New Delphi LS1 MAF design
02-25-2012, 10:57 AM
#22
It's not a screen like your screen door. It's an airflow straightener that smooths the airflow over the entire cross sectional area of the tube. It isn't there to keep cockroaches out of your MAF.
Those of you who think de-screening your MAF increases power. What exactly are your MPH increases in 1/4 to backup your theory?
Those of you who think de-screening your MAF increases power. What exactly are your MPH increases in 1/4 to backup your theory?
02-25-2012, 11:23 PM
#23
I've ben told by various tuners it really doesnt matter if its in or not but it can help hp a little bit because the screen is an obstruction. Any good tuner could monitor the car without the screen and make any adjustments as need IF it cause some weird readings a first...
I'll bite on this. It may help smooth airflow but I dont believe this really detrimental as if you remove the screen. By removing the screen you allow much more airflow through the maf. Many tuners suggest removing it before the tune because they can correct for any small quirks that may come up in the process. Also if the screen is such an essential piece then why does NO new gm maf have one? Even the c5z06 maf doesnt have a screen
I'll bite on this. It may help smooth airflow but I dont believe this really detrimental as if you remove the screen. By removing the screen you allow much more airflow through the maf. Many tuners suggest removing it before the tune because they can correct for any small quirks that may come up in the process. Also if the screen is such an essential piece then why does NO new gm maf have one? Even the c5z06 maf doesnt have a screen
When you say "much more airflow"...how do you quantify "much more"...go take a car that's not really setup for drag racing...like not really really really dialed in, suspension chassis and drivetrain, for the strip, dial in the full throttle air/fuel, and go make 10 passes at the track...now remove the screen, re-correct the full throttle air/fuel to the exact same AFR, and go make 10 more passes at the track..."much more airflow" at the same AFR, would result in "much more" mph too...and much less ET assuming the newfound tremendous increase in power doesn't result in additional tire spin.
That said...if you average the before MPH and the after MPH, and throw out any timeslips that had excessive wheelspin over the other runs from both sets of data...I bet you'll see an incredibly insignificant difference in the vehicles MPH.
Now...as I said in a previous post on this thread...in a car that is really truly a track only drag car...nobody really cares about the extremely light throttle low airflow driving characteristics. In that case...the chassis is tweaked in correctly...the suspension is setup properly...and the tune in the engine is probably right on the hairy edge of safety (something NOBODY in their right mind does on a "street car"), in that case...sure, go ahead and yank the screen from the MAF...you know what though...yank the whole MAF...you CAN dial the AFR and spark advance in properly in speed density, and you can now remove the entire MAF internals from the air path...and you'll still only see a minor minor minor difference in the ET and MPH.
What makes you so sure that no new GM MAF has a screen? The C5 ZO6 has a different intake path than the LS1 F-Body. And, when the C5 ZO6 was designed, GM was willing to make sacrifices to the cars refinement in order to make it a more rough around the edges version of the Vette, that can attack a track better...even the new card style MAF sensors used in the C6, and new Camaro's and lots of other vehicles...are you sure there aren't screens somewhere in the intake path when necessary...there's a LOT more to an air intake than a MAF, a filter, and a filter location to breath air that's as close to outside air temp as possible. Depending on the structure of the entire intake path, sometimes a screen is more of a necessity than others.
I have a cold air intake on my 2010 Camaro SS that drastically changes the air flow path from stock. Stock the 5th gen breathed air from a box located on the drivers side of the engine bay, through a tube, through an elbow, and into the throttle body...my aftermarket cold air intake breathes from right behind the grille in the middle of the car, over the radiator, and into the throttle body...and it HAS a screen built into it.
That said, if you look at the typical bolt on's 5th gen Camaro SS, with a TR6060, stock gears, full weight, and normal add on's like long tube headers, cold air intakes (of various types, including many that breath from the stock location), exhaust work and tuning...my high 116.xx mph trap speeds without any wheel spin at all, at full weight, on stock 20" wheels, are just about as fast as it gets...in fact, I only know of 1 that traps 117 on the same wheel setup, 1 that traps 117 on lighter 18" wheels, and 1 that traps 119 on front skinnies, even lighter 17" rear wheels, and the addition of an underdrive pulley...so what exactly am I leaving on the table by ADDING a screen to my car with the intake I chose?
...on and by the way, my car drives as smooth as glass...in ALL situations...I can let it idle in gear, on flat pavement, up an incline, down an incline...it'll just move very very very smoothly at all of 550 rpm, clutch fully engaged, my foot not touching the throttle at all...with a 100% stock spark advance table, no tricks in the PCM at all...just a MAF sensor cal that is dialed in as tight as I could dial it in, and speed density cal that is also as tight as I could get it, and allowing the GM algorithm to blend SD and MAF as it chooses to in the background.
02-26-2012, 10:01 PM
#24
I prefer the screen to be in the MAF... if you are going to go as far to punch the screen out then just ditch the hole damn thing and go SD... at least then you wont get erratic frequency readings from the turbulent air. The problem here is most people that are commenting in this thread aren't tuners but are people that have talked to tuners. The intake tract makes a huge difference on whether the screen is needed or not. LS1 Fbodies need the screen! With the MAF so close to the throttle body at partial throttle it draws air in around the top and bottom of the throttle bore, what do you think that does to the air in the ducting between the MAF and TB? The screen eliminates the erratic readings you get from that.
The C5Z obviously didn't have the screen but if you look at the placement of the MAF, it is much much further away from the blade and has to go through the bridge before it goes into the TB area, that in itself straightens the airflow out on that particular setup. So like stated above each intake tract is different and has to be looked at accordingly.
Having a dyno if people really want to see the difference and someone is willing to ship me a screenless MAF to test I will be more than happy to show dyno comparisons. I have stock Fbody MAF's with the screens still and also have a couple of 85mm MAF with screen still also. So either or will work. If I run across one here at the shop that doesn't have a screen anymore I will test also.
The C5Z obviously didn't have the screen but if you look at the placement of the MAF, it is much much further away from the blade and has to go through the bridge before it goes into the TB area, that in itself straightens the airflow out on that particular setup. So like stated above each intake tract is different and has to be looked at accordingly.
Having a dyno if people really want to see the difference and someone is willing to ship me a screenless MAF to test I will be more than happy to show dyno comparisons. I have stock Fbody MAF's with the screens still and also have a couple of 85mm MAF with screen still also. So either or will work. If I run across one here at the shop that doesn't have a screen anymore I will test also.
02-27-2012, 06:59 PM
#25
Having a dyno if people really want to see the difference and someone is willing to ship me a screenless MAF to test I will be more than happy to show dyno comparisons. I have stock Fbody MAF's with the screens still and also have a couple of 85mm MAF with screen still also. So either or will work. If I run across one here at the shop that doesn't have a screen anymore I will test also.
My cold air intake, as I said above, has a screen in it. It also has been replaced by the manufacturer due to a cosmetic issue on the outside, and they told me to just toss the original out, they don't need it.
That said...I guess I can gut the screen from the one with the cosmetic issue, drive around in a surging car with O2 sensors trying to correct for crappy airflow through the MAF, and see what she does on the dyno...then put the one with the screen back in, be thrilled with the smooth driving, and make another pull.
Maybe I will, I bet I'll see the same difference doing that as I'll see just making 3 pulls, walking away, walking back and making 3 more pulls.
02-27-2012, 09:44 PM
#26
I was mainly concerned on the dyno readings to see gains at WOT or not since there are people in this thread that claim a .1 and 1mph which should be a significant gain on the dyno. Logging dynamic airflow and keeping AFR consistent will also tell if it is in fact drawing more air in or not, or even enough difference to justify the crappy drivability compared to the screened MAF.
Back on the MAF... does it have a larger opening than the original LS1 MAF's? I can't find dimensions on the new MAF posted.
Back on the MAF... does it have a larger opening than the original LS1 MAF's? I can't find dimensions on the new MAF posted.
02-27-2012, 10:09 PM
#27
A really good tuner can re-calibrate the sensor for the lack of the screen and get fueling as consistent as possible, but depending on the vehicle's intake path, sometimes it's just not possible to dial out every last bit of surging that results from removing a MAF screen in an intake design that really dictates that it should have one. In those cases...a really adventurous tuner might go into the spark tables and "soften" the spark advance in that area to reduce the surging...typically it'd be low RPM and low airflow...like maintaining slow speed in a parking lot, or on a small side street, or maybe in stop and go traffic when you have those moments where you're creeping along at 5 or 6 mph.
When you say "much more airflow"...how do you quantify "much more"...go take a car that's not really setup for drag racing...like not really really really dialed in, suspension chassis and drivetrain, for the strip, dial in the full throttle air/fuel, and go make 10 passes at the track...now remove the screen, re-correct the full throttle air/fuel to the exact same AFR, and go make 10 more passes at the track..."much more airflow" at the same AFR, would result in "much more" mph too...and much less ET assuming the newfound tremendous increase in power doesn't result in additional tire spin.
That said...if you average the before MPH and the after MPH, and throw out any timeslips that had excessive wheelspin over the other runs from both sets of data...I bet you'll see an incredibly insignificant difference in the vehicles MPH.
Now...as I said in a previous post on this thread...in a car that is really truly a track only drag car...nobody really cares about the extremely light throttle low airflow driving characteristics. In that case...the chassis is tweaked in correctly...the suspension is setup properly...and the tune in the engine is probably right on the hairy edge of safety (something NOBODY in their right mind does on a "street car"), in that case...sure, go ahead and yank the screen from the MAF...you know what though...yank the whole MAF...you CAN dial the AFR and spark advance in properly in speed density, and you can now remove the entire MAF internals from the air path...and you'll still only see a minor minor minor difference in the ET and MPH.
What makes you so sure that no new GM MAF has a screen? The C5 ZO6 has a different intake path than the LS1 F-Body. And, when the C5 ZO6 was designed, GM was willing to make sacrifices to the cars refinement in order to make it a more rough around the edges version of the Vette, that can attack a track better...even the new card style MAF sensors used in the C6, and new Camaro's and lots of other vehicles...are you sure there aren't screens somewhere in the intake path when necessary...there's a LOT more to an air intake than a MAF, a filter, and a filter location to breath air that's as close to outside air temp as possible. Depending on the structure of the entire intake path, sometimes a screen is more of a necessity than others.
I have a cold air intake on my 2010 Camaro SS that drastically changes the air flow path from stock. Stock the 5th gen breathed air from a box located on the drivers side of the engine bay, through a tube, through an elbow, and into the throttle body...my aftermarket cold air intake breathes from right behind the grille in the middle of the car, over the radiator, and into the throttle body...and it HAS a screen built into it.
That said, if you look at the typical bolt on's 5th gen Camaro SS, with a TR6060, stock gears, full weight, and normal add on's like long tube headers, cold air intakes (of various types, including many that breath from the stock location), exhaust work and tuning...my high 116.xx mph trap speeds without any wheel spin at all, at full weight, on stock 20" wheels, are just about as fast as it gets...in fact, I only know of 1 that traps 117 on the same wheel setup, 1 that traps 117 on lighter 18" wheels, and 1 that traps 119 on front skinnies, even lighter 17" rear wheels, and the addition of an underdrive pulley...so what exactly am I leaving on the table by ADDING a screen to my car with the intake I chose?
...on and by the way, my car drives as smooth as glass...in ALL situations...I can let it idle in gear, on flat pavement, up an incline, down an incline...it'll just move very very very smoothly at all of 550 rpm, clutch fully engaged, my foot not touching the throttle at all...with a 100% stock spark advance table, no tricks in the PCM at all...just a MAF sensor cal that is dialed in as tight as I could dial it in, and speed density cal that is also as tight as I could get it, and allowing the GM algorithm to blend SD and MAF as it chooses to in the background.
When you say "much more airflow"...how do you quantify "much more"...go take a car that's not really setup for drag racing...like not really really really dialed in, suspension chassis and drivetrain, for the strip, dial in the full throttle air/fuel, and go make 10 passes at the track...now remove the screen, re-correct the full throttle air/fuel to the exact same AFR, and go make 10 more passes at the track..."much more airflow" at the same AFR, would result in "much more" mph too...and much less ET assuming the newfound tremendous increase in power doesn't result in additional tire spin.
That said...if you average the before MPH and the after MPH, and throw out any timeslips that had excessive wheelspin over the other runs from both sets of data...I bet you'll see an incredibly insignificant difference in the vehicles MPH.
Now...as I said in a previous post on this thread...in a car that is really truly a track only drag car...nobody really cares about the extremely light throttle low airflow driving characteristics. In that case...the chassis is tweaked in correctly...the suspension is setup properly...and the tune in the engine is probably right on the hairy edge of safety (something NOBODY in their right mind does on a "street car"), in that case...sure, go ahead and yank the screen from the MAF...you know what though...yank the whole MAF...you CAN dial the AFR and spark advance in properly in speed density, and you can now remove the entire MAF internals from the air path...and you'll still only see a minor minor minor difference in the ET and MPH.
What makes you so sure that no new GM MAF has a screen? The C5 ZO6 has a different intake path than the LS1 F-Body. And, when the C5 ZO6 was designed, GM was willing to make sacrifices to the cars refinement in order to make it a more rough around the edges version of the Vette, that can attack a track better...even the new card style MAF sensors used in the C6, and new Camaro's and lots of other vehicles...are you sure there aren't screens somewhere in the intake path when necessary...there's a LOT more to an air intake than a MAF, a filter, and a filter location to breath air that's as close to outside air temp as possible. Depending on the structure of the entire intake path, sometimes a screen is more of a necessity than others.
I have a cold air intake on my 2010 Camaro SS that drastically changes the air flow path from stock. Stock the 5th gen breathed air from a box located on the drivers side of the engine bay, through a tube, through an elbow, and into the throttle body...my aftermarket cold air intake breathes from right behind the grille in the middle of the car, over the radiator, and into the throttle body...and it HAS a screen built into it.
That said, if you look at the typical bolt on's 5th gen Camaro SS, with a TR6060, stock gears, full weight, and normal add on's like long tube headers, cold air intakes (of various types, including many that breath from the stock location), exhaust work and tuning...my high 116.xx mph trap speeds without any wheel spin at all, at full weight, on stock 20" wheels, are just about as fast as it gets...in fact, I only know of 1 that traps 117 on the same wheel setup, 1 that traps 117 on lighter 18" wheels, and 1 that traps 119 on front skinnies, even lighter 17" rear wheels, and the addition of an underdrive pulley...so what exactly am I leaving on the table by ADDING a screen to my car with the intake I chose?
...on and by the way, my car drives as smooth as glass...in ALL situations...I can let it idle in gear, on flat pavement, up an incline, down an incline...it'll just move very very very smoothly at all of 550 rpm, clutch fully engaged, my foot not touching the throttle at all...with a 100% stock spark advance table, no tricks in the PCM at all...just a MAF sensor cal that is dialed in as tight as I could dial it in, and speed density cal that is also as tight as I could get it, and allowing the GM algorithm to blend SD and MAF as it chooses to in the background.
http://www.saxonpc.com/100mm-cells-for-100.html
02-27-2012, 11:32 PM
#28
I prefer the screen to be in the MAF... if you are going to go as far to punch the screen out then just ditch the hole damn thing and go SD... at least then you wont get erratic frequency readings from the turbulent air. The problem here is most people that are commenting in this thread aren't tuners but are people that have talked to tuners. The intake tract makes a huge difference on whether the screen is needed or not. LS1 Fbodies need the screen! With the MAF so close to the throttle body at partial throttle it draws air in around the top and bottom of the throttle bore, what do you think that does to the air in the ducting between the MAF and TB? The screen eliminates the erratic readings you get from that.
The C5Z obviously didn't have the screen but if you look at the placement of the MAF, it is much much further away from the blade and has to go through the bridge before it goes into the TB area, that in itself straightens the airflow out on that particular setup. So like stated above each intake tract is different and has to be looked at accordingly.
Having a dyno if people really want to see the difference and someone is willing to ship me a screenless MAF to test I will be more than happy to show dyno comparisons. I have stock Fbody MAF's with the screens still and also have a couple of 85mm MAF with screen still also. So either or will work. If I run across one here at the shop that doesn't have a screen anymore I will test also.
The C5Z obviously didn't have the screen but if you look at the placement of the MAF, it is much much further away from the blade and has to go through the bridge before it goes into the TB area, that in itself straightens the airflow out on that particular setup. So like stated above each intake tract is different and has to be looked at accordingly.
Having a dyno if people really want to see the difference and someone is willing to ship me a screenless MAF to test I will be more than happy to show dyno comparisons. I have stock Fbody MAF's with the screens still and also have a couple of 85mm MAF with screen still also. So either or will work. If I run across one here at the shop that doesn't have a screen anymore I will test also.
Post up your Logs and configs when doing so.
Too much bad information floating around the internet... Shocking huh?
Last edited by The1N_only; 02-27-2012 at 11:39 PM.
02-28-2012, 11:00 AM
#29
TECH Senior Member
Look at these videos of Saxon's honeycomb screen:
(there was also the one showing smoke trails ("flux lines") getting straightened inside a box by the honeycomb, but I can't find this video).
http://www.youtube.com/watch?v=Xb6ANasThB0
http://www.youtube.com/watch?v=KNExOgtLt2w
(there was also the one showing smoke trails ("flux lines") getting straightened inside a box by the honeycomb, but I can't find this video).
http://www.youtube.com/watch?v=Xb6ANasThB0
http://www.youtube.com/watch?v=KNExOgtLt2w
02-28-2012, 11:14 AM
#30
Couldnt have said it better my self. While on the dyno do a steady state test comparing screen vs no screen. You will see a more stable MAF Airflow with the screen in. It will become more apparent if there in any turbulence prior to the MAF.
Post up your Logs and configs when doing so.
Too much bad information floating around the internet... Shocking huh?
Post up your Logs and configs when doing so.
Too much bad information floating around the internet... Shocking huh?
Last edited by NEokcTERROR; 02-28-2012 at 11:15 AM. Reason: Punctuation
03-01-2012, 06:47 PM
#33
I wouldn't say processor speed was wasted and the computer doesn't smooth anything. That is why a screen is *sometimes* important. Every vehicle dynamics is different. Some vehicles you fight turbulence esp in crappy cold air intakes, larger cam shafts where you see a lot of revision.
03-01-2012, 07:47 PM
#34
I wouldn't say processor speed was wasted and the computer doesn't smooth anything. That is why a screen is *sometimes* important. Every vehicle dynamics is different. Some vehicles you fight turbulence esp in crappy cold air intakes, larger cam shafts where you see a lot of revision.
I assume you do this as a living as well as myself. I have wasted hours upon hours on my own LS stuff just seeing exactly what little wierd things like this do. You would be correct in that the PCM views the MAF report "x" times per second no matter how erratic it may be, but the computing power would have to increase to handle the irregularities. The MAF is in the utmost foreground processes of the processor where total attention is a priority, unlike say canister purge monitoring or tank pressure etc. This stuff is prioritized in underlying code of everything electronically controlled.
I am not saying the 411 or E38 etc. is not capable of even more than it will ever see. Just thinking a little outside, and am sure it's a non-issue for the most part.
I put a saxon straightener in all the cars I see that have moderately erratic and worse MAF logs. It helps part thottle and idle tremendously and for the most part hinders performance only slightly if even at all.
03-01-2012, 09:33 PM
#35
TECH Senior Member
Many logs from many vehicles show that the MAF g/s waveform has many small squiggles, yet the PCM is fueling correctly, so it must be filtering/smoothing to some extent, it can handle those small squiggles;
and it seems that the PCM can't handle larger squiggles as can be seen by fueling diverging.
and it seems that the PCM can't handle larger squiggles as can be seen by fueling diverging.
03-02-2012, 09:36 AM
#36
A tuner will have a hard time dialing in the MAF transfer if there is turblance in the intake stream... Hints why there screen is there. Not all cars suffer from this but anytime you can straighten out the airflow before it flows over the MAF the better off you are and the tighter you can dial in the MAF. If you are seeing that big of a pressure drop you might want to look into this...
http://www.saxonpc.com/100mm-cells-for-100.html
http://www.saxonpc.com/100mm-cells-for-100.html
Couldnt have said it better my self. While on the dyno do a steady state test comparing screen vs no screen. You will see a more stable MAF Airflow with the screen in. It will become more apparent if there in any turbulence prior to the MAF.
Post up your Logs and configs when doing so.
Too much bad information floating around the internet... Shocking huh?
Post up your Logs and configs when doing so.
Too much bad information floating around the internet... Shocking huh?
I wouldn't say processor speed was wasted and the computer doesn't smooth anything. That is why a screen is *sometimes* important. Every vehicle dynamics is different. Some vehicles you fight turbulence esp in crappy cold air intakes, larger cam shafts where you see a lot of revision.
Many logs from many vehicles show that the MAF g/s waveform has many small squiggles, yet the PCM is fueling correctly, so it must be filtering/smoothing to some extent, it can handle those small squiggles;
and it seems that the PCM can't handle larger squiggles as can be seen by fueling diverging.
and it seems that the PCM can't handle larger squiggles as can be seen by fueling diverging.
Regardless...anyone who blindly says "remove the screen, then run this other cars MAF table" without knowing anything about the intake path on the car, the cam in the engine or anything else...sketchy.
03-03-2012, 03:39 PM
#37
New MAF is an ugly thing. Why does it have a connector going to another connector a short length away?
BTW I don't understand how people justify the headaches associated with descreening a MAF for gain of a 1/10 th of 1 horsepower. Each to his own but you won't feel the difference and you most likely won't see an ET drop.
BTW I don't understand how people justify the headaches associated with descreening a MAF for gain of a 1/10 th of 1 horsepower. Each to his own but you won't feel the difference and you most likely won't see an ET drop.
03-03-2012, 10:52 PM
#38
If you wanted to (unless they're modifying and removing the IAT in the sensor, which I doubt), you could just buy the correct matching connector, then remove your original IAT and MAF connectors from your vehicle, run all 5 wires as 1 "harness" to the new sensor, and pin them accordingly (should be Delphi GT 150 series) and have what I guess would be a cleaner look.
03-22-2016, 10:58 AM
#39
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Bringing this back from the dead!!! To go about this cleaner look and wiring the IAT into it I am assuming I just get the Delphi GT 150 series 5way female connector (no biggie) and wire the IAT into it and disregard the original little dongle type right? Just want to make sure it will all work together and not throw codes. I'm so sick of codes. Car will be getting retuned soon also.
