Want To Learm How To A/f Ratio
#1
Senior Member
Thread Starter
Join Date: Oct 2001
Location: Maryland, GERMANTOWN
Posts: 611
Likes: 0
Received 0 Likes
on
0 Posts
Want To Learm How To A/f Ratio
HEY guys looking to buy a wideband and im lost at reading, can anybody tell me how to read this 10:1 and 12:4 and all that thanks lol i have a narrow band that i was told now its the apexi turbo timer with a/f so help
#2
off camber
iTrader: (1)
Join Date: Dec 2004
Location: atl, ga
Posts: 482
Likes: 0
Received 0 Likes
on
0 Posts
10:1 means 10 parts air 1 part fuel. It is the ratio of air to fuel. 10:1 is more rich then say 12:1. You would not see a ratio like 12:4 unless you were running 3:1 (heh). My car is happy under boost in the low 11s (11.0:1 - 11.5:1). Typically you get more rich as you increase boost. Under vac. I tune for the mid 13s (13.5:1 to 13.8:1). At idle I like as close to 14.7:1 as I can get with out having to run excessive ignition.
Good luck.
Good luck.
#3
Eye In The Sky
iTrader: (2)
Join Date: Feb 2001
Location: In A Disfunctional World
Posts: 7,895
Likes: 0
Received 114 Likes
on
66 Posts
If your logged AFR is XXX, and you want to run YYY, change your fuel to:
(XXX / YYY).
Example:
You record 11.5AFRS for part of your map. You want to run 11.0AFRs.
11.5/11 = 1.0454545454 or 1.05 rounded up. That means you need to add 5% more fuel.
(XXX / YYY).
Example:
You record 11.5AFRS for part of your map. You want to run 11.0AFRs.
11.5/11 = 1.0454545454 or 1.05 rounded up. That means you need to add 5% more fuel.
#4
Mad Man
Originally Posted by cewrx7r1
If your logged AFR is XXX, and you want to run YYY, change your fuel to:
(XXX / YYY).
Example:
You record 11.5AFRS for part of your map. You want to run 11.0AFRs.
11.5/11 = 1.0454545454 or 1.05 rounded up. That means you need to add 5% more fuel.
(XXX / YYY).
Example:
You record 11.5AFRS for part of your map. You want to run 11.0AFRs.
11.5/11 = 1.0454545454 or 1.05 rounded up. That means you need to add 5% more fuel.
#5
Senior Member
Thread Starter
Join Date: Oct 2001
Location: Maryland, GERMANTOWN
Posts: 611
Likes: 0
Received 0 Likes
on
0 Posts
so are you saying at WOT i want to be as close to 14.7 as i can
what does it mean when my narrow band says 20 something maybe im reading the worng thing,
what wide bands are you guys running
what does it mean when my narrow band says 20 something maybe im reading the worng thing,
what wide bands are you guys running
#7
Ee / Cpe
Join Date: Jan 2003
Location: Gaithersburg, MD / WVU
Posts: 2,843
Likes: 0
Received 2 Likes
on
2 Posts
Originally Posted by mazda/feed
so are you saying at WOT i want to be as close to 14.7 as i can
what does it mean when my narrow band says 20 something maybe im reading the worng thing,
what wide bands are you guys running
what does it mean when my narrow band says 20 something maybe im reading the worng thing,
what wide bands are you guys running
you shouldent be tuning a car at this point. read up on tuning, their is a plethora of info on this site about it.
also im not quite sure what your trying to say, do you actually have a wideband?
Trending Topics
#8
Ee / Cpe
Join Date: Jan 2003
Location: Gaithersburg, MD / WVU
Posts: 2,843
Likes: 0
Received 2 Likes
on
2 Posts
Originally Posted by mazda/feed
is a EGR gauge needed if i have a wide band
thanks
thanks
no, a egt gauge is if you want to know how hot your exhaust gasses are.
a wideband oxygen sensor setup lets you know how much fuel compaired to how much air you are running.
completely seperate sensor setups, both give similar information. wideband is the more accurate tool for tuning.
#9
Ee / Cpe
Join Date: Jan 2003
Location: Gaithersburg, MD / WVU
Posts: 2,843
Likes: 0
Received 2 Likes
on
2 Posts
Originally Posted by cewrx7r1
If your logged AFR is XXX, and you want to run YYY, change your fuel to:
(XXX / YYY).
Example:
You record 11.5AFRS for part of your map. You want to run 11.0AFRs.
11.5/11 = 1.0454545454 or 1.05 rounded up. That means you need to add 5% more fuel.
(XXX / YYY).
Example:
You record 11.5AFRS for part of your map. You want to run 11.0AFRs.
11.5/11 = 1.0454545454 or 1.05 rounded up. That means you need to add 5% more fuel.
that dosent work exactly, a conversion like that would depend heavily on injector size, and would change as boost changes, or injectors are changed.
eg:
5% on a 1680cc injector is a hell of a lot more fuel then 5% on a 850cc injector.
#10
Senior Member
Thread Starter
Join Date: Oct 2001
Location: Maryland, GERMANTOWN
Posts: 611
Likes: 0
Received 0 Likes
on
0 Posts
sorry guys i meant EGT,
no im not trying to tune my car i was just told that its good to have one
thanks XS thats what i was trying to find out i knew that its was kinda close but the wide is more accurate
no im not trying to tune my car i was just told that its good to have one
thanks XS thats what i was trying to find out i knew that its was kinda close but the wide is more accurate
#11
multipersonality disorder
Join Date: Feb 2002
Location: so. cal
Posts: 5,656
Likes: 0
Received 0 Likes
on
0 Posts
just for fun-- since someone brought up getting richer as the boost increases... or you can get richer as rpm's increase also.
this dyno sheet is more or less typical.
that car ended up getting a little more fine tuning, but you can see the general slope going in the downward direction.
fyi, it wouldn't hold boost, so that's what the up n down "rainbow: torque curve was all about.
this dyno sheet is more or less typical.
that car ended up getting a little more fine tuning, but you can see the general slope going in the downward direction.
fyi, it wouldn't hold boost, so that's what the up n down "rainbow: torque curve was all about.
#12
Originally Posted by XSTransAm
that dosent work exactly, a conversion like that would depend heavily on injector size, and would change as boost changes, or injectors are changed.
eg:
5% on a 1680cc injector is a hell of a lot more fuel then 5% on a 850cc injector.
eg:
5% on a 1680cc injector is a hell of a lot more fuel then 5% on a 850cc injector.
-Max
#13
Ee / Cpe
Join Date: Jan 2003
Location: Gaithersburg, MD / WVU
Posts: 2,843
Likes: 0
Received 2 Likes
on
2 Posts
Originally Posted by maxcooper
It's just 5% more than the amount injected to get the previous AFR reading, so the size of the injector doesn't matter.
-Max
-Max
yeah but 5% more on an injector isnt going to directly relate to a cars afr because of variables like injector size, ect.
the formula used was based on air fuel ratio, but it dosent work in all, if any applications because of other variables.
#14
Mad Man
+5% will increase the time the injector is open by 5%, so, since the existing reading was derived from the same injectors, increasiung injection duration by 5% should increase fuel by 5%... Am I missing something???
Yes, you are injecting more fuel if you have 1680s, vs 850s, but 5% is 5% no matter what the value being modified.
Yes, you are injecting more fuel if you have 1680s, vs 850s, but 5% is 5% no matter what the value being modified.
#15
XS, I suspect you are thinking this:
850cc injector at 70% duty cycle gives 595cc to get 11.5 AFR
+ 5% absolute duty cycle
-------
850cc injector at 75% duty cycle gives 638cc, a delta of 43cc (+7.2%)
(with an AFR of about 10.7)
AND
1680cc injector at 35.4% duty cycle gives 595cc to get 11.5 AFR
+ 5% absolute duty cycle
--------
1680cc injector at 40.4% duty cycle gives 679cc, a delta of 84cc (+14.1%)
(with an AFR of about 10.1)
But Carl is talking about adding 5% of fuel, not 5% of absolute duty cycle (two very different things). To add 5%, you could enter 1.05 in the PFC injection correction map, or change the base map by adding 5% to the value that was in the cell when you recorded the 11.5 AFR. The duty cycle you will get with these changes will be 1.05 times the old duty cycle (+5%, but not 5 percent higher duty cycle, see examples below). Here's how it works out:
850cc injector at 70% duty cycle gives 595cc to get 11.5 AFR
+ 5% fuel
-------
850cc injector at 73.5% duty cycle gives 625cc, a delta of 30cc (+5%)
(with an AFR of about 11.0)
AND
1680cc injector at 35.4% duty cycle gives 595cc to get 11.5 AFR
+ 5% fuel
--------
1680cc injector at 37.17% duty cycle gives 625cc, a delta of 30cc (+5%)
(with an AFR of about 11.0)
-Max
850cc injector at 70% duty cycle gives 595cc to get 11.5 AFR
+ 5% absolute duty cycle
-------
850cc injector at 75% duty cycle gives 638cc, a delta of 43cc (+7.2%)
(with an AFR of about 10.7)
AND
1680cc injector at 35.4% duty cycle gives 595cc to get 11.5 AFR
+ 5% absolute duty cycle
--------
1680cc injector at 40.4% duty cycle gives 679cc, a delta of 84cc (+14.1%)
(with an AFR of about 10.1)
But Carl is talking about adding 5% of fuel, not 5% of absolute duty cycle (two very different things). To add 5%, you could enter 1.05 in the PFC injection correction map, or change the base map by adding 5% to the value that was in the cell when you recorded the 11.5 AFR. The duty cycle you will get with these changes will be 1.05 times the old duty cycle (+5%, but not 5 percent higher duty cycle, see examples below). Here's how it works out:
850cc injector at 70% duty cycle gives 595cc to get 11.5 AFR
+ 5% fuel
-------
850cc injector at 73.5% duty cycle gives 625cc, a delta of 30cc (+5%)
(with an AFR of about 11.0)
AND
1680cc injector at 35.4% duty cycle gives 595cc to get 11.5 AFR
+ 5% fuel
--------
1680cc injector at 37.17% duty cycle gives 625cc, a delta of 30cc (+5%)
(with an AFR of about 11.0)
-Max
#17
Eye In The Sky
iTrader: (2)
Join Date: Feb 2001
Location: In A Disfunctional World
Posts: 7,895
Likes: 0
Received 114 Likes
on
66 Posts
I use the PFC and this works very well, but this also applies to any ECU for fuel adjustment where you adjust total fuel flow.
Originally Posted by Carl Byck
Makes perfect sense, what engine management do you have, and how close does that generally get you? Thanks, Carl
#19
127,338 OEM, 11.5psi
Join Date: Jun 2005
Location: MARYLAND
Posts: 936
Likes: 0
Received 0 Likes
on
0 Posts
can you guys point me in to the right direction of learning how to tune, i tried to look it up but it gave me all the wrong info, i want to be able to understand what your talkin about like duty cycle and injector pulse, so please can you help, i love to work on my own 7
#20
Eye In The Sky
iTrader: (2)
Join Date: Feb 2001
Location: In A Disfunctional World
Posts: 7,895
Likes: 0
Received 114 Likes
on
66 Posts
If you have a PFC, go to that forum and see sticky.
Originally Posted by 7 BOUND
can you guys point me in to the right direction of learning how to tune, i tried to look it up but it gave me all the wrong info, i want to be able to understand what your talkin about like duty cycle and injector pulse, so please can you help, i love to work on my own 7
#21
I find that it helps a lot to imagine that you are the ECU. You only have a handful of inputs and you've got to deliver the right amount of fuel and get the spark timing right. Or your owner will likely pull you out and beat and/or burn you before replacing you wil a fancy new box.
-Max
-Max
#22
Indifferent
iTrader: (3)
Join Date: Mar 2001
Location: Long Island,NY
Posts: 979
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 7 BOUND
can you guys point me in to the right direction of learning how to tune, i tried to look it up but it gave me all the wrong info, i want to be able to understand what your talkin about like duty cycle and injector pulse, so please can you help, i love to work on my own 7
John
#23
Rotary Freak
Join Date: Feb 2001
Location: fort worth, tx, usa
Posts: 1,926
Likes: 0
Received 0 Likes
on
0 Posts
Rotary engine isn't the best platform to learn on how to tune. Make sure to do small increment changes at a time. don't try to adjust everything at once or else you can run into problem on what you changed previously. Everytime after you made a change (that's improved), save that map so that in case when you screw up, you still have the map in hand without having to start all over again. Kinda like writing a paper in word program, always save your latest update. Another suggestion is try not to rush your changes, make sure they're right and repeatable. I know of several rotary guys who started tuning their car (self learning) and could take up to 3-4 weeks adjusting the map and anywhere from 10-20 tanks of gas. At least by the time you have tune your car, you'll know alot about the software.
#24
multipersonality disorder
Join Date: Feb 2002
Location: so. cal
Posts: 5,656
Likes: 0
Received 0 Likes
on
0 Posts
a good thing for you might be to get in on dyno days. lots of guys are complete ******** and don't want you to see what they're doing, but every now and then, you can find someone who will learn ya the ropes.
see if there are any dyno shops in your local area--even if they're not doing rotaries that day, see if they'll let you come hang out and learn something. that should get you a basic idea anyway. if you do it that way, just remember rotaries like to run richer than piston engines.
see if there are any dyno shops in your local area--even if they're not doing rotaries that day, see if they'll let you come hang out and learn something. that should get you a basic idea anyway. if you do it that way, just remember rotaries like to run richer than piston engines.
#25
Senior Member
Join Date: Jul 2002
Location: Richland Wa.
Posts: 615
Likes: 0
Received 0 Likes
on
0 Posts
www.efi101.com if you want to learn the right way. It is worth every penny and then some.