Finally the V8 3.9 O2 project

[PhilipA]

I guess I should have done this long ago.
This is the project document
8226
Regards Philip A

[sclarke]

Nice tutorial...

So what do the O2 sensors do that yours does not, besides measure the O2 levels and keep the engine tuned at the required 14.7 AF ratio

So will this improve your economy?

If so what were the figures before and let us know the figures after...

Steve

[PhilipA]

Steve, have a search in fuel economy in technical. I have kept up a bit of a commentary over the last year.
The summary is, that I seem to have an increase of about 10%. Coming back from Canberra to Sydney a couple of weeks ago I got 16.2 Litres per 100Km ( on 91 unleaded) towing my 550 Kg camper at 110Kmh where posted. However going to Canberra into a 60Kmh Gale I only got 20L per100Km.( on E10). This is over the Great Dividing Range.
I have a long range tank so it goes a long way between fills, This makes it hard to generalise as I do all sorts of different driving. However locally my economy has increased from 22L100Km to about 20L100Km.
I am now keeping a log of each fill.
So my conclusions are
About 10% better economy
E10 gets worse economy by about 5%
Power/ responsiveness at light throttle is worse

I fitted new plugs the other day , as looking at my records I found I had forgotten , and they had done about 27K. They were all white ( beautifully lean) all over, which is different to previously.
Remember also that my car should have better economy than stock before the o2 sensors, as I have a Unichip, Thor Manifold, modded heads, high air intake, free flow muffler.
Probably the only mod that has given a noticeable difference in economy, vs power.
Regards Philip A

[Jim621]

I guess I should have done this long ago.
This is the project document
8226
Regards Philip A

Hi PhilipA,

Firstly - thanks for the write-up, very clear and precise.

I wish to do the O2 sensor retrofit to my 98 disco, but I cannot find the correct O2 sensor from the ebay seller you list in the write-up. (He may not sell them anymore)
Would you be able to link me the specific O2 sensor you used?

Thanks, Steve