Does anyone have data about this? Dynamic range as well as lower end response?
Landtank MAF surprising scangauge results
- Thread starter Brian894X4
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Does anyone have data about this? Dynamic range as well as lower end response?
- Thread starter
- #22
A few points…
Someone mentioned in this thread and in the below comment that h.p. gain could be in the 20 h.p. range. This is about what it felt like to me. See below…
From this thread, post no. 111
https://forum.ih8mud.com/80-series-tech/132012-test-maf-gen-1-a-4.html
Right now I think the testing phase is pretty much wrapped up. We did a comparison between my truck with the stock MAF and Cattledog's with the modded MAF and his truck reported 2 more lbs of air flow. A basic rule of thumb is that for every pound of air you get 10 HP. So a stock truck with my MAf will get basically a 20 HP gain. There is also a torque gain but I'm not aware of any way to quesstimate that from air flow.
My original sensor only had 106K miles on it. The “new” sensor is a used one from a 2003 Camry, unknown mileage, so not new. But I did clean it prior to installing.
Also as far as the accuracy of the scangauge, the h.p. readings at idle on both sensors, which I did record on the same day and under the same circumstances were nearly the same. About 6-7 h.p. at 600-650 rpm. When I test both sensors again, I’ll post all the data I can to verify this.
What I did find out was that gas consumption at idle (in park, no load) went down, even at the same rpm. It measured roughly .45-.46 with the old sensor and now measures roughly .38-.40. I’ve never seen idle gas consumption less than .45 before. I don’t know that this translates to better economy at higher rpms, but rather is probably a function of the MAF actually allowing controlling the fuel mixture better at idle whereas the old sensor used wasn’t really used to control mixture at idle, if I understand correctly.
Someone mentioned in this thread and in the below comment that h.p. gain could be in the 20 h.p. range. This is about what it felt like to me. See below…
From this thread, post no. 111
https://forum.ih8mud.com/80-series-tech/132012-test-maf-gen-1-a-4.html
Right now I think the testing phase is pretty much wrapped up. We did a comparison between my truck with the stock MAF and Cattledog's with the modded MAF and his truck reported 2 more lbs of air flow. A basic rule of thumb is that for every pound of air you get 10 HP. So a stock truck with my MAf will get basically a 20 HP gain. There is also a torque gain but I'm not aware of any way to quesstimate that from air flow.
My original sensor only had 106K miles on it. The “new” sensor is a used one from a 2003 Camry, unknown mileage, so not new. But I did clean it prior to installing.
Also as far as the accuracy of the scangauge, the h.p. readings at idle on both sensors, which I did record on the same day and under the same circumstances were nearly the same. About 6-7 h.p. at 600-650 rpm. When I test both sensors again, I’ll post all the data I can to verify this.
What I did find out was that gas consumption at idle (in park, no load) went down, even at the same rpm. It measured roughly .45-.46 with the old sensor and now measures roughly .38-.40. I’ve never seen idle gas consumption less than .45 before. I don’t know that this translates to better economy at higher rpms, but rather is probably a function of the MAF actually allowing controlling the fuel mixture better at idle whereas the old sensor used wasn’t really used to control mixture at idle, if I understand correctly.
- Thread starter
- #23
Another point is that Toyota gained significant power from the 1FZ after U.S. model production ended in 1997. The Aussie 1FZ was later rated at 221 h.p. and 285 ft/lbs of torque. From an Aussie Toyota press release they note the following about the “upgraded 1fZ engine…note the part about the revised MAF sensor....
source...
http://www.pressroom.com.au/pressroom/sample/presskits/78kit.htm
------------------------------
Toyota's new LandCruiser 78 Series has the most powerful engine in the 4x4 workhorse class.
It has the improved 4.5 litre EFI-equipped Toyota 1FZ-FE engine, which debuted in LandCruiser 100 Series.
The improved petrol engine has more power and, by a significant margin, the most torque of any workhorse 4x4 engine.
It has 7kW more power and 14Nm more torque than the superseded LandCruiser 75 Series petrol six, without sacrificing fuel economy.
The 4477cc engine delivers 165kW of power at 4600rpm and 387Nm of torque at 3600rpm.
It has more torque than the superseded powerplant from 2800rpm to beyond 4000, with 312Nm available at just 800rpm.
The new engine improves 0-100km/h performance by up to 11 percent (TroopCarrier model).
Toyota's 1FZ-FE engine was redesigned throughout for the introduction of LandCruiser 100 Series.
These benefits have flowed on to the workhorse models.
Power and torque were improved by adopting longer intake runners, new short-skirt pistons with higher piston rings to reduce dead air volume, an all-stainless steel exhaust system with fabricated headers and new engine electronics.
A revised cylinder head provides enlarged inlet ports and a revised combustion chamber design with increased squish area and larger valve seats.
Fuel system improvements include the adoption of full sequential injection with four-hole injectors and a hot-wire type air-flow meter for greater mixture accuracy.
The improved engine adopts direct ignition with three igniters and multiplex diagnostics.
Direct ignition improves reliability and emissions, and reduces service time.
NVH countermeasures include a redesigned cylinder block, with additional strengthening ribs, and reduced reciprocating mass achieved by adopting lightweight pistons.
Emission levels have been reduced compared with the superseded LandCruiser 75 Series petrol engine.
--------------------
That's a lot of improvements to make a gain of what amounts to about 9 h.p. Personally, I wonder if Toyota underrated the new 1FZ. In some very late model 1FZ where they incorporated a VVTi head, they rate the power output at over 240 h.p. It's well known that actual published h.p. numbers are not necessarily dead accurate but more political. In many european countries, the insurance rates are based on the h.p. rating of a vehicle, so it's hard to say. I still suspect that that MAF mod alone is worth at least and probably more than 10 h.p. on our engines, based on my experience.
source...
http://www.pressroom.com.au/pressroom/sample/presskits/78kit.htm
------------------------------
Toyota's new LandCruiser 78 Series has the most powerful engine in the 4x4 workhorse class.
It has the improved 4.5 litre EFI-equipped Toyota 1FZ-FE engine, which debuted in LandCruiser 100 Series.
The improved petrol engine has more power and, by a significant margin, the most torque of any workhorse 4x4 engine.
It has 7kW more power and 14Nm more torque than the superseded LandCruiser 75 Series petrol six, without sacrificing fuel economy.
The 4477cc engine delivers 165kW of power at 4600rpm and 387Nm of torque at 3600rpm.
It has more torque than the superseded powerplant from 2800rpm to beyond 4000, with 312Nm available at just 800rpm.
The new engine improves 0-100km/h performance by up to 11 percent (TroopCarrier model).
Toyota's 1FZ-FE engine was redesigned throughout for the introduction of LandCruiser 100 Series.
These benefits have flowed on to the workhorse models.
Power and torque were improved by adopting longer intake runners, new short-skirt pistons with higher piston rings to reduce dead air volume, an all-stainless steel exhaust system with fabricated headers and new engine electronics.
A revised cylinder head provides enlarged inlet ports and a revised combustion chamber design with increased squish area and larger valve seats.
Fuel system improvements include the adoption of full sequential injection with four-hole injectors and a hot-wire type air-flow meter for greater mixture accuracy.
The improved engine adopts direct ignition with three igniters and multiplex diagnostics.
Direct ignition improves reliability and emissions, and reduces service time.
NVH countermeasures include a redesigned cylinder block, with additional strengthening ribs, and reduced reciprocating mass achieved by adopting lightweight pistons.
Emission levels have been reduced compared with the superseded LandCruiser 75 Series petrol engine.
--------------------
That's a lot of improvements to make a gain of what amounts to about 9 h.p. Personally, I wonder if Toyota underrated the new 1FZ. In some very late model 1FZ where they incorporated a VVTi head, they rate the power output at over 240 h.p. It's well known that actual published h.p. numbers are not necessarily dead accurate but more political. In many european countries, the insurance rates are based on the h.p. rating of a vehicle, so it's hard to say. I still suspect that that MAF mod alone is worth at least and probably more than 10 h.p. on our engines, based on my experience.
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theoretically the fuel consumption at idle should be the same. That is because the ECU is in closed loop and adjusting fuel trim based on O2 readings.
The reason that you are seeing a drop in fuel consumption is that the new MAF reads the idle air flow more accurately and is operating the injectors at a lower duty cycle than with the stock MAF.
This is the reason for removing the vacuum line from the FPR. By removing the vacuum line the fuel rail pressure is now higher at idle and offsets the lower injector cycle that is calculated from the new MAF sensor.
Rick, the reason there is a vacuum line on the fuel pressure regulator is that Toyota wants the pressure differential between the intake manifold pressure and the fuel rail pressure to stay constant. At idle there is vacuum in the intake manifold, thus you need to decrease the fuel pressure, to keep the pressure differential the same. Disconnecting the line is causing excessive fuel pressure at idle. They did not install the pressure regulator because their sensor reads the air flow incorrectly idle. That is documented in the Toyota tech manuals.
if your MAF is causing high long term fuel trim at idle with the pressure regulator connected to vacuum, then it is measuring the air incorrectly and the truck is trying to adapt to that. You are telling the truck there is less air that what there is and the truck is trying to make up when it sees a lean condition. By disconnecting the fuel pressure regulator you are increasing the fuel rail pressure and it causes more fuel to be injected for a given duty cycle, so therefore the long term fuel trim goes down.
Where is the evidence that your sensor reads the low air flow better?
Also, how are you compensating for the increase in pressure in the manifold on boosted trucks if the fuel pressure regulator is not connected. If you don't leave the pressure regulator connected, the extra pressure in the manifold (due to the boost) is not compensated for and the pressure differential will not be constant again. If you leave the regulator connected, the possitive pressure on it will raise the fuel pressure in the rail, thus overcoming the extra pressure in the manifold.
if your MAF is causing high long term fuel trim at idle with the pressure regulator connected to vacuum, then it is measuring the air incorrectly and the truck is trying to adapt to that. You are telling the truck there is less air that what there is and the truck is trying to make up when it sees a lean condition. By disconnecting the fuel pressure regulator you are increasing the fuel rail pressure and it causes more fuel to be injected for a given duty cycle, so therefore the long term fuel trim goes down.
Where is the evidence that your sensor reads the low air flow better?
Also, how are you compensating for the increase in pressure in the manifold on boosted trucks if the fuel pressure regulator is not connected. If you don't leave the pressure regulator connected, the extra pressure in the manifold (due to the boost) is not compensated for and the pressure differential will not be constant again. If you leave the regulator connected, the possitive pressure on it will raise the fuel pressure in the rail, thus overcoming the extra pressure in the manifold.
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On another note, what is your long term fuel trim in closed loop under most driving conditions? Have you ever had a truck measure on a gas analyzer to make sure it is not running lean by checking the NOX readings? You can still be running lean, without tripping codes or having check engine lights.
- Thread starter
- #27
Rick or Christo,
What would be the consequences of leaving the pressure regulater hooked up with the new MAF installed?
What would be the consequences of leaving the pressure regulater hooked up with the new MAF installed?
you'll have an idle LTFT% that is way out of the norm during idle and could possibly throw a code. If you were to do a reset on the ECU, like removing the battery for a long enough period of time, you would be running very lean until the truck got hot enough to enter closed loop and start adjusting for that condition.
In my testing the only time that the vacuum line influenced the FT% was during idle and it accounted for a shift of about 18% from what I remember.
- Thread starter
- #29
By the way, I was thumbing through the International EPC over the 70 series board (awesome resource!) and it doesn't appear that any of the 1998 and later 1FZ-FE engines used any kind of MAF sensor. They all had an intake temp sensor, but that's it. I was trying to see if maybe they used the same part we retrofitted.
So, I'm curious how later model 1FZs controlled fuel mixture. In other searches, I've read that at least some models also didn't use O2 sensors?
The other interesting thing I found is that it looks like the 1998 and later 1FZ engines used the exact same fuel pressure regulator, same part and everything. However, I can't make heads or tails if the same vacuum line is used or not.
Here's the 1992-1997 diagram. 1FZ engine
http://www.toyodiy.com/parts/p_U_1995_TOYOTA_LAND+CRUISER_FZJ80L-GNPEKA_2211.html
Here's the 1998-2008 diagram. 1FZ engine
http://www.toyodiy.com/parts/p_G_2003_TOYOTA_LAND+CRUISER_FZJ105R-GNPNKQ_2211.html
So, I'm curious how later model 1FZs controlled fuel mixture. In other searches, I've read that at least some models also didn't use O2 sensors?
The other interesting thing I found is that it looks like the 1998 and later 1FZ engines used the exact same fuel pressure regulator, same part and everything. However, I can't make heads or tails if the same vacuum line is used or not.
Here's the 1992-1997 diagram. 1FZ engine
http://www.toyodiy.com/parts/p_U_1995_TOYOTA_LAND+CRUISER_FZJ80L-GNPEKA_2211.html
Here's the 1998-2008 diagram. 1FZ engine
http://www.toyodiy.com/parts/p_G_2003_TOYOTA_LAND+CRUISER_FZJ105R-GNPNKQ_2211.html
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But in an earlier post you quoted one of the benefits of the upgraded 1FZ-FE engine as...
"Fuel system improvements include the adoption of full sequential injection with four-hole injectors and a hot-wire type air-flow meter for greater mixture accuracy."
The hot-wire air-flow meter they are referring to is a MAF sensor. See this Mass flow sensor - Wikipedia, the free encyclopedia link for a description of how a hot-wire MAF works.
Christo, read the data logs. Rick and Turbocruiser had them at one point, Rick and I did most of the testing on my truck and then his. The rail pressure is conected to the vacuum in the intake on a stock truck. The change in pressure in the rail is not linear to the change vacuum in the manifold. Most of the pressure on the rail is with in a couple of psi off idle. If I recall correctly there are two readings for the rail pressure one for idle and one for higher rpm. I will look at the manual tonight.
Read the data... Long term trim is adjusted in intervals by several variables. The short term trim is adjusted VERY quickly.
If my truck was running lean It would have shown up in the o2 sensor reading in the datalogs and my mileage would be better.
I still get only 12 mpg....
So that means the sensor is reading the incorrect amount of air. How did you determine it is correct? Did you flow bench it?
How did you determine that your sensor reads better or more accurate than the stock one, other than your conclusion about the fuel trim that increased when you disconnected the FPR?
I reread the whole development thread and I saw your reasoning behind disconnecting the FPR and I believe it is simply not the correct thing to do. I can see that a newer sensor can have a better dynamic range, but if you cannot get the truck to idle correctly with all the fuel pressure systems hooked up, then something is wrong. If the sensor is reading the amount of air wrong at idle it is most probably wrong during driving as well.
How did you match the diameter of the housing to the sensor, other than monitor fuel trims?
I know everyone might now say, hey but the truck runs better. You might be experiencing a lean condition and not know it. Without putting the truck on a gas analyzer (to measure NOC) you would not know. Toyota traditionally tune trucks rich for safety. The truck will run better when leaned out, but that is not necessarily a good thing for the motor.
We have seen trucks fail emissions test (high NOX due to running lean) with no check engine lights or codes. The indicator was that it was running at 20% LTFT at idle.
Was this long term or short term you were measuring? What is the long term fuel trims on normal drive cycles?
I don't have the logs, but I would like to see what the LTFT is. See my comments on NOX. In this document is a good section on how the fuel pressure regulator work and how it keeps the pressure constant.
I know, but what is it?
Either running lean or rich, depending on what situation the truck is in. Everyone thinks that the O2 sensor feedback is enough to keep the truck in line, but that is not so. See comments about emissions and NOX measurements without throwing codes.
Also see document I quoted earlier. Toyota designed the system to operate with a constant pressure differential between the fuel rail and the manifold. The injector size and maps in the computer is designed to work with that. If you mess with that, you are relying on the feedback systems to keep things in check. Well sometimes they will not be able to.
Do you have a datalog that you can post?
How do you know that it samples better? It is an anolog device with a response curve. How does that produce better resolution? It can have a broader dynamic range and need a smaller sample to measure, but where is the documentation that says it is more accurate or better resolution?
How do you know that the factory sensor is restrictive for the air needs for a normally aspirated motor? If stand next to a stream and you drop a bucket (sampling device) into the stream for a second you will get a certain amount of water in the bucket based on the flow. You can then calculate how much water flows in the river, based on the size of the river.
If you now leave everything else constant, but you make the river twice the size, then you will have more flow but you will still collect the same amount of water in the bucket per second.
You can change the bucket size (new sensor), but you still have to calibrate it to be able to calculate the water blow.
How do you know the amount of air is correct? Also how do you know the computer maps go beyond what the MAF is designed for. I know turbocruiser reports more airflow as read from the OBD2. How do you know that is correct, ie, when the MAF sends out 3 volts to the ECU, it takes that reading (plus some other ones) and it makes it into a flow measurement. The new sensor sends out 3 volts as well, however the opening is much bigger so more air is entering the motor. The ECU does not know the opening is better. All it know is the 3 volt reading. So it thinks it gets a certain amount of air but it is in fact not.
I asked about the flow testing back then. As I recall he did not do it.
Christo, you are scaring me man.
I get some where from 14.46 to 14.98 mpg these days. I filled up this morning with 15.318 gallons after driving 221.5 miles. I am adopting to the habit of filling up when the tank is more than or equal to half empty. My gas mileage seems to have degraded over time after getting the new sensor. With stock sensor and (oem) exhaust with leak (between cats) I used to get some where between 16.45 to 16.88 mpg. It stayed that way for a little while after getting the new sensor. I have concluded that its my driving habit that caused the mpg degradation. After reading your post, sounds like I might be causing some long term damage to the engine; although I am not clear on what it is yet. I wonder if it would be wise to put the old sensor back with FPR hose.
I get some where from 14.46 to 14.98 mpg these days. I filled up this morning with 15.318 gallons after driving 221.5 miles. I am adopting to the habit of filling up when the tank is more than or equal to half empty. My gas mileage seems to have degraded over time after getting the new sensor. With stock sensor and (oem) exhaust with leak (between cats) I used to get some where between 16.45 to 16.88 mpg. It stayed that way for a little while after getting the new sensor. I have concluded that its my driving habit that caused the mpg degradation. After reading your post, sounds like I might be causing some long term damage to the engine; although I am not clear on what it is yet. I wonder if it would be wise to put the old sensor back with FPR hose.