2Bar OS Confused
10-21-2006, 08:04 PM
#1
2Bar OS Confused
Guys,
I just got done reading the thread started by Holty on 2bar tuning. Holty Thread
I am confused. I thought about going with the 2Bar OS awhile back and now have the MPVI pro on the way so thinking about it again but I do not want to go mafless. Here is a quote from HPtuners when I inquired about it earlier.
"You cannot run both a MAF and a 2bar. If you use our 2bar VCM Enhancement, you no longer use the MAF. Its a SD only mod."
I read in the above thread that you guys are keeping the MAF. Help me understand. BTW I am a very novice tuner. Keep it simple if you can.
I just got done reading the thread started by Holty on 2bar tuning. Holty Thread
I am confused. I thought about going with the 2Bar OS awhile back and now have the MPVI pro on the way so thinking about it again but I do not want to go mafless. Here is a quote from HPtuners when I inquired about it earlier.
"You cannot run both a MAF and a 2bar. If you use our 2bar VCM Enhancement, you no longer use the MAF. Its a SD only mod."
I read in the above thread that you guys are keeping the MAF. Help me understand. BTW I am a very novice tuner. Keep it simple if you can.
10-21-2006, 08:23 PM
#2
A quote from HPT forum or one of the mods? Linky?
You can use the MAF. The real question is, the whole point of 2bar is because our standard OS (MAP) can't see boost. We are relying on the MAF to get us through boost. Which is quiet okay since 4K RPM+ the MAF is doing all the air calcs (most). But as soon as your MAF fails (read as you have maxed it out) the pcm goes SD and reads the VE table. So you being 9#'s and your MAF fails your pcm is looking at a VE table that only sees 105kpa, not the 170kpa that you'd need. A 2bar VE table, and it will see the proper ve cell for air calc...proper fuel.
Now, why waste the money if you aren't maxing the maf? No real reason too, but your setup has to be damn close. So then the next question is, why not take advantage of awesome fueling tweaks with a 2bar ve table? You can keep your maf, just make it fail earlier. Like 9K hertz or something. That way you get your easy tuning of normal driving and also can tune the ve table to handle your WOT runs. Part MAF and part SD. I am full open loop/SD.
Plenty of different opinions on this, lots of opinions, but in short, I don't see why you can't keep your MAF...but why bother past 105kpa. You can really fine tune the fueling with SD in WOT.
You can use the MAF. The real question is, the whole point of 2bar is because our standard OS (MAP) can't see boost. We are relying on the MAF to get us through boost. Which is quiet okay since 4K RPM+ the MAF is doing all the air calcs (most). But as soon as your MAF fails (read as you have maxed it out) the pcm goes SD and reads the VE table. So you being 9#'s and your MAF fails your pcm is looking at a VE table that only sees 105kpa, not the 170kpa that you'd need. A 2bar VE table, and it will see the proper ve cell for air calc...proper fuel.
Now, why waste the money if you aren't maxing the maf? No real reason too, but your setup has to be damn close. So then the next question is, why not take advantage of awesome fueling tweaks with a 2bar ve table? You can keep your maf, just make it fail earlier. Like 9K hertz or something. That way you get your easy tuning of normal driving and also can tune the ve table to handle your WOT runs. Part MAF and part SD. I am full open loop/SD.
Plenty of different opinions on this, lots of opinions, but in short, I don't see why you can't keep your MAF...but why bother past 105kpa. You can really fine tune the fueling with SD in WOT.
10-21-2006, 08:57 PM
#3
Thanks Dewmanshu.
The quote was in an e-mail from HPTuners back in April when I had inquired about the upgrade to 2Bar OS.
Okay sounds like 2bar might work the way I want then. Here is what I need to do as I understand it.
Get the OS upgrade. Apply it. Rewrite the OS into the PCM. SD tune the VE tables (now at 2 bar resolution), made much easier with the wideband I'll be logging with the MPVI Pro. Easier said than done I supose
Plug the MAF back into the equation. Set it to fail somewhere near the boost region. PCM will revert to my perfect SD tune for boost/WOT and revert back to maf and closed loop when I'm just cruising around.
Sounds ideal to me.
The quote was in an e-mail from HPTuners back in April when I had inquired about the upgrade to 2Bar OS.
Okay sounds like 2bar might work the way I want then. Here is what I need to do as I understand it.
Get the OS upgrade. Apply it. Rewrite the OS into the PCM. SD tune the VE tables (now at 2 bar resolution), made much easier with the wideband I'll be logging with the MPVI Pro. Easier said than done I supose
Plug the MAF back into the equation. Set it to fail somewhere near the boost region. PCM will revert to my perfect SD tune for boost/WOT and revert back to maf and closed loop when I'm just cruising around. Sounds ideal to me.
10-21-2006, 09:56 PM
#4
Hey Dewy, got a question for you? When I max the MAF, and it goes to SD, does it stay in SD till you clear the code, or does if go back to MAF when the air flow drops back down. FWIW, I'm running OL MAF right now and I see just shy of 12,000 Hz at 6200 and 170kPa with the 4.8
10-21-2006, 10:17 PM
#5
Interesting thread, I am going Straight SD in a couple weeks. I am Maxing the MAF at 5200 w/ 6.5-7lbs. I am leaning twards the SD only becuase of the fact of my MAF placement being so far up stream. MAF/TB/Blower/Piping/intercooler/piping/intake. I know when I was VE tuning with the MAF unhooked my throttle response was crisper and the idle and decel were perfect.
10-21-2006, 10:35 PM
#6
kb you are efi right? dc_justin is real good with all of this and he is efi. He can hook you up. But my understand from reading on hpt and tech, as soon as the sensor is within limits, it works. No more SD. If the code stays for a short time it is assumably a lag. No facts or hard experiences to talk about there, just what I read. Again, I haven't tried the fail at a particular hertz yet, so I have no experience at it. I might be wrong due to bad info.
There's a thread in here that dc_justin talks about the concept of not using the MAF, it's a good thread. Really puts things into perspective. The crisp and responsive throttle is in part to that not having the MAF you now don't have a reading "pre-manifold". You are now relying on the MAP sensor which is reading something that is happening now, not past nor present. Soooo, you are by accident leaning out your "tip ins" as I like to call it. Nothing too bad, just make sure you have a wideband and tune the ve.
Great demo's by HPT here... http://www.hptuners.com/forum/showthread.php?t=5058
03...you are maxing the maf at 5200rpm and 6#'s?!?!?! Crazy!! Got a scan?
There's a thread in here that dc_justin talks about the concept of not using the MAF, it's a good thread. Really puts things into perspective. The crisp and responsive throttle is in part to that not having the MAF you now don't have a reading "pre-manifold". You are now relying on the MAP sensor which is reading something that is happening now, not past nor present. Soooo, you are by accident leaning out your "tip ins" as I like to call it. Nothing too bad, just make sure you have a wideband and tune the ve.
Great demo's by HPT here... http://www.hptuners.com/forum/showthread.php?t=5058
03...you are maxing the maf at 5200rpm and 6#'s?!?!?! Crazy!! Got a scan?
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10-21-2006, 10:50 PM
#8
Originally Posted by KySilverado
I don't understand guys saying their throttle response improves with SD. Mine is so darned crisp now I cannot imagine it being any better. Just hitting bumps with the foot on the throttle gets exciting sometimes.
10-21-2006, 11:04 PM
#9
Originally Posted by dewmanshu
LOL then it probably won't get better. You have probably already tuned the crap out of your maf and ve table now?