ZeroEyeQueue-Update 7/23/2012 MAF Setup to Speed Density
07-04-2012, 06:02 AM
#361
It's good that WR has taken action to fix everything instead of letting it escalate to where legal actions were necessary. I'm glad that it worked out for you and you're build is freaking amazing. I love it
07-23-2012, 06:30 PM
#364
Speed Density SD vs. Mass Air Flow MAF
Often we deal with the question, "Which is better speed density (SD) or mass air flow (MAF)". As with most things in life there are advantages and disadvantages for both. Its better to understand each strategy so as to make the most informed decision.
Mass Air Flow
Mass air flow sensor equipped cars fuel either directly from or by a blended model of both mass air flow and speed density calculations. The MAF sensor is located somewhere in the intake stream typically away from sharp bends and typically at least 8-10 inches away from the throttle body however these rules are not always followed. There are several different types of MAF sensors but for most GM applications it is a frequency biased "cold-wire" sensor that generates a signal between 0 and 15k Hz. MAF sensors read not just airspeed but the relative mass of the air which eliminates pressure and temperature as variables. They are usually positioned to sample from the middle of the intake tubing which should give the best average reading.
Since the MAF sensor samples from a specific spot in the inlet tubing changing the airflow in or around the sensor requires recalibration of the MAF sensor. Changing the airflow around a MAF sensor can be caused by a change in size of the intake plumbing, bends before or after the MAF sensor, and changes to the MAF housing.
Several applications that use MAF biased strategies also use Speed Density as a backup or for a blended fuel calculation. They also use Speed Density as a sanity check for MAF readings.
Advantages
Typically more forgiving and easier to tune
If the MAF sensor has been calibrated typically fueling remains consistent as modifications change. It can be said that the MAF equipped cars are a little more forgiving to new modifications
Since the MAF sensor measures air mass directly it can be said that a MAF equipped car might stay in calibration as the engine wears or in extreme environment changes (however this is not normally a concern for well tuned speed density applications).
_
Disadvantages
Sensitive to changes to the intake plumbing
Can be fouled by becoming dirty. Once fouled MAF calibration is skewed
Sensitive to cam reversion on large cammed cars. The MAF sensor isn't directional so air pulsing back and forth can affect repeatability and reliability.
Limits on performance. Most systems can not read at higher horsepower levels.
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_
_
Speed Density
_
Speed density systems calculate the density of the air first by measuring the temperature of the inlet air and manifold pressure. With the density of air known the engine controller then looks up how much air it expects to be moving at a specific engine speed and manifold pressure. This is done in the Volumetric Efficiency table or VE table. Traditionally the VE table is 3D and has two axes Engine Speed (RPM) and Manifold Pressure or % Load. A engine that is 100% efficient moves exactly its displacement every two rotations in 4-cycle engines.
_
Advantages
Less restriction in the intake tract
More freedom in the intake tract
Able to measure air consumption on very high horsepower builds where a MAF sensor might be limited.
Able to read boost if equipped with a greater than 1 Bar map sensor
Free from errors encountered in MAF fouling.
Works better with large cams where reversion affects reliability.
_
Disadvantages
Is a little more difficult to tune
Relies on a well tuned Volumetric Efficiency Table
Less forgiving to new modifications to the engine
Might have errors in large weather changes however a proper tune makes this minimal if any error.
_
There are several vehicles that come with MAF sensors from the factory and there are several vehicles that come speed density from the factory. Really which fueling strategy you should go with on a aftermarket application is up to your modifications goals and expectations. If you are not the one to be tuning your setup please consult with your tuner for what he or she recommends.
_
_
_
Often we deal with the question, "Which is better speed density (SD) or mass air flow (MAF)". As with most things in life there are advantages and disadvantages for both. Its better to understand each strategy so as to make the most informed decision.
Mass Air Flow
Mass air flow sensor equipped cars fuel either directly from or by a blended model of both mass air flow and speed density calculations. The MAF sensor is located somewhere in the intake stream typically away from sharp bends and typically at least 8-10 inches away from the throttle body however these rules are not always followed. There are several different types of MAF sensors but for most GM applications it is a frequency biased "cold-wire" sensor that generates a signal between 0 and 15k Hz. MAF sensors read not just airspeed but the relative mass of the air which eliminates pressure and temperature as variables. They are usually positioned to sample from the middle of the intake tubing which should give the best average reading.
Since the MAF sensor samples from a specific spot in the inlet tubing changing the airflow in or around the sensor requires recalibration of the MAF sensor. Changing the airflow around a MAF sensor can be caused by a change in size of the intake plumbing, bends before or after the MAF sensor, and changes to the MAF housing.
Several applications that use MAF biased strategies also use Speed Density as a backup or for a blended fuel calculation. They also use Speed Density as a sanity check for MAF readings.
Advantages
Typically more forgiving and easier to tune
If the MAF sensor has been calibrated typically fueling remains consistent as modifications change. It can be said that the MAF equipped cars are a little more forgiving to new modifications
Since the MAF sensor measures air mass directly it can be said that a MAF equipped car might stay in calibration as the engine wears or in extreme environment changes (however this is not normally a concern for well tuned speed density applications).
_
Disadvantages
Sensitive to changes to the intake plumbing
Can be fouled by becoming dirty. Once fouled MAF calibration is skewed
Sensitive to cam reversion on large cammed cars. The MAF sensor isn't directional so air pulsing back and forth can affect repeatability and reliability.
Limits on performance. Most systems can not read at higher horsepower levels.
_
_
_
Speed Density
_
Speed density systems calculate the density of the air first by measuring the temperature of the inlet air and manifold pressure. With the density of air known the engine controller then looks up how much air it expects to be moving at a specific engine speed and manifold pressure. This is done in the Volumetric Efficiency table or VE table. Traditionally the VE table is 3D and has two axes Engine Speed (RPM) and Manifold Pressure or % Load. A engine that is 100% efficient moves exactly its displacement every two rotations in 4-cycle engines.
_
Advantages
Less restriction in the intake tract
More freedom in the intake tract
Able to measure air consumption on very high horsepower builds where a MAF sensor might be limited.
Able to read boost if equipped with a greater than 1 Bar map sensor
Free from errors encountered in MAF fouling.
Works better with large cams where reversion affects reliability.
_
Disadvantages
Is a little more difficult to tune
Relies on a well tuned Volumetric Efficiency Table
Less forgiving to new modifications to the engine
Might have errors in large weather changes however a proper tune makes this minimal if any error.
_
There are several vehicles that come with MAF sensors from the factory and there are several vehicles that come speed density from the factory. Really which fueling strategy you should go with on a aftermarket application is up to your modifications goals and expectations. If you are not the one to be tuning your setup please consult with your tuner for what he or she recommends.
_
_
_
08-16-2012, 01:15 PM
#366
Eric at World Electronics/World Racing East is tuning the car. They had a race event last week so my car was put aside until they were back from New Jersey.
The week before they left Eric told me he was working on the start-up calibrations. And, this past Monday, he said he was working on the idle. That's all I got so far.
The week before they left Eric told me he was working on the start-up calibrations. And, this past Monday, he said he was working on the idle. That's all I got so far.
Last edited by ZeroEyeQueue; 08-16-2012 at 01:28 PM.
09-21-2012, 02:53 AM
#369
Lots of issues came up. Rob along with Eric from WR East have really stepped it up for me.
My Garrett turbo needs a rebuild and there was a problem with one of my injectors. We're not out of the clear yet, but finding those problems did move things along. Hopefully, that's all there is. I'm hoping Eric can get 400 whp out of it without running out of fuel.
My Garrett turbo needs a rebuild and there was a problem with one of my injectors. We're not out of the clear yet, but finding those problems did move things along. Hopefully, that's all there is. I'm hoping Eric can get 400 whp out of it without running out of fuel.
11-23-2012, 06:43 PM
#371
More crap.
So, I was looking forward to my car coming back after the holiday. Then, I received and email from the tuner @ WR East. Compression has dropped and I was told it has developed a "tick". So, he called their engine builder, and they're speculating that the rings haven't seated properly. I don't blame him because, he is kind of a neutral party in this and has been doing the work pretty much for free just to help me out (which brings me to say this: If you're getting work done @ WR East, Eric Plebani is awesome. He is the most professional and thorough guy I've dealt with.)
However, he did say it was probably like this before the car came out to him. I don't pretend to understand how or why this is true, but all that it means is that I will possibly need a new block. So, I'm pretty much back at square one again. The shop out by me isn't going to take responsibility for it because it was a bunch of miss-communication between them, WR, and myself. In the end, I get screwed again. And, I can't really put the blame on anyone since the miss-communication was with everyone.
Eric is doing all he can for me. He's even checking if WR has a built block in stock that I exchange mine for a discount, or something. We don't even know if they offer anything like that. During this frustrating build, his constant updates have been a silver lining. At the very least, I can say that I'm not in the dark about anything.
So, I probably won't see my car until mid next year and after several more thousand dollars put into it.
So, I was looking forward to my car coming back after the holiday. Then, I received and email from the tuner @ WR East. Compression has dropped and I was told it has developed a "tick". So, he called their engine builder, and they're speculating that the rings haven't seated properly. I don't blame him because, he is kind of a neutral party in this and has been doing the work pretty much for free just to help me out (which brings me to say this: If you're getting work done @ WR East, Eric Plebani is awesome. He is the most professional and thorough guy I've dealt with.)
However, he did say it was probably like this before the car came out to him. I don't pretend to understand how or why this is true, but all that it means is that I will possibly need a new block. So, I'm pretty much back at square one again. The shop out by me isn't going to take responsibility for it because it was a bunch of miss-communication between them, WR, and myself. In the end, I get screwed again. And, I can't really put the blame on anyone since the miss-communication was with everyone.
Eric is doing all he can for me. He's even checking if WR has a built block in stock that I exchange mine for a discount, or something. We don't even know if they offer anything like that. During this frustrating build, his constant updates have been a silver lining. At the very least, I can say that I'm not in the dark about anything.
So, I probably won't see my car until mid next year and after several more thousand dollars put into it.
11-23-2012, 08:52 PM
#372
Damn bro I want your build to be a success so bad. Your build is legit and I'm so proud of how far you have come. Builds like this is what the scion brand needs so we don't stay in that rice category. Hopefully you won't give up and just part the car out for another platform. Keep up the good work.
06-18-2013, 02:52 PM
#376
Been a while.
New engine is being installed this week. Some things are being changed. Intercooler piping is being reworked, talks of a 3" V-band turbo-back exhaust, and a new tune all after engine break-in. This is tiring, but it may be only a couple months more. Yep, I said months.
New engine is being installed this week. Some things are being changed. Intercooler piping is being reworked, talks of a 3" V-band turbo-back exhaust, and a new tune all after engine break-in. This is tiring, but it may be only a couple months more. Yep, I said months.
06-18-2013, 03:20 PM
#379
Senior Member
SL Member
Join Date: Nov 2011
Location: New York
Posts: 292
Man I can't believe you're still working on this! I would've given up like a year ago. You're definitely an inspiration to some of the guys on here. Hopefully my rebuilt block wont have the same problems.
On a lighter note, how much power are you thinking when its all over and done with?
On a lighter note, how much power are you thinking when its all over and done with?
06-18-2013, 04:54 PM
#380
ZeroEyeQueue-Not really an update. 6/18/2013
I'm expecting just over 400 WHP. Otherwise, I'd have to get a custom return fuel system to push for something higher, and at this point, I just want to drive it again.
Last edited by ZeroEyeQueue; 06-18-2013 at 05:44 PM.