Uprated Wing Mounted Inter-cooler
Cold air is the like the Holy Grail to a turbocharged engine. The colder the air entering, the better the performance. The way to achieve this is to 'charge cool' the air using an inter cooler. Unfortunately, the S14/a is not blessed with a particularly large inter-cooler and, to this end, a popular modification is to fit a Front Mounted Inter-cooler in front of the radiator. This is a very expensive option and requires some bodywork cutting. The battery also needs to be either relocated or replaced by a half size item.
It is a purely personal thing, but I preferred to spend my money elsewhere. [Addendum: with the introduction of cheaper non-brand front-mounted inter-coolers (some with can be fitted without cutting bodywork), they are a much more sensible and efficient option. I, in fact, fitted one to my S15.]
A much cheaper option is to fit an uprated Wing Mounted Inter-cooler. You can either purchase these new (although these are also quite expensive) or, as I did, asked a friend in Australia to keep his eyes open for a second hand WMIC from an S15. Luckily, fitting FMICs in Oz is quite common due to the climate, and Rhys quickly managed to find me a near mint condition cooler with all its pipework! The S15 WMIC (and pipework) is a straight replacement for the S14/a item, so fitting is relatively simple. It is also 33% bigger which, although not anywhere near FMIC standards, is a significant increase.
You will need 8 and 10mm sockets, pliers and a flat head screwdriver may be required to tease off rubber hoses.
First thing to do is to remove the air box. Unclip the box, loosen the jubilee clip on the AFM (the bulky bit in the hose connected to the air box) and remove the top section and filter. Remove the two retaining nuts and bolt and lift the bottom section of the air box clear. If you have an induction filter, remove the mounting bracket and remove the filter from the AFM. Remove the filter air scoop.
Next, undo all jubilee clip and grips from the inter-cooler to plenum and turbo to inter-cooler pipes and hoses and remove them. Figure 1 shows these pipes and hoses arrowed.
Figure 2 shows the pipes removed.
In Figure 3, the inter-cooler out-take is labelled 1 and the intake 2.
I swapped all of the pipes and hoses when I fitted mine. If just changing the WMIC, you obviously can skip the removal of these and simply loosen the two hoses connected to the cooler.
With the pipes and hoses removed, we can now move under the car.
Ensure the rear wheels are wedged, jack up the passenger side (RHD) and remove the wheel. Remove the screw clips shown in Figure 4 plus the two underneath and gently lift out the ventilated section of the arch liner.
Undo all the bolts arrowed in Figure 5 and carefully work the inter-cooler free.
Figure 6 shows the empty space left!
The S14 inter-cooler has an air scoop attached (Figure 7) which needs transferring. Do this after the replacement cooler is in place. Note that the S14a does not have this scoop.
Figure 8 shows the difference in thickness on the two inter-coolers.
Fitting the replacement cooler is simple so long as you haven't bolted the air scoop on. Once in place, replace all the mounting bolts. Figure 9 show the new unit in place.
Figure 10 shows a front view.
The hoses and pipes can fixed on now. If only replacing the WMIC, reattach the intake and out-take hoses shown in Figure 11.
You must ensure that the pipes and hoses and pushed together fully. When tightening the jubilee clips, DO NOT use a screwdriver. Do it properly and tightly with a socket.
Figure 12 shows the replaced pipework. As I fitted all the S15 pipework, you may notice that the resonator box is missing from the front pipe as it didn't have one.
Re-fit the air box or induction filter and filter air scoop.
Attach the inter-cooler air scoop (S14). You will probably only manage to fit two bolts.
Re-fit the arch liner. It will be tight on the S14. There is more room on the S14a due to its much deeper bumper.
Replace wheel and lower the car. Now enjoy the added cooling!
A number of people have asked me if I've noticed any performance difference since adding the WMIC. The simple answer is no. Come the summer, it may well be different. Without special measuring devices, it is difficult to accurately know the differences. However, 33% is 33% as far as I'm concerned.