Anyone tried mafless tune with boost
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Joined: Apr 2002
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From: Austin, TX
Anyone tried mafless tune with boost Curious if anyone has tried throwing on a two bar map sensor and tuning with VE. (It could give you decent control up to about 14psi)
I'm not sure if it could even be done, but it seems worth trying.
Anyone?
Here are some of the problems that I think could get in the way.
- The # of part throttle cells would be very small and the part throttle tune would be rough at best. The same problem might also exist under boost.
- some unknown internal limitation of the PCM could just make it impossible
Since the VE/massflow table has finally been cracked it would be easy to map the VE cells into all the other tables that use g/cyl...like timing advance.
any thoughts?
I'm not sure if it could even be done, but it seems worth trying.
Anyone?
Here are some of the problems that I think could get in the way.
- The # of part throttle cells would be very small and the part throttle tune would be rough at best. The same problem might also exist under boost.
- some unknown internal limitation of the PCM could just make it impossible
Since the VE/massflow table has finally been cracked it would be easy to map the VE cells into all the other tables that use g/cyl...like timing advance.
any thoughts?
Originally Posted by QuickSilver2002
- some unknown internal limitation of the PCM could just make it impossible
Also, besides the fact that you'd have less ve cells for part throttle, I have heard that when you run mafless it uses the secondary ve table which has half the cells of the main ve table. So you'd be using very few cells for part throttle.
Thread Starter
TECH Apprentice
Joined: Apr 2002
Posts: 308
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From: Austin, TX
Originally Posted by P Mack
The VE table only goes to 105 kpa so the pcm couldn't handle a 2bar map sensor.
Originally Posted by P Mack
but then your g/cyl would be off so you'd have to change other stuff like the injector tables.
The injector flow table would just need to change based on what you discovered with the PCM to true MAP mapping.
Originally Posted by P Mack
I have heard that when you run mafless it uses the secondary ve table which has half the cells of the main ve table.
Last edited by QuickSilver2002; Sep 16, 2004 at 04:06 PM.
You may want to email keith@hptuners.com, he has been looking into a safe solution along these lines.
Originally Posted by QuickSilver2002
Not sure I follow. You would be changing the values in the VE table dramatically, but that is a given. g/cyl is exactly what the values in the VE represent. It is a massflow table, not a true VE table. There is now a known equation to convert the number in the VE table to g/cyl.
Thread Starter
TECH Apprentice
Joined: Apr 2002
Posts: 308
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From: Austin, TX
Originally Posted by P Mack
In hptuners, ve is a true ve table in percentages, so I guess you are probably talking about ls1edit. Either way, I tried putting 200% in one of the 105 kpa cells and when i tried to save the table, it changed it to 141% so there's a maximum value you can put in the ve cells. I think if you were using a 2 bar map sensor, you'd need at least 190% to do it this way. That's why I was saying you'd have to fool the pcm from the fueling side too.
Edit is just a more raw representation of what the PCM uses for the VE table.
Hp tuners is putting a % facade in front of the underlying tables that the PCM uses. They just take the % you put in and calculate out a massflow value for the PCM based on 100% VE for the CI of the motor. The PCM is using a massflow calculation in the OS code no matter what software you are using to edit the calibration with.
But a hard limitation to the size of that # would create a much bigger challenge for sure. Edit seems to allow some crazy large #s but who knows if that is based on any real PCM limitations or not. I think I remember trying it and thinking it would allow over 900g/sec at 6000rpms (in ls1-edit).
I know there is the 512 g/sec limit with the MAF, but I don't think the same limitation is there with VE based massflow. I'm obviously only guessing, since I have no access to the OS code.
Maybe we could get Keith from HP tuners on this thread?
It does seem like someone would have already done it if it was a reasonable solution, but I figure it is worth some investigation.
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Well..
If you use a 2 bar MAP on a PCM with our product, 105 kPa ends up being 210 kPa. We simply use a cyl vol reference on the VE table to display it in a % to make it easier on you. Who wants to play with raw #'s?
What you guys want is this:
We will have more info on our forum SOON. That is all I can say.
- Keith, hptuners.com
If you use a 2 bar MAP on a PCM with our product, 105 kPa ends up being 210 kPa. We simply use a cyl vol reference on the VE table to display it in a % to make it easier on you. Who wants to play with raw #'s?
What you guys want is this:
We will have more info on our forum SOON. That is all I can say.
- Keith, hptuners.com
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