What AFR do you run on boost????
21-11-2005, 01:41 PM
#1
PassionFord Post Troll
Thread Starter
What AFR do you run on boost????
I am relatively new to mapping so am still finding my feet. My question to the massive is, what AFRs do you aim for whilst on boost in your car?
What do you consider safe? What is way too rich and what do modern manufacturers run?
I’m sure I recently read that a stock RS Focus runs 11:1 AFR whilst on boost. I always thought this was a bit rich? Does anyone know what a stock scooby runs? Are the manufacturers just playing really safe?
Why run 11:1 with a slower burn and more advance, if I could run 12:1 with faster burn less advance. Surely if they both put the peak cylinder pressure at the same point ATDC then I will end up with the same torque figure except one will use less fuel?
Do people run that extra fuel and therefore advance purely for det prevention?
What do you consider safe? What is way too rich and what do modern manufacturers run?
I’m sure I recently read that a stock RS Focus runs 11:1 AFR whilst on boost. I always thought this was a bit rich? Does anyone know what a stock scooby runs? Are the manufacturers just playing really safe?
Why run 11:1 with a slower burn and more advance, if I could run 12:1 with faster burn less advance. Surely if they both put the peak cylinder pressure at the same point ATDC then I will end up with the same torque figure except one will use less fuel?
Do people run that extra fuel and therefore advance purely for det prevention?
21-11-2005, 01:45 PM
#4
12:1 will involve more heat that 11:1 generally
Manufacturers dont care about full boost economy as its not covered by ANY of the stats quoted when selling cars
They do care though if people manage to blow cars up, and they arent livemapping each car so have to have a margin for error.
Manufacturers dont care about full boost economy as its not covered by ANY of the stats quoted when selling cars
They do care though if people manage to blow cars up, and they arent livemapping each car so have to have a margin for error.
21-11-2005, 01:49 PM
#5
PassionFord Post Troll
Thread Starter
Thats the question really. If manufacturers are running 11:1 to allow for a margin of error, should i be doin this also considering i might be using un tested plenum designs, not perfectly matched injectors etc????
21-11-2005, 01:52 PM
#7
Originally Posted by Garage19
Thats the question really. If manufacturers are running 11:1 to allow for a margin of error, should i be doin this also considering i might be using un tested plenum designs, not perfectly matched injectors etc????
Best thing you can do though IMHO is to keep an eye on EGT's if they are sensible on 12:1 then you dont have any reason to go to 11:1 IMHO
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21-11-2005, 01:52 PM
#8
Originally Posted by Itsmeagain
Totally depends on car, spec etc etc.
Ive seen many cars AFRs run well into the 10s
Ive seen many cars AFRs run well into the 10s
There are a few cars i can think of that run well in excess of 11:1.
The focus Rs is a great example. And the reason this particular one runs so rich? The Exhaust manifold is so crap they are running 1000deg C on teh power as STD!!
21-11-2005, 01:57 PM
#10
Originally Posted by Stu @ M Developments
Originally Posted by Itsmeagain
Totally depends on car, spec etc etc.
Ive seen many cars AFRs run well into the 10s
Ive seen many cars AFRs run well into the 10s
There are a few cars i can think of that run well in excess of 11:1.
The focus Rs is a great example. And the reason this particular one runs so rich? The Exhaust manifold is so crap they are running 1000deg C on the power as STD!!
Thats why i think its essential to monitor EGT's
21-11-2005, 01:58 PM
#11
Originally Posted by Mike Rainbird
You can't say, as too rich can be just as bad as too lean. Surely it would be better to take it to somewhere like Brunters and max the car out several times in a row to see what is safe for the car?
What can running rich do that is as bad?
21-11-2005, 02:05 PM
#13
Originally Posted by Mike Rainbird
Too rich and the excess fuel gets mixed with the oil = spun bearings, rod through block etc . Not nice either....
. Not nice either....You would have to be running VERY rich for a LONG period of time Mike, its on a totally different level of risk to running lean.
21-11-2005, 02:10 PM
#14
Why? You think everything is okay, because you "think" you have mapped it "nice and safe" and then one day it just lets go without warning - mmmmmm, nice 
. So in my mind, it's just as bad as mapping it too lean. Too lean doesn't always let go instantaneously either . This doesn't happen unless it is catastrophic det - equally you can have mild det that gradually eats away at things until it finally says enough is enough and shits the bed. You can then see that it has been detting for several thousand miles...
So in my mind, too rich can be just as bad....
. So in my mind, it's just as bad as mapping it too lean. Too lean doesn't always let go instantaneously either . This doesn't happen unless it is catastrophic det - equally you can have mild det that gradually eats away at things until it finally says enough is enough and shits the bed. You can then see that it has been detting for several thousand miles...So in my mind, too rich can be just as bad....
21-11-2005, 02:13 PM
#15
Originally Posted by Mike Rainbird
Why? You think everything is okay, because you "think" you have mapped it "nice and safe" and then one day it just lets go without warning - mmmmmm, nice . So in my mind, it's just as bad as mapping it too lean. Too lean doesn't always let go instantaneously either . This doesn't happen unless it is catastrophic det - equally you can have mild det that gradually eats away at things until it finally says enough is enough and shits the bed. You can then see that it has been detting for several thousand miles...
So in my mind, too rich can be just as bad....
. So in my mind, it's just as bad as mapping it too lean. Too lean doesn't always let go instantaneously either . This doesn't happen unless it is catastrophic det - equally you can have mild det that gradually eats away at things until it finally says enough is enough and shits the bed. You can then see that it has been detting for several thousand miles...So in my mind, too rich can be just as bad....
You wouldnt see enough use between oil changes for it to be an issue unless you are a complete numpty with changing your oil, plus doesnt anyone else give their dipstick a sniff now and then? (ooeerrr)
21-11-2005, 02:25 PM
#17
Originally Posted by Mike Rainbird
It still needed pointing out that too rich has it's own set of problems, and that you can't just throw in fuel and thing that will now be okay....
Its just when someone posts something like "its just as bad" without first phoning Harvey to check that it ends up not being very useful info
21-11-2005, 05:43 PM
#21
Originally Posted by Billabong
Originally Posted by Mike Rainbird
. Harvey was engaged 
. , just as well Mike DOES actually know his onions How come he always posts such bollocks then, or is that just a smokescreen to hide his true genius?
21-11-2005, 05:46 PM
#22
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It's all smoke and mirrors chip - especially the mirrors, for doing his 80's throwback hairdo
Back on topic, before we get told off again, I was quite shocked at the EGT's for the Focus
Back on topic, before we get told off again, I was quite shocked at the EGT's for the Focus
21-11-2005, 06:04 PM
#23
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Originally Posted by chip-3door
Originally Posted by Mike Rainbird
. Harvey was engaged . 
Originally Posted by Billabong
It's all smoke and mirrors chip - especially the mirrors, for doing his 80's throwback hairdo
my old engine was mapped on 12.3: at top, but 1 psi more boost and 2 top speed runs = 2 melted pistons.
i now run 12.2 mid range, then 11.8 top half of the rev's, but even richer if my egt's go higher than 850oC after turbo.
22-11-2005, 07:50 AM
#24
Originally Posted by fiesta cossie
Originally Posted by chip-3door
Originally Posted by Mike Rainbird
. Harvey was engaged .
Originally Posted by Billabong
It's all smoke and mirrors chip - especially the mirrors, for doing his 80's throwback hairdo
my old engine was mapped on 12.3: at top, but 1 psi more boost and 2 top speed runs = 2 melted pistons.
i now run 12.2 mid range, then 11.8 top half of the rev's, but even richer if my egt's go higher than 850oC after turbo.
.
22-11-2005, 06:05 PM
#27
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Originally Posted by chip-3door
Originally Posted by Stu @ M Developments
Originally Posted by Itsmeagain
Totally depends on car, spec etc etc.
Ive seen many cars AFRs run well into the 10s
Ive seen many cars AFRs run well into the 10s
There are a few cars i can think of that run well in excess of 11:1.
The focus Rs is a great example. And the reason this particular one runs so rich? The Exhaust manifold is so crap they are running 1000deg C on the power as STD!!
Thats why i think its essential to monitor EGT's
you will be wanting a set of these then
something else i have to sell
Which will go in the for sale forum
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