Interesting video on air intakes.

[Zspeed]

Absolutely. Most aftermarket intakes are not that good because they are not calibrated to the engine.
 Once a community of owners realizes this then it is presumed that all aftermarket intakes are junk. 
 That is not exactly true, there is always a reason why.  Most other platforms are ahead of the game where we are sill discovering a lot of this. Unfortunately exclusivity has a downside. I always found it peculiar that for out platform modifications that do make a genuine difference are often not popular. 

 


[/quote]

Any suggestions welcome? I know the bcm cda that @JB21 says in his car is pushed by rogue motorsports for track cars and they do very well in the mr2 championship.  I guess a lot of it is in the setup.

[onenastyviper]

It is a kind of straighter as I mentioned but that is not its purpose. Its purpose is the simulate a smaller tube so that the air is speeds up so the MAF sensor wire is cooled down to report the correct electrical resistance so the ECU knows how much air has entered the engine. 
Without the vanes the hot wire is not cooled down enough and therefore it under reports which is not good and you will lose power on various areas along the RPM band.   
Aftermarket intake manufactures recognize this now and are making calibrated intakes that either narrow the tube before the MAF or add walls as you see with the Apexi intake. The best intakes are the ones that use vanes like the factory however you just don't add them the entire intake has to be flow tested with the MAF and the electrical resistance has to be precisely measured which is not something a DIY person can do.

 Here is a video on the Injen MR technology which is nothing more than narrowing the tube so the MAF reports the correct amount of air.  I do not like this technology because it is less efficient.
 
If you add a honeycomb it will not do anything for this kind of intake system. Turbulence is not an issue with this kind of MAF housing because the foot print is very small. Honeycomb arrangement were what older air sensors used.

Don't take this the wrong way but I don't understand the reasoning behind the Injen videos. By reducing the tube diameter you speed up the flow at the expense of pressure drop. In N/A applications, surely you'd only want to speed up the flow whenever there is a secondary benefit (i.e. attempting to increase inertia, breakup of fuel droplets etc.) and you are happy accepting the restriction.

Deliberately reducing the tube diameter strikes me as a cost exercise to be able to use the same velocity sensing element(s) across a range of intakes.

I've only ever worked with continuous flow systems but engine intake systems are pulse-flow systems and not continuous flow systems so I can accept that my reasoning could be (very) flawed. This is demonstrated by the fact we can "tune" an engine simply by altering the length of the intake system. In an engine, there is an optimum position because the pressure pulses feed backwards into the intake system and can actually increase the available pressure to force additional air through the system. It's also why volumetric efficiency is a useful parameter for engines but not for pipework systems.

For those who have been to engine tuners and dyno sessions, do they report volumetric efficiency (VE) for your engines?

[shnazzle]

No, but that is what you're changing (for fueling) when you map a car. Normally. Some systems use injector pulse times, others use VE tables. So it's not your measured VE, but more a guess that seems to measure up based on the amount of measured air, the fuel's specific burn ratio, etc.

I.e. If I fill in a cell with the value 98, it's not because the VE is 98, but for a that cruise load cell where I want 14.7:1 ratio of air to fuel, the value 98 calculates against the measured air and my injector settings.

[onenastyviper]

No, but that is what you're changing (for fueling) when you map a car. Normally. Some systems use injector pulse times, others use VE tables. So it's not your measured VE, but more a guess that seems to measure up based on the amount of measured air, the fuel's specific burn ratio, etc.

I.e. If I fill in a cell with the value 98, it's not because the VE is 98, but for a that cruise load cell where I want 14.7:1 ratio of air to fuel, the value 98 calculates against the measured air and my injector settings.

So, what are the measurements that decide whether the parameter is within or outside of the desired tuning envelope?
I get that the are maxima and minima with all this (i.e. injector pulse width, rich/lean running) but what is someone actively looking at when tuning?

[Dev]

It is a kind of straighter as I mentioned but that is not its purpose. Its purpose is the simulate a smaller tube so that the air is speeds up so the MAF sensor wire is cooled down to report the correct electrical resistance so the ECU knows how much air has entered the engine. 
Without the vanes the hot wire is not cooled down enough and therefore it under reports which is not good and you will lose power on various areas along the RPM band.   
Aftermarket intake manufactures recognize this now and are making calibrated intakes that either narrow the tube before the MAF or add walls as you see with the Apexi intake. The best intakes are the ones that use vanes like the factory however you just don't add them the entire intake has to be flow tested with the MAF and the electrical resistance has to be precisely measured which is not something a DIY person can do.

 Here is a video on the Injen MR technology which is nothing more than narrowing the tube so the MAF reports the correct amount of air.  I do not like this technology because it is less efficient.
 
If you add a honeycomb it will not do anything for this kind of intake system. Turbulence is not an issue with this kind of MAF housing because the foot print is very small. Honeycomb arrangement were what older air sensors used.

Don't take this the wrong way but I don't understand the reasoning behind the Injen videos. By reducing the tube diameter you speed up the flow at the expense of pressure drop. In N/A applications, surely you'd only want to speed up the flow whenever there is a secondary benefit (i.e. attempting to increase inertia, breakup of fuel droplets etc.) and you are happy accepting the restriction.

Deliberately reducing the tube diameter strikes me as a cost exercise to be able to use the same velocity sensing element(s) across a range of intakes.

I've only ever worked with continuous flow systems but engine intake systems are pulse-flow systems and not continuous flow systems so I can accept that my reasoning could be (very) flawed. This is demonstrated by the fact we can "tune" an engine simply by altering the length of the intake system. In an engine, there is an optimum position because the pressure pulses feed backwards into the intake system and can actually increase the available pressure to force additional air through the system. It's also why volumetric efficiency is a useful parameter for engines but not for pipework systems.

For those who have been to engine tuners and dyno sessions, do they report volumetric efficiency (VE) for your engines?

I apologize for not having a disclaimer on the Injen video as the presenters explanation was spotty.
 
Before we complicate this with pressure drops, VE and all of this other debatable items let us keep it very simple.

 The reason for the reduction in size of the intake tube is to speed up the airflow for only one reason and that is for the MAF to read correctly, nothing more.  The MAF was designed to be in a calibrated MAF housing and when you buy a aftermarket intake it is not. The Injen solution is to reduce the intake diameter just before it reaches the MAF and then the tube is back to its original diameter which is most likely larger then OEM for less restriction.
When we use a uncalibrated MAF housing it lets in unmetered air which is not good for performance.
 Apexi solution is to add metal on the sides which also narrows the intake passage essentially doing the same thing but its not optimal. The best way is how Toyota originally designed the intake and that is to use intake vanes not for straightening the air but to speed up air flow though a segmented  section of the vanes to flow against the MAF so it will cool the hot wire.  The colder the hot wire the more air is registered by the ECU.  When the ECU knows there is more air that has entered the intake it can then make better calculations for fueling and timing under various load conditions.

[onenastyviper]

I apologize for not having a disclaimer on the Injen video as the presenters explanation was spotty.
 
Before we complicate this with pressure drops, VE and all of this other debatable items let us keep it very simple.

 The reason for the reduction in size of the intake tube is to speed up the airflow for only one reason and that is for the MAF to read correctly, nothing more.  The MAF was designed to be in a calibrated MAF housing and when you buy a aftermarket intake it is not. The Injen solution is to reduce the intake diameter just before it reaches the MAF and then the tube is back to its original diameter which is most likely larger then OEM for less restriction.
When we use a uncalibrated MAF housing it lets in unmetered air which is not good for performance.
 Apexi solution is to add metal on the sides which also narrows the intake passage essentially doing the same thing but its not optimal. The best way is how Toyota originally designed the intake and that is to use intake vanes not for straightening the air but to speed up air flow though a segmented  section of the vanes to flow against the MAF so it will cool the hot wire.  The colder the hot wire the more air is registered by the ECU.  When the ECU knows there is more air that has entered the intake it can then make better calculations for fueling and timing under various load conditions.

I get what you are saying but I think "unmetered air" is throwing me off. To me, it implies an unmeasured flow which would not happen with an inline sensing element (mass flow never changes in a series pipe) and more what would happen if the intake had a hole in it somewhere (i.e. loose clip, split pipe etc.).

I think the MAF is totally oblivious to the housing size and just measures velocity. For the same velocity, a small tube and large tube would have massively different mass flow rates and the engine runs on air mass flow not air velocity.

[Dev]

I apologize for not having a disclaimer on the Injen video as the presenters explanation was spotty.
 
Before we complicate this with pressure drops, VE and all of this other debatable items let us keep it very simple.

 The reason for the reduction in size of the intake tube is to speed up the airflow for only one reason and that is for the MAF to read correctly, nothing more.  The MAF was designed to be in a calibrated MAF housing and when you buy a aftermarket intake it is not. The Injen solution is to reduce the intake diameter just before it reaches the MAF and then the tube is back to its original diameter which is most likely larger then OEM for less restriction.
When we use a uncalibrated MAF housing it lets in unmetered air which is not good for performance.
 Apexi solution is to add metal on the sides which also narrows the intake passage essentially doing the same thing but its not optimal. The best way is how Toyota originally designed the intake and that is to use intake vanes not for straightening the air but to speed up air flow though a segmented  section of the vanes to flow against the MAF so it will cool the hot wire.  The colder the hot wire the more air is registered by the ECU.  When the ECU knows there is more air that has entered the intake it can then make better calculations for fueling and timing under various load conditions.

I get what you are saying but I think "unmetered air" is throwing me off. To me, it implies an unmeasured flow which would not happen with an inline sensing element (mass flow never changes in a series pipe) and more what would happen if the intake had a hole in it somewhere (i.e. loose clip, split pipe etc.).

I think the MAF is totally oblivious to the housing size and just measures velocity. For the same velocity, a small tube and large tube would have massively different mass flow rates and the engine runs on air mass flow not air velocity.

Using your analogy of having a hole after the MAF from a loose fitting or leaking gasket in the plenum is similar to what happens if the MAF does not read the amount of air that enters the engine due to an uncalibrated intake. Air should be hitting the MAF at the velocity  that is required to register the correct reading otherwise it gets passed the MAF ability to read how much air has entered and therefore it is unmetered because there is more air than is read. That is why vanes are used so that it directs and speeds up air flow so the MAF can have an accurate reading for the amount of air that is entering the engine and it does this by cooling the heated MAF wire. To cool the MAF wire sufficiently it needs more air velocity.

You might be wondering why do they do it this way. Why don't they simply calibrated it for the velocity of the tube with no vanes or reduction of the tubing size. That is a good question and the answer I was given by Cobb tuning and other sources was the MAF sensor design  has the ability to have a smaller foot print and the scaling of how the MAF reads proportionally and therefore accurately. The MAF sensor is primitive in the way it works but it works reliability.

If you look at some other MAF housing designs for other cars there will be a small tube in the intake or it is part of the MAF housing that samples the air at a higher velocity to hit the MAF sensor wire for the correct reading.
Keep in mind that the velocity of the air is speed up only in a very small 1 or 2 inch section in the tube of the MAF housing not for the entire intake track. The velocity of the air remains the same except at the MAF where it samples the air.

The housing size is very important otherwise more air enters the engine than is registered by the MAF creating a lean condition because the larger you make the intake you will have a reduction in air velocity. A reduction in air velocity on the MAF makes the wire hotter registering less air by the ECU.
 
For our car some misguided people have tried to hobble their own intake using a larger diameter intake in the belief they would get more power and were baffled why the car ran poorly and threw a CEL.
What is actually happening is the car is trying to compensate a lean condition using fuel trims but it has passed the limits of compensation.

[shnazzle]

No, but that is what you're changing (for fueling) when you map a car. Normally. Some systems use injector pulse times, others use VE tables. So it's not your measured VE, but more a guess that seems to measure up based on the amount of measured air, the fuel's specific burn ratio, etc.

I.e. If I fill in a cell with the value 98, it's not because the VE is 98, but for a that cruise load cell where I want 14.7:1 ratio of air to fuel, the value 98 calculates against the measured air and my injector settings.

So, what are the measurements that decide whether the parameter is within or outside of the desired tuning envelope?
I get that the are maxima and minima with all this (i.e. injector pulse width, rich/lean running) but what is someone actively looking at when tuning?

Air-fuel ratio (AFRs) and torque.

There are a number of reasons for chasing certain AFRs.
14.7 gives the most complete burn. 13 decreases exhaust temperatures and prevents knock, 15ish saves fuel. Etc. 
The there's torque (remember HP is calculated from torque) which obviously is your target. You want as much torque as possible and you tune your fueling and timing to increase torque.
You find the max, then dial it down a bit for protection. Do that across all the load cells.
That's why it takes hours and hours.

[shnazzle]

What Dev is trying to say is that all the same air is going through the pipe, but not all of it is being accounted for. So essentially the same as having a leak post-MAF.

Imagine a hallway and people walking through it into an auditorium. There's someone standing in the hallway counting the people that pass. They pass that information to someone in the auditorium so that they know how many chairs to put out.
Now imagine someone widens the hallway and the counter can't see that far. They report 50 people, but 67 people show up in the auditorium. 17 people have no chairs and all of a sudden they have to scramble to quickly try to find 17 people chairs. It's fine.
Now imagine 50 are counted, and 89 show up. Now there's 39 people too many. They manage 25 extra chairs but 14 people are left standing and cause a scene. The show is halted and everyone is naffed off.
... That's what's happening when you feck with the intake pipe.

[Zspeed]

@Dev this is quite an interesting video on this subject.

https://youtu.be/rqdvxfwFrHs

From my limited knowledge, my interpretation is that he basically says with an NA car the most effective way to make power from the intake is to reduce temperature. Outside of that you need an aftermarket ecu.

[Dev]

@Dev this is quite an interesting video on this subject.

https://youtu.be/rqdvxfwFrHs

From my limited knowledge, my interpretation is that he basically says with an NA car the most effective way to make power from the intake is to reduce temperature. Outside of that you need an aftermarket ecu.

Good video. Here are the take aways.
 
1.It depends on the application. This is the big one.

2. It is known that having a colder air source is beneficial for power. This is true. Having the intake that is sits behind the battery will bring in the lowest intake temps compared to almost all of the aftermarket intakes that make a curve and go to the back of the car near the exhaust components.  Those are some of the worst intake designs and it should be called a hot air intake. However I did not notice much if any difference when it came to added power when I tried to add additional shielding which reduced the air intake temps an additional 10f so I removed the shielding. I notice more power on a colder day than trying to make the intake the absolute coldest. 

3. The more bends you have in the intake and the longer the run the more resistive the intake is. This is why using the short ram intake that sits behind the battery is the best intake design for our car because its not only a short ram its also a cold air which is rare for most cars as you can only have one or the other.

4. If you notice at the end of the video he echos much of what I have been writing regarding calibrated intake tubes and how they work. However he mentions the vanes used in some of them as air straighteners but fails to mention that they are for the calibration. That segmented section in the tube is like having a smaller diameter tube that speeds up the air velocity to cool the MAF wire. Without it you will have a rise in fuel trims. I have data logged this and found it to be true. Later on someone else performed the same experiment adding his own vanes and had a reduction in positive fuel trims.

 Here is where you make power. With the less restive intake it becomes synergistic with anything that makes the engine spin up faster. If you add a less restrictive exhaust and so forth the benefits will be additive. When this happens the car can suck in more air, it will be read properly by the MAF so the ECU can calculate how much fuel to inject along with the timing. The increase in positive fuel trims will be genuine which results in more power. With an uncalibrated MAF tube the ECU reports less air but the 02 sensor reports more air or a leaner mixture. In order to keep the correct AF ratios for emission it will richen the mixture but there is no benefit for performance.

 As far as how much you can get out of a proper intake like adapting the 2ZZ housing. Probably a genuine 3-5 whp. That is a lot for a small engine like this one and it wont be just at peak, it should be across the board which is where it can be felt. There are many dynos that exaggerates their figures and that is why real low figures dont seem like much.

[Iain]

Just leave it stock and enjoy the drive

[shnazzle]

Just leave it stock and enjoy the drive

That is generally the advised conclusion, but it is one of the more interesting aspects of fuel injected cars. In my opinion anyway. How something as silly as a piece of plastic in a certain position is the difference between a well-running car and failing MOT.


Having said that... It does make one hark back to the days of carburetors. (yes, I do remember them)... If fueling was off, a bit twist here, tighten there and "does it sound right?".
So much simpler. But.. In the same vein, who remembers having to use the choke? Bit harder than just cranking the engine and letting the ecu figure it out.

[Joesson]

Just leave it stock and enjoy the drive

That is generally the advised conclusion, but it is one of the more interesting aspects of fuel injected cars. In my opinion anyway. How something as silly as a piece of plastic in a certain position is the difference between a well-running car and failing MOT.


Having said that... It does make one hark back to the days of carburetors. (yes, I do remember them)... If fueling was off, a bit twist here, tighten there and "does it sound right?".
So much simpler. But.. In the same vein, who remembers having to use the choke? Bit harder than just cranking the engine and letting the ecu figure it out.

Dual choke Webber carburettor, hand choke, even a hand throttle on the last car I owned (Fiat 1500) prior to driving Company owned cars.

PS
Not to mention the column gear change and horn ring!

[Iain]

Just leave it stock and enjoy the drive

That is generally the advised conclusion, but it is one of the more interesting aspects of fuel injected cars. In my opinion anyway. How something as silly as a piece of plastic in a certain position is the difference between a well-running car and failing MOT.


Having said that... It does make one hark back to the days of carburetors. (yes, I do remember them)... If fueling was off, a bit twist here, tighten there and "does it sound right?".
So much simpler. But.. In the same vein, who remembers having to use the choke? Bit harder than just cranking the engine and letting the ecu figure it out.

Used to love setting up and messing with the carb etc on my old 998 mini, taught me alot about engines.  Like you say you knew when it was right as it sounded so sweet. Miss doing that alot, still get the urge to get myself another mini one day.

[Zspeed]

2. It is known that having a colder air source is beneficial for power. This is true. Having the intake that is sits behind the battery will bring in the lowest intake temps compared to almost all of the aftermarket intakes that make a curve and go to the back of the car near the exhaust components.  Those are some of the worst intake designs and it should be called a hot air intake. However I did not notice much if any difference when it came to added power when I tried to add additional shielding which reduced the air intake temps an additional 10f so I removed the shielding. I notice more power on a colder day than trying to make the intake the absolute coldest. 

3. The more bends you have in the intake and the longer the run the more resistive the intake is. This is why using the short ram intake that sits behind the battery is the best intake design for our car because its not only a short ram its also a cold air which is rare for most cars as you can only have one or the other.

4. If you notice at the end of the video he echos much of what I have been writing regarding calibrated intake tubes and how they work. However he mentions the vanes used in some of them as air straighteners but fails to mention that they are for the calibration. That segmented section in the tube is like having a smaller diameter tube that speeds up the air velocity to cool the MAF wire. Without it you will have a rise in fuel trims. I have data logged this and found it to be true. Later on someone else performed the same experiment adding his own vanes and had a reduction in positive fuel trims.

 Here is where you make power. With the less restive intake it becomes synergistic with anything that makes the engine spin up faster. If you add a less restrictive exhaust and so forth the benefits will be additive. When this happens the car can suck in more air, it will be read properly by the MAF so the ECU can calculate how much fuel to inject along with the timing. The increase in positive fuel trims will be genuine which results in more power. With an uncalibrated MAF tube the ECU reports less air but the 02 sensor reports more air or a leaner mixture. In order to keep the correct AF ratios for emission it will richen the mixture but there is no benefit for performance.

 As far as how much you can get out of a proper intake like adapting the 2ZZ housing. Probably a genuine 3-5 whp. That is a lot for a small engine like this one and it wont be just at peak, it should be across the board which is where it can be felt. There are many dynos that exaggerates their figures and that is why real low figures dont seem like much.

So if I get this right, it would make sense that the bcm cda sealed and insulated type filter system or alternative, piped directly to the back of the battery should bring the coldest air available to the car, and used in conjunction with a Toyota maf pipe, should be the most efficient, even if the overall effect is minor.

It would appear to be the most efficient way of supplying the coldest air available rather than risking an open filter sucking air from inside the engine bay. I too struggle to see how the shields I have seen available would do any sort of job of stopping the air mixing and entering the filter. I have seen some with an entrance at the end, but the surface area on the side is massive and would expect it to be the main drawing area.

[shnazzle]

2. It is known that having a colder air source is beneficial for power. This is true. Having the intake that is sits behind the battery will bring in the lowest intake temps compared to almost all of the aftermarket intakes that make a curve and go to the back of the car near the exhaust components.  Those are some of the worst intake designs and it should be called a hot air intake. However I did not notice much if any difference when it came to added power when I tried to add additional shielding which reduced the air intake temps an additional 10f so I removed the shielding. I notice more power on a colder day than trying to make the intake the absolute coldest. 

3. The more bends you have in the intake and the longer the run the more resistive the intake is. This is why using the short ram intake that sits behind the battery is the best intake design for our car because its not only a short ram its also a cold air which is rare for most cars as you can only have one or the other.

4. If you notice at the end of the video he echos much of what I have been writing regarding calibrated intake tubes and how they work. However he mentions the vanes used in some of them as air straighteners but fails to mention that they are for the calibration. That segmented section in the tube is like having a smaller diameter tube that speeds up the air velocity to cool the MAF wire. Without it you will have a rise in fuel trims. I have data logged this and found it to be true. Later on someone else performed the same experiment adding his own vanes and had a reduction in positive fuel trims.

 Here is where you make power. With the less restive intake it becomes synergistic with anything that makes the engine spin up faster. If you add a less restrictive exhaust and so forth the benefits will be additive. When this happens the car can suck in more air, it will be read properly by the MAF so the ECU can calculate how much fuel to inject along with the timing. The increase in positive fuel trims will be genuine which results in more power. With an uncalibrated MAF tube the ECU reports less air but the 02 sensor reports more air or a leaner mixture. In order to keep the correct AF ratios for emission it will richen the mixture but there is no benefit for performance.

 As far as how much you can get out of a proper intake like adapting the 2ZZ housing. Probably a genuine 3-5 whp. That is a lot for a small engine like this one and it wont be just at peak, it should be across the board which is where it can be felt. There are many dynos that exaggerates their figures and that is why real low figures dont seem like much.

So if I get this right, it would make sense that the bcm cda sealed and insulated type filter system or alternative, piped directly to the back of the battery should bring the coldest air available to the car, and used in conjunction with a Toyota maf pipe, should be the most efficient, even if the overall effect is minor.

It would appear to be the most efficient way of supplying the coldest air available rather than risking an open filter sucking air from inside the engine bay. I too struggle to see how the shields I have seen available would do any sort of job of stopping the air mixing and entering the filter. I have seen some with an entrance at the end, but the surface area on the side is massive and would expect it to be the main drawing area.

It's not just the MAF pipe. That's 90% of it, but if you consider that the stock MAF is attached to the airbox, the airbox itself plays a role in how that air hits the MAF. But as a general rule of thumb, yes, plumbing it to behind the battery 100% keeps intake temps down. With the enclosed Hurricane intake behind the battery with the pipe fed directly by the side vent, and with heat-tape on the pipework, my intake temps generally 2-3deg above ambient at most while driving. At standstill, or traffic driving, my temps were worse than stock. 

Had I used a stock MR2 MAF pipe, my fueling would have been a lot better. 

Remember though that it is in NO way a "ram" effect. 
A) the vent is in a low pressure zone, so air is never forced in. 
B) there is far too much distance and pipework for any ram effect. 
That's all sorted by riding the exhaust pulses. 

The stock intake comes in from the side vent and goes behind the battery, then gets sucked into a pipe in the side panel,which then leads behind the left rear light and into the airbox. So, it IS "cold air" feed the way it is. As cold as it can be pretty much. You could replace the pipe between the MAF and the throttle body and cover it in heat-reflective tape but the effect will be minimal. 
All the hot air is going out the bottom and top engine lid vents, when you're moving. It's not double-backing to behind the battery. 
At standstill, the stock system is quite ingenious as the longest pipe sits in the side panel, shielded by metal, rubber and fabric insulation from the hot engine. It's kind of the best of both worlds.

[Zspeed]

2. It is known that having a colder air source is beneficial for power. This is true. Having the intake that is sits behind the battery will bring in the lowest intake temps compared to almost all of the aftermarket intakes that make a curve and go to the back of the car near the exhaust components.  Those are some of the worst intake designs and it should be called a hot air intake. However I did not notice much if any difference when it came to added power when I tried to add additional shielding which reduced the air intake temps an additional 10f so I removed the shielding. I notice more power on a colder day than trying to make the intake the absolute coldest. 

3. The more bends you have in the intake and the longer the run the more resistive the intake is. This is why using the short ram intake that sits behind the battery is the best intake design for our car because its not only a short ram its also a cold air which is rare for most cars as you can only have one or the other.

4. If you notice at the end of the video he echos much of what I have been writing regarding calibrated intake tubes and how they work. However he mentions the vanes used in some of them as air straighteners but fails to mention that they are for the calibration. That segmented section in the tube is like having a smaller diameter tube that speeds up the air velocity to cool the MAF wire. Without it you will have a rise in fuel trims. I have data logged this and found it to be true. Later on someone else performed the same experiment adding his own vanes and had a reduction in positive fuel trims.

 Here is where you make power. With the less restive intake it becomes synergistic with anything that makes the engine spin up faster. If you add a less restrictive exhaust and so forth the benefits will be additive. When this happens the car can suck in more air, it will be read properly by the MAF so the ECU can calculate how much fuel to inject along with the timing. The increase in positive fuel trims will be genuine which results in more power. With an uncalibrated MAF tube the ECU reports less air but the 02 sensor reports more air or a leaner mixture. In order to keep the correct AF ratios for emission it will richen the mixture but there is no benefit for performance.

 As far as how much you can get out of a proper intake like adapting the 2ZZ housing. Probably a genuine 3-5 whp. That is a lot for a small engine like this one and it wont be just at peak, it should be across the board which is where it can be felt. There are many dynos that exaggerates their figures and that is why real low figures dont seem like much.

So if I get this right, it would make sense that the bcm cda sealed and insulated type filter system or alternative, piped directly to the back of the battery should bring the coldest air available to the car, and used in conjunction with a Toyota maf pipe, should be the most efficient, even if the overall effect is minor.

It would appear to be the most efficient way of supplying the coldest air available rather than risking an open filter sucking air from inside the engine bay. I too struggle to see how the shields I have seen available would do any sort of job of stopping the air mixing and entering the filter. I have seen some with an entrance at the end, but the surface area on the side is massive and would expect it to be the main drawing area.

It's not just the MAF pipe. That's 90% of it, but if you consider that the stock MAF is attached to the airbox, the airbox itself plays a role in how that air hits the MAF. But as a general rule of thumb, yes, plumbing it to behind the battery 100% keeps intake temps down. With the enclosed Hurricane intake behind the battery with the pipe fed directly by the side vent, and with heat-tape on the pipework, my intake temps generally 2-3deg above ambient at most while driving. At standstill, or traffic driving, my temps were worse than stock.

Had I used a stock MR2 MAF pipe, my fueling would have been a lot better.

Remember though that it is in NO way a "ram" effect.
A) the vent is in a low pressure zone, so air is never forced in.
B) there is far too much distance and pipework for any ram effect.
That's all sorted by riding the exhaust pulses.

The stock intake comes in from the side vent and goes behind the battery, then gets sucked into a pipe in the side panel,which then leads behind the left rear light and into the airbox. So, it IS "cold air" feed the way it is. As cold as it can be pretty much. You could replace the pipe between the MAF and the throttle body and cover it in heat-reflective tape but the effect will be minimal.
All the hot air is going out the bottom and top engine lid vents, when you're moving. It's not double-backing to behind the battery.
At standstill, the stock system is quite ingenious as the longest pipe sits in the side panel, shielded by metal, rubber and fabric insulation from the hot engine. It's kind of the best of both worlds.

Seems everyone has had such different experiences with their attempts that opinions vary so much.  The lack of dyno I suppose. I Was hoping there was a consensus that you get the best result from doing something in particular, even if not with particular branded items. The dyno video and other conversations suggest there is some benefit even if small.

@shnazzle you seem to have put a system in yours but are suggesting stock is best, or am I misreading that? I'm not bothered about sound, more about a little value for money boost.

[Dev]

2. It is known that having a colder air source is beneficial for power. This is true. Having the intake that is sits behind the battery will bring in the lowest intake temps compared to almost all of the aftermarket intakes that make a curve and go to the back of the car near the exhaust components.  Those are some of the worst intake designs and it should be called a hot air intake. However I did not notice much if any difference when it came to added power when I tried to add additional shielding which reduced the air intake temps an additional 10f so I removed the shielding. I notice more power on a colder day than trying to make the intake the absolute coldest. 

3. The more bends you have in the intake and the longer the run the more resistive the intake is. This is why using the short ram intake that sits behind the battery is the best intake design for our car because its not only a short ram its also a cold air which is rare for most cars as you can only have one or the other.

4. If you notice at the end of the video he echos much of what I have been writing regarding calibrated intake tubes and how they work. However he mentions the vanes used in some of them as air straighteners but fails to mention that they are for the calibration. That segmented section in the tube is like having a smaller diameter tube that speeds up the air velocity to cool the MAF wire. Without it you will have a rise in fuel trims. I have data logged this and found it to be true. Later on someone else performed the same experiment adding his own vanes and had a reduction in positive fuel trims.

 Here is where you make power. With the less restive intake it becomes synergistic with anything that makes the engine spin up faster. If you add a less restrictive exhaust and so forth the benefits will be additive. When this happens the car can suck in more air, it will be read properly by the MAF so the ECU can calculate how much fuel to inject along with the timing. The increase in positive fuel trims will be genuine which results in more power. With an uncalibrated MAF tube the ECU reports less air but the 02 sensor reports more air or a leaner mixture. In order to keep the correct AF ratios for emission it will richen the mixture but there is no benefit for performance.

 As far as how much you can get out of a proper intake like adapting the 2ZZ housing. Probably a genuine 3-5 whp. That is a lot for a small engine like this one and it wont be just at peak, it should be across the board which is where it can be felt. There are many dynos that exaggerates their figures and that is why real low figures dont seem like much.

So if I get this right, it would make sense that the bcm cda sealed and insulated type filter system or alternative, piped directly to the back of the battery should bring the coldest air available to the car, and used in conjunction with a Toyota maf pipe, should be the most efficient, even if the overall effect is minor.

It would appear to be the most efficient way of supplying the coldest air available rather than risking an open filter sucking air from inside the engine bay. I too struggle to see how the shields I have seen available would do any sort of job of stopping the air mixing and entering the filter. I have seen some with an entrance at the end, but the surface area on the side is massive and would expect it to be the main drawing area.

It is my opinion that this using the MAF pipe along with the placing the filter behind the battery should yield power. Not much but enough that it matters and can be felt. I believe it will correctly report the correct amount of air just like the OEM intake system in the box. It also reduces the weight of the entire intake system and it will sound nice also. Regarding  cold air I have tested both the OEM box against the filter behind the battery.  The OEM box has more heat soak and higher IAT however at idle it is less than behind the battery.  Once you take off the intake behind the battery falls quickly and is less than the OEM and that is what matters more if cold air is your goal. 

 However if using the 2ZZ MAF pipe there might be further gains as it was reported in the video.

 That is why I am trying to get someone to do it to see what happens. If the video is correct you should certainly feel it even if it is half the power that was made on the dyno. 


 

[Dev]

 I will make one statement that goes in contrast with the leave it alone crowd.

You don't know unless you try. Just because others have done this improperly in the past  doesn't mean the proper way of doing it using the MAF tube will result in the same outcome. 

 I think the video is genuine but at the same time I think the hp numbers are a little more inflated but it doesn't matter because there is a baseline with the OEM system which shows that there are real gains. 

With the leave it alone philosophy you will never know unless an attempt has been made. Either way it is fun to find out especially when it has already been done by one person with actual dyno numbers.

[shnazzle]

@shnazzle you seem to have put a system in yours but are suggesting stock is best, or am I misreading that? I'm not bothered about sound, more about a little value for money boost.

I have indeed.
- Stock
- Stock + Panel
- Stock + markiii elbow pipe + panel
- OEM MAF pipe + cone
- Hurricane enclosed Lotus intake with direct feed from side vent
- piggyback ecu to fake MAF signal (electronic MAF mod).

Stock + panel + markiii elbow seems to be the sweet spot for the least money/effort.
The rest is just noise. Beautiful noise. Addictive noise. But just noise. And imperfect fueling.

There is 100% merit in experimenting. Look at "Cap's MAF Mod". Worked out well. Gains in the mids. And using the 2zz oem MAF. Proven gains in mids (same effect).

Wrt to the 2zz maf adapter from Danny's video that needs re-testing.
- tests against stock using same MAF
- tests using various cone filters and also stock box + panel filter.

[Zspeed]

Danny has done another video. It's sort of what I was expecting and the reason why I mentioned the enclosed filters.

The difference in air temperatures he mentions are massive.

https://youtu.be/fZMt34ZS6W0

[The Other Stu]

It was what I suspected all along. The tests he was doing with the lid open and forced air intake weren't real life.
I had exactly the same experience when I put my cone filter behind the battery - it was great until the engine got up to temperature.

I do wonder, however, if I was to design an intake that took all of the air coming in the side pod and throw it through a CDA. You'd need to open up the intake from the other side, because the engine bay would get no air in.

My issue with the Toyota designed intake is that yes, it works. But the air has to travel an awfully long way to get to the engine. Any front engined car has the intake as short as feasibly possible.

How do other mid engined cars do it?

[Dev]

I think the implementation could have been much better but I do think the shielding should work.


1. The tube needs to be longer and it should bend downwards in an angle closer to the vent in the path of getting air from the vent. What is making the air hotter is not just the migration of hot air to the front its also the radiator pipe just underneath where he is sucking up hot air. I did it kind of like his way and the IATs were higher.

2. Another reason why his IAT are higher is primarily because he has no battery in that location. The battery acts like a shield from the migration of hot air and creates a pocket of cold air from where the filter can draw from like the OEM intake.  Now he has to build a shield to compensate for it but its not a very good one. I built a better one that brought the temps to near ambient but removed it and now my IATs are just 10f over and I felt no difference in power. My ambient at idle at a stop light would creep up to 20f but will drop rapidly once I got going with in a minute. The OEM air box might be a little more stable in this respect but it takes forever for the temps to fall and they get progressively higher the longer you drive it.

I have tried many different ways and lengths of tube and it makes a big difference where the filter is situated especially if it is not in the path of the side vent air. I found that if the filter is closer to the port hole where the OEM air box gets its air from the side vent like how the car was designed the intake is much cooler. That filter he is using is just too short and large at the mouth.

There are ways he can fix this buy using a 15 degree silicon coupler from the throttle body so the tube is pointing downwards at an angle and to lengthen the tube.

This is how my set up is and after doing many data logs the air remains cool even on the hottest days or driven for a long time.
You cannot view this attachment.

[The Other Stu]

This is how my set up is and after doing many data logs the air remains cool even on the hottest days or driven for a long time.
You cannot view this attachment.

Interesting indeed. That's how I had mine setup and it was terrible. My cone (K&N) was very similar too.
Although I used a MAF adapter (which I think was probably part of the problem) because it didn't have the vanes.

Is there any reason why you couldn't put the cone even further into the intake? I mean, what else is that intake keeping cool? The battery?