Club 80-90 Forums

Oh the old baffle them with science routine

I was never one for chemisty but my unscientific reasoning is : a fire needs fuel and oxygen ( and a spark) 98 ron has to be a better fuel so with the same measured ammounts it will result in less oxygen left and deliver more energy.... am I wrong?

Alright you asked for it, simple version (nicked, not checked)

2 C8H18 (petrol) + 25 O2 = 16 CO2 + 18H2O

Of course petrol is a blend of different chain length hydrocarbons and other components and additives, so it's a damn sight more complex than this in reality

Now spell stoykimetrik

itchyfeet wrote:.... am I wrong?

only occasionally, and I wouldn't be so presumptuous

its wasted on me
anyway the advice you should have given is a four wire rich/lean sensor is useless for anything more than an indication , wide band lambda sensor and gauge is needed to know whats really happening
Answer courtesey of Marco Mansi

I can only work with the tools I'm given

Does this mean you're going to replace the a/f gauge with wide band lambda ?

Next you'll be adding knock sensors and changing the ECU. I'm sure Marco can help with that, from what I have read he does turbo WBX so he will certainly be on top of the fuelling dynamics.

937carrera wrote:
Does this mean you're going to replace the a/f gauge with wide band lambda ?

probaby if the cost is not excessive

itchyfeet wrote:2.1 DJ Air fuel gauge
on lower revs it tends to be jumping back and fourth unless on light throttle when its lean
High revs or low revs foot to floor its mid range to rich.
To those in the know does that sound right?

Yes, assuming you have a narrow band O2 sensor, wide band ones are expensive.
Jumping back and forth indicates you're as close to ideal as the gauge will tell you.
E D I T: The ECU makes it go rich/lean/rich/lean to give you an average ideal.
E D I T: Wide band sensors will tell you if you're slightly above or below ideal as well as if you're far above ideal.

https://www.haltech.com/wideband-o2-sensors-explained/

itchyfeet wrote:At higher revs it is lean with up to and past half throttle

this is what worries me

I have been told wide band are cheap now but not loked yet as I was on my holidays when I wrote that

400 miles watching a needle, well when I.wasn't watching the oil pressure, temperature, revs or the speedo bouncing

bigbadbob76 wrote:Wide band sensors will tell you if you're slightly above or below ideal.

Sorry, I didn't write that very well, yes they will so will narrow band ones.
but narrow band ones go full scale lean when you're only slightly lean and can't tell you if you're very lean.
If yours is going full scale it doesn't mean you're dangerously lean, just on the lean side of ideal.
However if you are dangerously lean it won't tell you.
Hope that makes more sense.

I knew what you meant and just looked on ebay, and they are quite expensive 200 quid ish.

So continue in blissful ignorance or blow more money

I'd expect it to be on the lean side of ideal with light throttle openings so I'd continue in blissfull ignorance.
Unless something other than the gauge suggests it's very lean I'd leave well alone, the ECU will take care of it.
That's the whole point of computer controlled fuel injection.

I did a diy fuel injection conversion on my trike engine (2cv6) so was starting to learn a bit about it, got it mapped well enough to get out and running but it needs an mot before I can get it on the road and log some runs so that's on hold due to other projects.
I'll finish it one day and learn more about it. It's a mind boggling subject.

Finally got around to fitting the PCV in place of the broken breather tower now oil filler.

P1100457 by Paul_Barr, on Flickr

I'm going to try a VDO oil temp gauge as this cheapo one is not very responsive.

looking at to m10x1 sensor but what connector goes on this?

If it's like ones I have seen before a simple spade connector, just try one