SAFC installed, questions...
02-02-14, 04:57 PM
#16
uhh if it was 15-16 and you tuned it to 14-15, you didn't lean it out. you richened it, ie-adding fuel.
remember that it's a ratio, ie 14.7:1 (stoich.). if the car was at 16:1 and you tuned it to 14:1, you just added fuel into it and lowered the amount of air to each unit of fuel.
No offense mate but I think you need to read up on EFI basics. Try this: http://www.importtuner.com/tech/0612...s/viewall.html
And look for the megasquirt tuning guide, those articles are well laid out as well.
remember that it's a ratio, ie 14.7:1 (stoich.). if the car was at 16:1 and you tuned it to 14:1, you just added fuel into it and lowered the amount of air to each unit of fuel.
No offense mate but I think you need to read up on EFI basics. Try this: http://www.importtuner.com/tech/0612...s/viewall.html
And look for the megasquirt tuning guide, those articles are well laid out as well.
02-02-14, 05:28 PM
#17
I did a lot of reading and I'm getting mixed opinions.
From my logic I would assume that the higher the number the leaner it is. When I calibrated the wideband it said 22.4 in the open air. But when I was reading about what the average N/A car should be running at people were saying different so I went with that. I'll do some more research I guess. Thanks for the links...
From my logic I would assume that the higher the number the leaner it is. When I calibrated the wideband it said 22.4 in the open air. But when I was reading about what the average N/A car should be running at people were saying different so I went with that. I'll do some more research I guess. Thanks for the links...
02-02-14, 05:53 PM
#18
Most widebands tend to stop displaying accurately after about 19:1 and a lot go into "-----" display around there... There is no need to display fuel ratios around there because no vehicle will run at that point... At least not in a way that you care about.
14.7:1 is considered stoich but is not a number you are really trying to get to, except on zero load cruise.
14.8-100:1 is considered lean
0-14.6 is considered rich
But those numbers are just numbers.
10:1 or richer, down into the 9s and you are washing the lubricant off your cylinder walls.
11.5-12.5:1 is a good AFR range for most boosted applications on loaded acceleration
12.5-13.5:1 is a good AFR range for most NA applications.
Anything between stoich and 13.5:1 is considered good for part throttle and cruise, but different cars all like different numbers based on engine design.
On decel, numbers from 15-20:1 are often seen as the fuel usually gets all but cut off.
There is a lot to tuning, it is better to err on the side or rich than lean. If you have the ability to map the AFRs with a laptop and a 3d graph, you can get a really good tune on the streets and then just hit the dyno for WOT tuning which you can usually extrapolate down into the upper cells of your street tune with a good margin of safety.
14.7:1 is considered stoich but is not a number you are really trying to get to, except on zero load cruise.
14.8-100:1 is considered lean
0-14.6 is considered rich
But those numbers are just numbers.
10:1 or richer, down into the 9s and you are washing the lubricant off your cylinder walls.
11.5-12.5:1 is a good AFR range for most boosted applications on loaded acceleration
12.5-13.5:1 is a good AFR range for most NA applications.
Anything between stoich and 13.5:1 is considered good for part throttle and cruise, but different cars all like different numbers based on engine design.
On decel, numbers from 15-20:1 are often seen as the fuel usually gets all but cut off.
There is a lot to tuning, it is better to err on the side or rich than lean. If you have the ability to map the AFRs with a laptop and a 3d graph, you can get a really good tune on the streets and then just hit the dyno for WOT tuning which you can usually extrapolate down into the upper cells of your street tune with a good margin of safety.
02-02-14, 06:30 PM
#19
One thing to consider and where a lot of people might get confused is when they read posts on forums.
Some guy running a specific setup will post a dyno with AFRs and someone will comment on how he is lean between a certain rpm range and/or too rich in another. This is usually in reference to the ideal for what he is posting, which is usually a wot pull on the dyno, for that specific setup.
That is often where you will see guys talking about something like a 13.5:1 AFR as "too lean" or 12.5:1 as "too rich."
This is not standard across all cars though, and is usually determined through extensive dyno tuning. Typically you will see gains across the board to a specific AFR or small range with drop offs on either side of that point (much like a bell-curve). There are also other variables to consider. EGTs and CO are just as telling to the output of the engine and just as critical.
Some guy running a specific setup will post a dyno with AFRs and someone will comment on how he is lean between a certain rpm range and/or too rich in another. This is usually in reference to the ideal for what he is posting, which is usually a wot pull on the dyno, for that specific setup.
That is often where you will see guys talking about something like a 13.5:1 AFR as "too lean" or 12.5:1 as "too rich."
This is not standard across all cars though, and is usually determined through extensive dyno tuning. Typically you will see gains across the board to a specific AFR or small range with drop offs on either side of that point (much like a bell-curve). There are also other variables to consider. EGTs and CO are just as telling to the output of the engine and just as critical.
02-02-14, 06:39 PM
#20
Moderator
Most widebands tend to stop displaying accurately after about 19:1 and a lot go into "-----" display around there... There is no need to display fuel ratios around there because no vehicle will run at that point... At least not in a way that you care about.
14.7:1 is considered stoich but is not a number you are really trying to get to, except on zero load cruise.
14.8-100:1 is considered lean
0-14.6 is considered rich
But those numbers are just numbers.
10:1 or richer, down into the 9s and you are washing the lubricant off your cylinder walls.
11.5-12.5:1 is a good AFR range for most boosted applications on loaded acceleration
12.5-13.5:1 is a good AFR range for most NA applications.
Anything between stoich and 13.5:1 is considered good for part throttle and cruise, but different cars all like different numbers based on engine design.
On decel, numbers from 15-20:1 are often seen as the fuel usually gets all but cut off.
There is a lot to tuning, it is better to err on the side or rich than lean. If you have the ability to map the AFRs with a laptop and a 3d graph, you can get a really good tune on the streets and then just hit the dyno for WOT tuning which you can usually extrapolate down into the upper cells of your street tune with a good margin of safety.
14.7:1 is considered stoich but is not a number you are really trying to get to, except on zero load cruise.
14.8-100:1 is considered lean
0-14.6 is considered rich
But those numbers are just numbers.
10:1 or richer, down into the 9s and you are washing the lubricant off your cylinder walls.
11.5-12.5:1 is a good AFR range for most boosted applications on loaded acceleration
12.5-13.5:1 is a good AFR range for most NA applications.
Anything between stoich and 13.5:1 is considered good for part throttle and cruise, but different cars all like different numbers based on engine design.
On decel, numbers from 15-20:1 are often seen as the fuel usually gets all but cut off.
There is a lot to tuning, it is better to err on the side or rich than lean. If you have the ability to map the AFRs with a laptop and a 3d graph, you can get a really good tune on the streets and then just hit the dyno for WOT tuning which you can usually extrapolate down into the upper cells of your street tune with a good margin of safety.
I tell you the method. Putting a low Vf diode in series with the O2 sensor can give you the AFR lower than 14.7 and also adding a DC bias upward gives you higher than 14.7. You can make this circuit spending less than $7. This needs some basic electronics skill though.
According to my experiments, I could get the AFR 11 to 18 by the method. The problem is that the engine check light sometimes turns on
and I need to add an extra circuit to avoid this and it is the major part of the parts cost $7. May be I can do a good business with this but .....
02-02-14, 07:06 PM
#21
Yeah I think I was getting confused on a couple of things I was reading. I kinda new where it needs to be as far as AFR's, but got mixed up as far as rich/lean go.
I got to play with it again tonight and have got it at a pretty steady 13-13.5 across the RPM's in WOT. Idle and cruising I've got it around 14.5 or so. I've got the throttle point for "low throttle" set on 5% and the "high throttle" set on 60%.
I got to play with it again tonight and have got it at a pretty steady 13-13.5 across the RPM's in WOT. Idle and cruising I've got it around 14.5 or so. I've got the throttle point for "low throttle" set on 5% and the "high throttle" set on 60%.
02-03-14, 02:14 PM
#22
No offense mate but I think you need to read up on EFI basics. Try this: http://www.importtuner.com/tech/0612...s/viewall.html
And look for the megasquirt tuning guide, those articles are well laid out as well.
buy this book, they have a kindle version as well. read up.
the book was made from the people over at www.diyautotune.com
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