3rd gen king
New member
One of the t4r junkies has dyno'd it, just wish I could find it.
Why the Deckplate Mod is Overrated*
- Thread starter spectre6000
- Start date
3rd gen king
New member
LINY4Runner
New member
boom. :trophy:
runnyrunnerton
New member
umpteen posts and no one has commented on the two most important reasons for doing this.
1. Throttle response.
2. Your motor gets that famous outboard sound.
Did i mention more power?
Project SportRunner - Deck Plate Mod
I just want to hear my motor when i get on it. That's why this mod is so awesome. Physics be damned.
1. Throttle response.
2. Your motor gets that famous outboard sound.
Did i mention more power?
Project SportRunner - Deck Plate Mod
I just want to hear my motor when i get on it. That's why this mod is so awesome. Physics be damned.
JohnsD90
New member
Holy sh*t you're alive!
98OzarksRunner
New member
The dyno test showed 2 HP difference, which is WELL within the tolerance of a chasis dyno (that is about 1.5%). Granted the difference is greater at lower RPM, but many factors can influence that (the dyno operator for one!). Were the runs back to back? How many runs were done before these? (As the oil in the dyno drum heats up the HP numbers go up - your 3rd run is always more than your first.) Did he take the worst stock box run and compare it to the best open box run?
Also, a dyno will show gains or losses (though in this case, again, they are well within expected variations), but dyno tests are also not real-world tests, especially for the deck plate mod. The issue with the deck plate mod is that it lets hot engine air into the intake instead of bringing in cooler outside air from the fenderwell. During dyno tests the hood is up and a fan is blowing air into the radiator and across the engine, which means the engine bay is not going to be anywhere near as hot as it would if the hood were closed. The issue with hot air is not only that it is less dense, but also that the ECM will pull timing when the the intake air temp is high (to prevent detonation), which reduces power and mileage.
What this dyno test shows is that the factory air box, given the air temperature is the same (or close), has enough flow to provide virtually the same power as a box with a big hole cut into it, meaning the big hole does virtually nothing to improve performance (and under real world conditions will degrade it by letting in that hot air).
Actually to run at a given speed it takes X amount of power and Y amount of fuel to make it (oxygen doesn't burn; fuel does). Power comes from burning Y amount of fuel, regardless of how dense the air is (provided it's running at the proper A/F ratio, which the ECM calculates using factors such as intake air temp). The main reasons you experience fuel economy changes between summer and winter are 1) the fuel blends change, and 2) there is much more rolling resistance from cold tires, bearings, etc. in the winter.
What the second dyno page showed (http://www.gadgetonline.com/AirInduction.htm) is that a supercharged engine can benefit from more air, provided you make other mods, like more fuel, tuning, and exhaust upgrades. What it also shows is that the elbow is where the real restriction is on the supercharged motor. If someone would come up with an 'elbow mod' that let more air in from the fenderwell it would be provide the additional air a supercharged motor needs (that a N/A motor does not) while keeping hot engine air out of the intake. That would be a better mod, but would probably only benefit supercharged motors. Our N/A motors have all the air they need (or can use) with the factory airbox.
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Millerad1651
New member
I did it for the sound...I Like it. I also noticed a quicker throttle response. Does it improve anything greatly, no. Does it give a new owner a chance to work on their truck and familiarize themselves with the engine, yes. No one is saying you can race the damn things if you do a deck plate. If you want to do it, go for it. If not, don't This thread is going to turn into another debate with no clear winner, and I'm going to continue to waste my time checking back to see what new things have been said!
^ Agreed, I would not be doing that mod just for 1-2hp that was shown on a dyno. Oil temp will make a larger difference on the dyno than that.... plus what was mentioned about the tolerance of the dyno is a good point.
A free flowing intake system might not be what you really want either. A restrictive intake system actually helps build torque. Free flowing intake systems are for hi reving high hp. I barely ever drive my runner past 3g rpm so I don't see the need to have a free flowing intake, other than sound, which is why I ditched the intake silencer. It also looks like a **** under the hood.
A free flowing intake system might not be what you really want either. A restrictive intake system actually helps build torque. Free flowing intake systems are for hi reving high hp. I barely ever drive my runner past 3g rpm so I don't see the need to have a free flowing intake, other than sound, which is why I ditched the intake silencer. It also looks like a **** under the hood.
LINY4Runner
New member
lookie who's baaaackkk...guess you're not paying attention to the build thread...
:shrug:
theizzardking
New member
i'm just going to say i've skipped the deckplate ages ago for some of the reasons mentioned here, and i'll just leave it at that, but am considering the ISR mod as that does seem it would have greater benefit than the deck plate and have less draw backs ...my view and i don't $80,000 shop full of equipment to back it up with so i'm just going to leave it at that....:banana:
PoRunner
New member
^^^^ that right there is why I like it. Pulling my 19' Bayliner around to the nearest watering hole in the New Mexico desert isn't easy for that 3.4. Fuel consumption did change with this mod slightly and that was worth the 20 minutes it took to do it. To each their own.
Where do people come up with this stuff??
Oxygen doesn't burn?! What does the fuel require to burn using simple chemistry?
How does the combustion engine come up with X amount of POWER?!?!
Those factors of air intake temperature have correlations to air density at that temperature. People don't talk air density for more nitrogen, they talk more air density in relation to more oxygen. A requirement of any combustion.
I'm not trying to be a smartass but some of this stuff is blowing my mind.
spectre6000
New member
Well this is encouraging! When I saw three pages of responses overnight, I fully expected to see lots of flaming. What I got was an actual discussion with a good bit of substance. Awesome!
I'm glad someone was able to produce dyno charts, that's very beneficial as numbers mean far more than subjective "feeling". My initial reaction to the first dyno link posted was essentially that it was very light on actual information, etc., etc.. and pretty much all of these concerns have been addressed by others and I think it's generally agreed that it doesn't hold water.
The second dyno link is for a forced induction setup, and was in context with several other mods. That said, the guy was thorough and documented things fairly well (as well as a blog can be expected to be). He did see a delta removing the deck plate comparable to that of removing the elbow on a dyno (which would be more or less expected as they accomplish the same thing). This is in a dyno scenario that, as previously stated by others, is hardly comparable to the real world. I would be interested to see the same test done with the same degree of attention with a natural aspirated engine in a more natural (not dyno clinic) setting.
Even with that positive delta in the second dyno link, there are a number of other factors at play. He changed a LOT of things on his engine before he got to the deck plate, and even then the final statement was to remove the elbow and before that he stated to address your fuel delivery before attempting anything else.
Despite all of these reservations, the second dyno link made an excellent suggestion to truly accomplish what the deck plate is supposed to accomplish, and that's cutting out the elbow in the fender. It's cheaper too! The problem here, of course, is that by doing this you remove the possibility of a snorkel from your future should you ever decide to go that route. Another possible addition (that could look pretty neat if done well) would be to press some louvres into the fender at the top/side near where the intake passes into the fender to increase available air flow from that restriction... You'd have to be careful to make sure that the louvres aren't in a negative pressure zone though... Wind tunnel testing anyone? I know an aero engineer I can talk to, if it's worth pursuing I'll hit him up about it, but I have no plans to that end.
To accomplish BOTH goals, you'd need to increase the diameter of the plumbing going from the box into the fender AND the diameter of the tubing therein all the way up (i.e. custom snorkel).
Blah blah blah... The opposition to my claim (that being deck plate is useless in NA engines, and might be useful for FI) seems to be for the NA scenario: "Ya huh!", "it sounds cool", and "I felt it!". The second dyno link suggests it can be beneficial to FI engines with a big asterisk but "not really recommended".
Conversation is begun! Also, since T4R's search tool is not very good, having a thread with an easily decipherable title and some substance will help future would-be air box hackers avoid the trouble. Maybe there will be some good unmolested air boxes in 20 years!
In closing, here's a good analogy: the deck plate mod is like a throttle body spacer. It kinda makes sense if you know just enough to be dangerous, but really it's just a sticker for your engine.
I'm glad someone was able to produce dyno charts, that's very beneficial as numbers mean far more than subjective "feeling". My initial reaction to the first dyno link posted was essentially that it was very light on actual information, etc., etc.. and pretty much all of these concerns have been addressed by others and I think it's generally agreed that it doesn't hold water.
The second dyno link is for a forced induction setup, and was in context with several other mods. That said, the guy was thorough and documented things fairly well (as well as a blog can be expected to be). He did see a delta removing the deck plate comparable to that of removing the elbow on a dyno (which would be more or less expected as they accomplish the same thing). This is in a dyno scenario that, as previously stated by others, is hardly comparable to the real world. I would be interested to see the same test done with the same degree of attention with a natural aspirated engine in a more natural (not dyno clinic) setting.
Even with that positive delta in the second dyno link, there are a number of other factors at play. He changed a LOT of things on his engine before he got to the deck plate, and even then the final statement was to remove the elbow and before that he stated to address your fuel delivery before attempting anything else.
Despite all of these reservations, the second dyno link made an excellent suggestion to truly accomplish what the deck plate is supposed to accomplish, and that's cutting out the elbow in the fender. It's cheaper too! The problem here, of course, is that by doing this you remove the possibility of a snorkel from your future should you ever decide to go that route. Another possible addition (that could look pretty neat if done well) would be to press some louvres into the fender at the top/side near where the intake passes into the fender to increase available air flow from that restriction... You'd have to be careful to make sure that the louvres aren't in a negative pressure zone though... Wind tunnel testing anyone? I know an aero engineer I can talk to, if it's worth pursuing I'll hit him up about it, but I have no plans to that end.
To accomplish BOTH goals, you'd need to increase the diameter of the plumbing going from the box into the fender AND the diameter of the tubing therein all the way up (i.e. custom snorkel).
Blah blah blah... The opposition to my claim (that being deck plate is useless in NA engines, and might be useful for FI) seems to be for the NA scenario: "Ya huh!", "it sounds cool", and "I felt it!". The second dyno link suggests it can be beneficial to FI engines with a big asterisk but "not really recommended".
Conversation is begun! Also, since T4R's search tool is not very good, having a thread with an easily decipherable title and some substance will help future would-be air box hackers avoid the trouble. Maybe there will be some good unmolested air boxes in 20 years!
In closing, here's a good analogy: the deck plate mod is like a throttle body spacer. It kinda makes sense if you know just enough to be dangerous, but really it's just a sticker for your engine.
theizzardking
New member
if you care that much go out and buy 15 airboxes now, that's basically the best way to ensure you have some NOS stuff laying around in 15~20 years....
Hepar
New member
I recently took out my straight pipe and put back in the intake silencer.
spectre6000
New member
Yeah, I caught that too. I also caught a number of other things across three pages of responses and didn't feel it was worth the time to address every one of them.
To more thoroughly address that particular point and to avoid further confusion, the less dense air means there's less available oxygen to burn the fuel (burning is, chemically speaking, rapid oxidation). By warming the air you are decreasing its density and thus decreasing the available oxygen. By decreasing the available oxygen, assume the engine continues to (at the split second the deck plat is removed) inject fuel at the "stock" rate. Once the available oxygen is decreased, the exhaust becomes rich. That rich condition is seen by the O2 sensors and a signal is sent to the fuel system to lean out to compensate. The decrease in available fuel for ignition leads to less power/response/etc.
To address a few recent posts (I guess I took a while to write up that last one), there is in reality a possibility to increase fuel economy (albeit every so slightly) in certain situations. As part of the manufacturers compliment of compromises, one is power. If you go back in time (or maybe forward in time the way things are going... double digit horsepower seem to be making a comeback), you'll find a LOT of tiny little engines pushing people around. Take a 1954-1962 Volkswagen Beetle. They made 36hp at the flywheel, and drove around just fine (surprisingly spry in fact for what you'd expect). Even the top of the line Porsche in the early '60s only pushed 90hp! Granted, cars were far lighter back then with far fewer luxuries like that fancy schmancy air conditioning I keep hearing about. It doesn't require a lot of horsepower to make a car go at the sorts of speeds people actually go. If your truck has almost nothing in it (as light as it can practically be), you're not running AC, a huge stereo, etc., and you're very judicious in your application of the skinny pedal, you can keep the load requirements low. Do that, and the deck plate mod could potentially net you a slight gain.
As someone who drove a '62 Volkswagen Bus (40hp stock, though mine was making around 75hp) around every day for a few years (I like the old German cars if you can't tell) and learned how to drive slowly, my driving mannerisms are such that I routinely net 21-23 mpg on a tank. I keep nothing in truck (save the handbook, an ice scraper, and a multi-tool in the glovebox), I live where it's pretty cool (it's probably in the upper 60s right now) so I don't run AC much, I coast where I can coast, and my truck has a manual that I keep in the gear that keeps the accelerator pedal as high as it can be to accomplish my driving goals (which varies widely depending on if I'm going up a mountain or down it). The temperature delta between the air in my fender versus the air in my engine compartment combined with the above stated driving habits COULD THEORETICALLY net me an additional mpg or two. Some testing of this would be worth the undertaking. I can't remember the name of the tool (fuel flow meter?) that would be used for this test off the top of my head, but if anyone has one and wants to burn a tank or two "for science" it would be a worthwhile contribution to the thread and the T4R community. I'm not yet ready to concede that point as a concrete gain of the deck plate mod, but I'll entertain it in the presence some factual data.
FancyPantsMcGee
New member
In regards to the intake manifold and heads on the 5vz; I understand they flow very well from the factory. In most sea-level FI applications it is the fuel system that is insufficient, causing a potentially damaging lean condition. I have reason to believe at 5000ft+ with a supercharger the fuel system is reasonably able to keep up with the air flow.
I'm not sure how much to say..
5vz's run in closed loop until almost WOT throttle anyway which means even if the intake system is limiting your available air: your sensors will tell the ecu and it will compensate via fuel and timing.
If you had a 2WD reg tacoma you were drag racing I could see the benefit of nickel and diming all the possible options for gaining HP. Otherwise it's just for fun. and there's nothing wrong with that.
I'm not sure how much to say..
5vz's run in closed loop until almost WOT throttle anyway which means even if the intake system is limiting your available air: your sensors will tell the ecu and it will compensate via fuel and timing.
If you had a 2WD reg tacoma you were drag racing I could see the benefit of nickel and diming all the possible options for gaining HP. Otherwise it's just for fun. and there's nothing wrong with that.
