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Old 07-09-2006, 01:33 PM   #1
QWKSNKE
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Fox body OEM 5.0 vs Cobra MAF comparison

Anybody seen this before? Fox GT vs Fox Cobra MAF.... http://www.veryuseful.com/mustang/te...ck-gt-maf.html
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Old 07-09-2006, 01:47 PM   #2
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Re: Fox body OEM MAF comparison

On my datalog I show about the same HP as the maf shows in volts. My MAF is off a 96 corba 80 mm I thinks'

My dyno is to the wheels and that one may be from the crank. If so then its dead on.
Pretty cool info.

Lot's of information on that site. Thanks
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Old 07-10-2006, 06:28 AM   #3
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Re: Fox body OEM MAF comparison

Yep, that's Joe Viola - (stangPlus2birds) from corral.net. Joe is some type of engineer, and actually works with flow meters for a living. You should see some of his posts ripping people who don't know jack about MAF and EEC stuff!

He has numerous OEM ford EEC's, tweecer, eectuner, etc. He actually built his own flow bench for MAF's, which is where those numbers came from. He's prob. tested 100's of different OEM MAF's, etc. Unfortunately, his delivery in his posts leaves a bit to be desired, and he usually makes people mad at him to the point where they don't believe him.
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Old 07-10-2006, 06:37 AM   #4
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Re: Fox body OEM MAF comparison

Yeah, Joe can be pretty harsh.
He hammered me on the TPS the other day.
Smart dude though.

I think the end conclusion on the use of a cobra meter has to consider the required use of the computers adaptive ability.

Since we only have 12-15% adjustability with the fox computers, it may not be a good idea.
The posted graph show that the difference between the stock MAF and Cobra MAF can exceed 24%.

Besides, do you really want to design in significant amount of error in your system?

If one has access to a tuner and can change the MAF Transfer, then there is no real downside.

jason
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Old 07-10-2006, 06:41 AM   #5
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Re: Fox body OEM MAF comparison

Exactly.

I'm still unconvinced on the TPS voltage thing (for those of you wondering, Joe contends that as long as your TPS voltage is under 1.25v, the EEC zeros out the reading at startup to 1.0v every time, just like the 94+ cars. Probst book says so, but I'm not so sure whether it was a typo or not).

We all know the EEC wants to see 1.0v or less, but the engineer in him won't let it go, so he throws that out there for the masses. Prob is that the masses isn't ready for that, and confusion ensues...
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Old 07-10-2006, 05:08 PM   #6
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Re: Fox body OEM MAF comparison

Quote:
Originally Posted by 93Cobra#2771
Exactly.

I'm still unconvinced on the TPS voltage thing (for those of you wondering, Joe contends that as long as your TPS voltage is under 1.25v, the EEC zeros out the reading at startup to 1.0v every time, just like the 94+ cars. Probst book says so, but I'm not so sure whether it was a typo or not).

We all know the EEC wants to see 1.0v or less, but the engineer in him won't let it go, so he throws that out there for the masses. Prob is that the masses isn't ready for that, and confusion ensues...
Based on the following from GUFB:

Quote:
OVERVIEW
The throttle mode scheduler is used to determine what engine operating
region is currently extant. The variable APT (At Part Throttle flag) is used
to indicate throttle mode and is assigned the following values:

Throttle Mode APT
------------------ ---
CLOSED THROTTLE -1
PART THROTTLE 0
WIDE OPEN THROTTLE 1

The value of APT is determined by the logic shown on the following page.
Briefly, throttle angle breakpoints, in terms of counts, are used to define
the CLOSED/PART_THROTTLE and PART/WIDE_OPEN_THROTTLE transitions.
Hysteresis is incorporated in both breakpoints to prevent jitter between modes.

The variable RATCH is the output of a ratchet algorithm which continuously
seeks the minimum throttle angle corresponding to a CLOSED THROTTLE position.

This alleviates the necessity to set the throttle position sensor at an
absolute position and compensates for system changes and differences between vehicles.


The ratchet algorithm uses filtered throttle position for the
determination of RATCH.

A more detailed explanation of the throttle position ratchets and throttle
position filter is contained in the SYSTEM EQUATIONS section.
It appears that annoying Joe may be correct on this. I can find NO reference to 1V as a breakpoint, only that the part throttle breakpoint is based on DELTA above RATCH. I think that if you were to adjust the TPS & get the ISC DC correct & restart the car to "relearn" the new position as RATCH, then it should work. The only issue I can find is a TP test that has limits that equate to 0.5 to 1.25V set as defaults for the acceptable window for closed throttle. Above 1.25V or below 0.5V the TP will throw an error. Anywhere in that range and it should work as described above. Now, if you go and adjust the TPS more than DELTA above where is is while the key is on, it will think you are in PT mode until you recycle the power, at which point it will rezero and treat the new voltage as "0".

If anyone can find information whereby 1V is used as a reference, I will be glad to admit I'm wrong (unlike annoying Joe).
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Old 07-11-2006, 07:07 AM   #7
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Re: Fox body OEM 5.0 vs Cobra MAF comparison

http://www.streetstangs.net/showthread.php?t=6801
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Old 07-11-2006, 05:06 PM   #8
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Re: Fox body OEM 5.0 vs Cobra MAF comparison

Apparently I was reading the GUFB document correctly

This is one of about 3 or 4 oft repeated EEC IV "facts" that I have found to be untrue after reading much of the GUFB strategy document this past week.
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