| Upgrade standard top mount intercooler |
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| Written by malarkeyGT | |
| Monday, 15 August 2005 | |
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How to install an rx7 intercooler in place of the original top mount: Firstly there are a few important points to make: 1. Consider your ultimate goal for the power of your car. Previously, members have got up to 160kw at the flywheel using a top-mount rx7 intercooler. If you want more than this, and are willing to save up and wait to get a good front mount, but don't want to waste $160-200au on something that will be replaced, then this isn't for you. 2. If you have no idea how to undo bolts or saw/bend bits of metal then this probably isn't for you. If you do, it's pretty easy. 3. This will end up costing you about $40au on top of the price of the intercooler, giving you a total of well under $200au. If you would rather use this toward a front mount IC setup, then this isn't for you. Consider though, a front mount using mandrel piping can cost easily over $500, will require a little bit of relocation/modification of front bodywork and you will need help (workshop or otherwise) to do it. 4. If however, you don't have enough money for a decent front mount, but still want to improve the cooling/flow of the standard GT and are not afraid to do a bit of work for yourself, then this is definitely for you! The project: Take a look in dmrvf's folder in the photo section of the gtstarlet yahoo group. This is what the IC looks like when mounted. You will see that the bottom inlet pipe is a new one that has been welded on. I have used a rubber 90deg bend in place of this. Decide whether you want the welded pipe or rubber bend. Ring a welding shop and get a quote, if it's under $15au then get them to do it. The instructions I have written are for the rubber hose bend method, read through the WHOLE document NOW, and take note of where the 2inch 90deg bend is mentioned. These parts will be different if you choose to get a welded pipe. Also take note of the materials/tools used to make the brackets. These are NOT essential, and you may like to complete the brackets at a later date. I have used #### to indicate which tools/materials are optional if you get a welded pipe or decide to leave the brackets for now. To complete this DIY project you will need: Tools Hammer Screwdriver to punch out rivet centres Various screwdrivers, and spanners for nuts and bolts Hacksaw for cutting inlet pipe down to size #### Kraft knife, or other rubber cutting instrument for 90deg bends Heavy pliers for bending/crimping duties Power drill for making brackets #### Vice/G-clamps for making/bending brackets #### Materials S4/5 Rx7 IC Around 1m of strip aluminium in 15mm width x 3mm thick #### 1 x 90degree 2/2.5 inch rubber radiator hose bend #### 1 x 90degree 3 inch rubber radiator hose bend Some stiff cardboard for making dummy brackets #### Some 7mm x 30/40mm bolts with nuts for securing brackets #### Extra hose clamps if old ones too worn Some electrical for odd jobs/sealing pipes Strip foam for sealing off edges of IC from underbonnet air Double sided tape for securing strip foam. Procedure: 1. Ring around your local wreckers/importers to find a series 4 or 5 IC in good condition. This should cost you anywhere from $100au upwards. Mine was $125 in Adelaide, but some other places in Brisbane were quoting over $200!. This description is for a series 4 core, the series 5 may be different. If you haven't seen one before, the cooler is about 30 cm square, has large tapered end tanks and most obviously has a flat silver surround riveted around the edge which has the words 'turbo II' or something similar in red writing written along the bottom part. It will have a short outlet pipe coming off the back of the top right corner, and a long inlet pipe coming off the left side of the bottom end tank. It may also still have another piece riveted to the back which is intended to channel air flow. There are mounting flanges off each side of the core with 2 mounting holes each. The right hand side mounting flange is angled 45deg downwards. When you inspect the IC check the condition of the core. If it only has some fins bent on the surface of the core, is generally without any other damage, and is pretty clean then it's a good find. (Check the photos of dmrvf's intercooler in the photos database to get a good idea of what it looks like when mounted). 2. Once you have your IC you need to prep it for install, firstly you need to remove the silver shroud that surrounds the front face of the intercooler. It is secured with rivets, use a screwdriver + hammer to punch the centres of the rivets out from the front, then pull the shroud off. You may have to use pliers and a lots of wiggling to get it off, but don't worry about messing the rivet holes up, you won't need them afterward. If you have a better method of doing it, do that instead  Repeat the same process with the rear shroud. 3. Hold the IC up to the light and take a look through the core. You will see some bent fins on the surface, we'll talk about these later. Look into the core and see if there is any major build-ups of dirt or bee colonies (found inside my IC) inside. This will give you an idea of how much cleaning you have to do. 4. Your next task is to straighten those bent fins so they don't restrict airflow through the core. Using a narrow, pointy, but not sharp instrument straighten the bent ones back to the same pattern as the others. Be careful doing this, they can rip and make your job even longer than it has to be. When you are doing this, check out how many bent fins are on your GT core. Mine had about 20% bent flat!! No wonder the rx7 cooler flows much better... 5. Get your hose out and give the core a good shower. Spray through the inlet/outlet pipes and get water flowing through the core in the same way the air will. Spray through the core systematically and get as much gunk out as you can. If you find some harder deposits in there, use a piece of small stiff wire (taking care of the fins too) to push them through. If you can't get the core nice and clean this way, you may want to consider using a high pressure sprayer (at self service car wash) or get it chemically dipped by a radiator shop (shouldn't cost you more than around $20au). 6. Once the core is nice and clean, you are ready to do some final preparations so that it will fit nicely. Firstly, decide what you want to do with the long inlet pipe. You will see from the photo's that dmrvf got a pipe welded on off the corner, not a bad idea. Check how much this will cost. If they can do it for under $15 then do it. Alternatively, use a hacksaw to cut the pipe down to around 5cm length. Keep in mind, you will be connecting a rubber tube and hose clamp here, allow enough inlet pipe for this. Secondly: You will have noticed that there are two small diameter pipes coming off the top left end of the IC. These need to be sealed. Cut them down, and crimp + tape them/weld them closed. It is imperative that these do not allow air in as you will lose boost pressure and get unfiltered air into the engine (For future reference, if you hear new loud sucking noises with the cooler installed when the turbo spools up, these are not sealed properly). 7. Attached to the underside of the bonnet there is the original rubber seal for the factory cooler. You will also see a piece of heat matting fixed to the bonnet. Take this of by squeezing the circular clip halves together and pull them out of the holes. Once the heat matting is off, you will need to undo four screws at the leading edge of the scoop to get the rubber thing off. The back half of the rubber is secured with plastic fasteners, use a flat screwdriver to lever these out. They may snap off, but you can get some more cheaply if you need to re-secure it later. 8. Undo the hose clamps, and screws that secure the GT IC in place and take it off. You will notice that the original rear IC hose tapers from 3inch to 2inch diameter. Use the 3 inch 90deg bend in this position. Cut the bend down so that it looks almost like the original, but retains the full 90deg bend so that the IC outlet pipe can fit vertically into it. Take your time and cut the bend down to size gradually by taking it off in slices. You want there still to be the 90deg bend, but want the cooler to sit as low as possible so it doesn't contact the under bonnet surface. A good rule of thumb is that if you retain the 90deg bend and can just fit the outlet pipe in, and clamp it tight, then it will be a good fit. Clamp the IC hose on, the IC should sit on a slightly less the horizontal forward slope, but the left side mounting brackets should be roughly horizontal to the ground (again, refer to dmrvf's photos to get an idea of what I mean). 8. With the IC in a test position you should now see where the other 90deg bend will fit in at the front inlet pipe. Using the same procedure, cut it down to size, and clamp it on. 9. Now the IC should sit square and slightly tilted forward. It will sit there quite happily by itself, but it's good to make up some brackets to keep it locked in place. Use the strip of aluminium for this purpose. Firstly make up some dummy brackets with stiff cardboard, use these to save yourself making mistakes with the aluminium. I put a bracket off the right front IC mounting hole to my right front GT mounting hole, but because of the angle of the IC bracket this is tricky. Despite the trickiness this seems to be where the IC needs the most support. Others have put brackets only off the left side mounting holes. This stage is up to you. 10. With the IC clamped in place, do a final check of all your hose clamps. You now need to seal off the side and rear top edges of the IC from underbonnet heat, and to channel air from the IC. There are 2 ways of doing this, you can secure the foam to the IC itself, or stick it to the underbonnet surface. I ended up using clear silicone sealant to stick some dense foam to the underside of the bonnet to seal off the IC when the bonnet is closed. 11. With everything sealed and tightly clamped, warm up the GT and take it for a spin. You'll notice that the spool up is quicker and power is up also. If everything has gone according to plan, you'll be much happier with the power the little GT puts out |
