I think the key point being missed in this discussion is that the deckplate mod alone does not increase the total volume of air being moved (which is what the vacuum test gauge is looking at) but that it does increase the total efficiency of the air movement. If the engine intake does not have to suck as hard to get the air it needs to function it can put more effort to the wheels where it counts. Similarly doing an oversize exhaust with high flow components yields the benefits it does because the engine does not have to work as hard to get the expended elements of combustion out. These gains do come at the expense of much noisier operation which is why mfgs. typically do not fit this equipment stock [though nowadays they do offer them through their performance divisions ie. TRD]
Granted the overall increase may be only 6-10hp and a few MPG but it is just about the cheapest increase you can find, the only way to get more is to re-engine or go forced induction and that will cost an arm and a leg.

 

Well said ^^^^^^^^^^^^^^^^

 

Well, when you say efficiency, you probably mean resistance. A restrictive intake presents more resistance, and from the perspective of the engine, a restrictive intake makes the engine less efficient, reducing volumetric efficiency. But the intake in it by itself can't be efficient, or inefficient. and it's not the "pulling" of the air that causes the engine to lose or gain power.

Lemme explain this. Basically it takes very little power to suck the air through the engine. We are talking about only around 300cfms at red line. It is very easy to calculate how much power is required to move a certain volume of air, with only 2 measurements, the vacuum reading on the intake, and the pressure on the exhaust. Given those 2 measurements, and provided they are accurate, it can be known how much mechanical power is lost to the piston overcoming the vacuum of the intake. The power requirements are tiny, we are talking about fraction of a HP difference between a very restrictive intake, and having no intake connected at all, that is no resistance to air flow before the throttle body.

There is a power loss with a restrictive intake not because the engine wastes power sucking air in, but because the air is at a vacuum, in other words, not as dense as it around the vehicle. Ring a bell with engine power loss at altitudes?

So when there is a vacuum present somewhere in the intake system, it is a direct indicator of resistance to air flow, and air densities lower than atmospheric (again high altitude power loss). When no vacuum is present, it means it flows at or more than is required by the engine without ANY resistance.

 

Will it ever end, Porsche or Porsche. Fahrvergnugen.

 

My question is, what makes any of you think that you have out smarted the engineers at Toyota? Could it be possible that the best way for the intake to be utilized is to just leave it the way it is?

 

well, jeez....thats no fun!! lol

 

Well the answer there is no. It is a well known fact that standard intake systems are restrictive. Why? Because they are not designed purely for maximizing power. They are a compromise between power, efficiency, noise, cost, control and engine longevity. The engineers know very well how to get max power, but they also know very well how to blend in all the other essential requirements for todays auto market.

Aftermarket stuff and modifications shift the balance towards the power side.

Funny you should mention Porsche, they used to have an intake system that used a butterfly valve to switch between different lengths off intake piping to achieve the best set up for the immediate requirements.


DailyDrive, I think we will have to agree to disagree on this one. Our knowledge and understand of physics are not in tune with each other on this topic.
However, yesterday I put my deckplate plug back in and I intend to leave it in for at least 3 months and I will do another comparison for my mileage records. This will be the decisive test for me.

 

Things can be designed for different purposes, such as 29" highway tires that 4Runners in basic trim come with, there is no denying that they suck for offroad. 35" M/T are much better, but they come at the expense of cost, noise, overall fuel efficiency and handling. You can tell that they are better at offroad by looking at them, by touching them, and actually testing them in some dirt.

The debate starts when claims are are made about things that go against the laws of physics. If someone claims that black cars are faster than any other color, there will be debate. If a black car and any other color can be weighed, and the weights are equal, there can be no difference in speed. No matter how many people claim that they felt black cars were slightly faster, there is no conclusive evidence for that claim.

Same with the deckplate, observable and repeatable measurements indicate that there is no theory that can prove any claimed improvement to power or overall fuel efficiency.

 

are you saying this is stupid?



and this?



and if the two above do work better than the standard air box, why don't the "smart" toyota engineers put them in all the trucks? gotta be a reason..... ahah, engineers don't make these decisions, people in suits do.

like i said, who cares(assume this kinda mod doesn't hurt anything)

most people on this forum are pretty keen on maintain their vehicles, but most people don't change their air filters every 15k miles. my ex girlfriend didn't change her car's filter because when she took it to Jiffy Lube, she was quoted $55 parts and labor(WTF ??) for a freaking $10 paper filter, she didn't have the money for it.

an open air box requires more attention then a enclosed airbox, who's fault it's gonna be if one forgot to close the deckcover when wet? for most of the customers, that's a hassle rather than advantage.

 

Even the most meticulous methodology to measuring MPG is highly inaccurate. Especially when we are dealing with changing weather (uhh 3 months), unknown accuracy of the pump and different driving routes. Not to mention the biggest variable called the human driver.

You can't prove a change, with a method that is much more inaccurate than the expected change. If you claim a 5% increase in fuel mileage, your measuring method better be much more accurate than 5%, and it isn't, by a long shot.

 

Ok, I get your assumption is that "engineers" have total control of how a vehicle is designed and built-far from it. If engineers had all the control, what kind of vehicle would you get? Also, every engineer is different. Some want a quiet ride, some want all power. There were 50,000 compromises at least on the 4runner. We are lucky to get what we got.

I think you are correct that the engineers had a heavy hand given an overbuilt motor and low power. Unlike today, underbuilt motors and high output...but I digress.

There are multitude of professions that build and design an SUV. Engineers, marketeers, artists, managers, accountants, sales etc.

Again, looking at the 4runner, out of the box is smokes almost anything but a jeep in off road compared to the vehicles of the time.

The SC solves the anemic engine problem but produces others (at sea level). Again, we are lucky to have that.

Again, the vehicle had to satisfy the soccermom and the off-road dad. Being obnoxiously loud for a mere 10HP isn't worth it.

 

I mentioned it before, but living at 6,000 feet (relative vacuum to sea level) a less restrictive intake may "feel" more pronounced than at sea level. I don't know as the mod was put in place after moving here.


Looking at the intake, I think it would be better to move the intake to the passenger side wheel well with the intake hole just inside the fender. This would produce fewer bend and a lower heater transfer.

In a perfect world, the vent on the sport hoods would be active and provide an intake port there.

Or the ultimate, the intake at the base of the windshield. That would be a sweet mod and really take advantage of "cold" air intake. Or heck, install a cold air intake.

You will still be up against the limit of the intake/supercharger as it produces mild boost.

Might as well rebuild the intake/exhaust, blueprint the engine...etc...

Or throw in an Iforce V8.

Or just do the intake mod and be happy knowing the engine sounds cooler, it produces a real RPM band at 6,000 feet.

 

This is really interesting. You say "may feel". Is this something arbitrary and open to debate? Or you are admitting to really having no idea no idea about what's being discussed here? Because it will be less pronounced at higher altitudes, for obvious reasons, and there is no two ways about it.

 

Are you just being a internet tough guy or do you have a question?

Yes, the feeling is arbitrary feeling depending on the person. If some huge 300lb person is sitting in the front seat, it may "feel" different to someone who doesn't have 150lbs of fat on them.


With the respect to the mods, I will leave it at that.

 

No, you said a less restrictive intake "may feel" more pronounced at higher altitudes. There is no "may" when it comes to what is very well understood by physics.

It's like saying "what weights 1000 pounds at sea level, may weight more at higher altitudes". First, it can't be "may", as what it will weight, and why, is very well understood by modern science. Second, that is simply false, as everyone knows that the higher altitude, the less the gravitational pull, the less something weights. Same with the restrictive intake, what you said, is opposite to reality.

 

I have no dyno so it comes down to how I "feel" about the change. The word "may" is a perfectly good modifier.

Since feeling isn't absolute to everyone.

The only way to solve this debate is to simply measure the input an output in a controlled environment.

Since few of us own or have access to a climate controlled dyno, the point is moot until then.

 

It is WEIGH.

Higher altitude has insignificant effects on what something weighs.

A 10,000 ft altitude change on a 300 lb man would be less than a 1 lb change in weight and irrelevant.

Read your physics book some more.

 

Absolutely not, that is not the only way. If you remove the spare wheel from your car, and want to know how many pounds of weight the car lost, you don't need to weigh the whole car. You can just measure what the spare wheel weights, and that will be enough to conclusive state by how much the car is lighter now. You infer the weight lost, on the single data point, the weight of the spare.

Same here, you only need one data point to conclusive prove if the deck plate has any effect. I've presented a very simple methodology to disproving a popular myth.

If you can argue with my methodology, be my guest, but so far it looks like you not the sciency type.

 

Significant or not, my point was that someone who understood the subject matter, would never ever say something will weigh more with higher altitudes. Just like they would never ever say a less restrictive intake will be more pronounced at higher altitudes.

 

this thread is silly. some one please take an IDS and monitor the MAF signal. (not some HVAC gauge) use the sensors that the engine is using. see if the ECU notices a difference with and without the deckplate. my bet is that it will. the ecu sees mV not pressures. i can guarantee that there is a difference in the MAF signal with the deckplate removed and installed. i will see if i can actually run the test myself but since i work on diesels i dont know if we would have the right software or OBD2 adapter.