Jump to content
SAU Community

Recommended Posts

Alright I was just wondering what is the leanest afr you guys would consider safe. Basically I have a stock rb26 with no boost restrictor, exhaust and a FMIC, so the boost is around 15psi. had the car on a dyno and the afr ratio was mostly in the high 11s and low 12s but spiked at about 12.9. Is this getting pretty dangerously lean? Thanks for any help. Also what AFR would you recommend tuning to when I get PFC?

Link to comment
https://www.sau.com.au/forums/topic/217188-safe-afr/
Share on other sites

As NYTSKY said you 11.8 is safe! Don't risk it with 12.9!! I know many tuners that tune with afrs like yours but it is risky and to have many horsepower!

Better safe than sorry!

If you have with 15psi 12.9, try 12psi or less!!

Better safe than sorry!

Buy a PFC or remap your stock ecu. It is cheaper than to rebuild your engine!!

Better safe than sorry!

:rofl:

Edited by GreeceS13
Link to comment
https://www.sau.com.au/forums/topic/217188-safe-afr/#findComment-3835250
Share on other sites

So the stock injectors should be good enough to keep up with the 15psi? Also is anyone sure what the boost is without the boost restrictor on a GTR? My car is swapped so I am not positive that the turbos are stock, since i got the motor with 30k on it. though I am pretty sure cause they appear to be stock. Also yes it is a stock computer. Fuel pump is a walbro 255lph so I would think it would be fine. I am gonna get it back on the dyno in a couple weeks and take another look at the afr.

Link to comment
https://www.sau.com.au/forums/topic/217188-safe-afr/#findComment-3838430
Share on other sites

A print out of the dyno sheet... power vs AFR & power vs boost would be able to tell me if its dangerous or not. The first one would help if thats all you have.

Alright I was just wondering what is the leanest afr you guys would consider safe. Basically I have a stock rb26 with no boost restrictor, exhaust and a FMIC, so the boost is around 15psi. had the car on a dyno and the afr ratio was mostly in the high 11s and low 12s but spiked at about 12.9. Is this getting pretty dangerously lean? Thanks for any help. Also what AFR would you recommend tuning to when I get PFC?
Link to comment
https://www.sau.com.au/forums/topic/217188-safe-afr/#findComment-3838453
Share on other sites

  • 1 month later...
A print out of the dyno sheet... power vs AFR & power vs boost would be able to tell me if its dangerous or not. The first one would help if thats all you have.

I will post a dyno sheet when if i can get ahold of one. Also what should the stock wastegate boost pressure be for the stock turbos? my car is boosting between 15 and 18psi. seems like that is higher than it should be.

Link to comment
https://www.sau.com.au/forums/topic/217188-safe-afr/#findComment-3945598
Share on other sites

12.9 isnt dangerous if you have timing to match, which out of a stock ECU shouldnt be too bad, but still dont drive it hard, i'd get it tuned properly first. that said i have seen cars (R34 GTR is the first one that comes to mind) that came out of racepace and was on a dyno elsewhere, its A:F ratio was 13:1 up top, and i believe thats just how it was tuned. i quizzed the dyno operator on it and said he'd seen it a few times from racepace adn it works fine, just less margin of error for crap fuel etc.

point is, i wouldnt say its bad if racepace is doing it (that said i could be entirely wrong lol)

Link to comment
https://www.sau.com.au/forums/topic/217188-safe-afr/#findComment-3947297
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Latest Posts

    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Awesome, thanks for sharing!
    • To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
    • So, now all you need to do is connect the 2 or 3x 12v feeds into the unit to permanent 12v, ACC 12V and IGN 12V that you can find in the spot behind the stereo, and the earth, and then it will switch on with the car.
×
×
  • Create New...