Safe - AFR's

[Kdawgboostin33]

Hi Guys,

What would be a safe Air / Fuel Ratio for an RB25DET running 14PSI - Everyday?? I have been told that a safe cruise level is around 14.7 / 1. My current cruise setting is 11.5 / 1. Can this in time cause oil to wash from the bore and what other dangers would I be looking at?? Thanks in advance.....

[Zahos]

for NA motor 14.7:1 is safe, but not for a turbo....

the only time 14.7 is ok, is at idle and very low revs (< 2000 rpm).

Once on boost 11.5:1 - 12:1 are safe ratios.

[N I B]

All skylines should cruise at 14.7 turbo or NA.Your car is in trouble and must be fixed asap.

11.5-12.0 is full boost on turbo engines.

[rs73]

I agree around 11.5 to 12.1 is the safest... anything above 12.5 on boost could mean trouble for the engine. on cruising not sure, but as long as no boost, i guess 14 is ok. 11 on cruise is way too rich, something is wrong man

[Kdawgboostin33]

What sort of problems. My car has started using a fair bit of oil of late!!! What should I look out for???

[BBQ]

Have you got white smoke comming out your exhaust ?

If so, your ring lands are probaly on thier way out !

[rs73]

Have you got white smoke comming out your exhaust ?  

If so, your ring lands are probaly on thier way out !

If he said car is using a bit of oil, so I reckon the exhaust smoke should have a bluish colour if it's burning oil. ring land issue too.. or perhaps oil seal on turbo, either way, better get it checked.

[The Alchemist]

I run 15:1 at light throttle on my GTR no problem at all. 40 to 42 degrees timing No problem. Once over 3600rpm though I increase it to 14:1, still 40 degrees timing too.

Boost> as per above posts

I think your car has a problem ....

Mike

[The Alchemist]

out of interest...what did you measure the 11.5:1 with ?