Okay, this is a test we've done time and again, and each time we do it, we're amazed by the results. It's a simple deal, really; we get a K&N air-filter assembly and bolt it on to the vehicle de jour, strap it to a chassis dyno, and ogle the resultant printout reporting a big power gain at the tires. We'll cut to the chase and tell you that bolting K&N's FIPK air-breather assembly in place of the stock piece on a '99 Dakota R/T gave us a net gain of 10 hp at the rear wheels. That's 10 hp and still smog legal in every state, for nothing more than about 20 minutes worth of work.
In with the good is always a fine place to start, but when letting more in, you're wise to open up the exhaust and let more out. To that end, we also installed K&N's free-flowing catalytic converter-back stainless-steel exhaust system. On the surface, we noted only a few extra ponies, some extra torque, and a slight shift in the power curve. While it didn't create extra power on the scale that the air-cleaner assembly did, it's important to notice what we replaced. The Dakota R/T's stock exhaust system is already an improvement over the regular Dakota's exhaust. Featuring twin head pipes feeding a single high-flow catalytic converter, the back half of the system is comprised of large, mandrel-bent pipes and a DynoMax muffler. From the factory, the Dakota R/T sports exhaust components performance enthusiasts would add in the quest for more power. As a result, though we saw an increase in power, it wasn't as dramatic as it would be with a non-R/T Dakota.
The K&N parts install with a minimum of hassle and mostly with simple hand tools, so the average enthusiast can do it in their own driveway. However, partly because a pro exhaust shop always gets better results than we do when we do it ourselves, and partly because one line in the instructions said to "use a heat source and force" (read "torch"), we elected to take it all to John over at The Muffler and Exhaust Center here in town. He made short work of the installation, and there were no rattles or leaks when he was done.
Dyno Results
Baseline Run w/ K&N OE-type replacement air filter RPMHorsepowerTorque3000N/AN/A3100161.2273.13200167.1274.23300177.8282.93400178.4275.63500184.9277.53600187.5273.53700191.2271.33800194.4268.73900197.9266.54000200.6263.44100200.9257.34200202.6253.34300208.8255.04400207.4247.64500204.9239.24600202.8231.54700197.6220.84800193.4211.64900186.8200.25000182.8192.05100176.8182.15200170.6172.3 K&N Filter Charger Kit RPMHorsepowerTorque3600N/AN/A3700201.3285.73800203.6281.43900203.2273.64000203.1266.74100208.7267.44200209.8262.34300214.7262.24400217.6259.74500210.3245.44600209.0238.74700204.7228.74800199.7218.64900197.1211.25000192.5202.25100188.8194.4 K&N catalytic converter-back exhaust system RPMHorsepowerTorque3500N/AN/A3600198.6289.73700203.7289.23800204.0282.03900203.6274.24000203.8267.74100208.5267.14200205.6257.14300209.0255.34400214.9256.54500216.0252.14600208.3237.84700207.4231.84800203.9223.14900198.6212.95000194.6204.45100190.6196.2