[a32guy]

Curious as to find out what was going on with the dyno jpsimon posted up (hope he doesn't mind me using him as a reference). He did a baseline pull and then a pull at stage 3+ with their default settings. Despite making 16.5 psi (2x the stock boost level), the AFRs were the same on both pulls.



Is this intentional? When I'm tuning a traditional EFI car, I target closer to 11.8 AFR at TQ peak. I understand DI helps control knock quite a bit, but is it safe to run that lean at TQ peak?

Thanks,
Chris

[jpsimon]

*peaked at 16psi, not 16.5

[OpenFlash]

Originally Posted by a32guy

Curious as to find out what was going on with the dyno jpsimon posted up (hope he doesn't mind me using him as a reference). He did a baseline pull and then a pull at stage 3+ with their default settings. Despite making 16.5 psi (2x the stock boost level), the AFRs were the same on both pulls.



Is this intentional? When I'm tuning a traditional EFI car, I target closer to 11.8 AFR at TQ peak. I understand DI helps control knock quite a bit, but is it safe to run that lean at TQ peak?

Thanks,
Chris

JP's baseline was done in valet mode which just brings down boost to stock levels and sets ignition correction to 0deg. The fuel mapping (afr targetting) is still functional. If he were to physically remove the Procede, the afr logs would be considerably leaner.

And to answer your question, yes, that afr trace is desired and perfectly safe. No need for overfueling for in-cyl cooling and mixture homogenization in a direct injection motor with a stratified air/fuel charge.

Shiv

[OpenFlash]

Originally Posted by jpsimon

*peaked at 16psi, not 16.5

Yep. And that peak is a temporary value caused by .6psi transient overshoot and/or measurment error. Maximim boost target (boost set point) for stg3+ map is:
rpm.... Psi
2000....9.3
3000....12.8
4000....13.8
5000....15.4
6000....15.4
7000....11.3

shiv

[mwahlert]

why is fuel mapping left in place in valet mode?

[a32guy]

Thanks.

[ajvee]

Good Thread!

I've actually been wanting to address a general question regarding AFRs and piggybacks. One of the things that we hear about GIAC (not sure about Dinan) is the rich air fuel mixtures, which translate into requiring less boost to make horsepower. Could a piggyback, either the JB3 or the PROcede, replicate such rich air fuel mixtures?

Based on my understanding, the answer is yes that piggybacks can replicate these rich air fuel mixtures, and if so I am curious about why the piggyback tuners opt not to do so?

I appreciate your inputs.

[hun77777]

Originally Posted by shiv@vishnu

Yep. And that peak is a temporary value caused by .6psi transient overshoot and/or measurment error. Maximim boost target (boost set point) for stg3+ map is:
rpm.... Psi
2000....9.3
3000....12.8
4000....13.8
5000....15.4
6000....15.4
7000....11.3

shiv

can there be little variation between what you just said and what i see on my rixster boost guage? because i'm on stg 3+ and i've seen 15.7 on my guage at wot run

[OpenFlash]

Originally Posted by hun77777

can there be little variation between what you just said and what i see on my rixster boost guage? because i'm on stg 3+ and i've seen 15.7 on my guage at wot run

Of course. These are just the targets. Actual boost can deviate slightly from there.

[Kelvin1000]

There has to be a good reason why GIAC would go out of their way to change the A/F ratios soo much... Take a look at my Dyno from last week:

I think that one of the ways that ECU throws "tuner codes" is by measuring fuel demands. Not really sure, but this might be the reason why the Procede and the JB3 keep the A/F ratio the same as stock, regardless of boost...

[ajvee]

Kelvin1000,

I appreciate the information. You make a really interesting point, as I haven't heard this perspective before. I have been keeping track of your dynos and posts and appreciate the information that you provided on GIAC.

Cheers.

[Sniz]

Originally Posted by Kelvin1000

There has to be a good reason why GIAC would go out of their way to change the A/F ratios soo much... Take a look at my Dyno from last week:

I think that one of the ways that ECU throws "tuner codes" is by measuring fuel demands. Not really sure, but this might be the reason why the Procede and the JB3 keep the A/F ratio the same as stock, regardless of boost...

hmmm......so it looks like the JB3 is running WAY leaner than both your GIAC and the procede. Both the GIAC and the Procede are in the 12's at 4500rpm while the JB3 is over 14.1. Huge difference right there.

[vase330]

Didn't Shiv say they trap tuner codes as soon as they pop up? If so, then why would they keep the A?F ratios stock?

Hopefully they will pop in and comment on the speculation.

[jpsimon]

Originally Posted by Sniz

hmmm......so it looks like the JB3 is running WAY leaner than both your GIAC and the procede. Both the GIAC and the Procede are in the 12's at 4500rpm while the JB3 is over 14.1. Huge difference right there.

yeah at that point kelvin has marked on his graph (4500rpm), my graph is at the same reading ~12.95

[jpsimon]

at 4500 rpm, the black line (AFR) at the bottom is right about at 12.95ish, the same place the GIAC graph is at and by redline it's nearly at 12

[Sniz]

Originally Posted by jpsimon

yeah at that point kelvin has marked on his graph (4500rpm), my graph is at the same reading ~12.95

yeah I saw that and that really surprised me, those are 2 very different tunes for sure.

I'd like the richer tune myself, safer in a big way. I know the n54 has some great engine control but I dont see the reason for pushing it like that. I'll have to admit I dont know the limitations of DI, but if both GIAC and Vishnu are running much richer I have to question the reasoning behind the 14+ afr the JB3 is running there.

[OpenFlash]

Originally Posted by Sniz

yeah I saw that and that really surprised me, those are 2 very different tunes for sure.

I'd like the richer tune myself, safer in a big way. I know the n54 has some great engine control but I dont see the reason for pushing it like that. I'll have to admit I dont know the limitations of DI, but if both GIAC and Vishnu are running much richer I have to question the reasoning behind the 14+ afr the JB3 is running there.

My guess is that the jb3 is running a higher resistor value in the wideband biasing circuitry. We reduced the value in ours when going from rev.1 to rev.2 to get more fuel enrichement authority range.

Shiv

[mwahlert]

Originally Posted by shiv@vishnu

My guess is that the jb3 is running a higher resistor value in the wideband biasing circuitry. We reduced the value in ours when going from rev.1 to rev.2 to get more fuel enrichement authority range.

Shiv

how large is the range now?

[OpenFlash]

Originally Posted by mwahlert

why is fuel mapping left in place in valet mode?

It's just the way we designed both v4 to work. No reason in particular. It's just nice to have a global fuel map with afr targets based on RPM and manifold pressure that we don't have to disable. Leaving it one doesn't effect power in valet mode. Nor does it trigger any tuner codes so we decided to keep it enabled all the time.

[Bimmer335i07]

Kelvin also dyno tested his Rev2 PROcede and was around 14.7:1 around
the same time he tested his JB3.... ?

http://www.e90post.com/forums/showthread.php?t=229096

[OpenFlash]

Originally Posted by Bimmer335i07

Kelvin also dyno tested his Rev2 PROcede and was around 14.7:1 around
the same time he tested his JB3.... ?

http://www.e90post.com/forums/showthread.php?t=229096

Read that thread. That is a dyno result of a v3 Doomsday map. We no longer care about the tuner code since the Procede can now read/clear them natively.

shiv

[Bimmer335i07]

Originally Posted by shiv@vishnu

Read that thread. That is a dyno result of a v3 Doomsday map. We no longer care about the tuner code since the Procede can now read/clear them natively.

shiv

OK, but here is another recent one with similar 14.7:1 air/fuel ratio?

http://www.e90post.com/forums/showthread.php?t=326844