wideband o2 setup?

way too lean dude

14.7:1 on idle..
should be same on cruising light throttle and wot should be in the 12.5 region

 

it says 14.7 : 1 in the innovate manual

But speaking to people and tuners 12.5 : 1 is a good figure, Mark Gunns took his Rado to Jabbasport the other week and it was running rich 525BHP they leaned it out and 575BHP with room for more adjustment but Mark left it at that.

 

righto, thanks. so on the basis of what it's reading now it could do with richening up about 1 or 2 AFRs.

i'm going to have to do something about these slip joints though, before i can discount an air leak upstream causing contamination. off into the garage in a mo to rip it all off again and tig them up quickly, then see if the AFR reads any richer. if not, 16v WUR time.

found this on the puma racing site:

so that'll give me something to aim for. as far as idle CO in relation to AFR is concerned i'll just have to get it checked at the garage in town. fuelling is kjet still so should i be thinking about adjusting system fuel pressure as well as playing with the WUR pressure?

thanks again for the advice chaps

 

When i was getting my car adjusted for MOT the CO and AFR didn't match up like that. To have a low CO% of 0.2, The AFR was nearer 16.5. Maybe its something to do with the MS not being fully sequential injection. Mine is around 13:1 at idle. and a bit lumpy. I can probably get it leaner and smoother by turning off EGO correction. Haven't had time to play with it yet.

 

turbo cars have fueling for reasons other than raw power tho..

leaned out from what to what? mad to rich sensible?

 

x2.


Not because the engine made more peak power means that the components on the exhaust side will be protected against excessive heat and then fatigue failure.
On some JDM vehicles a 10.5 A/F setting at high engine speed will reduce torque, yes, but keep the EGTs happy if you are already running spark timing near the det threshold or if possible MBT.

Engine mapping is skill that takes a long time to develop.

 

A/Fs 16:1 is probably on the misfire limit maybe not felt as it is part load.
15:1 @ WOT on a Kjet is well lean and you do need to get this checked. Should be around
13.0 tapering off to 13.9 near readline.
Idle 13.5 to 14.0 A/Fs should keep it stable then tweak the setting for MOT via the CO pivot.

 

Mines very Lumpy on idle so will be interesting to see what the AFR is when the Wideband is installed.

 

Just focus on idle quality rather than a target A/F mixture.

 

all the slip joints upstream of the o2 sensor are now tig welded, had to do it under the car as well, which wasn't pleasant. don't use jointing paste! makes disassembly somewhat difficult, what a bollox that was.

anyway, AFR is now reading about a whole point richer, so there must have been a leak somewhere.

idle on start up (20C) 11.5:1,
warm idle 13.5:1
part throttle high 14s - mid 15s :1 so i'll be looking to sort that by playing with fuel pressures
full throttle mid 13s:1 low revs - mid range.
overrun after blipping the throttle over 20:1, but i'm guessing that's to be expected?

i haven't tried high revs yet, nasty vibrations coming in under full load above say 3000 RPM.

 

Part throttle don't seem too bad. That should be cruise areas.

 

cool, so actually not too badly set up then, with system pressure and control pressure set as standard.

afr does get up to low 16s:1 on snap acceleration though, the vac accel enrichment of the 16v wur might help there. i've just been trying to get the 16v wur fitted but it's fouling the oil filter housing so will have to think of something cunning.

 

i've trimmed off the vac hose connector for the 16v wur today, and blocked it. i'll be using a banjo connection (if i can get one teeny enough) by drilling and tapping a hole on the other side of the housing. fitted the wur, set control pressure at 3 bar (a bit lower than book but then it's not a standard engine) and twiddled with idle mixture pivot as well.

before this i took it for a proper run, afr reaching over 16:1 on part throttle, over 3000 rpm, just before the second choke opened. above that it was fine. lowering the warm control pressure dropped the afr overall just right, between 14 and 15:1 until 3/4 load when it starts to rise to between 13 and 12:1. idle was a bit rich but tweaking the idle mixture screw brought it up to about 14:1. so i'm fairly happy with that, engine pulls a lot more smoothly now in the midrange.

i'd like to plot the AFR as a graph but i suppose i'd need an RPM input for that..

 

How did you get on after? where did you get yours from in the end?

 

It's an Innovate LC1. I found out later that the early models are less robust, so try and avoid the ones that come in a beige box if you decide to go for one of these. Red and white or blue and black boxed ones are re-designed with better overcurrent/overvoltage protection (according to DIYautotune site). I bought mine (red and white box) from a lithuanian chap on Ebay (user id: xenonlv), with a red DB gauge and sensor, for 165 with free shipping worldwide.

Tweaked the control pressure a few more times, but it still isn't perfect, which is to be expected with a non-standard engine running standard kjet. Ultimately it comes down to the shape of the cone in the air metering head (the fuel 'map') and that can't easily be changed, so it's always going to be a bit of a fudge.

Microsquirt is in the process of being installed, for ignition and fuelling. Wideband afr gauge will be a big help when setting it up no doubt.

 

Is that guide more for NASP engines? How would it look for turbocharged engines?

 

I've been advised to aim for 12.5:1 AFR or around 0.85 lambda. It's around 12 ish at the moment. It was nearer 11.5 on the dyno.

 

Turbocharged engines produce more power from a given size engine, which means they also produce more waste heat. It is necessary to avoid this heat getting hot enough to melt stuff. A rich mixture leaves unburnt fuel, in the form of carbon monoxide (CO), and lets it escape through the exhaust, thus avoiding building up too much heat in the combustion chamber, whilst extracting most of the available energy from the fuel. So there's an element of component protection in running richer than stoichiometric, but AFRs of around 12.5:1 also extract the most energy from the fuel in the shortest time, allowing higher revs operation which is where max power is to be found.

Running a leaner than stoichiometric mixture at power levels where the waste heat is high enough will cause serious bother, as the excess oxygen enables the alloy parts of the engine to actually catch fire and burn, rather than just melt a bit. Part throttle where the engine really isn't producing much power (around 40 bhp or so for 70mph cruising) it's actually good to have it as lean as possible for fuel economy. This reduces the power produced by the engine for a given throttle angle, meaning more throttle can be used, reducing manifold vacuum and thus throttling (pumping) losses and increasing mpg. The limit of this is the lean misfire, which is where leanburn technology, stratified charge operation, and direct injection (FSI) starts to come in. All interesting stuff.