Lowering Target AFR Properly

[Slowrc]

I have performed the autove several times to my Z and I want to try to lower my ratio some. I think my combo wants more fuel than the 12.95 to 1 that the auto Ve calls for. Should I change b3618 and b3605 to reflect my desires and retune??? Can I just change these and see how it runs ? (and then retune if it likes the fatness). I am getting the same power with a ls6 intake as I used to get with a ls1 intake. Only diff is I used to run a 11.0 to 1 mailorder tune and now I am around 13 to 1 after the intake swap and autove.

What is the benefit to switching back to closed loop?I have been daily driving olsd for months now:confused:

This car runs 7.70's and 12.0's no matter what I do to it:doh2:

[joecar]

Yes, change both B3605 and B3618 to your desired AFR...

If you did AutoVE (i.e. BEN's converge to 1.00), you will find that your BEN values will be the same (i.e. VE table will not change)...

i.e. what you dial in B3605 and B3618 is what you will see on the wideband.

[joecar]

I am told that people have found:
- LS1/LS6 best peak TQ is at AFR 12.6-12.8.
- LS1/LS6 best peak HP is at AFR 13.0-13.2.

You would set those in B3618.

Also note, when PE enables, the PCM selects the richer of B3618 and B3605.

[joecar]

If you're running cats, then you want to re-enable CL.

If you're running ORY, then you don't have to re-enable CL, you can just run OLSD or OLMAF.

If you swap to a COS then you can set your OL AFR with the MAPxRPM OL fuel table B3647 which replaces B3605.

[joecar]

You may also have to adjust timing a little... e.g. have a look B5913 in a Z06 file... but make sure you avoid knock.

[joecar]

Are you still running these:

firmware ver 2.06.16 boot block ver 2.06.02

[Slowrc]

Are you still running these:

Yes, I am. Big reason I should change now?


Are you saying that if I tune auto ve as described in the tutorial at 12.95 that if I changed B3605 and B3618 to 11.95 and went for a drive that I will still run 12.95 reguardless. I thought if I commanded more fuel in those two areas, I would get more. :confused::help2:

I have a 98 pcm so no cos. no maf. no cats.


Thanks for your input!!!

[5.7ute]

If you did AutoVE (i.e. BEN's converge to 1.00), you will find that your BEN values will be the same (i.e. VE table will not change)...



What this statement means is that your BEN values should not change. (As long as the injector modelling etc is accurate)
In other words your actual(wideband) to commanded AFR should still match.

[mr.prick]

Set {B3618} to what ever you want.
If VE/MAF are right that will be enough.

[Slowrc]

Set {B3618} to what ever you want.
If VE/MAF are right that will be enough.

yeah, thats it, 3618 and 3605. I always make em match just in case.

Any reason why my wideband reads richer and richer as the rpm goes up?


What this statement means is that your BEN values should not change. (As long as the injector modelling etc is accurate)
In other words your actual(wideband) to commanded AFR should still match.

Thank goodness, I have been sprayin a 75 shot with just changing those two tables.

THANKS GUYS!!!

[joecar]

...
Are you saying that if I tune auto ve as described in the tutorial at 12.95 that if I changed B3605 and B3618 to 11.95 and went for a drive that I will still run 12.95 reguardless. I thought if I commanded more fuel in those two areas, I would get more. :confused::help2:
...

No.

If your BEN converged to 1.00 then this now means your that wideband AFR equals commanded AFR (by virtue of VE table now being correct)...

Whatever AFR you set B3605 and/or B3618 to is what you will now see on the wideband... i.e. BEN will still be 1.00 (VE table will not change).

That is what 5.7ute and mr.prick are saying above.

B0101 VE table is the airmass table. B3605 and B3618 are commanded AFR tables.

[ PCM does this in OLSD:
- lookup B0101 VE table to get airmass,
- lookup B3605 and/or B3618 to get AFR (see * note),
- from AFR and airmass it calculates fuelmass,
- look IFR table to get flowrate,
- from flowrate and fuelmass it calculates injector time,
- lookup injector characteristics and modify injector time.

* note: PCM selects the richest of the active tables: if PE is active, PCM selects richest of B3618 and B3605
]

If your injector tables match the injectors, then BEN will also stay close to 1.00 during transitions.

[joecar]

That's the beauty of correcting the VE table... now whatever AFR you specify in B3605 and/or B3618 will be delivered (will be seen with the wideband).

If you drag-race, then this eliminates trial and error to achieve a specific AFR...
instead now you set a specific AFR in B3618, do a pass, compare ET/TS with other passes/AFR's.

[Slowrc]

That's the beauty of correcting the VE table... now whatever AFR you specify in B3605 and/or B3618 will be delivered (will be seen with the wideband).

If you drag-race, then this eliminates trial and error to achieve a specific AFR...
instead now you set a specific AFR in B3618, do a pass, compare ET/TS with other passes/AFR's.

SWEET!!!
-Thanks again