RX7 HKS air filters install

 Now that the RX7 was road legal, I had some HKS cold air intakes that had been sitting in the garage waiting to be installed. 

It should be quite an easy job to install but the kit came with som many extra hoses, that I decided to use google to translate the Japanese instructions just in case. 

I don't need to tell you that rotary engines are unique, however one of the quirks is that there is an air pump to suck in fresh air and blow it through a dedicated line to the catalytic converter to help with emissions. 

This air pump is in the engine bay and the HKS kit actually came with a hose line and small filter that had to be drilled and installed on the radiator mounted plastic intake plate that feeds the cold air to the factory stock air box. 

I want to keep the car as original as possible...meaning that no permanent modifications shall be made, only "bolt on" mods. 

Removal of the factory intake box was quite tight as the OEM hose clamps were rock hard over the years. All that you have to do is remove the upper filter cover, remove the factory panel filter and access a couple of bolts on the lower housing to remove free up the box from the chassis. You can then use some vice clamps to remove the entire housing, one hose at a time. 

Once out, install the small suction filter plate on the factory air pump suction hose. (When you start the engine, you will feel a strong suctions here)

Install the piping as per the diagram in the instructions. The two remaining silicone hoses that HKS supple were to allow you to fit the air pump filter in the factory slam panel plastic cover but for my application this was not needed. The second spare hose was for the factory air dump from the turbo back to the filter housing. Again, I kept the factory stock one in location and cable tied it in place. 

The engine now gives a glorious intake whistle and the factory blow off valve now discharges to atmosphere as there is no factory air box. Once the engine starts to spool up boost, from the 1800rpm, the sound is incredible. It also seems to give the exhaust a deeper base tone on idle. All small but subtle differences that add up to the overall enjoyment and experience of the car. 

Cold idle sound

Now its time to map it up......