Ported Lower Manifold

Last Updated on Saturday, 20 February 2010 22:00 Written by Rob Saturday, 20 February 2010 20:26

In February 2010, we ordered and received a ported and polished lower manifold for the 3.5L motor. Installing it is and can be a challenge, so we're going to walk through it here.

1: First, disconnect and remove your CAI or factory intake. Disconnect every electrical connection, sensor and vacuum hose thats connected to the upper intake manifold. Removing the electrical connections is easy- just pull out the small red tab as far as it will go then press down on the tab to pull the sensor out.

2: The upper intake manifold has a few bolts to remove. There are two bolts on the passenger side that also need to be removed that are on the support bracket.

3: When the bolts are all undone, the upper manifold can be removed. Pull it up and out. On the back of the manifold is the EGR valve- you might be able to pull it straight out from the rear before the upper manifold comes out. Or while you are pulling it out, you might need to use one hand to hold the tube when the manifold comes out. We didn't have a problem with the factory strut brace thats on the car, some may have a problem. If you need to, remove it. Once the EGR tube is disconnected, you'll need to pull up while turning the upper manifold so it clears from the transmission service tube.

The EGR valve is below:

4: Check the gasket on the valve to see if it's still in good shape. This one was, there was no need to replace it. Replace if needed.

5: On top of the head on the passenger side is a foam piece. Gently remove it and don't tear it.The upper manifold sits on this.

COOLANT HOSES:

We need to disconnect the coolant hoses. These are held on by clamps. We used pliers to loosen them. There are three you need to undo. But first, you need to drain coolant. On the bottom of the radiator on the passenger side is a hose that comes out the bottom. This is where the coolant will come out. On the bottom of the radiator is a tab. Turn it counter clockwise one full turn and the coolant will come out of the tube out the bottom of the car. Put something down to collect the coolant. Just drain enough that there's a bit left in the coolant reservoir, you don't need to do the entire system.

There's two coolant lines on the back of the manifold. Remove these FIRST before anything else.

Then you can remove the front coolant hose.

FUEL RAIL:

The next task is the fuel rail. The rail is bolted on with the same bolts that hold the manifold on. Towards the front of the car are two longer bolts. When you put this all back together, make sure these longer bolts are put back in the front. On the rail are the injectors that sit in the heads and squirt the fuel in. The fuel rail is quite easy to pop out. I started at the front of the car and popped it out towards the rear. Each injector has a small seal. Just be careful with these injectors and don't bump them around.

Once all the bolts are out and the fuel rail is loose, the lower manifold can come out. We put it up on the bench upside down.

On the bottom is a coolant tube. This needs to be removed and installed on the new manifold.

CLEANING AND HOUSEKEEPING:

While we had this all apart, I decided to clean up a bit underneath the plenum. This motor only has about 30K and is really clean, so there wasn't much cleaning to do. Also, when the old manifold came off, some coolant spilled into the head and I had some coolant at a valve. Not a big deal though. I took my shop vac and cleaned all around the heads, and inside each valve stem. I also took compressed air and blew out each valve stem and it was all nice and clean.

READY FOR THE NEW MANIFOLD:

After we cleaned the gasket surface on the heads, we were ready for the new gaskets. We bought all of our gaskets from Auto Zone for $21. It included the two manifold gaskets and a new plenum or upper manifold gasket. This was about half of what the dealer charges.

Next we placed the new manifold on the heads. We did this carefully. Look all around the manifold and see to it the gasket is on properly. Check and double check before you put the fuel rail back on and tighten up bolts.

Now you can pop the fuel rail back on.

When you put the upper manifold on, you can replace the old gasket with a new one.

INSTALLATION AND TIPS:

Installation will be reverse of removal. Also, here are some tips. Make sure the radiator valve is closed before you refill. You can re use your old coolant or use new. When you start your car, keep the radiator cap on the reservoir off so any air trapped in the coolant system can escape and keep the system running like it should. When putting the plenum back on, I put the EGR tube in first and seated it, ensuring it was in properly. If you have any EGR problems here, you will throw codes. Double and triple check all your connections. Check your vacuum lines. Make sure things are not crimped and put back exactly how it was removed.Disconnect your negative on your battery and let it sit for a couple of minutes. You'll need to reset your PCM because your computer has a lot of new learning to do. It will need about 300 miles to really learn the new system and fully awake the car.

DIABLO TUNING:

With the added air being used, we found we needed to add fuel to the mix. Using our Diablo, we added 3%, 4% and 5% fuel at each setting in the WOT area. These numbers were suggested to us by Ryan Walsh at AECarbon.

As always, we have all the photos shown above available as a slide show. Just click one.

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