Fuel injection? Open or Closed loop?

boster · 08-06-2012, 09:26 AM

In my opinion the tuner should always have full control of the fuel map and timing .

But on the new cars from the factory the oem computer controls everthing . If its oem the the computer can control the car down track and its more consistenbut not faster . NHRA has allowed both , but if its a aftermarket computer the computer is not allowed to make changes going down the track unless the car came with a computer that did .

I like were I have full control of the car bracket mode or heads up . I vote open loop

Ed Wright · 08-06-2012, 10:33 AM

Unless the new Fords are different, from the factory they all go to open loop in P.E. (Power Enrichment) mode, or wide open throttle.

DrHP · 08-08-2012, 10:50 PM

Gentlemen,

The question of closed or open loop is not really valid when the engine is using a narrow band O2 sensor. The stock systems normally use this narrow band sensor that is accurate only in a very narrow target area of about stoichiometric (14.68:1 with pump gasolne).The wide band sensors can be used with the appropriate control system, but I would think you want absolute control to be consistanrt. Some of you racers hit it on the head, mentioning that at WOT the system had better be in open loop, using the base fuel tables with its modifiers. The operational parameters regardng PE and the closed loop threshold are probably the areas that are highly tuned (along with base fuel and spark), that the successful guys paying attention to. Forced open loop would cerntainly be my choice!

Just an old racers two cents, Dennis Baccus
Former F/S record holder - 1969 Z28,
Current calibration engineer on GM MEFI systems and engine builder

View Poll Results: Fuel injection? Do you run in open loop or closed loop
Open Loop	80	65.04%
Closed Loop	43	34.96%
Voters: 123. You may not vote on this poll

08-06-2012, 09:26 AM	#1
boster Senior Member Join Date: Oct 2003 Location: usa Posts: 958 Likes: 0 Liked 0 Times in 0 Posts	Re: Fuel injection? Open or Closed loop? In my opinion the tuner should always have full control of the fuel map and timing . But on the new cars from the factory the oem computer controls everthing . If its oem the the computer can control the car down track and its more consistenbut not faster . NHRA has allowed both , but if its a aftermarket computer the computer is not allowed to make changes going down the track unless the car came with a computer that did . I like were I have full control of the car bracket mode or heads up . I vote open loop __________________ Bo Kenney

08-06-2012, 10:33 AM	#2
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Fuel injection? Open or Closed loop? Unless the new Fords are different, from the factory they all go to open loop in P.E. (Power Enrichment) mode, or wide open throttle. __________________ Ed Wright 4156 SS/JA

08-08-2012, 10:50 PM	#3
DrHP Junior Member Join Date: Feb 2011 Location: Walla Walla WA Posts: 8 Likes: 0 Liked 0 Times in 0 Posts	Re: Fuel injection? Open or Closed loop? Gentlemen, The question of closed or open loop is not really valid when the engine is using a narrow band O2 sensor. The stock systems normally use this narrow band sensor that is accurate only in a very narrow target area of about stoichiometric (14.68:1 with pump gasolne).The wide band sensors can be used with the appropriate control system, but I would think you want absolute control to be consistanrt. Some of you racers hit it on the head, mentioning that at WOT the system had better be in open loop, using the base fuel tables with its modifiers. The operational parameters regardng PE and the closed loop threshold are probably the areas that are highly tuned (along with base fuel and spark), that the successful guys paying attention to. Forced open loop would cerntainly be my choice! Just an old racers two cents, Dennis Baccus Former F/S record holder - 1969 Z28, Current calibration engineer on GM MEFI systems and engine builder

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