bad boy rs

iTrader: (7)

Hello there people hope everyones good and enjoying there run up to christmas and obviously drinking plenty About 6months ago i managed to melt a piston on a fully rebuilt cvh. Ive now gone 2.1 and bought a AEM wideband afr gauge to be safe, jus a few questions realy How accurate are these gauges ? Its all fitted and running.On idle its reading 10.8. On cruising its running in the 11's but flutuating and on boost in forth and fifth its 12.6. Does this sound about right? I took it out earlier and road was very damp so couldnt hammer it that much.

Christian and Beccy

iTrader: (14)

Sounds absolutely terrible to be honest. However, on MFi, the fuelling quality is challenging to say the least.

Ideally, you want 14.5-15.0 on Idle/Light cruise, progressively dropping to around 11.5 (give or take a bit) on boost and at higher RPM's. In your case, it's leaning off, 12.6 is dicey. Does the car have its original fuel pump?

I don't work in AFR, so I struggle to convert the figures, but my 350bhp RST fuels like a modern car off-boost, so around 14.5 at almost every RPM point where there is no boost, but that really is one of the main benefits of an advanced modern EFi system.

Fitting an AFR gauge is a dangerous thing, as it will just end up in you going EFi!!

bad boy rs

iTrader: (7)

Im running dta managment with a group a pump and dark green injectors only on 14psi at the moment sounds like it needes some serious mapping session. I was thinking 12.6 was spot on for boosting. So is that dangerously lean on boost and wasting loads of fuel on idle ? Good job i bought it Thanks for any info

Dragsteer

12.6 under boost is not so dangeours if ather things like ignition timing... are ok. but on 14 psi I think I will set about 12 : 1 for safety.

Christian and Beccy

iTrader: (14)

If it's on DTA, then that is a shocking map.

It is a tad lean on boost, not critical, but not great either.

However, 10:1-11:0 off boost is just absolute shit and in al honesty, not far from bore-wash territory.

bad boy rs

iTrader: (7)

Looks like a trip to a tuners after christmas for me then ! Whos the best at mapping dta ???

Rick

Fiecos Dan

As Christain said.


14-15.0 for idle, cruise upto 50-60% throttle.

12.6 is best for power, but unless monitored for det, egt's is too close to the edge for safety.

So 11.8:1 is what you want to be seeing, which is fine for 95% of RST's and cossie's., but some other engine's/cars will need to be richer on boost cos of engine/mani design's.

On my own cars, i map to 12.3 dropping to 12.0:1 at high boost/rpm's, but i'm monitorig all the margins all the time, for cars i tune i set to 11.7-11.9 on boost on average.

As for a AEM accuracy, my brother run's one in his Pulser, and it seems quite accuate, but i haven't tested it against my known accuare AFR meter.
But its safe to say its accurate to +/- 0.2 of a AFR.

xrsi

iTrader: (1)

stoichiometric AFR is 14.4:1 this idealy is where most engines should run to be most efficient, so off boost with little load on the engine and on tick over that is the sort of range you should be aiming for.

to get the most power you should be looking for the very low 13:1 - 12:1 ratio on full chat, that is running slightly rich so that the extra fuel providing cooling and also so that a more complete burn is achieved due to the decreased time that it has availiable to burn at the high RPM's

Fiecos Dan

i believe stoichiometric AFR to be 14.7:1,

best fuel economy by rule of thumb is 15.2:1, but depending on engine will differ slightly.

And the same can be said for power @ 12.6:1, but as you have said, it can be 12.4-13.0:1 on different engine setups, But is far too risky on a Hi boost engine on road fuel, and for the sake of 10-20 bhp loss from running at a safer 11.8:1, isn't usually seen a worth while trade off for the risk by tuners.
if fact some well known tuners setting cars in the 10's and low 11's, which on a cossie or a CVH is just crap tuning.

juffer

http://cgi.ebay.co.uk/BRAND-NEW-60mm...QQcmdZViewItem

are these any good?

Fiecos Dan

No thats a Narrow band AFR,
which are crap, slow, and not accuarte enough for anything, let alone tuning.

Christian and Beccy

iTrader: (14)

You ever heard the term 'Shonky Shit'??

You're better to have no AFR gauge, than a shit one. Innovate or VEMS is what you want.

Incidentally, I can't tell you how many Cossie managed RST's we have seen at RR days which are idling at under 0.80 lambda, which is sub 11.0:1.

Fuck knows why.

bad boy rs

iTrader: (7)

Does every one recommend leaving the car in the garage then till its set up was hoping for sum boosting over christmas. Is this boor wash thing serious ?

Dragsteer

bore wash starting under 10:1 afr or under, about 9.X : 1

Then is possible to have oil contaminated with fuel, so must change oil.

Fiecos Dan

Yep, get it sorted first.


Bore wash is damage to the bores and rings that cant be fixed with out a hone and new rings.

bad boy rs

iTrader: (7)

Ok people thanks for the information Im using DTA fast E48 managment and it has an input for closed loop control, is this worth seting up now i have the sensor and gauge ? What are the advantages ?

xrsi

iTrader: (1)

Yeah it is always better having reliability over all out power, for the sake of a couple of bhp over the cost of rebuild i know which i would take every time

i got 14.4:1 from lectures in uni, its prob the thing that has stuck in my head the most out of the whole degree is the engine and thermodynamics side of the degree as that had the most interest for me so i would imagine that was right (not saying your wrong as the lecturer could have got it from a source that was slightly inaccurate or had a different opinion to where yours came from)

i have got a autometer AFR gauge in the fiesta and frankly it is crap, i was going to try a wideband sensor with it to see of that helped but chances are it will not.

Fiecos Dan

not sure then,

i've always known lambda 1 to be 14.7:1, so thought stoichiometric is the same, but could be wrong.


I think your narrow band even with a wideband sensor will still be crap, in accurate and too slow still, but i've not tried it myself.

bad boy rs

iTrader: (7)

Its a five wire bosch sensor I paid enough money for it

Dragsteer

five wire is one which have integrated heating for quicker and precious readings. I think this must be WB but not 100% sure

Fiecos Dan

AEM will use a wideband sensor.