Air Fuel Ratio...Reading on R.R to high ?

[_jac_]

WAS CHATING AWAY TO YOU ALL TRYING TO WORK OUT HOW TO READ THE R.R REPORT FROM DAZTEC TODAY… I SHIT MY PANTS WHEN I WAS TOLD IF YOU ARE ABOVE 12 ON THE AFR CHART, ( YOU ARE IN DANGER OF BLOWING YOUR ENGINE AND SHOULD KEEP MY REVS TO A MAX OF 5500 TO KEEP ME UNDER THE 12 MARK) IAM PEAKING AT 12.8 @ 7200...A MAP FROM MR F SHOULD KEEP YOU SAFE THAT’S ALL GREAT BUT CANT AFFORD TO GET IT MAPPED NOW AND WOULD LIKE TO KNOW HOW MUCH DAMAGE I WILL DO LEAVING IT LIKE THAT FOR 4 MONTHS OR SO TILL I GET THE CASH TO MAP HER…

[drb5]

When mapping scoob engines, the target AFR should be 11.5, so you are way over it.

You could, if you don't have one fitted, get yourself a fuel pressure regulator and richen the mixture with a higher fuel pressure. I wouldn't go without a remap for long, even when doing this, as i'm only suggesting it as a precaution, till you DO get a remap.

The lean AFR could certainly claim your engine, due to detting, which i'd expect to be happening quite a lot. Running lean can also cause high exhaust gas temperatures.

Get it remapped asap.

[craigwrx]

I am sure drb5 is correct in what he is saying under normal conditions, although on this occasion he was not aware of the full facts.

 

Personally i don't believe you have a problem ..although i am far from any expert, i am just looking at the facts on the day

 

We have three cars, all the same model, all have the exact same setup, with only green filter fitted and ppp. 

 

All three cars produced roughly the same bhp (within 2bhp of each other) as you would expect.

 

All three cars also produced the same AFR readings, which i agree the chart does show the cars to be running very lean. BUT imo, its just to much of a coincidence for there to be a problem with all three cars. Actually the readings do show there to be a major issue ..

 

My conclusion, the prodrive setup on these cars (including mine) did not like the setup used on the day and produced inaccurate AFR readings, maybe even software related ??

 

I cant see that prodrive have got it so wrong ...jeez Subaru warranty all there work.

 

I am under the believe that any ppp car that went on them rollers that day would have produced very similar AFR readings ...

 

I am far from any expert, so i doubt my answerer will help u feel any better, at the very least it will bring this thread back to the top and tempt some more knowledgeable members to have an input.

 

[fai17]

There was a good numbers of car with lean afr including myself.......i wouldn't have thought my mapper would do that to my car so is it a coincidence or was it the weather?

But i'm still going to get my mapper to look into it.

[thefastone]

Yeah he said that to me too... my AFR was way up at like 15 at some points although mainly about 13-14....

[_jac_]

What is detting and how will I know if she is detting…

I must have high exhaust gas temperatures because on the way to Dastek brian had seen flames coming out the exhaust …

I am surprised at Dastek for not highlighting you have a prob, when they give you the report...

I had seen a few boys cars up in the 12 / 13 bracket and they weren’t told they have a prob either...

Thanks to Mark 29 and squirrel555 for informing me or I would have been none the wiser …

[the squiggle]

  Quote

Yeah he said that to me too... my AFR was way up at like 15 at some points although mainly about 13-14....

Thats the target area for your car, you crazy horse.

With regards to the other peoples readings being a bit off, there could well be an issue with the sensor used to obtain the AFR because too many cars had an issue with AFR for it to be coincedence.  Looking at Playsatan's graph for the first run, the AFR drops into the 12.5 region after 5000rpm but on the second run it holds a flat 11.5 after 5000rpm. If this was a direct corelation to the power produced then he would have seen more power on the first run due to the leaner AFR but the first and second run were pretty consistent.  This would point, IMHO, to an issue with the wideband sensor not being consistent.

With the amount of cars running leaner than safe AFR i am surprised there is not a pile of Subarus and the end of the Industrial Estate with melted pistons.  As Craigwrx said, too many for it to be coincedence

I should have put mine on the rollers as i know the AFR of my car under load, mapped to 11.2 and 11.2 is what appears on the AFR meter.  This was checked after extensive testing with STI_Bandit on the main road.............which was fun

Safe AFR for a turbo car is about the 11 - 1 region when the car is holding boost

[st3ph3n]

Detonation AKA Pinking AKA Pinging AKA Engine Knock.

Basic explanation - engine gets so hot that the petrol and air mixture ignites under compression before the spark is fired.

[Ross9]

  Quote

  Quote

Yeah he said that to me too... my AFR was way up at like 15 at some points although mainly about 13-14....

Thats the target area for your car, you crazy horse.

With regards to the other peoples readings being a bit off, there could well be an issue with the sensor used to obtain the AFR because too many cars had an issue with AFR for it to be coincedence.  Looking at Playsatan's graph for the first run, the AFR drops into the 12.5 region after 5000rpm but on the second run it holds a flat 11.5 after 5000rpm. If this was a direct corelation to the power produced then he would have seen more power on the first run due to the leaner AFR but the first and second run were pretty consistent.  This would point, IMHO, to an issue with the wideband sensor not being consistent.

With the amount of cars running leaner than safe AFR i am surprised there is not a pile of Subarus and the end of the Industrial Estate with melted pistons.  As Craigwrx said, too many for it to be coincedence

I should have put mine on the rollers as i know the AFR of my car under load, mapped to 11.2 and 11.2 is what appears on the AFR meter.  This was checked after extensive testing with STI_Bandit on the main road.............which was fun

Safe AFR for a turbo car is about the 11 - 1 region when the car is holding boost

Depends I would have thought, I've ran my Rover at 12.0-12.5 AFR for a while now, done lots of 1/4 days, KH, top speed runs at TOTB etc, head off and not a single hint of det.

Could well have a point about the AFR sensor.

The Rover didn't boost as high as I had set it up too during the week, I set it up to 20psi, tailing off a tad to 1.8.5ish in the last 1000rpm. On the rollers it got to 18 at most and was at 16psi by the time power peaked due to the controller not being set right (my own fault for not checking it after cleaning it out), anyway, as background info, the way my car is set up, is that the MAP voltage is capped at 14psi, after this, no matter how high the boost goes, the ecu still sees 14psi as there is a fuel cut at 14.5 (the car is way over standard spec and fine to run like this) ,  it basically gets set up at WOT with a wideband up the tailpipe and I adjust the fuel rail pressure to suit until I get the AFR right. Anyway with all that in mind, with the boost beign about 2psi low through the whole rev range  and me not having touched the fuel rail pressure , the ecu would still have been injecting the same amount of fuel but with less boost (air) coming into the mix, it should have been notably richer than when I set it up just 6 days ago, however it was reading pretty much the same, maybe even slightly leaner than the wideband was reading when I set it up. So I would say the one I used read richer than the one at dastek, which one is right I obviously cant say, but I've always used the same one to set the car up to mid to low 12's AFR, and it's never blown up yet.

Ross

[thefastone]

Thats the target area for your car, you crazy horse.

Oooooops.....

Meant to say that It was up hitting 16.... He says that it should be getting down to 12-13, but it wasn't getting below 14.... He did that whilst cruising after the 2 runs....

Sorry I was getting mixed up with me numbers.... and to be honest I dont know any better...  [:$]

[the squiggle]

  Quote

Thats the target area for your car, you crazy horse.

Oooooops.....

Meant to say that It was up hitting 16.... He says that it should be getting down to 12-13, but it wasn't getting below 14.... He did that whilst cruising after the 2 runs....

Sorry I was getting mixed up with me numbers.... and to be honest I dont know any better...  [:$]

For a normally aspirated car the ideal AFR is 14 - 1 to give the maximum power, so yes looking at your graph i would say there is a small problem located within the Mass Air Flow meter or the Lambda sensor

[sheep]

I also had the same problem as mentioned in the posts above, i was told that the car was running slightly lean as the revs increased and my graph looks like the one shown in craigs post.

[Dastek]

Hi Guys,

Gerry from Dastek here - be gentle now ;-)

Does seem that there are more than a few graphs that are going lean as the revs go up, I can't say I really noticed the trend at the time, but it might be that I do have a dodgy sensor (despite it being less than a week old!) as young Ali had problems with it not responding, soon after he took over from me, the new sensor did seem to cure the problem.

So, could someone give me the running order with regs (PM or email) & I'll take a look at the graphs again, as well as hooking up a car with the old & new sensors side by side.

 

Sorry for the hassle.

 

Cheers,

 

Gerry

[craigwrx]

Hi Gerry,

That would certainly explain the AFR figures.

Many thanks for a great day mate [] and i thought that the layout and infomation provided on the Graphs was very good [y]

PS Spooks really is the only person that would be able to provide you with the order list ...hopefully he will see this thread.

 

[coulty]

Gerry

Do the transmission losses make sense to you?

On colin's car (the 2.33) ran 411 bhp but had losses to the wheels of only 30bhp. Surely this should have been much higher?

[Carl Davey]

Couldn't have been something to do with the DCCD on Colins car could it?

[harvey_smith]

I have seen this happen on a few occasions where the AFR readings on the rolling road bear little relationship to what happens on the open road in the real world.

On MAF sensor equipped cars  I believe the problem is the way the air is fed to the induction system and MAF.  The forced air feed which is very good at Dastek may not represent the actual air flow to the filter on the open road causing the sensor to miss read and give readings which bear little relationship to the actual situation on the main road.

It would be worthwhile, at the earliest opportunity, to attatch a wide band lambda up the tail pipe connected to an LM1 or similar to cross check readings during a full power run in 4th or 5th gear on a suitable road.

To answer the original question, the effect of running 12:1 or similar on full boost on the open road for 4 months...........well your engine won't last 4 months and it will be an expensive experience when a piston picks up in the bore or whatever.  Getting a check as outlined above is only a 20 minute job for someone with the right equipment.  If you were close to me I would happily do it for you. 

[Dastek]

My bad!

Sensor is fecked - if someone can give me the order of runners, then I can sort out a retest  - sorry!

As for transmission losses, please see other thread on graphs, but your answer your questions, yes losses were correct.

Cheers,

 

Gerry

[craigwrx]

  Quote

My bad!

Sensor is fecked - if someone can give me the order of runners, then I can sort out a retest  - sorry!

As for transmission losses, please see other thread on graphs, but your answer your questions, yes losses were correct.

Cheers,

Gerry

Spooks is most likely the only one that can provide you with this info Gerry ..

Have sent him a pm ..

[spooks]

lol I will forward the order of runners on no probs......... Hats off the Gerry for looking into this.

 

[fai17]

  Quote

My bad!

Sensor is fecked - if someone can give me the order of runners, then I can sort out a retest  - sorry!

As for transmission losses, please see other thread on graphs, but your answer your questions, yes losses were correct.

Cheers,

 

Gerry

Does that mean we actually get a free RR if we wanted?

Thanks to Gerry for looking into too[Y]

[colin_ross]

  Quote

  Quote

My bad!

Sensor is fecked - if someone can give me the order of runners, then I can sort out a retest  - sorry!

As for transmission losses, please see other thread on graphs, but your answer your questions, yes losses were correct.

Cheers,

 

Gerry

Does that mean we actually get a free RR if we wanted?

Thanks to Gerry for looking into too[Y]

I wouldn't have thought so Peter, after all we've already had a free run. All the money went to Santa Cruise and not to Dastek

[Dastek]

Hi Guys,

I intend to give those that had the duff sensor fitted a re-run FOC (still needing the running order & number plates V's user names, so I can work out at what point we fitted the new sensor)

Cheers,

Gerry

[_jac_]

Thanks Gerry

For the time you have spent investigating this, it is much appreciated.

 

[_jac_]

I have seen this happen on a few occasions where the AFR readings on the rolling road bear little relationship to what happens on the open road in the real world.

On MAF sensor equipped cars  I believe the problem is the way the air is fed to the induction system and MAF.  The forced air feed which is very good at Dastek may not represent the actual air flow to the filter on the open road causing the sensor to miss read and give readings which bear little relationship to the actual situation on the main road.

It would be worthwhile, at the earliest opportunity, to attatch a wide band lambda up the tail pipe connected to an LM1 or similar to cross check readings during a full power run in 4th or 5th gear on a suitable road.

To answer the original question, the effect of running 12:1 or similar on full boost on the open road for 4 months...........well your engine won't last 4 months and it will be an expensive experience when a piston picks up in the bore or whatever.  Getting a check as outlined above is only a 20 minute job for someone with the right equipment.  If you were close to me I would happily do it for you. 

 

Thanks Harvey

For the input and your offer to check the afr for me, but iam just outside glasgow so a bit to far...

Will get it checked again soon...