OK guys, how to transfer MAF frequency from a later operationg system?
09-11-2008, 10:08 PM
#1
OK guys, how to transfer MAF frequency from a later operationg system? Now that I finally got around to upgrading to an 85mm MAF, I'm out of MAF frequency @ 11250 HZ in my 98 operating system. So, above 5,300 RPM, I'm out of MAF. Thought that I could just transfer an 02 operating system MAF frequency table that measures up to 12000 HZ, but, there doesn't seem to be a method to do so. Am I gonna have to click & paste the complete tune, table by table, from the 98 operating system on to the 02 operating system, just to get a MAF table that allows me scaling to 12000 HZ, or is there a way to add additional frequency scaling options to the 98 operating system table? Again, I'm talking about the frequency itself (in the grey), am not talking about the g/s (airflow) that has already been re-scaled up to 11250 HZ.
Currently 11250 HZ is max in the 98 MAF scaler & I'm pegged @ 385 g/s @ 11250 HZ & 5300 RPM. The max HZ in an 02 operating system goes to 12000 HZ, which will get me the scaling needed to get from 5300 to 6400+ RPM.
EFI Live; here is a copy of the tune file. Have a look @ the MAF table & you'll see the issue. I'd rather not copy & paste everything contained in the 98 file, just to get higher MAF scaling, if it can be helped. Thanks in advance
Currently 11250 HZ is max in the 98 MAF scaler & I'm pegged @ 385 g/s @ 11250 HZ & 5300 RPM. The max HZ in an 02 operating system goes to 12000 HZ, which will get me the scaling needed to get from 5300 to 6400+ RPM.
EFI Live; here is a copy of the tune file. Have a look @ the MAF table & you'll see the issue. I'd rather not copy & paste everything contained in the 98 file, just to get higher MAF scaling, if it can be helped. Thanks in advance
09-11-2008, 10:17 PM
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This is the same issue that I have with my '87 Camaro, I am out of MAF at 255 gms/sec.
By the time you go beyond the reach of your MAF, the PCM should be in PE mode. Simply add extra fuel via the PE vs RPM table. Probably want to add extra fuel around 5,000RPM and above.
By the time you go beyond the reach of your MAF, the PCM should be in PE mode. Simply add extra fuel via the PE vs RPM table. Probably want to add extra fuel around 5,000RPM and above.
09-12-2008, 05:23 AM
#3
Thanks for the reply. I want to measure airflow to 6400 RPM in order to get an idea of how much air the MAF, TB, intake, & heads are moving so that it can be compared to previous intake related set-ups. Will probably have to paste the 98 info to the 02 operating system in order to use the MAF frequency for measurement. Was hoping there was an easy way.
09-12-2008, 05:00 PM
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Frost--- what you say is true. I have the system tuned for cool nites when I need more fuel. However, we have the option to install a adjustable fuel pressure gauge in the engine bay on 3rd gen cars. Along with a WBO2, its relatively easy to dial in any AFR at WOT. No need for a new computer tune.
We need someone to come up with an AFPR for our 4th gen OBDII cars thats convenient to get to.
We need someone to come up with an AFPR for our 4th gen OBDII cars thats convenient to get to.
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09-12-2008, 05:14 PM
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LS1-450: Concerning running out of range. Going back to my example, I finally got tired of people saying that I was running out of MAF. So I took my good factory MAF (which I had plenty of data on) and cut away the outer shell, and then cemented it into a 3.5" OD aluminum tube. The cross sectional flow area was now 38% larger. Assuming that this is linear, my counts from the "Mega MAF" should be comparable linearily.
Possibly you can use the same logic in your sitution. Mount the electronics of the your MAF into a larger tube. Get the right rubber connectors, and compare away. My point is that 10,000Hz now might repsresnt 475 gms/sec inside the factory MAF. When you mount the electronics into a 4.0" tube, 10,000Hz now might represent 400 gms/sec. Scale by the flow area percentage.
Possibly you can use the same logic in your sitution. Mount the electronics of the your MAF into a larger tube. Get the right rubber connectors, and compare away. My point is that 10,000Hz now might repsresnt 475 gms/sec inside the factory MAF. When you mount the electronics into a 4.0" tube, 10,000Hz now might represent 400 gms/sec. Scale by the flow area percentage.
09-12-2008, 09:09 PM
#9
LS1-450: Concerning running out of range. Going back to my example, I finally got tired of people saying that I was running out of MAF. So I took my good factory MAF (which I had plenty of data on) and cut away the outer shell, and then cemented it into a 3.5" OD aluminum tube. The cross sectional flow area was now 38% larger. Assuming that this is linear, my counts from the "Mega MAF" should be comparable linearily.
Possibly you can use the same logic in your sitution. Mount the electronics of the your MAF into a larger tube. Get the right rubber connectors, and compare away. My point is that 10,000Hz now might repsresnt 475 gms/sec inside the factory MAF. When you mount the electronics into a 4.0" tube, 10,000Hz now might represent 400 gms/sec. Scale by the flow area percentage.
Possibly you can use the same logic in your sitution. Mount the electronics of the your MAF into a larger tube. Get the right rubber connectors, and compare away. My point is that 10,000Hz now might repsresnt 475 gms/sec inside the factory MAF. When you mount the electronics into a 4.0" tube, 10,000Hz now might represent 400 gms/sec. Scale by the flow area percentage.
That's a really good idea, thank-you. Earlier today, I re-scaled the 85mm MAF airflow from 11000-11250 HZ in order to get it closer to what wasn't being measured above 11250 HZ. Wasn't feeling great about doing it. I like what you have come up with much better. Have estimated that the MAF needs to be able to measure 446 g/s @ 11250 HZ & even if the newly mounted stocker doesn't quite make it, it should be close. Thanks again.
09-13-2008, 02:00 PM
#10
LS1-450: Assuming that this is linear, my counts from the "Mega MAF" should be comparable linearily.
Possibly you can use the same logic in your sitution. Mount the electronics of the your MAF into a larger tube. Get the right rubber connectors, and compare away. My point is that 10,000Hz now might repsresnt 475 gms/sec inside the factory MAF. When you mount the electronics into a 4.0" tube, 10,000Hz now might represent 400 gms/sec. Scale by the flow area percentage.
Possibly you can use the same logic in your sitution. Mount the electronics of the your MAF into a larger tube. Get the right rubber connectors, and compare away. My point is that 10,000Hz now might repsresnt 475 gms/sec inside the factory MAF. When you mount the electronics into a 4.0" tube, 10,000Hz now might represent 400 gms/sec. Scale by the flow area percentage.
Doc99SS,
Wouldn't the comparison of 10,000 HZ representing 475 g/s in a smaller (factory MAF) be 8421 HZ while representing the same 475 g/s in the larger MAF & not 10,000 HZ representing 400 g/s in the larger MAF? Realizing that the actual numbers mean nothing & were for example purposes only. My point is that the velocity in the larger MAF is reduced by the cross section of the larger MAF. Therefore, the same volume of air passes the sensors more slowly in the larger MAF. So, wouldn't this mean that the sensors (frequency) measuring the slower moving air would display as a reduced frequency; 475 g/s in a smaller MAF being 10,000 HZ & the same 475 g/s in a larger MAF beign 8,421 HZ using (475 to 400 g/s to define the area difference between MAF's)? This what I understand the meaning of your example to be; yes?
09-13-2008, 06:48 PM
#11
OK,
Just finished for today. MAF is now 100MM with no screen. From the MAF scaling, confirmed that indeed larger amounts of air pass @ a lower frequency (from example; if 475 g/s @ 10,000 HZ was the smaller MAF, then when using the sensors from the smaller MAF & installing into a larger MAF, 475 g/s is displayed @ a lower frequency (would have been 475 g/s @ 8,421 HZ in the example).
Difference in areas was 50% ish by calculation & 41% from calibrated measurement. Am thinking that this may have to do w/ the fact that my sensor is now just ahead of the TB. It remains in a straight line, as required, but, the cone into the TB must be having an effect on the net area. Anyway, there is more than enough room in the MAF now & it isn't an issue.
Doc99SS, only real problem is tuning the idle. My God what a pain in the a$$. It must be the no-screen coupled w/ the larger MAF area. Have it dialed in to about 85% & am thinking that re-scaling the IAC steps will settle it the rest of the way. We'll see tomorrow. Also, need to make some runs in dry weather to confirm the VE & PE w/ the new MAF.
Just finished for today. MAF is now 100MM with no screen. From the MAF scaling, confirmed that indeed larger amounts of air pass @ a lower frequency (from example; if 475 g/s @ 10,000 HZ was the smaller MAF, then when using the sensors from the smaller MAF & installing into a larger MAF, 475 g/s is displayed @ a lower frequency (would have been 475 g/s @ 8,421 HZ in the example).
Difference in areas was 50% ish by calculation & 41% from calibrated measurement. Am thinking that this may have to do w/ the fact that my sensor is now just ahead of the TB. It remains in a straight line, as required, but, the cone into the TB must be having an effect on the net area. Anyway, there is more than enough room in the MAF now & it isn't an issue.
Doc99SS, only real problem is tuning the idle. My God what a pain in the a$$. It must be the no-screen coupled w/ the larger MAF area. Have it dialed in to about 85% & am thinking that re-scaling the IAC steps will settle it the rest of the way. We'll see tomorrow. Also, need to make some runs in dry weather to confirm the VE & PE w/ the new MAF.
09-14-2008, 09:56 AM
#12
UPDATE:
Have now dialed in the idle much closer by playing around w/ "idle airflow", IAC steps, & matching idle timing w/ high & low octane timing @ idle RPM. Idle is much better, but, is just a tinge unstable @ times. As a direct result of a the more stable idle, the 41% noted above is now 47%. So, the poor idle was effecting my MAF table scaling. The current 47% is much closer to the calculated 50% & am more comfortable with the results. Expect it become a little better with a little more idle & driving tuning time.
Bottom line: By installing & sealing stock MAF sensors into a 100mm tube, MAF scaling inow does not run out of frequency before running our of airflow. Currently, 10,000 HZ is 511.9922 (512 g/s). Have added a couple of pics. The out of round shape shown w/ the elbow held by hand is a non-issue becuse once mounted to the TB, it becomes a true circle. Looks like an SD install & allowed the intake to be as short as it can be. Thanks, Doc99SS. You may want to consider starting a thread regarding this. Am sure there are 1000's of members that could benefit from your custom made MAF.
Have now dialed in the idle much closer by playing around w/ "idle airflow", IAC steps, & matching idle timing w/ high & low octane timing @ idle RPM. Idle is much better, but, is just a tinge unstable @ times. As a direct result of a the more stable idle, the 41% noted above is now 47%. So, the poor idle was effecting my MAF table scaling. The current 47% is much closer to the calculated 50% & am more comfortable with the results. Expect it become a little better with a little more idle & driving tuning time.
Bottom line: By installing & sealing stock MAF sensors into a 100mm tube, MAF scaling inow does not run out of frequency before running our of airflow. Currently, 10,000 HZ is 511.9922 (512 g/s). Have added a couple of pics. The out of round shape shown w/ the elbow held by hand is a non-issue becuse once mounted to the TB, it becomes a true circle. Looks like an SD install & allowed the intake to be as short as it can be. Thanks, Doc99SS. You may want to consider starting a thread regarding this. Am sure there are 1000's of members that could benefit from your custom made MAF.
09-14-2008, 11:47 AM
#13
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When I did my Mega MAF tuning on my OBD1 car, I let the LTFTs guide me in scaling the MAF table correctly. For example, I alter the MAF table so that the LTFTs are close to 0% in as many FTCs as I can get the PCM into while driving around, especially the higher ones, like 12, 14, 15 without going into PE mode. Then I swap to the new larger MAF, and tune the MAF table so that the LTFTs are once again back to nearly 0%. Now I have two MAF tables, one good the the smaller (factory MAF) and the other for the larger MAF. And now, you can see what effect of the larger MAF and the comparable air flow at the same frequency. I have always let the LTFTs guide me when re-tuning for some intake side mod. Does this make any sense? I am convinced it is the best method.
09-14-2008, 09:43 PM
#14
When I did my Mega MAF tuning on my OBD1 car, I let the LTFTs guide me in scaling the MAF table correctly. For example, I alter the MAF table so that the LTFTs are close to 0% in as many FTCs as I can get the PCM into while driving around, especially the higher ones, like 12, 14, 15 without going into PE mode. Then I swap to the new larger MAF, and tune the MAF table so that the LTFTs are once again back to nearly 0%. Now I have two MAF tables, one good the the smaller (factory MAF) and the other for the larger MAF. And now, you can see what effect of the larger MAF and the comparable air flow at the same frequency. I have always let the LTFTs guide me when re-tuning for some intake side mod. Does this make any sense? I am convinced it is the best method.
Sure it makes sense. I usually start in the garage tuning STFT's from -3 to 0. This also brings the LTFT's down. However, as you have stated, the LTFT's can only be dialed in while driving. Usually, I go back & check & change for the the LTFT's later, because I'm really lazy. Would agree that your method is more precise.
I have a near perfect (guess they're never completely perfect) small (stock) MAF table that was tuned over Months & was used prior to the few days when the troublesome 85mm MAF was installed. My comparison, thus far, with a good, but, not yet great tune using your MEGA MAF was made comparing the MEGA against the dialed in smaller (stock, un-modified MAF). Anyway, today my 47% droped back to 44%. So, I should really wait a couple of weeks before stating a final & as good as can be determined comparison.
In any case, it is very clear that your MEGA MAF solves the problem of running out of frequency before airflow.
