This project started out as most do with a collection of parts acquired over a period of time and the drive to upgrade. My set up previously was a bottom mount Thunderbird Supercoupe Intercooler modeled after Dimitri’s early 2.3T scorpio set up. After data logging with the Megasquirt I thought that this configuration was hurting my performance due to lack of airflow through the core. I’m finally pulling all the pieces together and hopefully this will help or at least answer a few questions about the installation of a sierra cosworth 4x4 intercooler into an XR4Ti. I’ve tried to include a bunch of picures here to make it a bit easier to duplicate if anyone wants to. There are some additional pictures here as well : http://s8.photobucket.com/albums/a41/jk ... tercooler/
I’ll preface this by saying that some of my goals for the project are as follows:
Use as many stock mounting points as possible
Provide the shortest intercooler piping possible
Don’t hack up the 4x4 intercooler
Use a Saab 900 radiator and fans
Minimize coolant and intercooler connections to make a more reliable install
I have also removed the AC condenser from the car but I’ve tried to leave as much room up front as possible. I do intend someday to replace the AC in the car by using a shorter condenser that doesn’t interfere with the IC airflow. I think that there will be enough room to accomplish this as you will see from the pictures later on.
There are a few pictures of a comparison between the 2WD cossie intercooler and the 4x4 unit over on Merkur Tech posted by Erik Cotos.
http://www.merkurtech.com/merkurtech/pi ... ler001.jpg
http://www.merkurtech.com/merkurtech/pi ... ler002.jpg
http://www.merkurtech.com/merkurtech/pi ... ler003.jpg
Take a look first at those and you can see that there is a fairly large difference in the thickness of the 2 cores. There is also a slightly different bypass valve outlet on the 4x4 unit. The 4x4 unit has a straight connection for the BPV as opposed to the 90 Deg connection on the 2WD unit.
The 2WD Intercooler can be made to fit in the xr in the stock mounting configuration but the 4x4 unit is a different story. As you can see from the first few pictures, if mounted in the stock orientation the outlet pipe comes very close to the Power Steering pulley and the intercooler core ends up about 3/8” away from the water pump pulley. The BPV connection is also not in the best orientation.
After seeing this I considering ditching the 4x4 core all together, hacking off the top mounting points on the core, and modifying the radiator support. I also considered mounting the core below the radiator as well. These options were not feasible or didn’t fit with the project goals. What I finally decided on was to invert the mounting of the intercooler core. This resulted in a pretty clean install from my perspective and only required a few extra fabrication steps.
After mocking up the core and radiator and checking for clearance it was on to making the mounting brackets and the intercooler piping. The top mounting brackets are made from basic aluminum angle with 1.5” legs and 1/8 “ thick.
These attach to the bottom of the radiator support through stock mounting holes and are sandwiched in place with ¼” hardware and a 1” square aluminum plate positioned inside the radiator support. Connecting the brackets to the 4x4 intercooler is done with rubber isolators from Mcmaster Carr and have a P/N of : 9217K35 . These have the proper metric studs and will screw directly into the intercooler, these can probably be used with the 2WD intercooler also but I’m not sure on that.
Since the upper mounts for the intercooler are now flexible compared to the hard mounting in the stock 4x4 you need to solid mount the radiator to the intercooler or else you will end up with an extra pivot point in the assembly which will screw things up.
The stock Saab fans were used but were actually flipped upside down from their original orientation. The curious thing here is that when you flip the fans there is actually mounting holes in the radiator at these locations. I removed the stock wiring from the fans and soldered on new 12 AWG wire to a Merkur fan plug I removed from a junk fan I had lying around. The fans each pull about ½ the current that the stock fan does so I opted to just wire them in parallel to both activate at the same time. At this time I’m not using the saab fan switch in the radiator but I may decide to at a later date.
The radiator to intercooler mount is probably the one area I might change if I had to do things over but I’m willing to deal with what I have at this point. The channel is made of 2 aluminum angles with 1” legs and are each 1/16” thick. The two angles are riveted together and mount around the top of the saab radiator and are held in place with #8 stainless hardware.
I actually opted to Tap the upper lip of the radiator instead of using self tapping screws. Two notches were also removed from the backside of the channel to allow the saab fans to mount directly to the radiator. Before installation of this piece you need to cut off the top 2 stock mounting brackets from the saab radiator. The way this piece mounts to the Intercooler it requires you to bolt the Channel to the Intercooler and then bolt the channel and intercooler to the radiator. I’ve used some delrin spacers to go between the channel and intercooler as well as some weather striping to make up the ~1/2” gap between the two pieces. This should provide a good thermal separation between the radiator and intercooler and keep the air from bypassing through the middle of the assembly.
The lower Radiator Cradle is made from 1” box aluminum. Aluminum 1 ½” angle is used for the top attachment points.
All these items were torch brazed together. This is probably the most complicated piece of the assembly. The top mounts on the cradle attach solid to the original radiator mounting points with shorter hardware. The bottom of the saab radiator has 2 pins that allow mounting in the original application. Two rubber mounts were installed in the box tubing and these bottom radiator pins fit into the rubber isolators. I looked for quite a bit of time for a good isolator to use here and actually bought 1 from Mcmaster Carr that I didn’t end up using. These are actually pieces cut from an auto tire valve stem. The top of the stem was cut off and the remaining metal was removed from the stem with a razor knife. The part that’s left is the perfect height and has a good lip to retain it in the box tubing with the properly sized mounting hole.
For Radiator upper/lower hose connections you simply use the stock hoses and they work with no mods at all. For the lower coolant jug hose I made up an adapter to put in place of the stock saab radiator drain this has a ½” brass connection on one side and the straight thread on the other side.
The straight thread portion I got from a brass transmission adapter I had lying around. I used a molded ½” heater hose elbow and a 1/2-5/8” adapter to go to the 85-87 style lower coolant jug connection. Alternately here you could use a different fitting with a drain incorporated.
For the upper radiator vent to coolant jug hose I made up a steel line from 3/8 tubing to route along the radiator support.
Two small brackets attach the steel line to the radiator support at the stock upper radiator mount locations. I used stainless self taping screws which thread into plastic inserts like you would use for a license plate mount. They fit perfectly into the stock holes. There is a slight bend in the middle of the steel line to accommodate a bracket which I will go into later. I preferred this method over a long rubber hose to hopefully increase reliability. At the radiator vent I used a molded hose to go from the steel line to the radiator(this is actually an XR cut down coolant jug vent hose).
When all mounted in the car this set up puts the bottom of the radiator an inch or so below the bumper cover. I wasn’t real concerned here due to the higher rate springs I have installed. I did want to keep the radiator hidden behind the bumper cover though. What I did here was to remove the stock plastic bumper cover supports and install some longer aluminum ones.
This pushed the bumper cover down enough to hide the radiator fully. Along with the aluminum extensions a couple pieces of angle were added so that the force was spread over a larger area and didn’t make the bumper cover bulge in one spot. A single hole was drilled in the plastic rib inside the bumper cover and the angle aluminum and aluminum extension are through bolted to the plastic rib. You can just see in these pictures where the stock plastic extension used to reside, the hole is just forward of the aluminum extension.
The intercooler piping is 2.5” steel tubing which was partially reused from my previous install.
The silicone elbows are 2.5 inch as well although the inlet and outlet on the cossie intercooler are just slightly smaller, probably around 2 3/8”. The silicone was bought from siliconeintakes.com and are of good quality. The elbows clamp down ok with good band clamps. The clamps here are constant torque type units bought from napa autoparts P/N: BK 7051509. These units are a little better than the standard tbolt style because they provide a better clamp force as the hose heats and becomes softer. The elbow at the intercooler outlet needed some trimming to shorten the leg that attaches to the core. A support was added to the outlet pipe to prevent the pipe from pushing back under boost toward the belts or power steering pulley. The support was made from ¼” rod with a 90 deg bend and then threaded after the 90. This support attaches through the bracket attached to the upper radiator support with a rubber isolator shown here. It’s a bit tough to see in the pictures but there is at least ¾” of clearance between the belts/pulleys and the intercooler pipe.
With the BPV connection now facing down on the drivers side there is enough clearance to mount my forge BPV directly to the intercooler. I may add in a crossover hose to bring this back to the air cleaner but for now with the megasquirt this is a nonissue.
The full assembly installs into the car from the bottom. Here are pics of the assembly before install.
Over the next couple weeks I’ll be finishing up the project but I thought this would be a good time to post what I have since John V has a fresh supply of cores at his doorstep.
