Page 4 of 8 FirstFirst 12345678 LastLast
Results 61 to 80 of 142

Thread: 100mm Maf kickin my Butt!!!

  1. #61
    Senior Tuner
    Join Date
    Dec 2004
    Location
    Laurel, MD
    Posts
    1,014
    at idle your typical lsx uses between 6-12g/sec, depends on displacement, temps, rpm, etc... 2000rpm depends on amount of applied throttle mostly, i'm not sure which case you're interesed with, but it's easily calculatable.

    saxxon: AWESOME pictures

  2. #62
    Potential Tuner
    Join Date
    Nov 2009
    Posts
    6
    To give you a rough idea, this is for my h/c ls1
    idle ~12g/sec
    highway cruising on flat surface, 6th gear, 65mph 1500rpm ~31g/sec
    WOT 5000rpm ~315g/sec

    Using the ideal gas law@ 70*F 0.98ATM and 29g/mol for air, it works out to about 0.03ft^3 per gram, so...
    idle ~21.6cfm
    highway cruising ~56cfm
    WOT ~567cfm

    Note, these values are read directly from my tune, so their is probably a bit of a fudge factor involved, but you get the general range. My problems with the ls7 maf are mostly in the 20-100cfm range.

  3. #63
    Potential Tuner
    Join Date
    Jul 2009
    Posts
    6
    I just added the plastic (mylar) screen to my 4" custom aluminum intake maf tube on my ls7. Thanks Jason for sending the samples. Here are some pictures:







    Now I have to retune the idle because it is idling way to lean at 16:1 af. The good news is that on cruise the AF is rock steady at 14.6 - 14.7 whereas before it was all over the place.

  4. #64
    Senior Tuner
    Join Date
    Feb 2006
    Location
    Canada
    Posts
    1,929
    I just found that the new Malibu has the same card MAF in it. Nice, will be a cheap way to get my hands on one!

  5. #65
    Potential Tuner
    Join Date
    Jul 2009
    Posts
    6
    Anyone have any idea as to why the addition of the honeycomb to my intake tube would cause the A/F ratio to max out my wideband at 16:1 at idle? The AFX wideband only reads up to 16:1, so I'm above that at idle. Once I start driving, I'm at a prettty steady 14.7:1 on steady state cruise. What parameters need to be changed? I want to do some data loging to fine tune the MAF, but before I start that It would be nice if I can get the A/F ratio in a readable range at idle. Where should I start?

  6. #66
    Senior Tuner 5_Liter_Eater's Avatar
    Join Date
    Nov 2005
    Location
    Houston, TX
    Posts
    3,970
    Not sure if it matters now but I just measured my piping with a telescopic gauge and a set of calipers and it came out to 3.89". this is on my old piping before I switched to the LS3 piping with the card style bung but I am pretty confident it's the same.
    Bill Winters

    Former owner/builder/tuner of the FarmVette
    Out of the LSx tuning game

  7. #67
    Tuner in Training
    Join Date
    Mar 2006
    Posts
    29
    Quote Originally Posted by RWTD View Post
    Make sure you have the sensor pointing in the correct direction.
    James have you tuned any 100mm MAFS

  8. #68
    Advanced Tuner
    Join Date
    Jun 2008
    Location
    Charleston, SC
    Posts
    971
    Quote Originally Posted by fperra View Post
    Anyone have any idea as to why the addition of the honeycomb to my intake tube would cause the A/F ratio to max out my wideband at 16:1 at idle? The AFX wideband only reads up to 16:1, so I'm above that at idle. Once I start driving, I'm at a prettty steady 14.7:1 on steady state cruise. What parameters need to be changed? I want to do some data loging to fine tune the MAF, but before I start that It would be nice if I can get the A/F ratio in a readable range at idle. Where should I start?
    the maf is probley reading a slightly lower hz, which puts you in a cell that wasn't tuned yet.

    just find the maf cell thats its idling in, and increase by the percentage of error and carry it all the way back to the first cell

  9. #69
    Senior Tuner 5_Liter_Eater's Avatar
    Join Date
    Nov 2005
    Location
    Houston, TX
    Posts
    3,970
    OK, I installed a couple of the samples that Jason sent (thanks Jason!). First I did a baseline (honeycomb-0), then I installed the 4:1 ratio sample (honeycomb-4), then I removed that and installed the 5:1 sample (honeycomb-5). I didn't use the plastic 6:1 sample because my intake tube has a dent in it from ECS to clear the radiator and it deformed the metal samples somewhat (pics tomorrow) so I didn't think the plastic 6:1 sample would like being deformed like that. I only scanned RPM and MAF Hz to get a good sample rate, I commanded 1200 RPM's with VCM controls (as high as I could command in the latest beta) and let it run for a minute. I set up the test config's histo #12 to display the MAF Hz right around 1200 RPM's and I looked at the average frequency, lowest and highest frequencies recorded. the high-low is what I'm looking at.

    No honeycomb:
    RPM Avg Low High High-low
    1190 2539 2024 2949 925
    1200 2526 2031 2920 889
    1210 2544 2105 2930 825
    Average frequency=2536
    Average high-low=880

    4:1 honeycomb:
    RPM Avg Low High High-low
    1190 2606 2147 2987 840
    1200 2659 2379 2891 512
    1210 2655 2407 2969 500
    Average frequency=2640
    Average high-low=617

    5:1 honeycomb:
    RPM Avg Low High High-low
    1190 2591 2152 2883 731
    1200 2596 2280 2898 618
    1210 2593 2318 2860 542
    Average frequency=2593
    Average high-low=630


    There may be a better way to do this but this is what I whipped up. The average high-low went down dignificantly with the honeycombs installed so the it definitely made a difference and the difference between the 4:1 and 5:1 ratio didn't seem very notable.

    The average frequency actually went up with the honeycombs installed which would indicate an increase in airflow but I believe this is erroneous. Maybe if I was logging VE airflow that would have been a better representation of whether the honeycombs reduced airflow.

    Note that these are MAF values recorded while I was in SD mode so it's not like the differences changed the tune.

    When I turned my MAF back on I STILL ran into the same issues I always have trying to get the LS3 MAF to work, artificially high MAF table (defeating the purpose of the 100mm MAf), noticably less stable idle or commanded RPM, fuel trims swinging, not being able to get them +-<5%. Weird stuff. Last time I tried going back to the stock MAF all this goes away and I've tried two different LS3 MAF sensors so I thought it was due to turbulence but even with the honeycomb, my 100mm MAF is still kickin' my butt!

    Bill Winters

    Former owner/builder/tuner of the FarmVette
    Out of the LSx tuning game

  10. #70
    Potential Tuner
    Join Date
    Nov 2009
    Posts
    6
    I'd be curious to see your intake tract, as poor maf placement could potentially lead to a SOL type situation.

    I think the best way to test these would be to drive the car at a steady load(ie flat road, constant speed) and just look at the graphs generated. If you zoom in to the curve a little bit, you can see if the maf is reading irregular airflow just by how spikey the curve is. FWIW, with no screen my car is by far most unhappy during light throttle cursing, and the idle isn't that bad. Your results may vary.

    For example, here is a quick comparison between a good functioning stock maf and the ls7 maf that I have been having problems with, both scales cover 1000hz and both were taken during constant speed highway driving at 65mph. I'll let you decide which line is which

  11. #71
    Advanced Tuner
    Join Date
    Jun 2008
    Location
    Charleston, SC
    Posts
    971
    5Liter,

    here is my tune.. the maf table will be higher in the lower cells.

    my tune is scaled 50% and uses the 60lb SD injectors. i know my tune wont work in your car, as im still runing the stock camshaft. but it will just give you an idea of how the flow rate vs kpa table relates to the maf table.

    -carl

    ok. well the forum wont upload the tune so here is a screen shot what i am talkig about



    my hz i hit now is 10600

  12. #72
    Senior Tuner 5_Liter_Eater's Avatar
    Join Date
    Nov 2005
    Location
    Houston, TX
    Posts
    3,970
    Here's some pics of the honeycombs installed as well as my intake tract which is as simple as it can get, the problem may be how the tube deforms near the front and the MAF bung is so close to that deformation. I'm thinking of going back to the LS2 pipe with an actual 100mm MAF housing. I went this route to eliminate couplers.
    Bill Winters

    Former owner/builder/tuner of the FarmVette
    Out of the LSx tuning game

  13. #73
    Senior Tuner 5_Liter_Eater's Avatar
    Join Date
    Nov 2005
    Location
    Houston, TX
    Posts
    3,970
    Quote Originally Posted by carlrx7 View Post
    5Liter,

    here is my tune..
    Thanks. I hadn't scaled my injectors yet except enough to fit the 63.5# limit so that would explain why my MAF numbers are so high but the other problems are still there.
    Bill Winters

    Former owner/builder/tuner of the FarmVette
    Out of the LSx tuning game

  14. #74
    Senior Tuner 5_Liter_Eater's Avatar
    Join Date
    Nov 2005
    Location
    Houston, TX
    Posts
    3,970
    Yea, my frequency deviation is still very erratic. My post honeycomb log looks like Carl's pre-honeycomb log. After he put his honecomb in his frequency range is within ~250 Hz whereas my best was >600. Like I said I've swapped sensors and it didn't go away and if I revert back to the stock 85mm MAF it does go away so it's not the sensor or the wiring; It's got to be the tube. Too bad I sold my POWRMAF housing when I got this tube. The funny thing is that this is ECS's LS3/LS7 intake tube. Not like I had it fabbed up.
    Bill Winters

    Former owner/builder/tuner of the FarmVette
    Out of the LSx tuning game

  15. #75
    Potential Tuner
    Join Date
    Jul 2009
    Posts
    6
    I've got a SNL 100mm MAF housing and a 100mm Haltech housing I'm selling if you are interested. $170 for the SNL and $60 for the Haltech.

  16. #76
    Potential Tuner
    Join Date
    Nov 2009
    Posts
    6
    I got my first chance to play with the screens Jason sent me(Thanks again!). I have only tested the plastic screen with the 6:1 ratio so far, and while its too early to say for sure, the results are definitely positive so far.

    It was raining, so all I got to do is some idle logs. It might be a couple weeks until I can gather all the data and put together my book report

    A few observations so far...

    When I first put the screen in with the tune I had been using on the open sensor, I also went very very lean. I soon found it was idling at a significantly lower frequency. If this effect carries on to some degree across the entire frequency range, then using a screen may actually extend the HP range in which this maf can be used.

    It only took a few minutes of idling and a few reflashes before my BENs in the idle range got back in line, this was also good.

    Finally, I made some preliminary graphs to see what it looked like at idle with and without the screen, and here it is(sorry for using efilive, but it's what I have )


    Top line is no screen, bottom is with the screen, both are on a 1000hz range scale. I know I need to do some more testing and driving before I call this case closed(for my case anyway) but things are looking up.

    Edit: I also noticed that over a 50rpm range at idle the maf range is now 256hz, with no screen it was 789hz *thumbs up* (stock ls1 maf was 226hz over the same range, for the record)
    Last edited by rosey; 11-25-2009 at 11:58 PM.

  17. #77
    Tuner in Training Saxxon68's Avatar
    Join Date
    Nov 2009
    Location
    Portland, OR
    Posts
    15

    Need a volunteer for some material

    Someone in the US want to volunteer to try some 1" thick plastic material that is 1/8" cells? Reply to this message of you can install this right away and get some results. It is 8:1 ratio.
    5 liter great pics

  18. #78
    Senior Tuner
    Join Date
    Jun 2005
    Location
    Mobile, AL & Colorado Springs, CO
    Posts
    2,046
    Saxxon68, I'd like to, but it'll be a few weeks before I'm ready to test it. It'll be on a PowrMAF, and in an '01 Camaro SS w/ a FAST 102/102 combo on a 413 LS2.
    RWTD
    True Custom Tuning & Performance Parts Specialists!
    Custom Tuning: dynotune@rwtd.com

    Toys: '08 C6 LS3 / '03 SVT Cobra / '08 Harley Davidson Nightrod Special / '11 Chevy Duramax

  19. #79
    Tuner in Training Saxxon68's Avatar
    Join Date
    Nov 2009
    Location
    Portland, OR
    Posts
    15

    addy needed

    Sounds good. PM me your shipping address RWTD. I have a few questions too for you guys using these:
    Are you running these full time in your rigs?
    Would this be applicable and beneficial to a 1998 firebird V-6. I can find the MAF although under the hood looks nothing like these photos.

  20. #80
    Advanced Tuner 69lt1bird's Avatar
    Join Date
    Oct 2007
    Posts
    983
    I have one of the screens in my intake tube, here is a screen shot. Very smooth. ID on my tube is 95.25 mm. Amsoil oil-less reusable cone on the end, 90 mm Holley and a Ported L76 intake.

    Don't mind the pedaling, this thing is running very good.
    Free HP Tuners Beginners Tuning Guide

    LS1 Tuning Guide
    Michigan Snowmobiler

    1969 Firebird: 11.67@114 7.55@97.93 1/8 1.70 60 ft. EPS cam 234/246 .602.606 114+3, 6.0 LQ4, L92 heads milled 10.5:1, Ported L76 intake, ported 90mm Holley TB, 100mm MAF, FIC Custom injectors, Hooker LT, PYPES dual exhaust with an X pipe, 4L65e with all of the good parts inside, FTI 4000 RPM Stall, 12 bolt with 3.73 gears. HP Tuner tuned by me