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Thread: 100mm Maf kickin my Butt!!!

  1. #1
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    100mm Maf kickin my Butt!!!

    hey guys,

    i thought i understood what i was getting myself into, but im at a loss of words of whats happening.

    i replaced my 06 ls2 MAF meter with a 4" tube and ls7 sensor.

    my problem is the car will not idle, ive gone as far as raising the idle to 1400 rpms just so it wont die,

    idle surges from 400 - 2000 rpms. afr goes from 10.3 to 18.1. freakin insane and quite scary, the misfires are threw the roof.

    ive tried doubling/tripling the maf table, tried using the powermaf, and tried scaling the stock ls7 table by % to my current ifr numbers around .86.

    my tune is a basically a stock 06 tune scaled to 50%. but i kept the idle airflow numbers to stock. using the 60's with all the correct data. gregs dvd doesn't cover scaling. i just got in his new book. at a quick glance i didn't see any topic about scaling, but am gonna finish reading it tonight.

    i think tommorow im gonna try a tune thats not 'scaled' , its late and the neighbors are pissed.

    -carl
    Last edited by carlrx7; 10-27-2009 at 08:49 PM.

  2. #2
    Tuner Mez's Avatar
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    Post the tune and scan.
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  3. #3
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    Make sure you have the sensor pointing in the correct direction.
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    Its probably too much turbulence causing erratic readings from the sensor.. So its not so much the new sensor, but rather the addition of the 4 inch pipe. Especially if the pipe ramps up to 4 inches too 'quickly' before the sensor.
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  5. #5
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    i actually just have the 4"x6"pipe installed with couplers on both ends to the TB. maybe it needs a longer path to smooth the air out. id have to cut the intercooler charge pipe for it to fit, so im waiting till i know i can at least tune it before i do anything perminate.

    ill try to post my tune, but hptforums doesn't like my laptop.

    -carl

    p.s. nope it wont uploadl. anything over 100kb wont upload
    Last edited by carlrx7; 10-28-2009 at 05:29 AM.

  6. #6
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    It's the version HPT is on. They need to upgrade to the latest version of vBulletin to get around the issue. It's a known issue.
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  7. #7
    Quote Originally Posted by Blades View Post
    Its probably too much turbulence causing erratic readings from the sensor.. So its not so much the new sensor, but rather the addition of the 4 inch pipe. Especially if the pipe ramps up to 4 inches too 'quickly' before the sensor.
    Hi !

    I have NOT seen THIS(wait) before in any thread. I have a "Z06"(?) alu housing MAF close to 100mm mounted close to my Tony ported LS2 throttle body/FAST intake. LS2 block based engine. AFR 59cc/G5X1 etc.. Car is C5-2000MN6. My problem was a HORRIBLE MAF output and some serious bucking in some low speed cruising.
    In idle, it always jumped between 4 cells(MAF Hz). At full throttle, Input from the MAF looked like the Alps, jumping up/down 15-20%. Wow ! Needed a solution. Found this honeycomb
    http://www.saxonpc.com/7-inch-black-cell-honeycom7.html

    Ordered a couple of the "3/4" Thick 3/16" Cell Aluminum" ones.
    ...waited a week or two....

    Cut out a circular piece of the VERY thin high quality honeycomb and pressed in carefully into the MAF housing. Honeycomb ended up around 1/2 inch from the MAF measuring device. Didn´t really secure the honeycomb any more at this stage. Have some ideas how to do it.

    Tested my solution and BOY did it work well
    MAF is moving like 1,5 cell in the scanner at idle(cammed car) and even more stable when revving. Have problems now to test full throttle in the street due to rain and 5 deg Celcius. (Sweden)

    This honeycomb may well NOT be the perfect sized one. Cells could be i bit smaller. But it shure seems to work and you guys are free to try to find a better one

    I´d like to se someone else test this solution. Maybee one of the guru guys ? I will work some more on this and probably make my own proper airflow total filter+airflow solution(my friend is an aerospace engineer) this winter. (Example : The connection to the air filter housing should be BIGGER that the MAF housing - don´t want the air pressure dropping from filter to MAF)

    Will try to get a picture of the MAF asap.
    Last edited by swebld; 10-28-2009 at 02:31 PM. Reason: more info

  8. #8
    Advanced Tuner Pulse_GTO's Avatar
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    I had issues with a 100 mm MAF as well until I Moved the sensor away from a bend and now it works perfectly.

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    I also used the 3/4" honeycomb from Saxon PC, and then a fine aluminum screen, much like household window screen. MAF output is steady as a rock. Before, the car wouldn't idle, and even under hard acceleration the MAF signal looked like a rusty sawblade. Now it is straight and solid.

    Cheers,

    Mike

  10. #10
    Quote Originally Posted by ZZMike View Post
    I also used the 3/4" honeycomb from Saxon PC, and then a fine aluminum screen, much like household window screen. MAF output is steady as a rock. Before, the car wouldn't idle, and even under hard acceleration the MAF signal looked like a rusty sawblade. Now it is straight and solid.

    Cheers,

    Mike
    NICE Mike !
    Now i can go back to sleep, knowning that MY rusty sawblade hopefully is history
    Though i´m not shure where to put the "fine aluminum screen" to get the best result, did you ever test without it ?

  11. #11
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    ok , i fixed it,, idles like a kitten ,,

    it was the temp install that was causing probs.

    before = wrong and will run like shyt!!!!


    p.s. yes the sensor was in and pluged in and installed facing the right way.
    -----

    correct temp install,, idles sweet!!



    ----

    final install complete,,



    p.s. total cost about 140 bucks TOTAL!!! i love custom!
    now off to some tuning!!! woohooo,, no more maxxed maf and 50% scalling - 1024g's!!!

    thanks yall

    -carl

  12. #12
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    Quote Originally Posted by swebld View Post
    NICE Mike !
    Now i can go back to sleep, knowning that MY rusty sawblade hopefully is history
    Though i´m not shure where to put the "fine aluminum screen" to get the best result, did you ever test without it ?
    I did test without it, but not on the car. I used a flow bench and smoke wand to work on getting the straightest possible flow across the MAF. It was much straighter with the screen, so that is what I used.

    I have to take some pics for some board members that have been PM'ing me. I will post them here when I am finally able.

    Mike

  13. #13
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    Carl, if I would have known that's how it was "temp" setup, I would have immediately told you to put a temp filter on the end of it (or do what you did). Nice job!
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  14. #14
    Senior Tuner 5_Liter_Eater's Avatar
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    Glad you got it resolved. I've tried this several times and it fights me like s son'beatch every time even with the complete piping installed. I'm fairly happy running 2 bar SD but whenever I feel like aggrivating myself I try it again. I've thought that the MAF is experiencing some turbulance too as I'm using an ECS LS3 IC - TB pipe and the MAF sensor is further upstream towards the IC than yours.
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  15. #15
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    the only tuning i did going from stock maf to 100mm was i took both lo and hi maf tables and multiplied by 2. got it pretty damn close +/- 10 ltft's , now its time for some OL maf WOT 3rd gear pulls to get it all dialed in.

    i do feel like there is some turbulence, as i did one 3rd gear part mini pull and saw the maf freqency go back and forth between cells. doesn't seem right. shouldn't it go, up, up, and up!

    -carl

  16. #16
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    going to try and putting the 3/16 honeycomb in. i can feel slight bucking at low airflow

  17. #17
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    UPDATE: posted this on the CF

    today i got my MAF screen in its 3/4" thick, 3/16" holes x 4" circle. i poped the hood of the vette and found this!!

    WTF!





    i have no idea how this happend!! i would never EVER leave my car in this condition. at first i thought maybe it popped off during a blast down my back road. for ****s and giggles i tried to start it,, wouldn't even run. SO i ask WTF! i haven't driven the car since Sunday.

    anyways,

    here is some pics of the screen i installed.


    sorry about the messy workbench.

    i put a little JB weld on the inside of the tube and fins and just pushed it right in, nice and flat


    p.s. notice the sweet RX7 threw the MAF!

    all done..


    after the jbweld sets, i will do some scans and see how much the Freq Hz straighten out compared to no screen.



    -Carl

  18. #18
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    Silcone hoses need some serious clamp force to hold. Either tighten the worm gear clamps better or look for a better style clamp.
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  19. #19
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    the thing is that i dont think it Blew off? because the car wouldn't even start, as expected.

    im gonna try some hair spray.

  20. #20
    Tuner 07MontRedcp's Avatar
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    Quote Originally Posted by carlrx7 View Post
    the thing is that i dont think it Blew off? because the car wouldn't even start, as expected.

    i'm gonna try some hair spray.
    Good idea, one should always look their best when working on their car.

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