AFR`s After fitting Relocation Pipe

[olliecast]

Evening all,
Bit of a confusing one this.
Put on my filter relocation pipe, and in doing so have blocked off my inlet return from my forge seperator.
The maf has been relocated with the filter and the earth is 1mv (should aim to be under 9mv in the how too).

Now when driving the car my afr at both 1.2 bar and 0.8 bar seemed to have leaned off slightly. They used to start at 12.5 when boost was building then richen up to ~11.5 at ~6,5k rpm.
Now the afr is about 13 when boost is building and ends up at about 12 at 6.5k @1.2bar.

I`ve ran the free air calibration on my innovate wideband twice now but the results seem to stay the same (i have to recalibrate the unit after the car has been stood for more than a week, don`t know why as it should hold the settings).

Has anybody else notice this after fitting a relocation pipe, or should i suspect my wideband may be faulty?

Cheers in advance,
ollie

 

[youngsyp]

I think the relocation pipe is a red herring. The actual culprit is the now missing oil separator/ crankcase breather ?!

Paul

 

[olliecast]

I think the relocation pipe is a red herring. The actual culprit is the now missing oil separator/ crankcase breather ?!

Paul

could it`ve been the oil vapours then richening up the mixture in the first place?
I thought people blocked them off to stop the vapours lowering the octance level and therefore increasing the chance of det?

or are me knickers in a twist?

 

[warringtonjack]

As far as I can work out, removing the vapour intake would cause the mix to run slightly richer, not leaner. :noidea:

 

[youngsyp]

As far as I can work out, removing the vapour intake would cause the mix to run slightly richer, not leaner. :noidea:

The crank case breather could/does contain unburnt fuel so, that would explain it ! ;-)

Paul

 

[youngsyp]

I thought people blocked them off to stop the vapours lowering the octance level and therefore increasing the chance of det?

or are me knickers in a twist?

That's a separate issue but yes, any oil vapour would lower the fuels octane level !

Paul

 

[Shaun]

A contributing factor is also the fact that you have shortened the physical pipe length and also the flow length as the 2 90deg bends in the standard plastic pipe have now been removed placing the airflow meter closer to the turbo altering the airflow over the sensor.

 

[olliecast]

well i`ve compared the two pipes tonight and my new pipe has two 90 degree bends in it anyway in order the get the airflow sensor far enough away from the turbo with the standard filter and maf on (it`ll be right on the limit when i put my z32 and bigger filter on), so i`m pretty sure the maf ain`t the problem.
changed back to the old pipe and its slightly richer again, however....

The thing that concerns me the most is when i first go wot, my afr leans out to about 16.5 until the boost builds. It then richens up as the boost comes in.

The plot is below. Is it safe to have it lean like this before the boost comes in? The run was taken in 3rd gear btw.

cheers ollie

 

[olliecast]

fixed this issue today!!
took the airflow meter to bits and cleaned the resistor thingies.
Its now running richer and doesn`t have the nasty lean spike or hunt when on full boost. hits 12 then richens up nicely
just used electrical contact cleaner and a cotton bud. job done !

 

[campbellju]

hits 12 then richens up nicely

:?:?

12 is rich enough for power.

 

[olliecast]

its down to about 11.6 so not to worried. its better than it was though! now got to sort my low oil pressure prob

 

[olliecast]

My new Scooby is running 10.2 :shock: :roll: , It's going back this week though :roll: .




Rob

slluurrp, just like its daddy