How does the ecu determine which gear you're in?
#1
How does the ecu determine which gear you're in?
I've always noticed a few things about the ecu when driving on the freeway. When i'm in 4th gear at cruising speed, it uses ign map #1, but when I shift to 5th at the same speed it uses ign map #2.
also, how does the speed limiter work? I have it set for 75mph (~120kph), but it only works in 3rd/4th gear, in 5th the speed limit bumps up to 85mph.
I speed too much and need a limiter in 5th.
So that was making me wonder, how does he ecu know you're in 5th?
And why does it use different maps for 5th, and which ones are affected.
Is there a "high gear offset" for the speed limiter?
Is there a routine that is changed when in a higher gear? (other than boost)
I have logs demonstrating the conditions. I can't post my rom from my phone...
P.s. AFAIK, the ecu uses maps labeled #1 at WOT...
also, how does the speed limiter work? I have it set for 75mph (~120kph), but it only works in 3rd/4th gear, in 5th the speed limit bumps up to 85mph.
I speed too much and need a limiter in 5th.
So that was making me wonder, how does he ecu know you're in 5th?
And why does it use different maps for 5th, and which ones are affected.
Is there a "high gear offset" for the speed limiter?
Is there a routine that is changed when in a higher gear? (other than boost)
I have logs demonstrating the conditions. I can't post my rom from my phone...
P.s. AFAIK, the ecu uses maps labeled #1 at WOT...
Last edited by SoCalRedLine; Aug 19, 2009 at 03:25 PM.
#3
See that's wierd, cause it seems like there is a switch telling it it's in 5th.
And why does it wait till 85 in 5th to cut me off (about 4000 rpm)
p.s. I know that evoscan uses mph/rpm calc to find the gear...but is there something else in the ecu that does the calc a different way?
And why does it wait till 85 in 5th to cut me off (about 4000 rpm)
p.s. I know that evoscan uses mph/rpm calc to find the gear...but is there something else in the ecu that does the calc a different way?
#5
It's not rlly that weird, when you're going like 60mph and making 3000-4000 rpm, it just knows you're in 5th gear. should you have been in 4th gear going 60mph, you'd make atleast 5000rpm r something
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#10
It's all good, thanks for the input. I'm starting to wonder if that rpm crossover might affect other tables, or if each section (ign, fuel, etc) has it's own rpm crossover table.
Oh, and load is the same in all gears as long as you're at the same speed/boost level. Something else I noticed...
Oh, and load is the same in all gears as long as you're at the same speed/boost level. Something else I noticed...
#11
Rather than having the ECU actually limit your speed, I think it would be preferable to use a spare ECU output to just flash an LED/sound a buzzer instead, to warn you that you are exceeding your desired speed limit.
I can see some very rare occasions when you might want to exceed a pre-defined speed limit e.g. rushing a friend to hospital, chasing a drunk hit-and-run driver who fled the scene, closed course track event etc.
Not being able to exceed a certain pre-defined speed artificially limited by the ECU doesn't seem ideal to me. I'd rather just have an LED/buzzer telling me I'm being an idiot instead ;-)
I can see some very rare occasions when you might want to exceed a pre-defined speed limit e.g. rushing a friend to hospital, chasing a drunk hit-and-run driver who fled the scene, closed course track event etc.
Not being able to exceed a certain pre-defined speed artificially limited by the ECU doesn't seem ideal to me. I'd rather just have an LED/buzzer telling me I'm being an idiot instead ;-)