So what would you say is too Lean? Too Rich ? Opinions Pls. - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

BC-Boy · 05-27-2014, 05:16 AM

This is a topic to which i hear a very wide array of awnsers,
This is all based on a WOT situation with the engine on load as a typical dyno run would be performed , for the sake of simplicity.
What do you think a desirable AFR curve should look like N/A or F-I ?
What number would start to get you worried ? N/A or F-I?

Also what is your point of view on Rich conditions, and what is .. too rich ?

It would be nice to share opinions on this subject.

s2d4 · 05-27-2014, 06:06 AM

Opinions are nice and all but experience probably trumps all.

All I know is documentation from badnoodle and tuners on this platform have basically followed this except your previous choices tuners.
@jamesm may shed more light on this.

Sent from my Galaxy Nexus using Tapatalk

blackhawkdown · 05-27-2014, 07:33 AM

14.7 baby! just trolling for post counts, don't mind me.

J_kennington · 05-27-2014, 08:58 AM

On FI under WOT(full boost) I wouldn't go any leaner than 13-1. And would tune as rich as 10 or 11. On my eclipse, I consistently tune to 11-1 AFR at wide open under full boost. It's easier for me to replace 4 spark plugs than it is a block.

On NA under WOT I think I would want to stay around 13-14. It's been awhile since I've messed with an NA though...but if memory serves right, you would get the most power the closer to stoich you are.

Apoc · 05-27-2014, 09:40 AM

Based on my limited experience with tuning, the sweet spot for N/A AFR at WOT is between 12-12.5 to 1. The AFR from stock o2 sensors is not that accurate, so most tuning I've seen done here lately keeps a bit lower at 11.5-12 as a safety margin without any loss of power.

jamesm · 05-27-2014, 11:13 AM

on pump gas...

NA: low 12's tailing to mid-high 11's above 6.5k or so. this is because the car is crazy knock-prone up high and you can usually make more power by richening it up a bit and keeping more timing. the rich afr's we run on these cars has nothing at all to do with an O2 sensor (the car doesn't even use the O2 sensor in open loop), it's because it buys you knock resistance, and this car is extremely knock sensitive. higher DI ratio + slightly richer than typical AFR allows you to run a lot more timing and ultimately make more power.

FI: 11.6-11.4:1, again maybe richening up a bit as you get above 6.5k... for the same reasons as above. I've found that range is a really good spot for power... still allows you to run decent timing without having to give up a bunch of power going rich. power drops off pretty hard as you get into the very low 11's or down into the 10's.

As far as what AFR is 'safe' there is no right or wrong answer. There are obvious limits: if you're running 14:1 under load NA or 13:1 under load boosted that's obviously bad... but the car can start to knock just a few tenths of a point leaner than target if it's tuned fairly aggressively. The key is just to make sure that the AFR is consistent and stays where you put it... this means minimizing fueling error to less than 2% across the board and turning off LTFT in open loop, basically. You'll never have a consistent AFR with LTFT acting in open loop and high fueling error.

Ironsquid · 05-27-2014, 11:40 AM

Quote:

Originally Posted by jamesm

on pump gas...

NA: low 12's tailing to mid-high 11's above 6.5k or so. this is because the car is crazy knock-prone up high and you can usually make more power by richening it up a bit and keeping more timing. the rich afr's we run on these cars has nothing at all to do with an O2 sensor (the car doesn't even use the O2 sensor in open loop), it's because it buys you knock resistance, and this car is extremely knock sensitive. higher DI ratio + slightly richer than typical AFR allows you to run a lot more timing and ultimately make more power.

FI: 11.6-11.4:1, again maybe richening up a bit as you get above 6.5k... for the same reasons as above. I've found that range is a really good spot for power... still allows you to run decent timing without having to give up a bunch of power going rich. power drops off pretty hard as you get into the very low 11's or down into the 10's.

As far as what AFR is 'safe' there is no right or wrong answer. There are obvious limits: if you're running 14:1 under load NA or 13:1 under load boosted that's obviously bad... but the car can start to knock just a few tenths of a point leaner than target if it's tuned fairly aggressively. The key is just to make sure that the AFR is consistent and stays where you put it... this means minimizing fueling error to less than 2% across the board and turning off LTFT in open loop, basically. You'll never have a consistent AFR with LTFT acting in open loop and high fueling error.

You mean every car is different??!?

solidONE · 05-27-2014, 11:42 AM

Quote:

Originally Posted by Ironsquid

You mean every car is different??!?

You think every car/engine is the same??!?

Ironsquid · 05-27-2014, 11:43 AM

Quote:

Originally Posted by solidONE

You think every car/engine is the same??!?

Missed sarcasm is an epidemic.

solidONE · 05-27-2014, 11:47 AM

Quote:

Originally Posted by Ironsquid

Missed sarcasm is an epidemic.

BC-Boy · 05-28-2014, 01:44 AM

I want a thicker head gasket,

Apoc · 05-28-2014, 09:09 AM

Quote:

Originally Posted by BC-Boy

I want a thicker head gasket,

Is this to lower the compression ratio?

BC-Boy · 05-28-2014, 12:51 PM

Quote:

Originally Posted by Apoc

Is this to lower the compression ratio?

yup

wparsons · 05-28-2014, 02:07 PM

Why do you want to lower the c/r?

05-27-2014, 06:06 AM	#2
s2d4 Senior Member Join Date: Mar 2013 Drives: R32 GTR, AW11 MR2 SC, GTS86 R Location: OZ Posts: 2,615 Thanks: 603 Thanked 1,223 Times in 708 Posts Mentioned: 35 Post(s) Tagged: 0 Thread(s)	Opinions are nice and all but experience probably trumps all. All I know is documentation from badnoodle and tuners on this platform have basically followed this except your previous choices tuners. @jamesm may shed more light on this. Sent from my Galaxy Nexus using Tapatalk __________________

05-27-2014, 09:40 AM	#5
Apoc Senior Member Join Date: Jul 2012 Drives: Raven FR-S 6M Location: Calgary, Canada Posts: 638 Thanks: 348 Thanked 375 Times in 232 Posts Mentioned: 3 Post(s) Tagged: 1 Thread(s)	Based on my limited experience with tuning, the sweet spot for N/A AFR at WOT is between 12-12.5 to 1. The AFR from stock o2 sensors is not that accurate, so most tuning I've seen done here lately keeps a bit lower at 11.5-12 as a safety margin without any loss of power. __________________ “The World is Flat” [\|\|•]=(86)=[•\|\|]

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05-27-2014, 11:13 AM	#6
jamesm Banned Join Date: Mar 2013 Drives: 2013 FR-S Location: Orlando, FL Posts: 2,929 Thanks: 1,166 Thanked 2,293 Times in 1,180 Posts Mentioned: 313 Post(s) Tagged: 4 Thread(s)	on pump gas... NA: low 12's tailing to mid-high 11's above 6.5k or so. this is because the car is crazy knock-prone up high and you can usually make more power by richening it up a bit and keeping more timing. the rich afr's we run on these cars has nothing at all to do with an O2 sensor (the car doesn't even use the O2 sensor in open loop), it's because it buys you knock resistance, and this car is extremely knock sensitive. higher DI ratio + slightly richer than typical AFR allows you to run a lot more timing and ultimately make more power. FI: 11.6-11.4:1, again maybe richening up a bit as you get above 6.5k... for the same reasons as above. I've found that range is a really good spot for power... still allows you to run decent timing without having to give up a bunch of power going rich. power drops off pretty hard as you get into the very low 11's or down into the 10's. As far as what AFR is 'safe' there is no right or wrong answer. There are obvious limits: if you're running 14:1 under load NA or 13:1 under load boosted that's obviously bad... but the car can start to knock just a few tenths of a point leaner than target if it's tuned fairly aggressively. The key is just to make sure that the AFR is consistent and stays where you put it... this means minimizing fueling error to less than 2% across the board and turning off LTFT in open loop, basically. You'll never have a consistent AFR with LTFT acting in open loop and high fueling error.

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