AFM voltage offset not reporting properly?
Posted: Sun Dec 09, 2007 8:45 pm
Hey Matt,
Well long story short, i've been road tuning the car for a few dyno days that have come and gone during the last fortnight.
I tuned the lower boost setting first around 9 psi, had perfectly flat AFR across the board.
Then when i was running higher boost (targeting 14-15psi) the car would go through this surge/hesitation around round 4000rpm, where the boost spiked, looking at the log showed lean afr, especially around the 4000rpm mark, ok i though, odd because it should calculate TP and keep AFR the same with increased air flow.
Anyway kept tuning around the hesisitation believing it was AFR related.
Got the AFR reasonbly flat, went to dyno day, done low boost run, 9psi, spun up 195rwkw, ok i thought this is good, i want over 300rwhp (225kw)
Dyno operator tried high boost and told me that it was pinging its arse off and backed off, resulting in 216rwkw at low rpm (4000rpm)
Dyno operater then tried middle boost setting around 12psi, same thing pinged its arse off.
He said minus some timing, so I expanded the maps because it was on the last load area during high boost and reduced the timing.
Took car out today, also thought it wise to drop the boost a little as well, just incase because it still seemed to have the hesitation/pinging to me.
Anyway put in on dyno, low boost run was 180rwkw, down 15kw on last dyno, went to middle boost done setting done 202rwkw, went high (but lower then last dyno) done 217rwkw, but i could still feel the hesitation there, just not as bad.
On the lower boost settings AFR was all over the shop, mainly rich coming onto boost.
Anyway came home, dissapointed again because the setup should crack 300hp at the treads but it didn't.
Long story short, I've been thinking, went into the logs and the AFM voltage was dead flat, which how can air flow ever be dead flat, so I worked out the AFM is maxed and i have been trying to tune around that, but i didn't think it was that because the software was showing only 4.6V (which i thought was low originally, but didn't think anymore of it)
So the software was/is not showing the correct voltage on the VQ map etc, it isn't adding the extra 1.5V to realtime readings, even though its in the adr file?
Is the adr file correct?
Anyways, ordered a Z32 AFM today, should be able to tune it properly.
But the stock AFM peaks out at approx 190-200rwkw(max)!!!!!!!!!!!!!!
Pics attached
this is the 15psi run, where he had to back off at 4000rpm due to pinging (because it was not calculating a higher tp and not going to higher ignition load point on map) notice afr are ok because i tuned around the afm, not realising at the time it was actually pinging.
this is the middle boost setting run, 12psi done today, notice the afr dips, because this is the area where the afm is rich because its the highest load point the airflow meter can measure but not running 15psi today to use the fuel.
a log, showing air flow voltage dead flat @ 4.6V, it can not be dead flat unless maxed, notice on VQ map its not adding the offset, also notice the area where the fuel map is heaps rich, this is as high as the afm would read, but it would get to that load point at only 9psi, that why after i done the high boost mapping not realising it was fucking my 9 psi map, because it was using the same cells.
adr file showing offset should be added?
Well long story short, i've been road tuning the car for a few dyno days that have come and gone during the last fortnight.
I tuned the lower boost setting first around 9 psi, had perfectly flat AFR across the board.
Then when i was running higher boost (targeting 14-15psi) the car would go through this surge/hesitation around round 4000rpm, where the boost spiked, looking at the log showed lean afr, especially around the 4000rpm mark, ok i though, odd because it should calculate TP and keep AFR the same with increased air flow.
Anyway kept tuning around the hesisitation believing it was AFR related.
Got the AFR reasonbly flat, went to dyno day, done low boost run, 9psi, spun up 195rwkw, ok i thought this is good, i want over 300rwhp (225kw)
Dyno operator tried high boost and told me that it was pinging its arse off and backed off, resulting in 216rwkw at low rpm (4000rpm)
Dyno operater then tried middle boost setting around 12psi, same thing pinged its arse off.
He said minus some timing, so I expanded the maps because it was on the last load area during high boost and reduced the timing.
Took car out today, also thought it wise to drop the boost a little as well, just incase because it still seemed to have the hesitation/pinging to me.
Anyway put in on dyno, low boost run was 180rwkw, down 15kw on last dyno, went to middle boost done setting done 202rwkw, went high (but lower then last dyno) done 217rwkw, but i could still feel the hesitation there, just not as bad.
On the lower boost settings AFR was all over the shop, mainly rich coming onto boost.
Anyway came home, dissapointed again because the setup should crack 300hp at the treads but it didn't.
Long story short, I've been thinking, went into the logs and the AFM voltage was dead flat, which how can air flow ever be dead flat, so I worked out the AFM is maxed and i have been trying to tune around that, but i didn't think it was that because the software was showing only 4.6V (which i thought was low originally, but didn't think anymore of it)
So the software was/is not showing the correct voltage on the VQ map etc, it isn't adding the extra 1.5V to realtime readings, even though its in the adr file?
Is the adr file correct?
Anyways, ordered a Z32 AFM today, should be able to tune it properly.
But the stock AFM peaks out at approx 190-200rwkw(max)!!!!!!!!!!!!!!
Pics attached
this is the 15psi run, where he had to back off at 4000rpm due to pinging (because it was not calculating a higher tp and not going to higher ignition load point on map) notice afr are ok because i tuned around the afm, not realising at the time it was actually pinging.
this is the middle boost setting run, 12psi done today, notice the afr dips, because this is the area where the afm is rich because its the highest load point the airflow meter can measure but not running 15psi today to use the fuel.
a log, showing air flow voltage dead flat @ 4.6V, it can not be dead flat unless maxed, notice on VQ map its not adding the offset, also notice the area where the fuel map is heaps rich, this is as high as the afm would read, but it would get to that load point at only 9psi, that why after i done the high boost mapping not realising it was fucking my 9 psi map, because it was using the same cells.
adr file showing offset should be added?