
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Originally Posted by rallyracer
