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MEDIK418 · 10-11-2002, 11:14 PM

My son's 89 was doing the same thing after he added a conical K&N filter. The problem was he added it to the plumbing just ahead of the Pro-M bullet. It would surge so bad that after about three-four cycles it would just die. I took the filter off and left the intake open and it died on the first surge. Adding a 7 inch "play-pipe" between the MAF and the filter almost stopped the surge but it's still there every once in a while. I put the stock airbox back on and it stopped completely. I am guessing here but, you can do the same thing to a flow meter run on a fire pump. If the fluid flow is turbulent enough it will intermittently miss the metering part of the pipe and cause a bad reading. This apparently does the same thing with the MAF. Adding enough smooth pipe ahead of the MAF smooths out the flow enough so that the small portion of the pipe that actually takes the airflow sample will get plenty of air sample. Anyway, it worked for my particular application. Not advocating doing away with the cold
air but it might explain why this causes surges.

10-11-2002, 11:14 PM	#7
MEDIK418 Registered Member Join Date: Mar 1999 Location: Amarillo, Texas, USA Posts: 780	My son's 89 was doing the same thing after he added a conical K&N filter. The problem was he added it to the plumbing just ahead of the Pro-M bullet. It would surge so bad that after about three-four cycles it would just die. I took the filter off and left the intake open and it died on the first surge. Adding a 7 inch "play-pipe" between the MAF and the filter almost stopped the surge but it's still there every once in a while. I put the stock airbox back on and it stopped completely. I am guessing here but, you can do the same thing to a flow meter run on a fire pump. If the fluid flow is turbulent enough it will intermittently miss the metering part of the pipe and cause a bad reading. This apparently does the same thing with the MAF. Adding enough smooth pipe ahead of the MAF smooths out the flow enough so that the small portion of the pipe that actually takes the airflow sample will get plenty of air sample. Anyway, it worked for my particular application. Not advocating doing away with the cold air but it might explain why this causes surges. __________________ 1986 four-eyed LX coupe, 358 Cleveland, Tremec TKO600/centerforce clutch, dish cut Probe forged pistons, comp cams hyd.roller cam, .579/.588@224/230, Edel.performer, 670 holley street avenger, CPR custom built long tubes, ported and polished 4bbl heads, manley valves, beehive springs, MSD peo-billet dist/MSD6AL, fluidamper, 5 lug conv. with 17x8 bullits there's more but it's still not finished yet. Oh, and the oldest boy is turning his 89 GT into a FFR cobra this next summer.