MAFT-Pro VE Table

D

Doward

Banned
Jan 11, 2006
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Alachua, FL
So with all the MAFT-Pros finding their way into Supras these days, how many of you are actually working the VE tables, to get readings for the TCCS?

So far, I'm between 1.25-2.50 Vf at basically any part throttle, under 100kPa (that means no boost) after extensively going over the VE tables. Driveability is exactly as it was, stock.

Once I start to climb into boost, though, my Vf drops to 0.0 (I did this on purpose, as I had to max out the TCCS's ability to adjust the AFR, so I could get it where I wanted), my AFRs drop to ~13.5, down to ~12.8 @ 120kPa (~3 psi), and it falls to 11.6 around 3400rpm and 14psi. Runs like a scalded dog right now :)

BTW, if you have the TPS Start (for boost control) set too low, a heavy part throttle run will give you a full 14psi, and you WILL hit FC with only ~1000hz. I guess FC really is tied into RPM as well as Frequency! :icon_bigg
 
CRE

CRE

7M-GE + MAFT Pro + T = :D
Oct 24, 2005
3,485
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Denver, CO
I'm planning on digging in, but I'm waiting until I can pickup a wideband. Unfortunately, my Vf isn't reliable (possibly due to the altitude here), so until I can make sure of the effects of the changes I'm not touching a thing. ;)

I am kinda surprised at the lack of response to this thread though.


Grim, you just reminded me... I was going to try to take some time to get the timing control up and running this weekend. Damn, next weekend I guess.
 
americanjebus

americanjebus

Mr. Evergreen
Mar 30, 2005
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u kick ass ^

any pics??? or screenshots? right now im just looking to source a cheep laptop just for my car and little things.
 
90T04

90T04

New Member
Mar 30, 2005
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Tucson, AZ
www.azsupras.com
I just got my maft-pro updated to 4.80. With 550cc injectors at ~30psi fuel pressure I needed to pull -13% on the main scale, and another -10% off of user tune low to even get the vf to register a solid 2.5v at idle. At cruise and part throttle im staying right at 2.5V with some dips into the 1.25 to 3.75 volt ranges. So im pretty satisfied with it. My only problem is when im going into positive boost at part throttle, it takes longer than I like to break out of closed loop (i guess) and start adding fuel. I can be making 10 psi and still showing 14.7 until I flooor it then it will drop to a safe AFR.

Im interested in what you are doing with the VE tables to fine tune. I see the columns are RPM, the rows must be absolute manifold pressure in KPA? Im sure you can run the engine while monitoring the cell block of the VE table that you are in at any given time, and change it accordingly. Ill go check out your thread at mkiiitech.com.
 
90T04

90T04

New Member
Mar 30, 2005
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Tucson, AZ
www.azsupras.com
Wow great info there Doward! One question: when making changes to the "user tune low, mid, and high" tables, is there any effect upon the values in the VE table? You would think it should, but I havent played with the VE tables enough to know.
 
D

Doward

Banned
Jan 11, 2006
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Alachua, FL
The user tune I have set to zero across the board. You use the User Tune to do a general tune on the VE table, to come out to about what you are looking for. Say the VE table says XX VE, and your user tune @ that RPM = -10% (remember the Load Set Points for user tunes? That's where it comes into play) so you end up with VE table - 10%. You can not get the fine tuned control using User Tunes, that you get with doing the VE table. That said, it is much EASIER and QUICKER to use the user tunes.

If you go in and do the VE table yourself, you'll find that you can richen the mixture as soon as you hit boost - I had the exact same problem you are having, with heavy part throttle runs - and do you want to know the scary part? The TCCS is actually programmed that way!

Remember too, you are scaling the airflow signal - stock, the TCCS allows about 4 psi before it starts to actually richen up the mixture (in my testing, anyway). 10psi + 14.7:1 afr = eventual BHG. Just toss that into my evidence box, of my theory that the majority of BHG, and multiple BHGs per car, is due to the Lexus/550s swap, and heavy part throttle boosting.

I'm using the MAFT-Pro's VE table to override the TCCS at heavy throttle, and I'll be writing that up later tonight ;)
 
D

drjonez

Supramania Contributor
Mar 31, 2005
3,061
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the motor city
www.4cefed.com
90T04 said:
...My only problem is when im going into positive boost at part throttle, it takes longer than I like to break out of closed loop (i guess) and start adding fuel. I can be making 10 psi and still showing 14.7 until I flooor it then it will drop to a safe AFR...
Click to expand...

that's the essence of the TCCS- open loop doesn't happen until ~70%, ~3500 RPM. makes for nightmarish tuning @ part throttle if you have a turbo that spools quickly...
 
D

Doward

Banned
Jan 11, 2006
4,245
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36
Alachua, FL
Or if you increase the VE, causing you to run richer for that few seconds than the TCCS can correct for, giving you the AFR you want - I haven't had the TCCS throw me a rich code, yet. Maybe JJ can share how long the TCCS will deal with a rich condition, before the CEL takes? Or better, I bet it's @ Mkiiitech.com... gonna go look :)
 
P

pimptrizkit

thread killer
Dec 22, 2005
1,572
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vancouver Wa
awsome doward, i've hard the maft pro for awhile, and i admit it's a learnin curve for most.

my biggest mistake so fas was not soldering my connections from day one. it made my afr unstable and across the board, also gave me stumble during tipin or starting from a stop.

i admit i haven't played with the ve table at all, im doing my best to absorb the info like a spung that im learning. although i did fault and when i flashed to 4.8 and set it up, i set it to use ve table 1, and that made the car run like crap, well ontop of the crappy connections i had, when i changed to table 2 the car became driveble, and wasn't sitting in 19afr while idleing and so on

well im going to play with my tune alittle more after i read the write up your doing, but i admit i cant romp on her since she is noisy and will be pullin her guts again..
 
D

Doward

Banned
Jan 11, 2006
4,245
0
36
Alachua, FL
Updated with some heavy part throttle information.

Also as a small aside, I cracked up today - this is the FIRST time I have cracked 200 miles on a single tank. 13.5 gallons took me 215 miles. 15.7mpg, and this is WITH constant 16psi runs! I'm extremely happy with out well my car is running.

From a 20-30 mph roll, if I stomp on the go pedal, I will actually loose traction when the turbo spools :naughty:
 
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