Sept 2006. Odometer 273644km. While looking for easy power upgrades for my stock SETA engine, I came across a bunch of noisy debates about cone air filters and heat shields. Many companies seem to claim that a performance air filter can add noticeable horsepower to a car. Here's a testimonial from a Signature Motoring customer: "I had recently added several performance items to my car now and your heat shield with the K&N cone filter proved to be the most bang for the buck I've gotten so far." (see the companion video promising power gains). Just as many mechanics (including mine at eurotech), however, say there's no power gain to be had at all. But everyone agrees that the filter makes a nice noise, and some argue it looks nice. All I'm really interested in is the power, so to find out the definitive answer I ordered a Signature Motoring K&N air filter and heat shield. I *specifically* asked the sales rep if I could expect a power gain. Here's his verbatim reply:
Performance cold-air intake systems are one of the benchmark tried and true performances upgrades the world over. No reputable source holds otherwise. If you are just starting out with your E30, the top power enhancers you can start with are: 1) Cold-air performance intake. 2) Performance chip (in ECU). 3) Performance exhaust (straight from CAT back).
Was the sales guy right or was my mechanic right? Read on.
Project Total: $291.90
No noticeable power increase whatsoever. Zero. Zilch. Maybe for some engines the filter/shield make a difference, but for a 1988 325 e30 (stock SETA), I'd say don't waste your money. It does sound nice though! ;).