Bumpin' Yota

you need 10rwhp or more to notice a difference from what I have heard.

I am no mechanic so if I'm offbase someone please correct me.

As I understand it, the ECU uses the MAF to gauge the air volume and more importantly it's density. From there it looks at the throttle position and determines the injector duty cycle. If the throttle position is above 80%, the ECU jumps into open circuit (I think) and the engine runs PIG rich.

When the throttle position is below 80% the O2 sensor is doing cross sweeps. That is that the O2 sensor is reading rich then lean then rich then lean. The more you get into the throttle, the faster and faster it does this. It does this to help improve econcomy, by keeping the burn closer to stoichiometric.

If the O2 sensors die, the ECU has no way of telling if the engine is running lean and automatically goes to a predetermined fuel map garunteed not to be lean even at WOT. This results in poor milage, slight loss of power, and running that rich will eventually kill your cat....

So after doing the deckplate, or any other performance mods, most people get into the gas that much more to see if it made a difference. If you did that and went over 80% throttle position a lot, you could have killed the cat from an overrich condition. Hence why I said check the O2 sensors for proper operation. The ECU wont necissarily trip a CEL light if the O2 sensors die, so definately check them out...

ColImport

so how do I check the o2 sensor out ??

RockComa

I to did a deckplate w/ no noticeable difference other than sound. My question though what is the difference between the hole in the air box vs flipping open the lid of the V6 or moving the lid aside on the 4 cyl

Beartracker

By just moving the lid aside your letting in air and dirt that bypasses the filter.
From what I have read so far I don't think I'll do this mod. Just don't think there is much to gain and more air just means more dirt and a need for faster filter changes.Maybe I'll play with taking out the filter on the wet days after a rain so that there is very little dust in the air. Maybe that will tell me if it's worth it.

rimpainter.com

Well, in theory yes. Really all you are losing is the added bracing to the filter provided by the tabs on the bottom of the lid. You are not bypassing filtration, just increasing the chances of dirt getting by.

FingerMan20

So a deckplate is a hole in your airbox??

Makes you wonder... why do they call it this fancy name?

linjy2

i have the deckplate mod with an amsoil filter. definitely felt a gain in the butt o meter.

rimpainter.com

Because a marine deckplate is used to close the hole as needed.

PistonSlap

I would not call a 5hp gain significant and you are looking at single pass test. You could run the same car through a dyno and get a 5hp difference without making any changes what so ever.

The other thing that this test doesn't take into consideration is the fact that the truck is sitting still. The way the air flows while sitting still is totally different than the way it flows when the truck is moving. I also don't like the idea of bringing in warm air from the engine compartment. There is a reason that we have moved from the old 70's style of the air intake sitting on top of the engine.

The only thing I could tell by doing this was that my truck ran like garbage made a loud unpleasant hissing sound.

I think this mod is more show than go.

rimpainter.com

Your opinion is noted.

Tacoma Dude

Just FYI - you're in the minority with the people who have done this mod.
I have a double cab with 3" lift, larger tires, and Magnaflow. I know that when I seal up the deckplate that I have a loss of power. I've run from Irvine to San Diego with the deckplate off and cruise control on and know exactly where the engine will downshift to maintain the cruising speed. I've run with the deckplate on and will experience a lack of OR delayed downshifting.

Beartracker

In the write up about this mod it states that you wont notice much of a difference in horse power until your doing 70 on the freeway.
It seems to me that some people are exspecting to much from this mod and others seem to be real happy with the difference.
I took off the top of my air box today and even removed the filter to drive to town over these mountains. It sounded better but I can't say that it felt all that much better, but I'm happy with the way mine runs anyway :0) Mike

Tacoma Dude

If it didn't feel all that much better it was probably because you were running without the filter and allowing the road debris in.

Beartracker

You may be right but it rained all night so there was no dust or dirt flying around and it's all paved road. As i stated earlier I was going to try it after it rained and that's what I did. It's eight miles to towm over two mountains that go from 1100 to 2900 feet above sea level very quickly.
If I had tried it on the exspressway it may have been alot different but over these mountains there was not much difference that I could tell. The temp today never made it past 65 and that's the kind of weather this Taco loves .

PistonSlap

It is impossible to feel 5hp and if you look at the gain, that gain is at peak. Through the lower RPMs the gain is negligible. I guarantee that the feeling is in your head. That is ok. If It makes you feel better because it is louder, so be it.

Your engine does not down shift, that is your transmission and it has nothing to do with airflow.

Tacoma Dude

Well my terminology may be incorrect but I've done this test many times and I know for a fact that with the deckplate off I have an increased amount of power. I can't tell you how much in numbers but *my* experience has shown that I am better off with this mod.

If you don't want to do it that's cool - not my problem

EDIT:
...and yes, I do know that it is the tranny and not the engine that does the shifting. I'm not a complete idiot.

Gangus2006

Heh...I saw this thread and called the marine store...$10 for a 6" deckplate. That sound good?

Guess what Ill be doing this Memorial Day?

TACOMANATOR

I removed the door to my airbox, but I have a 1 inch c-clamp holding the filter tight against the airbox. Works well and no cutting.

midiwall

Hmmm... well, I have a couple of things to say...

• It's very well known that the 3.4L engine in these trucks is starved for air. The only inlet into the stock airbox is through a (relatively) small pipe through the fender well that has a _nasty_ 90* bend in it. A starved engine will _never_ put out maximum power.
  
  
• Given a fuel injected engine that's driven by an ECU which is taking air flow as one of it's inputs (and the 3.4 is just that) then, More air = More fuel = More power. It's a pretty simple concept to get your head around.
  
  
• I put my truck through a dyno a while ago and had a chance to run the deckplate in & out. I also have documentation of the 5hp gain with it out.

Believe what you want, and be a naysayer if you will, but... enjoy being in the minority.

MTL_4runner

This has been scientifically proven on a dyno many times (even by Gadget).
There is nothing "for show" about this mod.