After Tob began his thread about installing the 13-14 Pierburg intercooler pump in an earlier model in this thread, I’ve been slowing working toward making this one of the mods for my 2012. This write-up is a compilation what I did, my findings regarding the factory intercooler system and what we can do to improve it on a budget. As far as I know, everything discussed here with respect to the intercooler system will be the same for 2007 to 2012. Much of it will also apply to the 2013 – 2014 as the intake manifold and intercooler connectors haven’t changed over the life of GT500 program, with the exception of an upgraded intercooler and the Pierburg pump. This will be a long read, but there’s a lot of things I encountered I’ve not read anywhere else. I’m going to ask the mods to lock this write up in the How-To section and start another thread in the forum for comments, questions, etc. Back when I was installing a built 5.8 aluminum block in my car in late 2013, I upgraded my intercooler to the 13-14 unit while the engine was apart. There is not a lot of visual difference between it and my OEM unit, other than it’s supposed to flow more air. Since it does not have a larger surface area, the flow increase is accomplished through a lower fin count which likely decreases cooling surfaces. Note, there are no claims by Ford that it decreases charge temperatures. While taking the manifold apart I was somewhat baffled why Ford plumbed the intercooler for ¾” hoses and then reduced the internal diameter of the crossover tubes between the intercooler and the intake manifold hose adapter to something just over ½” (.55”). Seems to me the smallest internal diameter of tubing in the system will become the biggest restriction to coolant flow and a source for higher pressure within the system. Based on the Ford part number for the tubes, since I ordered new ones to modify, the part number indicated it’s from a model year prior to 2007. With a little more research it was apparent they are a carryover from the 03-04 Terminator which were used for the same purpose. Ford saw fit to use the same tubes in a new supercharged model with a bigger engine and more horsepower. But then Ford didn’t design the system for more than the OEM ratings anyway and initially for only 9 lbs. of boost. Most of the data I’ve seen on these smaller OEM pumps is that they flow as advertised with little or no pressure, but as pressure increases (i.e. smaller connectors, coolant volume, bends, etc.) the pump can’t maintain the same amount of flow and drops off in efficiency as pressure increases. This is a pretty interesting discussion on that topic as it pertains to supercharged Chevys, but it also comes from a highly credible source. Note that two of the pumps in that discussion are the same and similar to the pumps that Ford has used in the GT500. The CTS-V pump is the same Bosch pump you’ll find on the 07-12 models. The ZL1 pump, while not the same as the Peirburg, has very similar flow characteristics from what I can tell. The Peirburg pump is used in other applications and if you look up Pierburg CWA 50, you’ll see it’s the same pump. Here’s the graph of pumps from that discussion. In the Lingenfelter graph, note the impact of higher pressure downstream of the pump. The CWA 50 also appears to do a much better job at encountering pressure and doesn’t drop off in efficiency as the Bosch pump does with as little as 5 psi of pressure. Now, what would you think if I told you that the Pierburg pump in the GT500 is wired to run at less than 50% of its capacity in the 13-14? At that rate it’s likely to come in a lot closer to the Bosch pump in our intercooler system by virtue of increases in pressure, although it has the ability to overcome the effects of pressure (restrictions) in the intercooler system more efficiently than the Bosch pump. More on that later. With knowledge of the small cross over tube diameters in the intake manifold, I set out to determine what the minimal diameter the tubing should be for the crossover tubes based on the design parameters of the intercooler system. In doing so, I found an even larger restriction in another OEM component and in an aftermarket part many of us are using. I started measuring the inside diameter (“i.d.”) of some of the major components that make up the remainder of intercooler system. It stands to reason that to use ¾” i.d. rubber hose, the outside diameter (“o.d.”) of the connector would have to be the same diameter or only slightly oversized. In effect, a component with a ¾” o.d. would have to have a smaller passage for the corresponding i.d. to have sufficient wall thickness to support the component. Even the i.d. of the inlet/outlet on both intercooler pumps are in the range of 5/8” (.625”), as are the inlet and outlet for the heat exchanger. It seemed to me, my objective was to make every i.d. in the system a minimum of 5/8”. So where are these mystery tubes you ask? If you’ve changed out an intercooler, you know already know the answer to that. If you look at the front of the intake manifold, you’ll notice the adapter in the front of the manifold with 5 bolts holding it to the intake. The adapter has an inlet that is connected to the heat exchanger and an outlet that is connected to the degas tank. Many of you have replaced three of these bolts to mount an auxiliary idler for your supercharger. With all bolts removed, the adapter can be removed from the manifold. Here’s an exploded diagram of the intake manifold. Items 28 are the tubes I’m referring to. This is the crossover tube. You have two in the manifold. If you take this on, I would do what you can to make sure as much of the coolant is out of the intercooler before removal of the adapter, because you may end up with a little coolant in the intake manifold. It can be suctioned out from the vacuum tube that connects to the downward facing vacuum line at the back of the supercharger. The other end terminates at the bottom of the intake manifold. Both ends of each tube have an o-ring groove cut into the tube and uses a rubber o-ring to seal off coolant from the intake or air in the intercooler under boost. Removal of the 5 bolts allows access to everything I will discuss below. I would suggest replacing the o-rings, if you attempt to do this. The Ford part no. is N802927-S and you’ll need 4. I’ve since seen posts about better o-rings made of viton material, but I have not experimented with that yet. Here is a another pic of the tubes with the o-rings. You’ll notice the o-rings are no longer rounded which is why I think they should be changed. Let me say this because I’m sure the question will come up, while alternatives exist to go with larger tubes in the manifold by way of boring out the intercooler and using a fabricated manifold adapter, unless you intended to plumb the entire system with a larger pump, hose diameters, and comparable inlets and outlets on all the other components in the intercooler system, I’m not sure what you would accomplish. No doubt it would create better cooling than the smaller diameter stock tubes, but it seems to me you would just move the restriction downstream to the next smallest component in the system unless the whole system is upgraded to similar size. The process of installing larger tubes also requires removal of the supercharger, the intake manifold and the intercooler so it can be sent off and machined for the larger diameter tubes. Unless you’ve taken the intake manifold off your GT500, you truly don’t realize how big a job it is. Even if you were able to open all the passages to 7/8”, I’ve yet to see anyone test just how much flow the intercooler itself is able to handle before it might become the primary restriction. I see upgrading hose diameters, inlets and outlets along with a larger pump as a max effort, and it would ultimately come at a fairly high price tag to do it right. With an ice tank in the trunk, it would no doubt be the ultimate standing mile setup. Here is the OEM tube next to the larger tube. A system sized to match would certainly flow some coolant. I briefly looked into the possibility of having a machine shop drill out or open up the i.d. of the tubes to 5/8”, or mill new ones out of suitable tube stock, but I decided to give it a shot by opening them up myself. Based on measurements of the tubes, it seemed to me that they could be opened up safely to .63” and still have sufficient wall strength. While that’s only removing .040” of wall material to open up the i.d. by .080”, it’s very slow going. I initially attempt to use various flex-hone tools to open up the diameter. That proved to be a bust, as the tubes are likely stainless steel and the metal is extremely hard. I ended up using a combination of the flex-hone tools and a die grinder to open the i.d. to .63”. The o-ring grooves in the tubes are .675”, so opening them up more than that may be risky. While it doesn’t seem like much, going from .55” to .63” opens up the area by 31%. There’s also a notable difference in the weight of the OEM tube and a tube that’s been opened up. Hopefully, it relates to an increase in flow by a similar amount. Increasing the passage size also has more to do with reducing pressure, than increasing flow. Here’s the flex hone tool, I referred to. You just chuck it in your drill and use a bit of oil with it. There are a lot of hours opening the tubes up in the manner I used. Part of the problem is that the tubes get too hot to handle to handle, even with gloves. My solution was to wrap the tube in electrical tape and use pliers to hold them while grinding or honing. After a while the tape adhesion turns to a gooey mess, but it cleans up easy enough. I dropped the tubes into a small container of water before attempting to handle them. Using the flex hone tool between cuts helps keep the bore straight and you can measure your progress using calipers. These pics are not that great, so it’s hard to see the difference. Notice the bevel on the inside which further reduces i.d. in the tubes at the top of the pic. That bevel is essentially gone with the opened up i.d. The next thing I needed to do was open up the diameter and surrounding wall of the manifold adapter where the tubes terminate. This was easily done with a die grinder as well. I used electrical tape on the outer walls to prevent nicking them. A nick with your grinding tool in this area may result in a leak when the system is pressurized. Here is my stock adapter next to a bored out adapter. The new adapter is a little too shiny to see the difference, but these now match the tube diameter and the transition to the sand cast lines were also opened up. What remains unknown is how large the sand casting passages are between these holes in the adapter and the inlet and outlet tubes. Judging by the hole beyond the inlet and outlet, the passage may not be a full 5/8, because material needed have a slightly smaller i.d. to machine and provide support for the inlet and outlet connectors pressed into the adapter. But you can get your flex hone tool in there up to the bend. Extrude honing may be the only way to open these up. I then started measuring the barbs on all of the connectors in the intercooler system. I ended up grinding the tips of the hose barbs on the manifold adapter back about ¼” to get the inner diameter at the tip of the barb to be equal to the i.d. of the body of the individual connectors. At least for the inlet and outlet on the adapter, they had been formed to a smaller inner diameters at the tip (i.e. too pointed) than the straight section of the main body of the coolant fitting. Grinding the tip back will open up the i.d. and remove the restriction. I was again surprised to see how small the inlet and outlet of the plastic 3x degas tank has because of an aluminum insert that necks the i.d. down to .48”. Having read a few complaints about coolant frothing with the 13-14 pump on an otherwise stock 07-12 intercooler system, I have to think that this reduction in the inlet may have a lot to do with that. Since my intent was to run a by-pass hose around the degas tank, I did not do anything about this restriction. I located my original degas tank and it is constructed similarly except the inlet and outlet diameter measured at .45”, which is even smaller. I assume the inserts used in both are to keep the plastic barb from collapsing or breaking over time and under the compression of hose clamps. Unless you incorporate a by-pass around the degas tank, something probably needs to be done with these inserts. If you do nothing at all with the tubes, I’d at least open the inlet and outlet of the degas tank to .55” or thereabouts to match the intercooler tube diameters. That’s a 30% increase in area right there. It’s doubtful that aluminum tanks will have this issue, but I’d measure the tip of the barb to make sure the i.d. is no smaller than it should be. Using a by-pass was my solution and might be the only solution around the inlet/outlet on the degas tank. Since we’re talking about such small diameters, some may assume this is hardly worthwhile. I did a scaled graphic to show what I’m talking about. If you don’t think these smaller diameters create restrictions and resultant higher pressures, this may put it into perspective. Since I have provision for another analog device on my Aeroforce gauges, I decided to add a coolant sending unit downstream of the heat exchanger. I initially got a ¾” gauge adapter, but realized that the sensor for the sending unit creates a big restriction in the line. I ended up getting a larger diameter adapter to remediate the restriction the sensor created and used silicone reducers to go from the 1.25” o.d. for the adapter to the .75” o.d. of the inline connector. I don’t know that I’ve ever heard anyone comment on the correlation between IAT2s and intercooler coolant temperatures. Here are some shots of the adapter. Sticking a pencil sized sending unit in the 5/8” internal passage of the ¾” gauge adapter was sure to become the restriction in the smaller diameter housing.