i am currently using K&N air filter.
i wondered around and saw some notes mentioning about a complete Cold air install may
1. increase HP
2. increase gas milage
3. air filter lasts longer
does anyone know if any of those claim is true?

since the gas is still pricy, is there any other mod can increase gas milage on gen2 gs400?

thanks,

 

My DIY cold air intake system gave a consistent 0.5mph in the 1/4 mile which is about 5rwhp.

The other claims are less likely especially the filter lasting longer.

 

The stock intake system is already kind of a "cold air" compared to most cars out there. It has a snorkel that pulls air from the front of the car. As for increasing HP. Yes it probably will increase a little bit on the top end, but at the expense of losing some of your low end torque. The filter lasts the same amount of time as the stock one. The only difference is that the filter in those cold air intake systems are usually washable and reusable while the stock one is not. I guess if you keep cleaning it then you can use it forever. As for increasing mileage....i dont know about your car but my intake killed my gas mileage so I took it off (I had an AEM).

 

I agree. The stock intake on the GS4 is well designed, and not as restrictive as other factory intakes. If you examine it closely, there are not a lot of twists and turns, the culprit of restriction. With the k&n drop in, you can hear the air being sucked in at idle compared to the stock intake. Also, when you have a clean k&n drop in, you here a slight hissing sound when you floor it, much quieter than a cold air intake. The aftermarket intakes are not true cold air intakes unless you fabricate a cold air box, otherwise you are just sucking in hot air which decreases horsepower . The stock one is pulling in cold air from the outside via the duct. Love the stock intake