ive just fitted a stack afr gauge heres my finding.. on my escos

idle 14.6 afr
0.5-0.7bar boost 14.6 afr still??
1bar boost 12.8 afr
2.0 to 2.2bar 11.6 afr

it drives fine but when im just building up abit of speed using a little bit boost the afr seems abit week but i dont know much about this sort of thing..

cheers merry christmas

 

does look a tad weak on boost

 

Should the AFR not be a very similar shape to the boost curve, meaning that once in positive boost, the AFR should richen up to suit... so from my limited understanding of this subject, under 1bar boost, you're actually running leaner than you should be going by those numbers?? I think that the numbers at 1bar and over look reasonable and in the correct ballpark from what I understand and have read about.. however, being in the correct ballpark isn't quite as accurate as it needs to be!!

Who mapped the car?? Can you give them a wee email or call to discuss it??


Cheers,
Grant

 

just goes to show that a gauge is only as good as the instrument reading it

 

i thought that looks right , stoichiometic value is 14.7 for the mass of air to 1 part fuel , so at idle your about spot on, 0.5 to 0.7 maybe a little lean then 1 bar and 2 bar looks spot on as anything lower than 14.7 to 1 is classed as a rich mixture and anything over is a lean mixture so thats the mapper adding the extra fuel for the boost . iam sure this is right but anyone can correct me if iam wrong
i know my engine was on the dyno but every step of boost on the map the afr was 12.3/12.4 even upto 30 psi

hope this helps

cheers paul

 

did you lower the boost to 0.5-0.7bar or are you just trying to read the gauge as the boost rises?

 

thats about what i get on my escos as long as that 11.6 reading is no higher on full boost thats cool but maybe could be a bit lower for safety like 11.4

 

This was mine running on the 403's, T38



On Siemens now so maybe look a little different

 

Not struck on the stack its a bit clunky on its reading in my testing and at on point it shows 10.5 when my meter shows 11.8,
So I would recomend taking it to a pro before you run it to hard and check for dett and fueling with a meter they trust.

Mark

 

that goes as rich as 10 afr!! over 6k

 

You should have seen the flames that comes out of it when you let off at full pelt, the reason i went for the new setup

 

ahh i see whats it like now??

 

basically i fitted a different ecu and had no map so i called msd and stu said he didnt have a map for my car but he could make one for me, so i bought this from him, got it and set the co etc cold starts are fine, hot starts are fine. i put it on a dyno and made 443bhp on a t38 about a year ago! mad that he made it!! the dyno guy said it was abit rich so it fine to drive..

but as ive been changing bits over the past year since that r&r day eg.. ive fitted a 2wd exhaust manifold and small turbo inlet, it didnt drive very well, so i just took it up the road and kept adjusting the co screw untill it felt nice to drive again..

drove it about another month giving it shit but never holding past 5k for more a couple of seconds.. had no problems

just bought a stack gauge and there the readings i found.

i dont really want to rush it down to a dyno just yet as i want to be sure this is the spec i want.. bear in mind my escos is my only car and daily driver.. so since ive done the ecu screw ive done 5kmiles easy! so i'm not overly worried about it poping as i reacon the fueling must prity good....

shall i just richen up the co2 screw a tad to make it richer at 0.5 bar boost or turn the fuel pressure up a tad? i know it will be richer all the way through but if i get 0.5 boost in the 13's and flat out 11.0 surely it will be a tad better in the mean time..

please save the comments about the risks etc i read it all before.... this is my 3rd year of owning cossies and i use them everyday and never had a engine problem... sorry to say that just dont want the insults..

cheers i will get it mapped feb march time..

 

i sure the co2 screw only adjusts the idle mixture not on midrange or boost mixture.
i could be wrong?

 

also when i asked stu about adjusting my map for a hart plenum, he told me its a different map altogether, needs a full mapping session again
it might be the same for you with the st inlet?

 

the Durham rsoc did a R/R day in june and about 5 cars had just been "live mapped" and all of there print outs showed doddgy AFR readings (10's).......i'd trust a mappers gear over anything else........jmo.....

 

Different engines do respond to different AFRs

Only way to really know if they are right is with a rolling road and an EGT probe, to make sure they arent losing your power or generating too much heat.

They dont look too bad though at first glance if they are accurate in the first place (cheap gauges are a guide only really, best checked out on something like a dyno dynamics)

 

Wrong

CO Screw is a global adjustment.

 

so who would richen it up abit? and using what adjustment screw or fuel reg?

cheers

 

i would leave as is