tuning VE, question about disconnecting maf
12-16-2004, 05:12 PM
#61
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The IFR is a global value, as has been mentioned. However it is not what is changing in cammed cars (unless of course you change the injectors). Your VE has changed, which is why that table is there. Why scale a table, and then make your top end fueling wrong?
12-16-2004, 05:28 PM
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Originally Posted by NoGo
The rating of the GM injectors are given at the rated fuel pressure of the GM cars.
Most other injectors on the planet are rated at 43.5 psi (or 3 bar). In order to correct them to our table you have to account for fuel pressure.
If you just take 30 lb injectors straight across it comes out to 3.77. That would be far to rich for that injector size.
Most other injectors on the planet are rated at 43.5 psi (or 3 bar). In order to correct them to our table you have to account for fuel pressure.
If you just take 30 lb injectors straight across it comes out to 3.77. That would be far to rich for that injector size.
Quick question I ws under the impression that 1 bar =14.7 psi
If the above is tru then 3 bar = 44.1 psi and 4 bar =58.5 psi
12-16-2004, 07:02 PM
#63
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Originally Posted by NoGo
The rating of the GM injectors are given at the rated fuel pressure of the GM cars.
Most other injectors on the planet are rated at 43.5 psi (or 3 bar). In order to correct them to our table you have to account for fuel pressure.
If you just take 30 lb injectors straight across it comes out to 3.77. That would be far to rich for that injector size.
Most other injectors on the planet are rated at 43.5 psi (or 3 bar). In order to correct them to our table you have to account for fuel pressure.
If you just take 30 lb injectors straight across it comes out to 3.77. That would be far to rich for that injector size.
You're right. OF COURSE.
I zeroed the MAF.
Changed my IFR values as suggested. It was about a 13% increase at 100kPa. I had to increase my VE's and after 2 try's it needed a 9% increase to achieve (0 to -6 max ltrims). Brought back the MAF and the ltrims went to +12. I then increased the MAF #'s 13% ( 2 tries). The ltrims now range (.3 to -2.3) and the strims(1.3 to -4.2).
Thanks for the help NoGo.
This has been a terrific thread. I can't believe how easily I got the tune in the ballpark. It needs more work but this is a good start.
One other thing I noted. Maf gms are closer to what they are set at than before. In fact very close. They also now match iacdes.
Next week I'll see where the AFR is before fine tuning it.
Last edited by gojo; 12-16-2004 at 08:13 PM.
12-16-2004, 08:01 PM
#64
Wow, I just found this thread!!
I feel all warm and fuzzy!!
I checked to make sure it wasn't an old one!!! 
FWIW. I calculated my VE table from NoGo's Eq One year ago.
I have an FJO Wideband O2.
My part throttle AFRs pretty much match my F/A table since I discovered an Offset table that I assume is for the 42# injectors I run ( from the ASA GM tune)
My biggest problem has been "lean at idle" - damn overlap. I used DYNAIR and MAF g/sec to bump my MAF airflow reported in tandem with my VE. Seems to have worked well.
Here is what I assumed DYNAIR is:
g/cyl = VE%*178.33*0.708* MAP / ( 273 +IAT*C)*5120 ( from gameover )
g/cyl = MAF * 15 / RPM
So,
MAF = VE%*178.33*0.708* MAP*RPM / ( 273 +IAT*C)*5120 *15
Calculated MAF = DYNAIR
I was very intrigued by HumpinSS' thoughts on back-tracking an entire MAF table - I only used it to make my idle adjustments.
gojo - i never thought about the transitions. Didn't I remove most of the "transition" data when I selected for cell 22 in my calcs??
NoGo - How the heck are you?? You are THE MAN!!...sorry I had to say that!!
I feel all warm and fuzzy!!
I checked to make sure it wasn't an old one!!! FWIW. I calculated my VE table from NoGo's Eq One year ago.
I have an FJO Wideband O2.
My part throttle AFRs pretty much match my F/A table since I discovered an Offset table that I assume is for the 42# injectors I run ( from the ASA GM tune)
My biggest problem has been "lean at idle" - damn overlap. I used DYNAIR and MAF g/sec to bump my MAF airflow reported in tandem with my VE. Seems to have worked well.
Here is what I assumed DYNAIR is:
g/cyl = VE%*178.33*0.708* MAP / ( 273 +IAT*C)*5120 ( from gameover )
g/cyl = MAF * 15 / RPM
So,
MAF = VE%*178.33*0.708* MAP*RPM / ( 273 +IAT*C)*5120 *15
Calculated MAF = DYNAIR
I was very intrigued by HumpinSS' thoughts on back-tracking an entire MAF table - I only used it to make my idle adjustments.
gojo - i never thought about the transitions. Didn't I remove most of the "transition" data when I selected for cell 22 in my calcs??
NoGo - How the heck are you?? You are THE MAN!!...sorry I had to say that!!
12-16-2004, 08:36 PM
#65
Originally Posted by gojo
NoGo,
You're right. OF COURSE.
I zeroed the MAF.
Changed my IFR values as suggested. It was about a 13% increase at 100kPa. I had to increase my VE's and after 2 try's it needed a 9% increase to achieve (0 to -6 max ltrims). Brought back the MAF and the ltrims went to +12. I then increased the MAF #'s 13% ( 2 tries). The ltrims now range (.3 to -2.3) and the strims(1.3 to -4.2).
Thanks for the help NoGo.
This has been a terrific thread. I can't believe how easily I got the tune in the ballpark. It needs more work but this is a good start.
One other thing I noted. Maf gms are closer to what they are set at than before. In fact very close. They also now match iacdes.
Next week I'll see where the AFR is before fine tuning it.
You're right. OF COURSE.
I zeroed the MAF.
Changed my IFR values as suggested. It was about a 13% increase at 100kPa. I had to increase my VE's and after 2 try's it needed a 9% increase to achieve (0 to -6 max ltrims). Brought back the MAF and the ltrims went to +12. I then increased the MAF #'s 13% ( 2 tries). The ltrims now range (.3 to -2.3) and the strims(1.3 to -4.2).
Thanks for the help NoGo.
This has been a terrific thread. I can't believe how easily I got the tune in the ballpark. It needs more work but this is a good start.
One other thing I noted. Maf gms are closer to what they are set at than before. In fact very close. They also now match iacdes.
Next week I'll see where the AFR is before fine tuning it.
12-16-2004, 08:53 PM
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Originally Posted by Bink
My biggest problem has been "lean at idle" - damn overlap. I used DYNAIR and MAF g/sec to bump my MAF airflow reported in tandem with my VE. Seems to have worked well.
12-16-2004, 08:56 PM
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Originally Posted by Bink
gojo -I'll try this and let you know how it goes. I haven't been closed loop for over a year.
You will likely stay open loop with your cam. I tuned mine in SD and it ran as smooth as aba. It really isn't necessary for my car. Anyone with EFI BI-D controls can get a sense of how smooth a richer idle AF is.
12-16-2004, 09:35 PM
#68
gojo - I just want to try it. At 14.7 - 15.5 it idles nicely ( smells like **** though and it makes the house and garage reek for a couple hrs! ) I had to think about the info in this thread a bit before I realized the significance of zeroing the MAF 
.
Another_User - thanks, I'm open loop. I'll try it closed loop.
No surging, no cruise, no hanging and no bucking - thank you gojo and Nick Williams.
Hot starts are finally ironed out -> Crank VE.
I had to think about the info in this thread a bit before I realized the significance of zeroing the MAF .Another_User - thanks, I'm open loop. I'll try it closed loop.
No surging, no cruise, no hanging and no bucking - thank you gojo and Nick Williams.
Hot starts are finally ironed out -> Crank VE.
12-16-2004, 10:09 PM
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Originally Posted by Bink
gojo - I just want to try it. At 14.7 - 15.5 it idles nicely ( smells like **** though and it makes the house and garage reek for a couple hrs! ) I had to think about the info in this thread a bit before I realized the significance of zeroing the MAF .
Another_User - thanks, I'm open loop. I'll try it closed loop.
No surging, no cruise, no hanging and no bucking - thank you gojo and Nick Williams.
Hot starts are finally ironed out -> Crank VE.
I had to think about the info in this thread a bit before I realized the significance of zeroing the MAF .Another_User - thanks, I'm open loop. I'll try it closed loop.
No surging, no cruise, no hanging and no bucking - thank you gojo and Nick Williams.
Hot starts are finally ironed out -> Crank VE.
12-16-2004, 11:26 PM
#71
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Another shorter quicker idea would to be this:
Log in EFIlive v6 or v7 and log MAF raw frequency and AFR. In V7 make a map to plot the Freqeuncy against rpm 8000 (1 column = 8000) adn the data would be the AFR. If the car is in open loop and the commanded afr is 12.96:1 or 1.13 then you can take the afr at that frequency/commanded and multiply the maf table by the percentage that its off. This still leaves you assuming SOME of the tables are right such as the IFR table, Ve table adn the injector offset table.
Log in EFIlive v6 or v7 and log MAF raw frequency and AFR. In V7 make a map to plot the Freqeuncy against rpm 8000 (1 column = 8000) adn the data would be the AFR. If the car is in open loop and the commanded afr is 12.96:1 or 1.13 then you can take the afr at that frequency/commanded and multiply the maf table by the percentage that its off. This still leaves you assuming SOME of the tables are right such as the IFR table, Ve table adn the injector offset table.
12-17-2004, 04:35 AM
#72
Originally Posted by gojo
Are the cats working?
Less stink hopefully?
Last edited by Bink; 12-17-2004 at 04:43 AM.
12-17-2004, 06:08 AM
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Originally Posted by Bink
Nope, fried those - spring 2003. That's where I'm headed - new dual FJO, 3 " x-pipe and the newer Random Tech cats ( placed at the rear of the x-pipe).
Less stink hopefully?
Less stink hopefully?
