Can someone explain battery offsets a little??

Hybrid96EK · Post by **Hybrid96EK** » Thu Feb 26, 2009 2:14 am

I got two questions really. I got my tune pretty good, I'm happy with it. Now I want to swap out the stock map sensor and put in this Omni 3 bar I got. Is there an EASY way to rescale the maps and keep my current values so I don't have to completely retune? I tried just changing the map sensor listed and allowing it to rescale, but nothing changed on the screen... the map values were all the same. Second, can someone explain battery offsets and how I might be able to find out the ones I need for my Delphi 550's? I have the RC 550 one in there now. Its not TOO bad, little rough on initial startup (when cold) and the wideband shows lean. Once it completely reaches operating temp, I am good. With the headlights on the idle gets rough also. I am assuming this is all related to battery offsets, no?

Post by **Bugermass** » Thu Feb 26, 2009 5:47 am

Yes, the map rescale stuff is kinda weird.. I think we need to figure out a better way to rescale so that a change of map sensor doesn't require a retune of the whole map.

Hybrid96EK · Post by **Hybrid96EK** » Fri Feb 27, 2009 3:43 am

Bugermass wrote:Yes, the map rescale stuff is kinda weird.. I think we need to figure out a better way to rescale so that a change of map sensor doesn't require a retune of the whole map.

Do you know anything about setting up the injector battery offsets... more specifically how to get them correct.

elevation · Post by **elevation** » Fri Feb 27, 2009 3:58 am

different voltage has effect on injector dwell. you need to adjust (take off or alt belt) so you can adjust with the table your different voltages to AFs

Hybrid96EK · Post by **Hybrid96EK** » Fri Feb 27, 2009 4:05 am

elevation wrote:different voltage has effect on injector dwell. you need to adjust (take off or alt belt) so you can adjust with the table your different voltages to AFs

This is what I don't understand. Why do I need to mess with the alt belt? I mainly need to correct the piss poor idle it has when then headlights are on.

elevation · Post by **elevation** » Fri Feb 27, 2009 4:11 am

Is the voltage the same at the battery terminal with the lights on and off......then you need to adjust it.

Maddog20 · Post by **Maddog20** » Sat Feb 28, 2009 5:17 pm

I turn on different combinations of accessories (radio, headlights,rad fan) and tune each table to have the most consistent A/F ratio at idle possible.

Hybrid96EK · Post by **Hybrid96EK** » Sun Mar 01, 2009 11:11 pm

elevation wrote:Is the voltage the same at the battery terminal with the lights on and off......then you need to adjust it.

I didn't think my question would generate so much anger. I simply didn't understand the pricipal here with the battery offsets. Its more clear now and I think I can get things under control. Sorry for irritating you with my question.

elevation · Post by **elevation** » Sun Mar 01, 2009 11:18 pm

Who's angry?......your mistaken.

JaredKaragen · Post by **JaredKaragen** » Mon Mar 02, 2009 5:11 am

Hybrid96EK wrote:
elevation wrote:Is the voltage the same at the battery terminal with the lights on and off......then you need to adjust it.
I didn't think my question would generate so much anger. I simply didn't understand the pricipal here with the battery offsets. Its more clear now and I think I can get things under control. Sorry for irritating you with my question.

Basic voltage principals: V/IR This being introduced; when you have less of a voltage on the injectors, they do not react as fast. The adjustment allows the injectors to behave the same throughout a voltage range to keep a [example] .2ms pulsewidth an actual .2ms pulsewidth when voltage drops... otherwise it would be [example] around .18ms meaning a drop in fuel because it did not fully open or open fast enough. Hopefully that helps alot. You can interpret/research the "dwell" reference by looking at an automotive ignition system... same concept.

Hybrid96EK · Post by **Hybrid96EK** » Wed Mar 04, 2009 12:27 am

Maddog20 wrote:I turn on different combinations of accessories (radio, headlights,rad fan) and tune each table to have the most consistent A/F ratio at idle possible.

Yep, this is what I did just this afternoon. We will see how much it helps. I know as it was with the RC 550 battery offsets I was off from 14.7 to 16.9!! with the wipers, headlights, and heater going. I'm sure now that the offsets are set it should help considerably.

HiProfile · Post by **HiProfile** » Wed Mar 04, 2009 10:44 am

The problem is that each injector type is different. Its basicly a magnetic coil pulling a ferrious (steel) rod, and each company has slightly different coils. Unless you pick the injector type that matches yours PERFECTLY, you'll be lean or rich depending on voltage changes. FYI a 12v battery at rest is ~11.7-12.5v; a typical alternator runs the car voltage at ~14.5v to charge the battery (read up on how batt's work). Hondas are intended to have a high RPM, and generally voltages drop at & near idle, especially when the lights go on. The headlights draw a large amount of power, relative to alternator output. With a walbro pump running on stock wiring, you can hear the difference at idle with the blinkers flashing

Hybrid96EK · Post by **Hybrid96EK** » Wed Mar 04, 2009 11:08 am

HiProfile wrote:The problem is that each injector type is different. Its basicly a magnetic coil pulling a ferrious (steel) rod, and each company has slightly different coils. Unless you pick the injector type that matches yours PERFECTLY, you'll be lean or rich depending on voltage changes. FYI a 12v battery at rest is ~11.7-12.5v; a typical alternator runs the car voltage at ~14.5v to charge the battery (read up on how batt's work). Hondas are intended to have a high RPM, and generally voltages drop at & near idle, especially when the lights go on. The headlights draw a large amount of power, relative to alternator output. With a walbro pump running on stock wiring, you can hear the difference at idle with the blinkers flashing

The alternator should only be pushing that amount depending on the state of charge in the battery... this much I do know... but yeah, I know what you are saying. Which is why it makes sense to me to tune the offsets how I did. Sitting in the garage with the car idling and turning on random items until I hit the target area in the map, then adjusting the offsets to best match the widebands reading at idle with nothing on.