<blockquote><font class="small">In reply to:</font><hr>

Gurgen,
Thanks for the scoop I too believe I have a rich problem not a lean problem. Can the TS guys program for that? I worry about mail order tuning no dis to any one. Can they program to just my issues with my mods?...Rod

03 5AT-Premium-Aero-Tire & Wheel Pkg-Splash-Z tube-K&N Filter-32% Tint-10 wire Grounding Gear-Crawford Plenum Ver 5

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I understand your concern. Unfortunately, unless you live in SoCal, mailing in your ECU is the only way to get your ECU done. And IMO that's the best way to get it done, without any piggybacks that may interefere with the ECU's function; just have your ECU do the job, only differently. TS is one of the most dynamic companies out there, they will taylor the program to your mods, and they recognize that it is hard to get it right sometimes when your car is not right there at their shop, and they will reflash it if necessary to get it to your liking. They will never leave you hanging...

Yeah, you definitely do not want to take your a/f measurements from pre-cat factory 02 bung on the header, who knows how it messes with the ECU.

 

Thanks, Gurgen for the scoop I'm learning.....Rod

03 5AT-Premium-Aero-Tire & Wheel Pkg-Splash-Z tube-K&N Filter-32% Tint-10 wire Grounding Gear-Crawford Plenum Ver 5

 

Rod,
Ok ... I thought that's what I read. However, I'm still a little confused here ... sorry, I'm a little slower than the others By "going to the oem O2 sensor" ... do you mean:

1. He tap'd into the wires of the oem O2 sensor?

or

2. He unscrewed and disconnected the oem O2 sensor and replaced (temporarily) withi his *wideband* O2 sensor?


If 1, then that explains the ugly AF curve as the oem sensor is non-wideband. You can effectively throw out the AF data you've collected ... unfortunately

If 2, the AF data you've collected is good for the particular run. However, as Gurgen has put it ... the missing oem O2 sensor may trigger some flags within the ECU ... possibly effecting your performance negatively.

Hope that helps.


Clint (THX723)

 

Clint, I think he did 2 (no pun) but I didn't go under the car with him to check but I know what to ask him about tomorrow. He did have a wrench....Rod

03 5AT-Premium-Aero-Tire & Wheel Pkg-Splash-Z tube-K&N Filter-32% Tint-10 wire Grounding Gear-Crawford Plenum Ver 5

 

Rod,
Sounds like #2 to me as well, if he had to use a 'wrench'. This brings up another dilemma, but one that could explain your eventual rich condition. Since you never got a 'Check Engine Light', he probably left the oem sensor connected. This would have given a false lean condition as seen by the ECU (one that is not enough to throw another CEL) ... which then proceeded by dumping more fuel to compensate (to protect the engine as well as being a little more environmentally friendly). This is my speculation, however.

I have spoken to Tadashi at Techno Sqaure at length in the past and learned that our ECU, even at wide-open throttle is never in full 'open-loop' mode. The ECU is constantly monitoring and influencing AF and timing under all conditions. The only difference being less trim (correction) is in effect when under WOT condition.

LOL ... betcha weren't expecting things to get so complicated when you made the inital dyno run post huh?

Cheers,

Clint (THX723)

 

THX723, I did not get a check engine light. I'll call the dyno guy tomorrow to get the low down on just what he did and you are right I'm down a rabbit hole here and I did not expect this much complication but I guess that's the fun of it, THE SCHOOL OF HARD LEAN/RICH ....Rod

03 5AT-Premium-Aero-Tire & Wheel Pkg-Splash-Z tube-K&N Filter-32% Tint-10 wire Grounding Gear-Crawford Plenum Ver 5

 

True, well said Clint. We just do not know how the ECU operation was affected wit hrespect to the trim effected during that WOT run. I am really surprised that a dyno operator, who does this all day every day, would do that. It may not affect other cars however, those that have a true open-loop mode.

Gurgen

 

It sure IS, ain't it FUN!!!!

 

Nissan has always used the MAF in WOT conditions to double check the look up tables and to trim them but only recently were the microprocessors fast enough to rely much on the readings...........engine acceleration too fast......in rpms per second [50-80 in a Q in 2nd gear = 3700>6,000 = 5.3 seconds = 433 rpms per second] but the ecu cycle time was like 40 times a second so only 10 adjustment possible per second..........hope I'm being clear enough.

The MAF can trim the look up table [actually calculated now] by 20% but not instantly it goes up in steps trying and measuring effect.

After all the look up table was correct in the lab and only needs temperature/MAF corrections for altitude/weather to be correct under any circumstances.

"Smoothing" "NON ABRUPT" of corrections might be the best term to use.


This faster than normal acceleration in direct gear on a DYNOJET is the source of the problem. The acceleration fuel may be way too rich because the ecu is confused. It knows what it is seeing is impossible because it doesn't have a table or equation that covers impossible road events.

The Mustang with eddy brake slows [loads] the engine to real world conditions [an acceptable number of revs per second increase] and the ecu has time to think about evaluating the MAF vs table and calculating a compromise.

 

Hey Q,
Are you saying NO readings off a dyno with normal set ups for AF are useful?...Rod

03 5AT-Premium-Aero-Tire & Wheel Pkg-Splash-Z tube-K&N Filter-32% Tint-10 wire Grounding Gear-Crawford Plenum Ver 5

 

Q45,

Not to hijack the thread, but this one is an important one:

There is 1 fuel table and 3 timing (ignition) tables in our cars. That's a fact. Now, I'd really like to know exactly what correction factors go into the equation in determining the final (1) A/F ratio (or amt of fuel added), and (2) timing advance? MAF is already a part of the equation, as it is directly part of the calculated load (the x-axis of these tables), so let's not consider it a mitigating factor in this case. Are any of these part of the eqn?

1) ambient air temp
2) intake air temp
3) oil temp
4) coolant
5) atf temp
6) oil pressure
7) atf pressure

We are real sure of #2,and 4. But are the rest part of the eqn? THis is like the $64000 question to me.
BTW, I am also leaning toward #1 because I can see on my w/b o2 gauge that a/f get about ~0.2-0.3 units leaner at night, while my intake temps stay approximately constant.

Any input from anyone would be greatly appreciated.

Gurgen

 

Q45Tech,
Agreed ... which is why I prefer doing the dyno measurements on a DynaPak which also simulates varying road loads. I did a session on a DynoJet only as a point of reference so I know where I stand comparing to other DynoJet numbers on the forum.

One more question regarding ECU ...
What are the conditions for the ECU to downgrade or upgrade bewtween the 3 available ignition maps? Knock I'm sure is one major factor and I suppose all the temp sensors are in the mix as well.


Clint (THX723)

 

gurgen, keep fighting to find an answer to these questions!

I really would like to know this too.

2004 G35C 6MT Black. Killer.

 

Good stuff, guys. I just purchased an ODBII logger to try to get a better feel for what the ECU is doing re: timing and what conditions affect it.

BTW, I'm also a big fan of the DynaPack dynomometer. Definitely loads the car up more than a DynoJet. I don't know how the raw numbers compare to a DynoJet. My most recent DynaPack was 385 rwhp and 325 ft/lb torque. It's been several mods ago since I did my last DynoJet comparison.

--Steve

 

Steve,
Neat! ... which OBDII logger did you get? I too have been searching for a good logger for a while. I think I've finally settle on one that supports all three OBD-II protocal (including CAN used by all '03+ Nissan/Infiniti cars). It is made by Auterra for PDAs that run Palm OS.

In regards to DynaPack ... I had a good conversation with an experience DynaPack owner/operator durring a sound recording session for EA's next Need for Speed video game. What I've learned from him was there's not an x-percentage factor used to convert to the DynoJet number. Too many factors are involved. Roughly, it's an x-offset instead. For my range (around 240rwhp) the DynaPak reads about +10 higher than DynoJet. I'm not sure if the same offest is still valid for your horsepower range (>350). Funny enough, a few hours later ... I managed exactly +10.1hp from the DynoJet number I got a few weeks earlier


Clint (THX723)