AF ratio questions

[yanay]

just got my innovate wired up and in and had some questions about my A/F ratio
im running a precision 5252e turbo on a s2 rb25det stock manifold external wastegate screamer pipe fmic walbro 255lph pump full 3" exhaust straight off the turbo

Wide open throttle i have a 10.7 a/f ratio @ 7psi
idle is anywhere from 13.8-15.2
after a pull if i pop the clutch in the idle drops to 150-300 rpm and i richen up to 9.8 a/f ratio but after a couple seconds it will climb back up.
as well as if im in 4th cruising its in mid 11's but if i take my foot off the gas completely and let it ride it jumps up to 21.9 a/f ratio
Are these numbers pretty normal? Just would like some insight on how its running this is my first wideband

[fullthrottle]

All of that is good except your cruising a/f. That can be a lot leaner for gas mileage reasons since there is no load on the car. Its kind of rich in boost but I bet it.will be perfect if you up the boost

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[yanay]

what would you think optimum is at boost? any idea of the low idle flooding?

[gtrjon]

every car is different and every tuner tunes different based on their comfort level and experience. your afr is a good way to judge how experienced your tuner is. lean is mean but its a very fine line between optimal power and safety. the less experience your tuner has the richer he will make it. the richer it is the less power you make but the safer it is. ideally under wot on pump gas you should be low 11s.

[Skym]

just got my innovate wired up and in and had some questions about my A/F ratio
im running a precision 5252e turbo on a s2 rb25det stock manifold external wastegate screamer pipe fmic walbro 255lph pump full 3" exhaust straight off the turbo

Get a ECU tune with those mods. Link G4 ECU (with optional IAT sensor, MAC boost control solenoid), ViPEC ECU (with optional IAT sensor, MAC boost control solenoid), Z32 ECU (modified internally to plug into stock loom with Z32 MAF + Z32 MAF plug).

Wide open throttle i have a 10.7 a/f ratio @ 7psi

Normal with upgraded fuelpump, stock ECU tune.

idle is anywhere from 13.8-15.2

o2 sensor + ECU making engine go lean, rich, etc.

after a pull if i pop the clutch in the idle drops to 150-300 rpm and i richen up to 9.8 a/f ratio but after a couple seconds it will climb back up.

o2 sensor + ECU.

as well as if im in 4th cruising its in mid 11's but if i take my foot off the gas completely and let it ride it jumps up to 21.9 a/f ratio Are these numbers pretty normal?

That could be the fuel cut feature on decel.

Just would like some insight on how its running this is my first wideband

From what I understand, cheap wideband can be out by up to 0.6:1. Expensive widebands (as used on dyno) can be out by roughly 0.1:1. Also with tuning, have to take into account engine running leaner due to fuelpump, clogged fuelfilter, leaking exhaust, intake manifolds, just to name a few.

Safe A/F ratio (on boost) with taking above into account is around 11.4:1-11.5:1.

[yanay]

im going to be running a safc when my injectors show up until im done school and have money again.. should i throw in my adjustable fpr and lower fuel pressure or should i raise the boost a little?

[Skym]

From what I understand, should never lower fuel pressure to reduce fuel. You remove fuel via fuel map on ECU. 10-11psi is safe boost level with stock turbo, stock ECU tune on RB25DET. If have bigger turbo, FMIC, etc, it would be running leaner, so would run a lower boost level to help prevent engine running lean. Lean = blown headgasket or hole in top / side of piston due to knock. High compression engines really need a good tune to last.

[yanay]

im running quite a bit bigger turbo thats why im confused that its rich

[Skym]

ECU could be detecting knock. ECU can switch to knock maps (also known as low octane maps) that makes engine run richer when on boost, pulls ignition timing (as low as 0 degrees). Also with bigger lph fuelpump, slightly higher fuelpressure, injectors open more (when on boost), engine can run richer at mid to high rpm on dyno chart.

Fitting bigger lph fuelpump, adjustable FPR is known as band aid mod vs fitting bigger lph fuelpump, upgrading injectors, which is the proper way. With band aid mod you're limited by how much injector can flow.

If running rich off boost and at idle, o2 sensor could be faulty (o2 sensor could be fouled by running engine rich). o2 sensor is ignored by ECU when engine is on boost.

[yanay]

hmm well ill replace that next.. anyway i can find out if it is pulling timing? Injectors will be coming soon, but im in school so i have to do it piece by piece as of now

[yanay]

i put on a adjustable fpr tonight and set it for 2.3 kg at idle
wideband reads:
13.0-14.9 at idle
and 11.5-11.8 wot @ 6psi
cruising is 11-13.5
do these sound good? can i raise the boost a little bit? im hoping to run 10-12 psi

[Skym]

That looks better. I wouldn't raise boost level higher than 6psi (might go too lean at lower rpm) until get ECU retune with Z32 ECU + Z32 AFM or aftermarket ECU.

[mightyrocker]

11.5 is a little rich I would aim for 12.5-13 at WOT if you can keep your cruising below 14.5

[Skym]

For turbo engine it's safe. If intake or exhaust manifold leaks, etc, it can go leaner. If at 12.5-13 (A/F ratio for NA engine) it could go too lean on turbo engine and engine knocks thus lose engine.