thinking of porting my ls1 maf sensor

[4-71/Z-28]

forst off my ls1 maf is blowthrough, i am having some compressor surge on my gn , it has a gtq70 turbo and its surging under boost so there must be a restriction on the cold side. the ls1 sensor looks kind of restrictive so im considering porting it but am worried if the ability to read and measure will go out the window (im sure GM spent millions of dallors on that design for a reason)

 

[DailyDrifter]

I wouldnt do it. Its already a LS1 MAF, how big do you really need it? You could always get a blow-off valve :biggrin: . But I guess if you really want to do it, my advice is dont go near anything electrical. You could take out the air foil, but that helps direct air over the element for accurate readings.

 

[pacecarta]

its an LT1
see if the screen is still in there , if so remove the screen and try it

i pushed a 71gtq through the lt1 blowthrough (no screen) and had no issues

dont port it , it will only screw up driveability

 

[4-71/Z-28]

i pulled the screen off tonight so ill try it out tomarrow. so pacecarta, you blew through a lt1 sensor? it looks pretty restrictive to be pushing all that air though it. im only makeing 20psi and im surging, i doubt the screen could restrict THAT much, but hopefully itll solve my issue.

 

[pacecarta]

yes blow through with it in the up pipe , went 10.8s at 20psi, 10.4xs pushed a little harder on a 200-4r (in the vid in my sig)

went 10.46 129.8 with it in there at over 6k rpm (6125) with the 400 trans.

 

[4-71/Z-28]

i just clicked on the video in youre sig and it was "a little fun with the gn's at atco" do you know shawn farrell?

 

[pacecarta]

yup , hes the one running the camera in the video

know your car pretty well too

 

[4-71/Z-28]

since you know the car pretty well, what do you think i should try to do?
the car is compressor surging under WOT, it doesnt do it like most others at part throttle or anything, just WOT. still pulls very hard though, its not falling on its face or anything. i talked to sean and he said to pull the screen out of the maf, i did that but have the freakin flu so i havent been able to drive it. when i pulled the screen out is when i noticed that the maf is sort of restrictive and thats when i got the idea that i could port it. any ideas would be greatly appreciated

 

[pacecarta]

the T+,modded ecm,75 injectors came out of my 86 , i never got to run the car with the setup , the weather here was lousy and he never made it to the track to see where she was with the chip I popped in there (75#TT 5.3 non alky race chip, same chip i ran in video)

my old chip was ok to drive on but too much timing for everyday wot with only a single nozzle(26/25 and only able to adjust out -1*) and the T+ didnt work too well with it at dropping timing..it works better if chip is low timing and the t+ adds it .
i'm not sure what chip he popped in the car i think it was his newer tt 6.0WB chip from one of his past cars because it was easier to adjust (gas pedal programming) and had a greater adjustment range
if thats what he put in there it really works best with an LC1 wideband,(ive been running the 6.0WB in both my cars since since 2007) he would have set up the chip to have the WB correcting turned off because there was no wb on the car. making the chip run on a default wot fuel map which was built for a 70 turbo combo but not specific for your high flowcombo.

check the trans+ and make sure he reset the settings in the box for the alky chip... first knob should be set to 3" maf , and the rest to no adjust for fuel or timing (0)

if you didnt get the new chip from eric , wait for that one.

 

[4-71/Z-28]

what new chip from eric? is he coming out with a newer version? hopefully a chip will cure it, my original intention was to immediatly turn the car up to 23-25# and take it to the track but its surging on 20psi so im assuming more boost will just make it worse. so you dont think its the maf in the up-pipe "backing up" the airflow causing it to surge?

 

[Just a Six??]

Check Erics site as he is adding & improving daily to his new line of chips for Power logger cars.

 

[pacecarta]

what new chip from eric?

it was my understanding that you were going to get a chip from eric for the car , i wouldnt just go cranking boost up on any car without feeling it out and working the boost up slowly as long as the everything looks good

if you havent done it already call eric and order a new chip for the combo , the 5.6 should be fine for now
keep in mind theres only one nozzle on that setup , not sure it will have enough methanol flow to run at 25psi for a full 1/4 on just 93 octane, it was only 1/8th miled before shawn bought it .... id start at 18 and see where she is...... at 25psi that car should be 9s... my freinds T (murphster) with unported gn1s , 224roller cpt70Dbb and single pump dual nozzles is 10.18 129 at 20psi -on 93octane

 

[4-71/Z-28]

looks like i better just get another nozzle and a chip. so in your opinion the maf that i have would be good enough for more than 20psi. but first things first, i still need to figure out this compressor surge . maybe taking the screen out will help i will try it later today, shawn pulled fuel out before he sent it my way, right now its running 770's but maybe i should give it another 5% or so

 

[4-71/Z-28]

gave the car more fuel via tt chip, removed the screen, and it seems to be fine. (i dont think fuel needed to be pulled from it because of the elevation difference after all). now just waiting on my second nozzle, for safety precautions .