Mod your ACT Sensor And Gain HP?!

look the one ive done yesterday(99%oem) afe intake only 3000miles on it oil,oil,oil,oil and the sensor was on the plastic to,,i did 3 and all the same....

like some ive said this mod will only give the sensor/ecu the 1000%(well i guess ) accurate reading

When I took mine out yesterday (850 miles), it was already covered with a fine film of oil. Too bad there isn't a AOS for this car (I came from the Subaru crowd before).

Kekela98a said:

When I took mine out yesterday (850 miles), it was already covered with a fine film of oil. Too bad there isn't a AOS for this car (I came from the Subaru crowd before).

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We are working on this! The trick part is the drain required for how ours works. The best solution isn't a cheap one at the moment. But we have some ideas!

My personal CTR has about 5K on it and it was pretty oily. The best part is our shop car with around 250miles on it almost looked as bad!

PERRIN_Jeff said:

We are working on this! The trick part is the drain required for how ours works. The best solution isn't a cheap one at the moment. But we have some ideas!

My personal CTR has about 5K on it and it was pretty oily. The best part is our shop car with around 250miles on it almost looked as bad!

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With this much oil on the sensor. I wonder what our intake valves must look like.

I will try this once a better guide is posted!

But I feel I won't notice any difference because its chilly out here in Canada now lol.

Walnut blasting of the intake system on Direct Injection motors is typically part of the general maintenance. The good thing is there are more and more DIY kits out there that make it more affordable and easier to do.
Don't quote me, but I think BMW requires this every 40K on most of their turbo models.

FK8_K20c1 said:

Modifying the sensor will not give you more boost. The readings are not inaccurate and is not nearly the same thing as spoofing the sensor. This mod tells the ecu the exact temp of the air going in. Give the op post another read. I think you got confused.

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I thought I read that it would produce more boost than if it were to get the stock reading. In either case, the engine would be pulling power due to the higher temp reading than a lower temp reading would cause it to do (basically making the motor produce more power in conditions it wasn't designed* to do so). You're still sending the ECU a reading that is different than what should be expecting*. It's spoofing the sensor through mechanical means, the spoofing in this case is smaller than what the software would do, but it's still being handed a different value than it would if it were OEM spec*.

An example, let's say that I had a microphone (audio sensor) that has a calibration file from the factory to adjust its inputs to be accurate from 20Hz-20kHz. Let's say that it's inaccurate from -5dB down to -10dB across said range (but corrected from software). Now, let's say that I go ahead and modify the microphone so that it is nearly perfect and within -1 dB (20Hz-20kHz). With said calibration file (software), it's no longer accurate as it'll be +4dB up to +9dB off from what it should be. I've spoofed the software into thinking everything is louder than it actually is.

*I want to assume that the Honda engineers already know about this and calibrated the motor for this to what they wanted it to do (for example longer engine life), they did design the motor after all. It's good to see a mod like this come to light, don't get me wrong. This is literally tuning the motor through physical means. The thing is, we'll never really know whether Honda engineers know about this or if it was intentionally part of the design. But if it was, the ECU was adjusted for it (whether that's a positive or negative thing for the end user).

JESFromASC,
I wasn’t 100% sure what to cut either when PERRIN_Jeff first shared, until pulling the sensor and looking at it. Then it made sense.

The sensor is much smaller than it looks in the photos. I used an exacto knife as suggested and did the mod sitting at a desk with plenty of light so could see it clearly.

Hopefully these pics will help, sorry no video. Recycling some of Perrin_Jeff’s photos:


The piece we want to trim is this center rectangular piece the arrow is pointing to and the cut line is where the arrow is touching. Removing 2/3 of it will allow the thermistor bulb to move but still give some protection to the thermistor wires.

Do not cut the thermistor wires or side housing plastics.


Looking top down, the lower arrow is again touching the same piece to trim.

The upper arrow is pointing to the thermistor bulb you ultimately want to bend away from the side plastic. That white circle the arrow is touching does not exist. It’s just circling the bulb so we can see it.

See.. it’s very small. Was very careful when trimming the rectangular tab as didn’t want to nick the thermistor wires...the tab doesn’t cut in one shot. Gotta score it and keep going over the same spot until it grooves enough to snap off.


Here’s a photo of the rectangular tab trimmed off. The arrow is now pointing to the freed up thermistor bulb.

I cut my tab a little bit lower. I removed 2/3 of it.



After the tab was cut, I used the flat tip of the exacto knife to gently push the thermistor bulb away from the side. Almost got it perfectly centered.


Here is a close up of the now centered thermistor bulb. Make sure no oil on it, reinstall and enjoy

JESFromASC said:

Better yet folks - maybe someone could shoot a how-to VIDEO of this mod?
I have yet to see one good picture of what exactly it is that you are trimming.
I have yet to see one good picture of how you are trimming it.
I have yet to see one good picture of a before and after.
Even the language is misleading...
I'd like to do it but not until I have a better idea of the right way to do it.

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Just attempted this today...definitely no graceful way to do this lol. Ended getting X-acto marks everywhere but was successful and most importantly didn't damage the probe or the remaining shroud.

What's this people saying they have oily probes? Mine was bone dry at 28k miles. But then again, I've had a catch can since 5k miles...maybe that made a difference?

tinyman392 said:

I thought I read that it would produce more boost than if it were to get the stock reading. In either case, the engine would be pulling power due to the higher temp reading than a lower temp reading would cause it to do (basically making the motor produce more power in conditions it wasn't designed* to do so). You're still sending the ECU a reading that is different than what should be expecting*. It's spoofing the sensor through mechanical means, the spoofing in this case is smaller than what the software would do, but it's still being handed a different value than it would if it were OEM spec*.

An example, let's say that I had a microphone (audio sensor) that has a calibration file from the factory to adjust its inputs to be accurate from 20Hz-20kHz. Let's say that it's inaccurate from -5dB down to -10dB across said range (but corrected from software). Now, let's say that I go ahead and modify the microphone so that it is nearly perfect and within -1 dB (20Hz-20kHz). With said calibration file (software), it's no longer accurate as it'll be +4dB up to +9dB off from what it should be. I've spoofed the software into thinking everything is louder than it actually is.

*I want to assume that the Honda engineers already know about this and calibrated the motor for this to what they wanted it to do (for example longer engine life), they did design the motor after all. It's good to see a mod like this come to light, don't get me wrong. This is literally tuning the motor through physical means. The thing is, we'll never really know whether Honda engineers know about this or if it was intentionally part of the design. But if it was, the ECU was adjusted for it (whether that's a positive or negative thing for the end user).

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You are still confusing what modifying this sensor does. If the car wouldn’t be designed to allow colder aircharge temps. All mishimoto and big intercooler owner would already have a broken motor. Honda choose a specific brand for the sensor it was not designed by them. Its was designed by Bosch. Every other car with such Bosch sensor looks the same. You cannot make more power that what it was written on the ECU no matter what mods you do on the car.

FK8_K20c1 said:

Modifying the sensor will not give you more boost. The readings are not inaccurate and is not nearly the same thing as spoofing the sensor. This mod tells the ecu the exact temp of the air going in. Give the op post another read. I think you got confused.

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While you are correct that the mod allows the sensor to respond faster, it does not mean that the "heat soaking" of the sensor was not taken into account by Honda. The design may as well have been introduced purposefully to provide a hysteresis in the readings (although it would be a very "analog" solution to a problem easily solved by software).

While I don't think we will ever know for sure, I would be cautious before jumping to conclusions that this mod does not skew the readings as it seems very unlikely to me that Honda (Bosch) would manufacture these sensors with a "flaw" (being the shrouding touching the probe) and not take its specific design into account when tuning the car afterwards.

Conducting a longterm test in extreme conditions with datalogging commanded boost, ignition, knock and EGT's AND an auxiliary temp. sensor could provide some scientific insight to this. Otherwise we are just guessing.

elmerzasty said:

While you are correct that the mod allows the sensor to respond faster, it does not mean that the "heat soaking" of the sensor was not taken into account by Honda. The design may as well have been introduced purposefully to provide a hysteresis in the readings (although it would be a very "analog" solution to a problem easily solved by software).

While I don't think we will ever know for sure, I would be cautious before jumping to conclusions that this mod does not skew the readings as it seems very unlikely to me that Honda (Bosch) would manufacture these sensors with a "flaw" (being the shrouding touching the probe) and not take its specific design into account when tuning the car afterwards.

Conducting a longterm test in extreme conditions with datalogging commanded boost, ignition, knock and EGT's AND an auxiliary temp. sensor could provide some scientific insight to this. Otherwise we are just guessing.

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The mod does not allow the sensor to respond faster, it allows the sensor to measure the right temperature of the air coming in. There is no flaw on the sensor, it was designed that way by BOSCH. The legs of the sensor are very fragile hence why the shrouds are there to stabilize it. Im testing a brand new sensor to compare the data and conclude what I have personally gathered this week. An auxiliary sensor is OVERKILL, I have all I need on the flashpro datalog.

FK8_K20c1 said:

The mod does not allow the sensor to respond faster, it allows the sensor to measure the right temperature of the air coming in.

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With sufficient airflow at a given temperature the sensor, the shroud and air will have the same temperature, so it actually is about increasing response.

What you should bear in mind is that you are assuming that Honda/Bosch wanted to measure the "right air temperature" at the sensor sans the impact of the shroud on the readings. Bear in mind that the whole purpose of measuring air temperature in this place is to determine the temperature of the air in the cylinders, not at the sensor. The sensor is close to the cylinders, but is not inside any of them. Given the manifold and head get hot and influence the air temp., the "heatsoak design" of the sensor might be intentional to account for what happens to the air after passing through the sensor.

elmerzasty said:

With sufficient airflow at a given temperature the sensor, the shroud and air will have the same temperature, so it actually is about increasing response.

What you should bear in mind is that you are assuming that Honda/Bosch wanted to measure the "right air temperature" at the sensor sans the impact of the shroud on the readings. Bear in mind that the whole purpose of measuring air temperature in this place is to determine the temperature of the air in the cylinders, not at the sensor. The sensor is close to the cylinders, but is not inside any of them. Given the manifold and head get hot and influence the air temp., the "heatsoak design" of the sensor might be intentional to account for what happens to the air after passing through the sensor.

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Having difficulty understanding this "sensor sans the impact of the shroud"

FK8_K20c1 said:

Having difficulty understanding this "sensor sans the impact of the shroud"

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... that Honda/Bosch wanted to measure the "right air temperature" at the sensor without the effect that the shrouding has on the sensor readings.