121 replies to this topic

[speedster]

AFR and RPM only

I take it that AFR spike to 22:1 was a glitch?!

Not what I thought it was.... looks like my spikes are caused by the unconditioned 12v supply that I am using to feed the LM-1 controller. I need to put a 12v noise filter/conditioner, like the ones you have on audio equipment, on the LM-1's 12v supply to insure the LM-1 has a steady 12v at all times.

[speedster]

OK, my analysis may be not be 100% correct but I will add the noise suppressor anyway. Here what the guys in Innovate said about my log data.

Your AFR measurements are actually VERY clean without any spikes associated with electr. noise or ign. misses. From the cleanliness I assume you are running EFI, not a carb.
The maxed out AFR areas in your log happen when you get off the throttle, right?
This comes from injector shutoff during coast-down. A typical ECU shuts down the injectors when RPM is above a certain threshhold (typically ~1500 RPM) and the throttle is closed to conserve fuel. Some ECUs also require a certain min. time for closed throttle as well. The engine then of course pumps pure air. Pure air is infinite AFR. That's why the AFR maxes out.

Looking at the snapshot on the previous page you can see the throttle has been released just prior to the AFR spike.

[cicastol]

yes,that spike is a normal fuel cut during throttle release

Edited by cicastol, 05 January 2006 - 12:03 PM.

[speedster]

Yup, looks like I am good to go I just took delivery of a dbilas intake, hoping to get it installed over the weekend BTW what r u going to use to help you tune?

Edited by speedster, 05 January 2006 - 12:28 PM.

[cicastol]

[quote name='speedster' date='Jan 4 2006, 10:55 '] In our case the wideband can be used to replace the O2 sensor after the CAT (replace the standard sensor with an O2 sim to prevent an EML) though a CAT will effect the sensor reading, making it a little leaner.
[/QUOTE]

[/quote]
Beware, because if you are reading after the CAT this will affect reading make it RICHER not leaner...... !!!
Cat will act as an oxygen trap and use it for oxydizing HC,CO ecc.
so after the cat there is less oxygen than before,making the mixture richer(less oxygen).
Take the readings before the CAT if you want reliable number..!!

[speedster]

[quote name='cicastol' date='Jan 6 2006, 11:07 '] [/QUOTE]
Beware, because if you are reading after the CAT this will affect reading make it RICHER not leaner...... !!!
Cat will act as an oxygen trap and use it for oxydizing HC,CO ecc.
so after the cat there is less oxygen than before,making the mixture richer(less oxygen).
Take the readings before the CAT if you want reliable number..!! [/quote]
Interesting, the LM-1 documentation indicates you may get a leaner reading....

Exhaust Clamp: You may use the optional Exhaust Clamp to mount the O2 sensor to the car’s tail pipe when taking readings from cars with catalytic converters (see below). However, it is recommended instead to use the bung (as described above) to give you the most accurate reading. Measuring
after the cat will result in leaner-than-reality readings, depending on the
efficiency of the cat. Some operators of chassis dynos use this method
and roughly “correct” the reading.

but you can't simply remove the O2 Sensor before the CAT, correct? I have the addition bung which can be welded into the exhaust above the CAT so guess I should take the exhaust out and do it correctly

[cicastol]

I have the addition bung which can be welded into the exhaust above the CAT so guess I should take the exhaust out and do it correctly

Watch the actual readings,idling motor (ex. at 1500 rpm) ,you should read exactly 14,6:1 during closed loop operation,in theory with the probe after the cat you should read richer than 14,6:1

[paulf-cam]

I thought it was 14.7:1 at idle and much richer at WOT (closed loop), like 11:1 etc... That always interested me; is it a coincidence that atmospheric pressure is 14.7 psi and at idle the AF ratio is 14.7:1....? I think i need to get out more! Ta, Paul.

[cicastol]

I thought it was 14.7:1 at idle and much richer at WOT (closed loop), like 11:1 etc...

That always interested me; is it a coincidence that atmospheric pressure is 14.7 psi and at idle the AF ratio is 14.7:1....?

I think i need to get out more!

Ta, Paul.

yes, it is a coincidence the PSI atmospheric pressure and gasoline A\F ratio,this depend upon the fuel used,for example for methanol A\F ratio is 6,5:1 .
During WOT operation motor need extra fueling for cooling purpose(best power mixture),for turbo engine best a\f ratio in WOT operation is near 12,5:1 depending upon the boost pressure,gasoline quality ecc. and many other variables,for the N\A motor is in the 13:1 14:1 range,better the latter but things are becoming really hot and used only in race engine.
My goal is to reach a 13,1 \13,3 :1 during WOT for my speedy.

[speedster]

Watch the actual readings,idling motor (ex. at 1500 rpm) ,you should read exactly 14,6:1  during closed loop operation,in theory with the probe after the cat you should read richer than 14,6:1

I am reading between 14.74 and 14.95 AFR @ around 800 RPM idle. Under load and WOT I am hitting as low as 11.00 AFR.

The graph below is a 3rd and 4th gear shift. In 3rd & 4th I ran out of straight road so didn't get into the 6k RPM range in 3rd or the 5k range in 4th. 3rd gear is the 11 second (approx) ramp on the left, 4th gear is the 14 second (approx) ramp on the right. Interesting I am only getting 4.0 volts on WOT hence the 79.5% reading in the log, thought it was a 0-5 volts system? If it is 4.0 volts I need to re-configure the software to accept 4.0 volts as WOT. Whats even more interesting is the fluctuations in the AFR values up to about 4k RPM on WOT....where AFR takes a dive. 3rd and 4th gear appear to have a similar AFR profile, just happens over an extended period of time in 4th gear.

I expect the AFR should change slightly when I install the Dbilas intake. cicastol did you keep the Dbilas exhaust manifold? Available?

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Edited by speedster, 06 January 2006 - 05:52 PM.

[cicastol]

Watch the actual readings,idling motor (ex. at 1500 rpm) ,you should read exactly 14,6:1  during closed loop operation,in theory with the probe after the cat you should read richer than 14,6:1

I am reading between 14.74 and 14.95 AFR @ around 800 RPM idle. Under load and WOT I am hitting as low as 11.00 AFR.

The graph below is a 3rd and 4th gear shift. In 3rd & 4th I ran out of straight road so didn't get into the 6k RPM range in 3rd or the 5k range in 4th. 3rd gear is the 11 second (approx) ramp on the left, 4th gear is the 14 second (approx) ramp on the right. Interesting I am only getting 4.0 volts on WOT hence the 79.5% reading in the log, thought it was a 0-5 volts system? If it is 4.0 volts I need to re-configure the software to accept 4.0 volts as WOT. Whats even more interesting is the fluctuations in the AFR values up to about 4k RPM on WOT....where AFR takes a dive. 3rd and 4th gear appear to have a similar AFR profile, just happens over an extended period of time in 4th gear.

I expect the AFR should change slightly when I install the Dbilas intake. cicastol did you keep the Dbilas exhaust manifold? Available?

IMHO Your's reading is right during idling, BUT is much richer than real on WOT,real reading should give to you near 13.5:1 on WOT as mine do to me,for me this is caused by the CAT,if you are running at 11:1 your's exhaust should be completly fouled by such enrichment in mixture.,also you must see the smoke coming out like a diesel!!
Check the maximum voltage of the throttle in the sensor check of the ETC SAFC menu,at WOT if i remember well, it should be around 3,8V .
I didn't have such fluctuation of the AFR on WOT operation.......
Install the bung before the cat or take out the cat and put the wide band in place of the lambda after the cat(O2sim required) this is mine setup.
I've sold the Dbilas exhaust manifold to a guy here in Italy,take another one,this is really a crap,heavy piece of sh*t, ...now i have the regal,no better flow but at least is only 2,7Kg
I read your PM,I don't remember if the kit was supplied with hoses,probably only needed an L 90° hose for the vacuum line of the brake.
Try to re- route the vapor oil line to vent to air operation as this cause the TB to be fouled with a lot of sh*t inside...
Good work!!

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[cicastol]

This is the regal manifold installed last W.E.

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[speedster]

I read your PM,I don't remember if  the kit was supplied with hoses,probably only needed an L 90° hose for the vacuum line of the brake.
Try to re- route the vapor oil line to vent to air operation as this cause the TB to be fouled with a lot of sh*t inside... 
Good work!!

Thanks cicastol, this image helps loads. I already removed the oil vapour return when I installed the KomoTec Induction kit

I could use my original exhaust down pipe and get it's CAT replaced with a straight through pipe. As i would like to maintain a CAT during normal day to day use, would reinstalling the Milltek Cell 200 CAT after I have finished tuning have any impact on my set-up?


Regal looks

Edited by speedster, 06 January 2006 - 06:44 PM.

[cicastol]

As i would like to maintain a CAT during normal day to day use, would reinstalling the Milltek Cell 200 CAT after I have finished tuning have any impact on my set-up?


Regal looks

I think you should not have any impact reinstalling the cat after the car is tuned

[speedster]

IMHO Your's reading is right during idling, BUT is much richer than real on WOT,real reading should give to you near 13.5:1 on WOT as mine do to me,for me this is caused by the CAT,if you are running at 11:1 your's exhaust should be completly fouled by such enrichment in mixture.,also you must see the smoke coming out like a diesel!!

Hi cicastol. I been going through my log figures. I am reading a max value of 13.5 AFR on WOT. The higher AFR values are only appearing during the initial periods when the throttle is shut off from WOT. I assume this is due to the fact that the injectors are dumping the last of their fuel into the system whilst the throttle is moving back from WOT to full shut (that taking the foot off the pedal, WOT to Zero).

On WOT I am getting AFR values between 13.4 and 13.1. Assuming these are a bit rich due to my CAT how does these figures look?

Edited by speedster, 12 January 2006 - 06:25 PM.

[cicastol]

On WOT I am getting AFR values between 13.4 and 13.1. Assuming these are a bit rich due to my CAT how does these figures look?

The problem is to know exactly how much this values are affected by CAT!!
Best is to keep the engine between 13.1 and 13.5 on WOT ,little leaner you could gain more power but is not safe.... better some cv less than the risk to blow up the engine

[garyk220]

The higher AFR values are only appearing during the initial periods when the throttle is shut off from WOT. I assume this is due to the fact that the injectors are dumping the last of their fuel into the system whilst the throttle is moving back from WOT to full shut (that taking the foot off the pedal, WOT to Zero).

Do you realise the higher the value of AFR, the leaner the mixture? so the spikes above 14 are due to the injectors shutting off the fuel, rather than dumping more as you stated. As cicastol has stated, 13.1 to 13.5 AFR is a little richer than the ideal 14.7 ratio.

I've not read through the whole post, so apologies if I've completely misunderstood the point you are making.

[speedster]

The higher AFR values are only appearing during the initial periods when the throttle is shut off from WOT. I assume this is due to the fact that the injectors are  dumping the last of their fuel into the system whilst the throttle is moving back from WOT to full shut (that taking the foot off the pedal, WOT to Zero).

Do you realise the higher the value of AFR, the leaner the mixture? so the spikes above 14 are due to the injectors shutting off the fuel, rather than dumping more as you stated. As cicastol has stated, 13.1 to 13.5 AFR is a little richer than the ideal 14.7 ratio.

I've not read through the whole post, so apologies if I've completely misunderstood the point you are making.

Correct by higher AFR above what I really meant was the lower numeric values i.e down to 11 AFR. I should of correctly said a higher fuel ratio in the A/F mix which of course is a lower AFR If you look at the graph above you can see values that dip into 11 AFR. I was/am trying to understand this phenomenon.

New to tuning so all input most welcome

Edited by speedster, 13 January 2006 - 03:52 PM.

[speedster]

Quick update

SAFC-2 Set-up
Pressure Sensor Number 10 10 appears to give the best results when tuning.

[cicastol]

I've tested on track last WE,all worked smoothly,i've also tryed to play a bit with SAFC II and worked well,only a bit rich (12.9:1 under WOT) but i'm running with +6% fuel over 5000 next time i will try to reduce fueling in order to reach near 13.2:1 on WOT,probably better to do on a braked RR dyno. What is the difference between 5 5 and 10 10 on fueling??

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