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03-03-2006, 08:18 PM
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#11
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Join Date: Oct 2005
Posts: 1,460
Country: United States
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What about startup?? If the
What about startup?? If the dyno shop programs it for 1000,1200,1400,1600,1800,2000,2200,2400,2600,2800, 3000,3200. Which is 12 points in the RPM, how will this affect startup?
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03-03-2006, 11:34 PM
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#12
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Join Date: Feb 2006
Posts: 311
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Are you asking about the
Are you asking about the startup "circuit"? In which the ECU riches the mixture? If so, lets say the ecu richens it by 15%, if you fuel trim settings are set to -5% from 1800 and below (this should be about your cold running RPM), the overall effect will be +10% fuel enrichment.
The only way the SAFC II has to change the amount of fuel is to modify the input the ECU sees, which is either the MAF or MAP sensor.
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03-03-2006, 11:49 PM
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#13
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Join Date: Oct 2005
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so basically what you're
so basically what you're saying it's not what the ECU is doing, it's what I'm doing to the gas pedal that makes it change the fuel input?
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03-04-2006, 12:00 AM
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#14
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Join Date: Feb 2006
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Well the throttle input does
Well the throttle input does change how much fuel the ecu inputs, but think of it like this:
The ECU monitors MANY things and then cross references a table to determin the amount of time to keep the injector open (amount of fuel). The basic things are MAP (or MAF in your case) and RPM. Other inputs such as throttle position, intake temp, altiude, engine temp, and O2 readings will then make smaller alterations.
The SAFC modifies the MAP sensor voltage, so that the ECU think there is more or less load on the engine and thus increases or decrease the amount of fuel.
That's the basics of it.
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03-04-2006, 12:41 AM
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#15
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Registered Member
Join Date: Oct 2005
Posts: 1,460
Country: United States
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So now what would be a
So now what would be a better buy?? The safc2 or the E-manage??
The SAFC2 can be bought for $270 shipped, the E-manage can be bought for $400 shipped. Which one is a better deal?? The e-manage costs more but will I be able to tune better with it? I've hit the point where I did everything I can to the car. Once I have some more time I'll fix the belly of the car and should get 35mpg on the freeway at 65mph. What concerns me the most is my low end, on the street I'm only getting 22mpg.
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03-04-2006, 02:35 AM
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#16
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Join Date: Feb 2006
Posts: 1,480
Country: United States
Location: Myrtle Beach, SC
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Re: So now what would be a
Quote:
Originally Posted by Compaq888
So now what would be a better buy?? The safc2 or the E-manage??
The SAFC2 can be bought for $270 shipped, the E-manage can be bought for $400 shipped. Which one is a better deal?? The e-manage costs more but will I be able to tune better with it? I've hit the point where I did everything I can to the car. Once I have some more time I'll fix the belly of the car and should get 35mpg on the freeway at 65mph. What concerns me the most is my low end, on the street I'm only getting 22mpg.
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You might want to step back and think about this. $400 plus a dyno tune so you can increase your city mileage from 22 to maybe 24? Ive got to think that if you have truly done everything you can to drive economically and still only 22MPG in the city, that maybe there is problem with the engine. I dunno. I am just thinking of my 97 Subaru Outback with 120k miles. It is probably bigger and heavier that the Altima, has a larger engine, 2.5L and also has an automatic transmission with all wheel drive. I drove it for about 3000 miles last fall befire I got the del sol and averaged 32 MPG on my commute, which is only 25% highway. I'm not saying that you are not driving economically, what I am saying is that maybe your route sucks and you can't do anything about it. If that is the case, I would not expect much gain at all out engine management. But thats just my opinion. 5-10% is all that I am hoping for when I get my chipped ecu setup properly.
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03-04-2006, 02:56 AM
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#17
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Registered Member
Join Date: Oct 2005
Posts: 1,460
Country: United States
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Re: So now what would be a
Quote:
Originally Posted by krousdb
Quote:
Originally Posted by Compaq888
So now what would be a better buy?? The safc2 or the E-manage??
The SAFC2 can be bought for $270 shipped, the E-manage can be bought for $400 shipped. Which one is a better deal?? The e-manage costs more but will I be able to tune better with it? I've hit the point where I did everything I can to the car. Once I have some more time I'll fix the belly of the car and should get 35mpg on the freeway at 65mph. What concerns me the most is my low end, on the street I'm only getting 22mpg.
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You might want to step back and think about this. $400 plus a dyno tune so you can increase your city mileage from 22 to maybe 24? Ive got to think that if you have truly done everything you can to drive economically and still only 22MPG in the city, that maybe there is problem with the engine. I dunno. I am just thinking of my 97 Subaru Outback with 120k miles. It is probably bigger and heavier that the Altima, has a larger engine, 2.5L and also has an automatic transmission with all wheel drive. I drove it for about 3000 miles last fall befire I got the del sol and averaged 32 MPG on my commute, which is only 25% highway. I'm not saying that you are not driving economically, what I am saying is that maybe your route sucks and you can't do anything about it. If that is the case, I would not expect much gain at all out engine management. But thats just my opinion. 5-10% is all that I am hoping for when I get my chipped ecu setup properly.
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Yes my routes suck plus I drive in the morning and again during the afternoon. Both times in rush hour. I still have to get my engine cleaned with auto-rx. Don't forget I bumped up my psi to 44 during the middle of the tank and I'm at 307 miles and I already see a difference. I still haven't put my rear belly back and still haven't tinkered with the PVC catch can. I really don't think I'll break 30mpg mixed without engine management.
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03-04-2006, 04:02 AM
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#18
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Join Date: Oct 2005
Posts: 1,460
Country: United States
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Read some reviews on the
Read some reviews on the e-manage and the safc2. Some people say the e-manage sucks. All I heard from the safc2 is praise. I'm going to contact a dynoshop and ask what they can do to my tuning.
apperently 14.7a/f ratio is good for idle and light loads. I might want this for 1000-2000rpm then 13.5 a/f ratio for top end. The safc2 is only $270 shipped.
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03-04-2006, 08:04 AM
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#19
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*shrug*
Join Date: Sep 2005
Posts: 6,195
Country: United States
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14.7 is stoich, which is
14.7 is stoich, which is what the car is sposed to be doing already.
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03-04-2006, 08:40 AM
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#20
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Registered Member
Join Date: Oct 2005
Posts: 1,460
Country: United States
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I know. But I want less fuel
I know. But I want less fuel consumption. You got any better ideas?
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