On a modded 996 turbo what should the air fuel raio read on my gauge? At idle and wot? Whats normal and whats high?

 

At idle around 14.5 and at full throttle between 11.5 and 12.5. A low number is when running rich,a high number is running lean..

 

For some reasone at idle my afr is at 13.8 and at full throttle its at about 1o.5 to 11.5 is that okay or is it a problem

 

you are running rich, which is bad for mileage but ok for the engine and hp...could be high fuel pressure (fuel pressure regulator), a malfunctioning injector(s) or air/fuel sensor(s). Could cause you a problem if you have to smog it

 

+1

 

If I was running 10.5 I would be worried because the fuel that is not burned can push away the oil between the pistons and cylinderwall (hope you understand because it's difficult to explain in English for me)

 

Well i have 65lbs injecters and a high flow fuel pump. My car was recently dynoed at 731 rw hp. Am i going to hert the motor if the air fuel ratio stays at 10.5 at idel and about 12 to 12.5 at wot. This stuff is a little new to me so i'm tring to uderstand all of it.

 

don't confuse us lenny....now you say 10.5 at idle when before that was at wot...figure you just turned it around...when you upped the injectors and fuel pump did you install an adjustable fuel pressure regulator? Unless you had a way to add more air at the same time there was no doubt going to be a fuel rich situation unless you reduced the fuel pressure...do you know the pressure setting at idle? chances are you could still pull the same hp with a slightly leaner mix and not risk the motor...there is still the possibility that the afr sensor is off too...I would check that first and if still rich then get the fuel pressure checked...if you are running stock regulator I would get an adjustable one and reduce fuel pressure until afr comes in line

 

Sorry i screwup At idel my afr is 13.8 and at wot its 10.5 10 11.5. at wot it jumps around. I'm just tring to figuer out what should the afr be at on a modded 911 turbo or i should say a safe afr. I dont want to blow the motor on my car. I sorry for the mix up i was alittle tied when i typed the last reply.

 

lenny
your car is 100% fine.
your motor wont blow.
the guys who tuned your car(rpm racing) know exactly what theyre doing. trust me

 

Let me try to simplify this in general terms.
wot at full boost should be 11.5-12: depends on the feedback from the dyno and egt's. On a good tune, afr's should count down just before the higher boost #'s to keep exhaust temps high and promote spool.
Idle with a warm motor should stay around 14.7 (stoichometric).

I'm not too familiar with the goings ons or aftermarket 911T's but as stated-if your running rich throughout, its generally a leaky injector or an inaccurate fuel pressure regulator. If both work as designed... you may want to question your tune or atleast do a boost leak test.
my vague input.
Steve

 

I agree.

 

your afrs are FINE....

 

little rich at idle have them lean out the idle. On WOT your fine. 14.7 at idle is ideal. Im sure its just a slight ecu adjustment.

S

 

Hi... Lenny's car was tuned to make a SAFE 700 plus whp... His car is not driven daily! Lenny also has the option to up the boost some more then what he is running.. He is also using race gas so the air/fuel will run richer. Lenny will you post times or some kill stories. Tim