I am sure most of you have seen my personal website, www.GadgetOnline.com
. Back in 96 I started doing performance mods on my 4Runner and came up with some very cheap mods that worked to make real power. These were some simple mods to the air filter box and intake system.
I did a bunch of dyno testing and found that removing the elbow in the fender or opening up the front of the air filter box gave at least 6+ real RWHP gain. These mods are FREE. I tested the only intake that was available at the time and it did not give as much of a gain so it was more cost effective to do the free mods.
When I got my 2005 Tacoma XRunner I went to the dyno and tried some free airfilter box mods.
I tested removing the carbon trap. NO GAIN.
I tested removing the big air tube. NO GAIN.
I tested removing the entire air box lid. NO GAIN.
I tested removing the tube, lid, both filters. NO GAIN.
So, it seems that the problem was the air filter box its self. If you look at this convoluted air filter box, you can see the air makes a few hard turns in there before it gets to the MAF tube. Because of the turns the air is turbulent as it reaches the MAF tube. To settle down this turbulence, they installed a flow straightener screen to get rid of the turbulence. All these things add up to a nice flow restriction at higher power levels. Clearly the to increase power the airfilter box had to go.
We all know that if the engine can get all the air it can take in it will make the more power. If it can get the coolest air possible, it will make more power.
So, we set out to make an intake that was going to reduce restrictions and get the coolest air possible. After about 11 months of design changes, flow bench testing, and dyno testing we came up with the URD True Cold Air Intake. I think it was the first aftermarket intake that got true cold air into the engine.
Here is a dyno chart done on my 2005 XRunner with just the URD TCAI and no other mods:
Since then there have been a couple more that have come out that reduce restrictions and get cold air into the engine without drawing that air from inside the engine compartment. These are the TRD and aFe Stage 2 Si (both made by aFe).
I like all three of these designs because they are high quality and they work.
If you are interested in seeing an assortment of quality intake systems available for the Tacoma you can check them out here: