Here's a write-up on how I did my intercooler install on my base model 99' NB. The install took place over two different time frames. June 08' I mounted the intercooler when building a SC setup that I never finished. Then in December 08' I finished the IC install when I turbo'd the car. I'll do my best to put this in order so that it makes sense.
I didn't take pictures of everything, but I'll try to explain how I did it all. I know several NB owners who wanted a detailed write-up so here it is.
What: I installed an intercooler between the stock condenser and stock radiator.
Why: There were several reasons for doing this.
- Hides the intercooler and all piping for stealth (original motive)
- No pipes running under the car that could affect ground clearance/hang low/be seen
- Stock plastic under tray and front plastic stuff behind front bumper fits with no modification
- Short, simple, easy to access, easy to fabricate, and easy to inspect charge pipes with minimal bends and connections.
- A/C and P/S compatible
- Retains all factory mounting points (no drilling into car to mount anything)
- Took me a combined 14 hours to do this
- Had to cut some sheet metal out of my way in 2 different spots for the IC to fit, and one additional spot for the A/C drier to remain in its stock location.
I will say that it can be done in 8-10 hours from start to finish. It took me longer because I was figuring it out as I went. I wasn't sure of many details when I first started. So I took my time as to make sure everything went as I wanted it. Didn't want to rush and make a mistake.
What you'll need:
1 20x12x3 core IC from ebay
3 2.5" 90* silicone couplers
1 2-2.5" 90* silicone transition (assuming you have a 2" outlet on your turbo)
2 2.5" 90* metal mandrel bends (I used steel as it's strong and easy to weld)
Then go to Lowes and buy some 1" x 1/8" aluminum flat stock. Get a couple 4' sticks as you'll need it. And a stick of 1 1/2" x1/8" aluminum flat stock too to fab new upper radiator mounts. Also while you're there, get a couple bolts that will screw into the intercooler mounting tabs and two rolls of 5/16" weather stripping.
Then go to Autozone and buy 3' of 3/16" vacuum hose.
20x12x3 core IC:
First, take off the front bumper, plastic piece that directs air behind front bumper, both headlights, the radiator, and unbolt the factory P/S cooler and A/C condenser from their original mounts.
Should look like this:
Now that the condenser is unbolted, go ahead and unbolt that big A/C line that goes from it to the compressor. It has a bracket that mounts it for support. I unbolted it because the condenser needed to go forward and never re-bolted as that would require making the mount bigger. 15K miles and so far, no ill effect.
Now the condenser is now hanging by the A/C lines and can easily be persuaded forward. You'll need to move it forward a good bit, and the factory drier will hit the car. For my install, I cut some of the car out of the way. I just pushed the condenser forward till the drier hit, then used a pencil to draw a circle for a relief, and used a 1/4" die grinder w/ carbide bur and a sawzall to cut the metal out.
You should be able to get the condenser forward enough to slip in the IC and then drop in the radiator into its factory lower mounts. In my case, I used 5/16" weather stripping to space/steady/seal the IC to the condenser and radiator. Once you're satisfied with the fitment, you should split some of the vacuum tubing you bought to cover the sharp edges from where you cut for the A/C drier.
Once it fits, I zip tied the IC in place to see how it all fit. I cut/ground the upper mounts off of the IC so that it would slide up higher. In my setup, the bottom is supported with brackets, and the top is supported with two charge pipes, and it's sandwiched between the radiator and condenser. So I wasn't worried about it going anywhere.
Since we moved the condenser forward, it will no longer drop down into the factory mounts. I simply made two new mounts from the aluminum bar stock. This seriously only took 10 minutes tops to do both mounts. We had an old steel file cabinet that we were throwing away, so I just held the bar stock against a corner of it and used a hammer to make the angles I wanted. Also made the top mounts too. They're just short little pieces I bent into a 90* ell. The pictures show where the mounts go. All the condenser mounts I made bolted up to stock mounting points. I believe I bent the factory upper condenser mount forward and reused it on the passenger's side.
**See pictures below for much better pics of actual mounts**
Then do the same thing to bolt the IC into place. Remember to use some 5/16 weather stripping to keep the heat exchangers from touching one another. Again, I forget where the mounts bolt to on the car, but there are bolts there for them.
In my case I could have reused the factory upper radiator mounts. However, I didn't want to put the heat exchangers in a bind. So I made a new pair of upper mounts to space the radiator forward a bit more. I think they moved it back an inch or so, but it wasn't a lot. Just enough to take everything out of a bind. I also drilled a hole and then used a small file to make a little square for the factory plastic hood prop to snap into. NOTE: don't put the hole in the same location relative to the old mount. It needs to move forward too or the hood prop will interfere with the radiator cap. I gotta redo mine one day.
Now you need to cut out for where the charge pipes will come out. I used a pencil to mark around the sheet metal where the pipe would need to come out. Give yourself some clearance as the silicone coupler's OD is more like 3"+, and it too will need some wiggle room when the engine torques. This took me 30 minutes to cut out for both sides using a die grinder with a 1/2" carbide bur and a sawzall. Just take your time and make it look good. I would cut, then test fit, mark any tight spots, and cut again. Finally got it so I had 1/4" clearance everywhere when the IC was mounted and silicon coupler installed. Then I split some vacuum tubing and installed it where I cut to protect my silicone couplers from being cut if they every touched.
Lastly, get out the 5/16 weather stripping and apply it to the condenser and IC to seal the heat exchangers up. This does a couple things. One, it ensures that any air that travels into the condenser will have to go through the IC and radiator, not around them. Also the 5/16" spaces the heat exchangers a bit so that air can smoothly transition from one exchanger to the next.
Now, you just need to fab up your IC pipes. Thankfully, this is pretty easy. First, take a 90* bend out of the box. There's the passengers side pipe. I cut like 3" off each end on mine. Keep one of these 3" pieces as you'll need it for the other pipe.
The driver's side pipe is a bitch in comparison to the passenger's side. Take a 90* bend and cut it in half so that you have two 45* bends. Now butt the two cut ends together and rotate to make an "S" bend. Weld them together. You'll need to leave ~1.5" of straight pipe sticking off of one end and you'll need to weld a short piece to the other end so that it will reach your silicone coupler on the turbo. This is why you keep a straight piece.
If you used mild steel tubing, now would be a good time to paint them. I ground my welds down and then used wrinkle finish paint on my charge pipes. NOTE: don't paint in the dark… Yeah, mine didn't turn out too well. I'll redo them eventually. But for now, at least they're black and protected.
So, how's it working? So far I get 2-5*F higher than ambient temps during cruise and it climbs up 30-40*F if you sit at idle for 5 minutes. But they quickly drop to 10*F above ambient as soon as you start rolling again or the cooling fans come on.
I have only logged 2nd and 3rd gear pulls. I've been seeing a 1-4*F increase in AIT's over normal when I boost. I ran 8 PSI, 12, 14, and now I'm at 11 PSI.