Quote:
Originally Posted by Denny_A
......has a K&N Air Intake System also. The claim is that the peak HP is boosted from 245 to 255. I can't confirm that since it was already installed when I bought the truck....but, that truck can giddy-up and go!  |
Those K&N intakes have a really, really bad reputation amongst those of us who know what does and does not really improve Tundra engine performance...especially towing performance. K&N engineers have publically admitted there really wasn't anything they could improve on the Tundra intake system so they just tweaked the torque curve toward more top end horsepower at the expense of less mid range torque. That's great for the street racers but bad news for those who haul or tow with these trucks.
First, they do not "flow" any better than the stock intake filter/air box. The very slight horsepower gains come only because there is a tiny lip inside the tube that distorts airflow enough at high intake velocity to fool the Mass Airflow Sensor (aka MAF) into thinking a bit less air is coming in than is. The engine control unit (ECU) therefore runs a slightly leaner mixture, which at full throttle produces a tiny bit more power than the stock, richer mixture will.
Second, at low to mid range RPM (around 2500 to 3500 RPM) where the engine is at peak torque, the K&N reduces torque by about 10% because it very adversely affects the tuning of the intake tract.
Third, if you are not exceedingly careful when oiling the filter after cleaning it, you
will get too much oil on the gauze and that extra oil will be sucked down onto the heated sensor wire inside the MAF. Once on the sensor wire, it bakes on and makes the sensor less sensitive...the net result is the ECU thinks less air is coming in than actually is and tries to lean out the mixture. Eventually, you'll get a Malfunction Indicator Light (MIL...aka check engine light) and the underlying trouble code will be excessive leaning (which in turns leads to excessive pre-ignition and a bunch of other nasty outcomes). It's sometimes possible to restore the MAF sensor wires by removing the MAF and dousing the wires with electrical contact cleaner. More often than not, the cure is a brand new MAF at around $250 to $300. This is such an endemic problem with K&Ns that the first step that virtually all dealer service departments do with an ailing Tundra is rip the the K&N off the engine and clean or replace the MAF. If there's still a problem (a rare situation), then they do further investigation.
Fourth, a Tundra K&N is NOT, repeat NOT a cold air intake (to bring cool, dense air into the engine). The stock system is a true CAI because it pulls air out of the inner fender. Despite the appearance of having an air dam, the K&N mostly just sucks in hot, low density engine compartment air, especially at low speed.
Finally, K&Ns make a huge amount of gratuitous noise...noise that becomes extremely tiring when towing because of the much larger throttle openings.
I personally wouldn't install a K&N on my Tundra if you paid me $10000 to do so and I strongly recommend you get that thing off your engine ASAP.