Which MAF sensor is sufficient enough for me?
05-10-2007, 01:08 PM
#21
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Originally Posted by Kage
I have an OEM MAF screenless with almost new/ported MAF ends made out of black composite plastic from PFYC. Had no probs with it at all, worked just fine for me.
Later switched to Granatelli w/polished red ends.
Will sell it, PM me.
Later switched to Granatelli w/polished red ends.
Will sell it, PM me.
05-10-2007, 01:42 PM
#22
What about the MAFs that places like JEGs and Summit sell. They say they are already calibrated for a LS1. They offered 2 different MAFs 1 was regular and the other one was for people who had cold air intakes/kits. I have been curious about this also because i was thinking about going the Fast 90/90 setup. Do people run the stock MAF when they go to a 90/90 setup or is that a waste of time because of its smaller size?
05-10-2007, 04:21 PM
#23
Some facts about MAFs:
SSpdDmon is correct and I will back up his comments!
1.
Topic - SLP/PACE/larger MAFs cause tuning issues.
False - If the MAF Table is properly tuned, and the tune is done properly, you will not have any issues with larger MAFs.
2.
Topic - SLP/JEGS MAFs are calibrated to LS1.
True - Those places add a resitor to alter the frequency signal the ECM uses to calculate airflow. This can also be accomplished by a proper tune.
3.
Topic - Descreen MAF for more power.
Plausible - It will make the vehicle run leaner and more inconsistent, since the airflow is no longer laminar and predictable. If you do this, you will need to get the MAF Table recalibrated.
4.
Topic - Screen is not needed
False - the screen is there to smooth out the airflow and make airflow (actually fuel) calcualtions more consistent and predictable. Without it the airflow can be very turbulant during hard throttle transitions.
Also, when the MAF is active (this is for you auto guys), it uses the MAF signal to calculate delivered torque. It uses this data for torque management and transmission line pressure requirements. So if you mearly swap out the MAF for a larger unit, without tuning ... you will be affecting the line pressure the ECM will be commanding, and consequently ruin your trans. It is imperrative to get a tune if you decide to swap in a larger MAF unit, regardless of being calibrate for you vehicle or not. The benefit of a larger MAF is increased airflow (like a lid), but more so then a lid it needs to be recalibrated, since the ECM uses it for many airflow and torque calculations.
To summarize: If you alter anything with the MAF, you need to get it recalibrated for proper ECM operation and durability or your drivetrain.
Hope that helps!
SSpdDmon is correct and I will back up his comments!
1.
Topic - SLP/PACE/larger MAFs cause tuning issues.
False - If the MAF Table is properly tuned, and the tune is done properly, you will not have any issues with larger MAFs.
2.
Topic - SLP/JEGS MAFs are calibrated to LS1.
True - Those places add a resitor to alter the frequency signal the ECM uses to calculate airflow. This can also be accomplished by a proper tune.
3.
Topic - Descreen MAF for more power.
Plausible - It will make the vehicle run leaner and more inconsistent, since the airflow is no longer laminar and predictable. If you do this, you will need to get the MAF Table recalibrated.
4.
Topic - Screen is not needed
False - the screen is there to smooth out the airflow and make airflow (actually fuel) calcualtions more consistent and predictable. Without it the airflow can be very turbulant during hard throttle transitions.
Also, when the MAF is active (this is for you auto guys), it uses the MAF signal to calculate delivered torque. It uses this data for torque management and transmission line pressure requirements. So if you mearly swap out the MAF for a larger unit, without tuning ... you will be affecting the line pressure the ECM will be commanding, and consequently ruin your trans. It is imperrative to get a tune if you decide to swap in a larger MAF unit, regardless of being calibrate for you vehicle or not. The benefit of a larger MAF is increased airflow (like a lid), but more so then a lid it needs to be recalibrated, since the ECM uses it for many airflow and torque calculations.
To summarize: If you alter anything with the MAF, you need to get it recalibrated for proper ECM operation and durability or your drivetrain.
Hope that helps!
05-11-2007, 07:42 AM
#26
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I was on the corvette forum and to my surprise alot of the guys have ported and polished or just ported and descreened their stock MAF's and have not had any problems. Its funny because the ones that didnt do it say not to and all the ones that did actually had gains from doing it. One guy even went as far as to say that doing the TB coolant mod was not beneficial to the car hahaha 
but he was the one that also said to leave the car alone. Again when I get my ported ends Monday I will report back here to you guys with my mods and gains. No dyno numbers just sotp and if any codes are being thrown. 
but he was the one that also said to leave the car alone. Again when I get my ported ends Monday I will report back here to you guys with my mods and gains. No dyno numbers just sotp and if any codes are being thrown.
05-11-2007, 07:55 AM
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Originally Posted by SSpdDmon
I hate this mis-information. SLP MAF's don't suck *****. People who put a different MAF on their car and expect it to act identicle to the stock MAF suck *****.
Air passes over the MAF leads. The MAF generates a frequency. The PCM looks that frequency up in a table that corresponds to an airflow value of XXX.XX grams/second. If you change the metering device (by descreening, porting, or swapping for something new) or even the path of airflow (eg an aftermarket lid), you WILL need to re-map the table for the PCM's commanded AFR to equal the actual AFR produced. Plain and simple....
People don't see the numbers unless they have a tuning suite like EFI Live or HPT. That means they're talking out of their asses 90+% of the time. Yes, you can take a stock car, port and polish the MAF, throw on a catback and a lid and get HP gains. Some of that gain is not just the engine breathing better, it's also the AFR leaning out. The PCM is still commanding something rich like an 11.7:1 AFR at WOT. However, the mods throw off the accuracy of the fueling calculations and the car is actually running an AFR in the mid to high 12's. At least, that's been my experience.
A good example...my bolt-ons Z28 (with stock MAF, SSRA, lid, headers, !CATS, and Magnaflow) had a 6.5% error between the commanded and actual AFR at WOT. I had to increase the MAF table to adjust for the changes in the airflow characteristics so that when I told the car (through the PCM) to run a 12.8:1 AFR, it did.
Air passes over the MAF leads. The MAF generates a frequency. The PCM looks that frequency up in a table that corresponds to an airflow value of XXX.XX grams/second. If you change the metering device (by descreening, porting, or swapping for something new) or even the path of airflow (eg an aftermarket lid), you WILL need to re-map the table for the PCM's commanded AFR to equal the actual AFR produced. Plain and simple....
People don't see the numbers unless they have a tuning suite like EFI Live or HPT. That means they're talking out of their asses 90+% of the time. Yes, you can take a stock car, port and polish the MAF, throw on a catback and a lid and get HP gains. Some of that gain is not just the engine breathing better, it's also the AFR leaning out. The PCM is still commanding something rich like an 11.7:1 AFR at WOT. However, the mods throw off the accuracy of the fueling calculations and the car is actually running an AFR in the mid to high 12's. At least, that's been my experience.
A good example...my bolt-ons Z28 (with stock MAF, SSRA, lid, headers, !CATS, and Magnaflow) had a 6.5% error between the commanded and actual AFR at WOT. I had to increase the MAF table to adjust for the changes in the airflow characteristics so that when I told the car (through the PCM) to run a 12.8:1 AFR, it did.
Ive seen as high as 14% off from commanded.
05-11-2007, 09:10 AM
#28
Originally Posted by SlowazzVette2
I was on the corvette forum and to my surprise alot of the guys have ported and polished or just ported and descreened their stock MAF's and have not had any problems. Its funny because the ones that didnt do it say not to and all the ones that did actually had gains from doing it. One guy even went as far as to say that doing the TB coolant mod was not beneficial to the car hahaha but he was the one that also said to leave the car alone. Again when I get my ported ends Monday I will report back here to you guys with my mods and gains. No dyno numbers just sotp and if any codes are being thrown.
but he was the one that also said to leave the car alone. Again when I get my ported ends Monday I will report back here to you guys with my mods and gains. No dyno numbers just sotp and if any codes are being thrown. I have seen some "calibrated aftermarket MAFs" make a factory stock SS run as much as 25% leaner vs. using a stock MAF. Most people that say what you are saying, never get it tune for the increased airflow, then run lean. Running lean can lead to an increase in SOTP feel, but you run the risk of knock. We are no opposed to doing that (running a larger MAF, porting it), but we are trying to educate those that do not know ... get the MAF Table recalibrated.
05-12-2007, 03:48 AM
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Originally Posted by 12secSS
Get it scanned, I bet you that you are running at least 5%-7% lean fuel trims. I have seen some "calibrated aftermarket MAFs" make a factory stock SS run as much as 25% leaner vs. using a stock MAF. Most people that say what you are saying, never get it tune for the increased airflow, then run lean. Running lean can lead to an increase in SOTP feel, but you run the risk of knock. We are no opposed to doing that (running a larger MAF, porting it), but we are trying to educate those that do not know ... get the MAF Table recalibrated.
I have seen some "calibrated aftermarket MAFs" make a factory stock SS run as much as 25% leaner vs. using a stock MAF. Most people that say what you are saying, never get it tune for the increased airflow, then run lean. Running lean can lead to an increase in SOTP feel, but you run the risk of knock. We are no opposed to doing that (running a larger MAF, porting it), but we are trying to educate those that do not know ... get the MAF Table recalibrated. . I didnt throw any codes at all and I am going to reset my battery to get the full affect. I have a diablo predator so I am not sure if that has anything to do with my engine condition not running lean. I also added a few more degrees of timing with the modify parameters option and I have the SLP resistor that adds a few degrees as well. For 82 bucks shipped to my door and a 10 minute install in the Texas heat it was well worth it. I also have a ported LS6 intake manifold and a ported TB, Vara ram air, plugs, wires, 160 thermostat. My car is a 2000 C5 corvette. Last edited by SlowazzVette2; 05-12-2007 at 03:50 AM. Reason: spelling
