Air fuel ratio 02 sensors for data

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Re: Air fuel ratio 02 sensors for data

Post by smeg » Fri Sep 08, 2017 6:18 pm

If anyone is interested I have a good little used Innovate LM12 for sale, can log up to 12 wideband AFR and log other things like oil pressure, rpm, etc.

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Re: Air fuel ratio 02 sensors for data

Post by joe 90 » Fri Sep 08, 2017 7:30 pm

Warp Speed wrote:And again, what are EGTs good for?
Certainly not much relating to this thread! LOL
EGTs are also a safety limit, specially with an expensive industrial engine. The actual temp depends on the engine and the fuel. Typically up at 600 deg C you'll see a 20 or so deg C variance between cylinders and maybe 150 deg across the turbo.
If you let the EGTs get too high while tuning, then you might end up melting something.
A WB can't help you in that respect.

More tools are always better than less tools.
A WB, like a NB tells you rich or lean.
Not how hot.
Won't tell you if it's pre igniting and won't tell you if it's knocking.

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Re: Air fuel ratio 02 sensors for data

Post by Firedome8 » Fri Sep 08, 2017 8:05 pm

Would the EGT drop if the cylinder goes into Pre ignition?

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Re: Air fuel ratio 02 sensors for data

Post by David Redszus » Fri Sep 08, 2017 8:10 pm

Firedome8 wrote:Would the EGT drop if the cylinder goes into Pre ignition?
With regard to engine temperatures, there are four possibilities.

Piston temp goes up, EGT goes up
Piston temp goes up, EGT goes down.
Piston temp goes down, EGT goes down.
Piston temp goes down, EGT goes up.

Each will result from some combination of tuning or operating conditions.

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Re: Air fuel ratio 02 sensors for data

Post by hoodeng » Fri Sep 08, 2017 8:18 pm

There are two courses of discussion occurring here, one is from the engine builder and in house dyno sector the other is from the track sector, both have very relevant and important inputs here, but coming back to ALKYBURNERS question ,he was looking for track relevant ,specifically drag racing data acquisition ,and that is EGT in conjunction with AFR being the most suitable first step of de mystifying his tune and performance.
I personally have little experience with dyno cell operation but with track experience i could dig myself out of a hole so to speak , no problem, and there are a multitude of guys out there that would make me look novice!
the validity of track data logging to this day is an irreplaceable tool .
If the trace of AFR is irregular but the EGT will nearly follow an overlay line from previous good passes[in our case] ,if it doesn't ,start looking there will be a reason,if you have stable EGT and a higher or lower AFR and the ET is off ,alter the fuel delivery to suit.If data is irregular, find out why and rectify ,throwing your arms up in the air publicly and ditching the technology will attract a very interested crowd,,,your category's competitors.
Dave is right in my opinion, Good data is king!!

A long long time ago i was told at the track that if we "Tip the can and bump the mag the ET"S will be in the bag" probably the worst piece of advice given in confidence, if only it was that simple there would be no need for data acquisition.

Cheers.

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Re: Air fuel ratio 02 sensors for data

Post by The Radius Kid » Fri Sep 08, 2017 9:21 pm

perhaps you can elaborate on wgi
David Redszus wrote:
Firedome8 wrote:Would the EGT drop if the cylinder goes into Pre ignition?
With regard to engine temperatures, there are four possibilities.

Piston temp goes up, EGT goes up
Piston temp goes up, EGT goes down.
Piston temp goes down, EGT goes down.
Piston temp goes down, EGT goes up.

Each will result from some combination of tuning or operating conditions.
Perhaps you can elaborate on what conditions cause each scenario?
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Re: Air fuel ratio 02 sensors for data

Post by Belgian1979 » Sat Sep 09, 2017 5:04 am

I don't see how EGT would be able to predict pre-ignition, but maybe I can learn something.

Like I said, I think EGT's combined with WB could probably tell you more about variances in ignition timing and let you detect misfires, but I don't see more use for EGT's further than that. On the cost aspect I'm not sure it would bring additional value.

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Re: Air fuel ratio 02 sensors for data

Post by The Radius Kid » Sun Sep 10, 2017 4:09 am

Belgian1979 wrote:I don't see how EGT would be able to predict pre-ignition, but maybe I can learn something.

Like I said, I think EGT's combined with WB could probably tell you more about variances in ignition timing and let you detect misfires, but I don't see more use for EGT's further than that. On the cost aspect I'm not sure it would bring additional value.
I think you'll find that if you correlate the two together(O2/EGT),you predict disaster before it happens.
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Re: Air fuel ratio 02 sensors for data

Post by joe 90 » Sun Sep 10, 2017 5:39 am

Coupled with a knock sensor which works.

As opposed to one which doesn't.

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Re: Air fuel ratio 02 sensors for data

Post by Warp Speed » Sun Sep 10, 2017 8:16 am

joe 90 wrote:Coupled with a knock sensor which works.

As opposed to one which doesn't.
Unfortunately, with most any solid roller performance engine, there is so much engine noise, that a knock sensor becomes useless!

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Re: Air fuel ratio 02 sensors for data

Post by In-Tech » Sun Sep 10, 2017 12:43 pm

Warp Speed wrote:
joe 90 wrote:Coupled with a knock sensor which works.

As opposed to one which doesn't.
Unfortunately, with most any solid roller performance engine, there is so much engine noise, that a knock sensor becomes useless!
Hi, do you have much experience with GM's knock control strategies? I don't have a ton of experience with EFI and solid rollers but one comes to mind that worked very well. It was a pair of ~1500hp blown 571 BBC's for a boat. I spent about 3 days on the dyno just on knock control. Using a crank/cam sensors and 8 coils(sequential spark), the GM strategy allows you to listen at a programmable time before and after TDC on the compression/combustion stroke for each cylinder and ignores all other noise outside that window of time. It will also only retard the cylinder that is knocking instead of all of them at a whack.

I think I have a "data "screen shot of this somewhere, I'll post it when I find it.
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Re: Air fuel ratio 02 sensors for data

Post by MadBill » Sun Sep 10, 2017 4:40 pm

Belgian1979 wrote:I don't see how EGT would be able to predict pre-ignition, but maybe I can learn something.

Like I said, I think EGT's combined with WB could probably tell you more about variances in ignition timing and let you detect misfires, but I don't see more use for EGT's further than that. On the cost aspect I'm not sure it would bring additional value.
Just speculating, but preignition is in some ways similar to advancing the spark timing and so would likely result in an unexpected drop in EGTs, probably not simultaneously in all cylinders.
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Re: Air fuel ratio 02 sensors for data

Post by joe 90 » Sun Sep 10, 2017 4:42 pm

I've got a solid roller engine and a knock sensor but it's a japper.

It doesn't make much noise.


If you've got one and it DOES make lots of noise....it's built wrong.

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Re: Air fuel ratio 02 sensors for data

Post by Belgian1979 » Sun Sep 10, 2017 6:07 pm

MadBill wrote:
Belgian1979 wrote:I don't see how EGT would be able to predict pre-ignition, but maybe I can learn something.

Like I said, I think EGT's combined with WB could probably tell you more about variances in ignition timing and let you detect misfires, but I don't see more use for EGT's further than that. On the cost aspect I'm not sure it would bring additional value.
Just speculating, but preignition is in some ways similar to advancing the spark timing and so would likely result in an unexpected drop in EGTs, probably not simultaneously in all cylinders.
That's a possibility Bill, like I said I never used EGT's so don't have much to add. I used O2's extensively though.

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Re: Air fuel ratio 02 sensors for data

Post by Belgian1979 » Sun Sep 10, 2017 6:09 pm

joe 90 wrote:I've got a solid roller engine and a knock sensor but it's a japper.

It doesn't make much noise.


If you've got one and it DOES make lots of noise....it's built wrong.
I have got a question : if you can hear valvetrain noise outside of the engine bay, why wouldn't a knock sensor not hear that noise ? After all, it's a microphone attached to the engine.

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