The Infamous Deckplate Modification
The Infamous "Deckplate" Modification
Okay. So the idea behind this one is to make is easier for your engine to take in air. Back in the "old" days, racers would remove the air filter and it's cover when at the track. This made the intake system less restrictive and when the engine breathes easier, it turns out more power. Of course, only a serious twit would offroad without an airfilter. Since the stock Tacoma intake system is fairly restrictive, this mod gets you the best of both worlds; relatively unrestricted intake with full filtration. Plus, it sounds great :)
One word of caution; this mod is not recommended for supercharged Tacoma's unless you have performed some serious fuel system upgrades. The engine breathes quite well with the stock intake system and opening the airbox contributes to "pinging" with the supercharger.
This write up is from a 2001, V6. But all V6 Tacoma airboxes are the same. This mod can also be done with the 4 cylinder air box, it just takes a bit of work to fit a deckplate larger than 3" onto the flat side of the box. The procedure is the same.
Parts/Materials Needed:
Stock Airbox
3" or 4" or 5" Deckplate (purchase from a marine supply store)
3/4" Stainless, Pan-head screws
1 Tube "Sensor Safe" Silicon Sealant
Tools Needed:
Metric Socket Set
Screwdrivers
Drill and Bits
Dremmel or similar tool suitable for cutting 1/4" plastic
Towels
Sharpy Marking Pen
Estimated Time: < 1 Hour
Procedure:
Here is a view of the airbox as you will find it and one of the same area after the box has been removed.
Once you have the airbox out, place the deckplate against the front side of the box and trace around the hole with a Sharpy marking pen. I used a 4", black deckplate, purchased from a boat parts counter. I offset the deckplate slightly to the passenger side to better clear the washer fluid neck for ease of removal/install.
Once you have the deckplate traced on the box, you need to remove enough material to pop the deckplate in. I drilled a starter hole, then used the Dremmel to cut the hole.
You may need to trim a bit of material away to enlarge the hole before fitting the deckplate. You want the hole to be a snug fit, but a bit of irregularity in your cutting will be covered by the flange on the deckplate itself.
Once the hole is suitable, mark the screw holes with the sharpy and remove the deckplate. Drill pilot holes for the stainless-steel screws. Before you reinsert the deckplate, place a continuous bead of "sensor-safe", black, silicon around the flange, align the screw holes and fit the deckplate to the airbox. Sensor-Safe silicon can be purchased from almost any auto parts store. Look for the words "Sensor Safe" on the package. If it doesn't say sensor-safe, it's not, no matter what the sales clerk says. If you must use the non sensor-safe stuff, you will need to leave your airbox out of the truck for at least 24 hours or you will get a "Check Engine" light from the fumes coming off the sealant messing with the MAF sensor.
Insert the screws and tighten them down.
All that is left is reinstalling the airbox into the truck. Go slow and take your time so that you don't miss anything.
Operation is simple. Plate out for street and dry off-road. In for puddles, small lakes and wet off-road. The first time you drive it with the plate out, you will hear the difference. The engine sounds stronger and there seems to be a "seat of the pants" horsepower increase. Some folks have also reported an increase in mileage of a few MPG, others have reported a loss of a few MPG.
-Rob (WATRD)
http://www.watrd.com
Note: 05/15/2004 - We dyno'd a 4runner today, first several runs to set the baseline, then we opened the deckplate and did a few more. With the deckplate removed, it dyno'd consistantly at 8 HP more than it did with the plate in. Everything else was the same between runs. This mod appears to work.