What trumps what in fuel management?

[carnut169]

Running a stock 07 GSXR, the stock water temp sensor sends a signal to the ecu which makes adjustments in leaness based on temperature. The mapping for each gear is also different, but I run a TRE which fools the ecu into thinking its always in 5th. Then I install a PC3 or a Bazzaz... PC3 has preloaded, adjustable maps which are designed to make max hp based on air/fuel mixtures. Bazzaz has the ability to make real-time adjustments! So what is really controlling the mix? Does ECU make it run richer regardless of what the mix is if it starts getting hot? What about a conflict between the Bazzaz and the ECU?

[Mark H]

It seems that using an ECU over-ride system ie. rewriting the fuel trim and ignition timing maps,the PROM, your always in open loop anyhow so the OEM ECU is only used for inputs and outputs throwing out any factory strategies?
The misconception that the ECT controls fuel trim, or discharge duration as its now referred to, goes back to the old vacuum thermo coupler, carburetor days.
On modern fuel injection engines the ECT only serves as one of the "go - no - go " inputs (apx. 80c deg.) that sends the ECU into closed loop. After closed loop is achieved the ECT only effects ignition timing and the HO2 takes over the acceleration and deceleration fuel trim(what your concerned with!!!).
Part throttle drivability not being a concern (except in the paddock and on starts)
I would think that the over-ride system your using has a 100% injector on time map 90% of the time anyways, to achieve the Nirvana(we love you Kurt) of the infamous 14.7 to 1 ratio, for most of the situations it sees....matted ?
Even OEM ECU's go to 100% injector on time (no pulse, just spray) at WOT.

OR

Call the MFG.?

[carnut169]

Mark! Where have you been man?


I've read the ratio I'm looking for is 13-13.3.... I'm installing a O2 sensor which will go to the Mychron for logging. Then I'll adjust fuel up/ down to get the mix right.

90% true 50% of the time?

[Art Smith]

Sean-

the only way to know with certainty what your engine needs to make maximum horsepower is to take it a dyno. it's my opinion anything else is best-on-best a guess, a prayer, or a piece of well intended misinformation from someone who probably stayed at a Holiday Inn Express the previous night. my good 1600 engines (uniquely configured compared to the general population) with one of my aluminum heads with one of my exhaust system makes maximum power between 13.6 and 13.8. different heads and exhausts make a big difference and the effects of water temperature / cooling design can be measured. again with my 1600 hardware, dyno testing has shown conclusively that A/F is a poor metric on a good day and I only use it for diagnostics, not for tuning. it's my opinion exhaust gas temperature is a far better metric for tuning since it includes the effects of ignition timing. if all four of the EGT's are reading 1365F on one of my engines you should expect the home team to be making serious horsepower. single oxygen sensors read the average from the number of cylinders involved with all the same limitations of reading the color of a single exhaust pipe.

given a sensor "conditioning box" with a little programing capability, closing a control loop around variable cam timing, variable ignition timing, fuel injection, water temperature, throttle position, rpm, and four EGT's might be fun........................

Art
artesmith@earthlink.net

[Stan Clayton]

given a sensor "conditioning box" with a little programing capability, closing a control loop around variable cam timing, variable ignition timing, fuel injection, water temperature, throttle position, rpm, and four EGT's might be fun...

Come on over to C/DSR, Art, where you can do those things to your heart's content!

[Art Smith]

Stan-

unless I've missed some changes to the GCR, my read of the rules as currently written permit intelligent conditioning boxes for input to the stock ECU. mapping a stock ECU wouldn't be that hard; a good digital scope, a half dozen voltage dividers, a signal generator or two, and some very structured patience. not that many years ago you could get a disasembler for just about anything in the valley although that wouldn't be needed for the envisioned control system. the algorithms in the stock ECU would have to simplely be given the inputs to get the "right" answer; A x B equals C, the answer. 15,000rpm is unbelieveably slow in the digital domain so the computing timeline would be a piece of cake.................. hardest part of the project would be isolation of the digital computing section from the A/D's and D/A's; in the end it always works out that way

you are right thou, it would be a lot easier and not nearly as constrained in a world where use of the stock ECU wasn't required for compliance[/FONT

Art
artesmith@earthlink.net


H.4. Engines

A. Motorcycle-based 4-cycle up to 1000cc.

B. Engine internals and compression ratio must remain stock. The
competitor must present, on demand, an original factory manual
for the engine to allow compliance verification
C. The stock ECU shall be used. The ECU fuel map may be changed
Devices that modify inputs to the ECU (e.g., Power Commander)

may be used. Stand-alone after market ECUs are not permitted