Jump to content
SAU Community

Recommended Posts

Forgot to ask this before.

When i got by car dynoed it showed an AFR of between 12-13

Is this ok?

I thought it was running a bit rich, but the workshop said that this is fine

Excuse the quality...taken with phone

post-38029-1184018127_thumb.jpg

post-38029-1184018101_thumb.jpg

Edited by Fujiwara
Link to comment
https://www.sau.com.au/forums/topic/175808-what-should-my-afr-be/
Share on other sites

that all depends on where in the rev range and load you are talking about. if we are talking light throttle, cruise then yeah 13 is too rich. if we are talking full throttle, high load and rpm then 13 is too lean.

Depends on boost!!!!!!!

I aim for:

Cruise/light throttle can see stochiometric (14.7) to 16

1-6psi 13 afr

7-14psi 12afr

14-23psi 11-11.5afr

30 psi 10-10.5afr

All depends on compression ratio and head design. On my higher compression engine, I drop AFRS earlier.

My afrs are always fatest where max torque/VE occurs

So your afr of 12-13 is mostly fine. Hard to say without dyno sheet and boost used and other impt factors (fuel, CR etc).

Edited by 180bfj20det

you may pick up a bit of power going a touch richer. my mate had his 33 on the dyno and i had 2 maps saved on his emanage and we changed between the 2 and picked up hp by adding in 4% more fuel. and his afr was around 12.1. there was no adjusting of the car other than flicking the switch on the emanage to change between the 2 maps. the runs were done about 20 seconds apart and the run with the extra fuel was done second so it would've had more heat in the cooler etc.

Mate, that looks perfect, 12:1 at full recs, and a little dip at peak torque. At that power level you wont gain anything from adding more fuel, you would probably gain some by leaning it out but at the expense of high EGT't and combustion temps. I would leave it exactly as it is.

it depends on what is causing it to run lean. i highly doubt it will be the injectors maxing out. they may need cleaning though. your fuel pump may be dying, or you could get an aftermarket ecu. if the problem is the pump or injectors the ecu won't really help much and the problem will just get worse.

Guest
This topic is now closed to further replies.


  • Similar Content

  • Latest Posts

    • Yep, there's a very minor drift left that happens a few seconds after letting go of the steering wheel, but not enough to bother me. Enjoying the car still!
    • Got you mate. Check your email!
    • I see you've never had to push start your own car... You could save some weight right now...
    • Sounds good.  I don't 100% understand what your getting at here. When you say, "I keep seeing YouTube videos where people have new paint and primer land on the old clearcoat that isn't even dulled down" do you mean this - there is a panel with factory paint, without any prep work, they paint the entire panel with primer, then colour then clear?  If that's what you mean, sure it will "stick" for a year, 2 years, maybe 3 years? Who knows. But at some stage it will flake off and when it does it's going to come off in huge chunks and look horrific.  Of course read your technical data sheet for your paint, but generally speaking, you can apply primer to a scuffed/prepped clear coat. Generally speaking, I wouldn't do this. I would scuff/prep the clear and then lay colour then clear. Adding the primer to these steps just adds cost and time. It will stick to the clear coat provided it has been appropriately scuffed/prepped first.  When you say, "but the new paint is landing on the old clearcoat" I am imagining someone not masking up the car and just letting overspray go wherever it wants. Surely this isn't what you mean?  So I'll assume the following scenario - there is a small scratch. The person manages to somehow fill the scratch and now has a perfectly flat surface. They then spray colour and clear over this small masked off section of the car. Is this what you mean? If this is the case, yes the new paint will eventually flake off in X number of years time.  The easy solution is to scuff/prep all of the paint that hasn't been masked off in the repair area then lay the paint.  So you want to prep the surface, lay primer, then lay filler, then lay primer, then colour, then clear?  Life seems so much simpler if you prep, fill, primer, colour then clear.  There are very few reasons to go to bare metal. Chasing rust is a good example of why you'd go to bare metal.  A simple dent, there is no way in hell I'm going to bare metal for that repair. I've got enough on my plate without creating extra work for myself lol. 
×
×
  • Create New...