hydrocarbin air filter delete....
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fedrlbiker
New member
It does not make it a "cold air intake". All it does is eliminate an extra stage that slows the air. I removed mine and cleaned my Mass Air Flow Sensor after 100k miles and saw almost a 2mpg average gain on the very next tank. I think I went from like 17mpg to 18.8mpg or something on my V8...
fedrlbiker
New member
Also, your air intake and exhaust are not all or nothing... You can upgrade either and see performance increase. It may lower your mpg's though.
More Horse Power = Less Mileage
More Horse Power = Less Mileage
Adumb
New member
upgrading performance is increasing efficiency. = more mpg
more horsepower from increased displacement would = less mpg
I'm pretty sure intake and exhaust have nothing to do with displacement though. lol
I will say though, that with increased performance would come wanting to mash the pedal more.
Synister
Member
I think its worth noting that the factory air intake is in fact, a cold air intake, as it pulls air from outside the engine compartment, namely the fender well. The problem with most aftermarket exhausts and intakes is that their performance claims are almost always at the very top of an engine's RPM curve, especially in a normally aspirated engine. These systems can and do flow more air but only when the engine is really pulling hard for more air, i.e. at high rpms, i.e. when fuel efficiency has gone out the window. The idea that somehow the engine is going to "notice" better breathing over stock at 2-4k rpm is pretty absurd. If you like the sound of more open intakes or aftermarket exhaust, awesome, just don't expect performance gains at any kind of useful rpm.
Umm not really. You would have to fool the computer to run off it's preset mixture. Therefore anything that adds air will make the computer add fuel to keep the ratio the same. Keeping you MAF sensor clean and injectors clean will help maintain your best chance of efficiency as the system will be using good data.
Ohhh S.k. CFPB
New member
from my understanding the our v8 air box is the best one, their are only 2 companies that make the v8 CAI's for us. K&N and Volant. Volant has fillment issues and you have to drill for the MAF sensor and the K&N is exposed in the engine compartment.
only thing i could say is get the AFE dry air filter and keep the Hydrocarbon filter
only thing i could say is get the AFE dry air filter and keep the Hydrocarbon filter
I figure it was just something to do under the hood of our 05 with 75k and the V6. Probably will not be poking my head in there as often as I was with our VWs, Audis, Subies, _____.
I have not cared to notice if our MPG have increased before versus after though. We drive like old folks who drive slowly since we have the kiddos in the rear most of the time. We have averaged 24mpg on all tanks.
You could give the money you would spend on a CAI or muffler (for some reason) to charity or me. Then you could feel good about where the money went and not regretful for doing something just because it sounds better with little to no preformance gain...
I have not cared to notice if our MPG have increased before versus after though. We drive like old folks who drive slowly since we have the kiddos in the rear most of the time. We have averaged 24mpg on all tanks.
You could give the money you would spend on a CAI or muffler (for some reason) to charity or me. Then you could feel good about where the money went and not regretful for doing something just because it sounds better with little to no preformance gain...
Adumb
New member
My bad i forgot that giving air an easier path to flow ISNT increasing efficiency. In a naturally aspirated engine, the engine has to pull air into the cylinder. The easier that is, the less engine power is wasted on getting air into the engine.
BlackWorksInc
New member
I ended up taking my Hydrocarbon filter because of damaging it accidentally. Hasn't made any significant difference so far.. Hell my Smog was so clean I thought we didn't put the probe in.
No mechanical power was wasted in generating this post.. In all seriousness though the engine doesn't spend power to suck air in. The volumetic effiecency is based on how easy it is to get air in each of the cylinders but that still wont change the fact that the engine computer will do it's job to maintain a certain fuel to air ratio. More air = more fuel. You have a better chance gaining fuel mileage by properly maintaining tire pressure, lowering the vehicle and stripping weight.
97BlackAckCL
Elite Member
I found that my engine breathes way better without the HCF. I removed it when I installed my K&N drop in filter. The combination of the 2 definitely gave the truck more pep, but I don't think it really adds much other than more air flow. That thing is so restrictive
Adumb
New member
Its just common sense. When an intake valve opens and the piston moves down it creates a vacuum in the cylinder.
Alot like a wetdry vac. The motor runs smooth when there is no obstruction in the tube. And as you start to cover the opening of tube with your hand you can hear the motor working harder to pull air in.
Also an engine controls fuel off of the tps. Thats why the engine starts to diesel and slow the vehicle when you downshift at a high speed. The a/f ratio gets leaned out. It sounds like you are saying at 4200 rpm the engine always puts in enough fuel to maintain a proper a/f ratio
Common sense isn't really common anymore, I know lots of mechanical engineers that don't know how to turn wrenches or are afraid too. I won't argue the wet vac analogy or the fact that you now increased the amount of air the cylinder can suck in but we don't drive using large swings in throttle settings. If you were to look at how people drive most people are in a steady or near steady state of driving. Yes during acceleration tps, maf, and a fuel chart drive injector duty cycle to produce acceleration. But when you cruise down the highway or at a constantish speed the MAF, O2 sensor, engine temp, etc all make adjustments to run the vehicle in the sweet spot for both efficiency and emissions. That is what drives the larger component of MPG.
I have yet to feel this diesel condition you speak of. I push on the throttle, the engine determines to downshift and off I go. With the onset of fly by wire the hesitation is longer than what the old cable driven cars were like but that is because the controllers have to make decisions and the OEM build in lags to make sure it's a smooth transition. In the cable versions you had no choice, air is increased so fuel must follow or the engine coughs.
Adumb
New member
By dieseling i am saying when you are going 55 and downshift to 3rd without hitting the gas the vehicle slows because the. Cylinders arent getting enough fuel to create power.
Air and fuel are not always at optimal mixture as you said. Just because the engine is getting more air the ecm doesnt automatically dump more gas in.
Air and fuel are not always at optimal mixture as you said. Just because the engine is getting more air the ecm doesnt automatically dump more gas in.
OrangeTexan
New member
In most cases, the vacuum that the engine works against (cylinder pulling in air) is created by the restriction of the throttle body valve.
There are 2 scenarios we need to consider:
1. When the TB valve is 0% to 50% open. This is where most of us spend our time on the highway, cruising unloaded and towing nothing. This is the region where daily MPG will come into play. Under this scenario, the valve is more of a restrictor plate in the air flow and is the most restrictive object in the intake tract. Because of this, modifications to filters etc. do not give much effect to cruise MPG, since the TB valve is this largest restriction. Engine vacuum is not changed in this scenario.
2. When the TB valve is 51% to 100% open. This is the region where we do our accelerating. Most of our city driving is affected by this. Also while towing or loaded down, or going through lots of hills or mountains. Under this scenario, the valve looks more like an airfoil or a aero vane in the flow. Depending on other restrictions and the amount that the valve is open, it now may NOT be the most restrictive object in the intake tract. If you have a heavy foot, or do a lot of towing/hauling or generally live in an area where there are a lot of hills or you spend a lot of time in stop/go traffic, you MAY see improvements to MPG as well as power if you remove restrictive objects before the TB like filters, accordian style piping,etc. because this will now affect the engine vacuum seen at the cylinders and will improve overall efficiency. Even though you may use a bit more fuel, less HP is being used to pull vacuum and is freed up to power the drivetrain.
The V6 does not benefit from the improvements in scenario #2, simply because the whole engine has been designed to provide low end torque. Because it is a V6, the design considerations required to accomplish this restrict air flow throughout the engine via specifically designed intake manifold, heads, cams, intake/exhaust valves, and exhaust manifolds, which in turn significantly impacts the engine's ability to flow more air at higher RPMS and compromises peak HP. The point is - the V6 engine itself is more restrictive to airflow than even the TB valve. This is why it is hard to get good HP gains out of the V6 unless you improve volumetric efficiency by addressing the items designed to improve low end torque...
V8s in general do not have a problem generating low end torque because of their inherent larger displacement.
There are 2 scenarios we need to consider:
1. When the TB valve is 0% to 50% open. This is where most of us spend our time on the highway, cruising unloaded and towing nothing. This is the region where daily MPG will come into play. Under this scenario, the valve is more of a restrictor plate in the air flow and is the most restrictive object in the intake tract. Because of this, modifications to filters etc. do not give much effect to cruise MPG, since the TB valve is this largest restriction. Engine vacuum is not changed in this scenario.
2. When the TB valve is 51% to 100% open. This is the region where we do our accelerating. Most of our city driving is affected by this. Also while towing or loaded down, or going through lots of hills or mountains. Under this scenario, the valve looks more like an airfoil or a aero vane in the flow. Depending on other restrictions and the amount that the valve is open, it now may NOT be the most restrictive object in the intake tract. If you have a heavy foot, or do a lot of towing/hauling or generally live in an area where there are a lot of hills or you spend a lot of time in stop/go traffic, you MAY see improvements to MPG as well as power if you remove restrictive objects before the TB like filters, accordian style piping,etc. because this will now affect the engine vacuum seen at the cylinders and will improve overall efficiency. Even though you may use a bit more fuel, less HP is being used to pull vacuum and is freed up to power the drivetrain.
The V6 does not benefit from the improvements in scenario #2, simply because the whole engine has been designed to provide low end torque. Because it is a V6, the design considerations required to accomplish this restrict air flow throughout the engine via specifically designed intake manifold, heads, cams, intake/exhaust valves, and exhaust manifolds, which in turn significantly impacts the engine's ability to flow more air at higher RPMS and compromises peak HP. The point is - the V6 engine itself is more restrictive to airflow than even the TB valve. This is why it is hard to get good HP gains out of the V6 unless you improve volumetric efficiency by addressing the items designed to improve low end torque...
V8s in general do not have a problem generating low end torque because of their inherent larger displacement.
OrangeTexan
New member
From what you are describing, that is normal (but is a special case and doesnt really apply to what we are talking about). Downshifting like that will cause you to slow because the drive train is suddenly spinning faster than the engine wants to (because at that moment the engine is making less HP than required to spin the engine at the new higher RPM, remember you did not hit the gas), and the engine produces drag on the drivetrain. This is also described as engine braking and is an off-throttle situation. In some ECUs this is obviously in a totally different region of the fuel map since now you are in a very high vacuum situation for the given RPM. Some other ECUs use a totally different fuel map for off-throttle.
Dieseling is a situation where a gasoline engine continues to run after it has been turned off.
Unless Toyota does something different than most other OEMs I think you would find that no fuel is injected under decel. Only diesels do post and pre injection on off throttle conditions but they also don't change air flow as there is no throttle plate.
What most call dieseling is when you get combustion due to self ignition during compression.
Optimum mixture is a term used for all power levels it just not the same mixture. Under load and high power you want a rich condition while a cruise you want to run at idea mixture that takes into consideration emissions, fuel consumption and load.
There are several good books out there that discuss EFI tuning and control I have a few from my Audi and Subaru days when wanting to modify turbo charged engines. Most OEM tuners design the controller to work for the life of the vehicle and work for any vehicle which means they are not always an optimium tune for the actual build. That said they are pretty darn good at what they do. On a side note most folks that complain about the smell of these trucks at cold idle it's because for some reason Toyota overfuels when cold and the cats have to work harder to meet emissions.
Adumb
New member
Okay. This was the statement I started to argue. I think even you know this is an untrue statement now.
