granatelli 85 mm MAF...? inside
06-07-2004, 10:48 AM
#2
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Join Date: Mar 2001
Location: SLC, UT
Posts: 2,668
Not worth what you're going to pay for it, May not fit correctly in your application, tuning of your car will be effected in an unknown way; could be good, could be bad.
There's a LOT of discussion on this, and the verdict is still out...
But to give a summary, Your PCM uses a table to interpolate the frequency that your MAF sends it, it takes the frequency and "looks up" how much air is flowing through your MAF.
No one but Grantenelli knows what the "correct" table for their MAFs are, and AFAIK no one has gotten them to release what the table is. Thus you are running a MAF that is "supossedly" calibrated to work in our cars, but no one really knows. This inherently is the issue what that MAF, no one knows what the real Freq Vs Flow chart/table is.
That's probably TMI, but incase you were wondering.
There's a LOT of discussion on this, and the verdict is still out...
But to give a summary, Your PCM uses a table to interpolate the frequency that your MAF sends it, it takes the frequency and "looks up" how much air is flowing through your MAF.
No one but Grantenelli knows what the "correct" table for their MAFs are, and AFAIK no one has gotten them to release what the table is. Thus you are running a MAF that is "supossedly" calibrated to work in our cars, but no one really knows. This inherently is the issue what that MAF, no one knows what the real Freq Vs Flow chart/table is.
That's probably TMI, but incase you were wondering.
06-07-2004, 11:46 AM
#4
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Join Date: Aug 2001
Location: Cuyahoga Falls, OHIO
Posts: 870
Well if you think its the MAF then just get another stock one. As mentioned above, the granatellit supposedly makes more power by fooling the PCM. But it figures it out and readjusts the fuel trim to bring it back to its programmed A/F ratio.
06-07-2004, 01:30 PM
#5
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Join Date: Mar 2001
Location: SLC, UT
Posts: 2,668
Well, for most people I just recommend replacing it with another stock unit.
If you have the capability to program your PCM or are planning on tuning your PCM you can use a GM Z06 MAF on a LT1 car; it's what Grantenelli hacks apart to make their 85mm MAFs. I have the correct table, and the adapter cable required costs about $20 from Ramchargers. This MAF can be obtained from any GM dealership/GMpartsdirect.com/Jason/Hal for ~ $100.
This can have some fitment issues due to a 4" inlet Vs the stock MAF 3.5" inlet. Depending on what CAI you have this can be an issue.
If you have the capability to program your PCM or are planning on tuning your PCM you can use a GM Z06 MAF on a LT1 car; it's what Grantenelli hacks apart to make their 85mm MAFs. I have the correct table, and the adapter cable required costs about $20 from Ramchargers. This MAF can be obtained from any GM dealership/GMpartsdirect.com/Jason/Hal for ~ $100.
This can have some fitment issues due to a 4" inlet Vs the stock MAF 3.5" inlet. Depending on what CAI you have this can be an issue.
06-07-2004, 01:42 PM
#6
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Thread Starter
Join Date: Nov 2002
Location: south carolina
Posts: 491
when car is in closed loop, whats the major things that usualy go wrong? my car only does it when it gets warmed up, and only does it until the SES light comes on, then it runs with teh ocasional stumble...any help apreciated
06-07-2004, 02:32 PM
#7
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Join Date: Mar 2001
Location: SLC, UT
Posts: 2,668
Before you go start replacing thigs, figure out what code your car is throwing. There is a trick with the OBDI cars like yours, but I personally don't know it.
Always start with the code if your car is displaying a SES light.
Always start with the code if your car is displaying a SES light.
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