Intercooler Upgrade

You will need to retain the S13 pipes. I believe the S15 pipes are considerably different in shape and size, thus unsuitable for an S13. It is unlikely that you will remove the pipes without damaging the gaskets, so ensure you purchase a couple of new gaskets before attempting the upgrade. The correct gasket is Nissan part number 14465-50F00 (you'll need two - one each for intake and outlet). Clean up the gasket surfaces on both pipes and the S15 intercooler in preparation for fitting.

Here I have test fitted the S15 intercooler with the cooling duct installed. This confirmed my suspicion that the duct will sit too low. Looking through the intake in the bumper, the duct appears to now sit 1 to 1.5 cm too low, with only about half the duct intake visible from the the intake.

At this time I also discovered that the bar going under the intercooler and attaching to the mud guard fouls the intercooler slightly. This was easily fixed by loosening the bolt on the chassis end and rotating the bar slightly.

The best solution I could find was to slot the mounting holes for the the duct, moving the duct higher up the slope of the intercooler. Slotting the holes to this extent resulted in the top edge of the duct meeting the extreme top edge of the intercooler body. After test fitting again, I found the duct still sat a little low, but now only by about 2 - 3 mm. I felt that further adjustment was not warranted, as the duct would then not seal on the surface of the intercooler reducing it effectiveness once again.

Now that the duct has been modifed, it is a simple matter of reinstalling the intercooler and reattaching the piping - not forgetting to install the gaskets. Use a good quality gasket goo on both sides of the gasket (I use Permatex Aviation Form-a-gasket). Ensure all bolts are firm (don't forget that this will be under pressure, so it must seal). I found it easier to install the intercooler in place before attaching the piping (even though when I removed it, I removed it all in once piece).

Take the car for a test run after fitting to ensure all is well. With my car, I found everything worked as it did before - no change in boost pressure (I didn't expect any) - and the car ran smoothly with no problems throughout the rev range - success!