From Faq
Read First!
- Before beginning the process(es) described in this article, please read all the instructions/information presented before making the modification(s) detailed herein. Ensure you have all the necessary materials, tools, and anything else required to perform the process(es). If you do not understand any of the steps, contact the submitter listed at the end of the article. The Tacoma Territory Off-Roader's Association (T.T.O.R.A.) and the authors of these articles assume no liability for how any particular individual chooses to use the information presented herein.
Air Intake Modification for 3.4L V6 Engines:
Background:
This modification improves the air intake ability of the Toyota Tacoma’s 3.4L V6 engine, improving overall response and upper range power. The stock air box intake goes through a sharp, constricting elbow on the left side of the air box, and this elbow and bend impairs the engine's ability to efficiently draw in air. The main purpose of this elbow seems to be to reduce or eliminate the possibility of water or debris entering the air box in off-road conditions, such as encountered when fording streams or large mud pits. By creating a large opening in the front of the air box with a marine deckplate, the engine is allowed to draw air freely into the air box and through the air filter. When wet or heavy muddy off-road conditions are expected, the deckplate lid can quickly be inserted in seconds, re-sealing the air box back to original settings. Rain does not seem to be any problem at all with the lid off — only off-road or wet conditions where a large amount of water or debris is forced up into the engine compartment from below seem to require the lid to be in place.
Installation:
I picked up a 4-inch deckplate and silicon adhesive at the local boating shop. They happened to have a white deck plate with a clear cover, so I got that. I painted the outer white rim to a glossy black, and left the center clear. I also picked up some stainless steel screws while I was there. Total cost was about $16 for the deckplate, silicon adhesive, and #8 screws.
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1. Remove your air box. There are 3 bolts, two tubes, and a sensor to remove. Remove the 3 bolts (it helps to have a long ratchet extension to reach down in there to get the bolts).
front bolts
2. Next loosen the clamp holding the large air tube with a Phillips-head screw driver, carefully unplug the sensor connectors on the left side, and then remove the large tube from the air box. Next remove the smaller tube to the right. The whole air box should now come out; just pull a bit to remove it from the left side elbow.
hose connectors
3. While you are under the hood, pull the EFI fuse from the fuse box in the right side of the engine compartment and leave it out for now. Pull the small 15 amp one - not the big one. This will reset your EFI computer so it will relearn your air intake settings.
fuse location
4. Air box as removed, and painting of outer deck plate rim.
air box removed
5. With the air box removed, I took the inner cover of the deck plate and traced it into the front of the air box. (Trace is enhanced in photo.) You want it to be just to the left of center to clear the windshield washer fluid when reinstalled, but still have plenty of room to mount the outer ring.
marked cut
6. I then took a Dremel cutting tool and cut roughly 1/8 inch larger around than my trace. I tested with the outer ring until it fit. The hardest part of cutting is cutting through the raised grids on the inside of the box.
IMPORTANT: Once you are done cutting and the ring fits, smooth out the cut and then thoroughly clean out the air box and remove any debris from cutting. You don't want any of it to get sucked into your engine.
hole cut
7. Using the ring as a template, I marked the screw locations with an ice pick to make starting the screws easier. I then coated the back of the ring with a nice bead of silicon adhesive, and pressed it into place. Next I installed the 6 screws to really make sure it didn't go anywhere. The silicon adhesive is utilized to make sure the air box is once again water and air tight when the lid is in place.
ring installed
8. Air box finished with lid installed.
all installed
9. Now just reinstall the air box back into the truck, reconnecting the hoses and sensor. Bolt back down. Reinstall the EFI fuse — it should be plenty of time for it to have reset by now.
air box reinstalled
10. Final picture with cover installed. As a nice little test of the lid seal, I did a full cleaning and detailing of the engine compartment, including using a power sprayer. Not a drop of water got into the box with the lid on.
cover installed
The weekend after the install I drove about 200 miles. There is a noticeable increase in response and power, especially in the higher RPMs. There is also an increase in induction noise from the air box at full throttle — it is a low tone rumble — I personally like the sound a lot. Overall, for $16 this has got to be one of the cheapest ways to increase the horsepower and response of the Toyota Tacoma V6 engine.
A WORD OF CAUTION: (by Dick Foster) Be sure to let the silicone adhesive fully cure - when you can't smell it anymore - before you start the engine. Otherwise use a sensor-safe silicone. The fumes from uncured silicone can ruin or shorten the life of your O2 sensor.
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