The most basic of basic upgrades, in our opinion, is an intake. So cheap that you can't afford not to do it, and easily one of the best upgrades you can do. But do they really make power? Does a simple pipe and cone filter make more power than an OEM engineered intake system? It's an argument we hear way too often and wanted to know for ourselves.
Our guinea pigger, is Jonny's 1991 Civic fitted with a 1992 B16A SiR engine. This motor is nearly all stock with original internals and an untouched factory USDM P30 ECU. The only things it has are a DC Sports header and Mugen muffler. In it's completely stock form, it's rated at 170hp to the crank, so we weren't really expecting much at the dyno.
At the time of testing, Jonny had a stock EF intake with a 10-year-old filter that looked like it was made out of used tissue paper. We're not like everyone else who will skew test results in order to please our cohorts or ourselves. So instead of leaving that old filter element in there, we dropped in a brand-new filter in order to have the absolute best hp numbers from a drop-in style filter.
With our $37.26 K&N drop-in filter we took the car to SP Engineering, in the City of Industry (AKA the City of Nudie Bars). At the wheels we were able to get 150.0hp and 103.7 lb-ft of torque.
About five minutes later we had the K&N cone air filter kit installed. This unit retails for $167.70 and we wanted to know if the extra bucks could really give anymore bang. In the packaging K&N included instructions that claimed a 4hp increase on a stock engine. We were all thinking that must have been on some miracle dyno, and thought maybe we'd make about half as much power. To our surprise the new intake arm and cone filter pulled 157.4hp and 107.4 lb-ft of torque to the wheels. Not only did it give us 7 more horsepower at the peak, you can tell from the dyno curves that we picked up more horsepower and torque from 5,000rpm all the way to redline.