Author Topic: EGT or O2  (Read 8348 times)

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Offline jdincau

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EGT or O2
« on: June 15, 2012, 03:21:33 PM »
     For an unblown gas application, which is more helpful for tuning purposes EGT or O2 monitoring?
Unless it's crazy, ambitious and delusional, it's not worth our time!

Offline Bob Drury

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Re: EGT or O2
« Reply #1 on: June 15, 2012, 03:36:11 PM »
  On my car I run both. 
  The EGT is very helpfull for tuning AFTER a run as a backup to reading the plugs.
  The O2 is great as a REAL TIME indicator of rich/lean conditions and may save you buying new pistons, head gaskets, etc.
  My O2 gauge is located next to my tach and low oil pressure (50 psi) warning light (Auto Meter red shift light).
  The entire enchelada is located right above my field of vision so I don't have to look around for it.
  I also run a GPS speedometer to tell me if it is worth running the last mile or not.                               
Bob Drury

Offline jdincau

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Re: EGT or O2
« Reply #2 on: June 15, 2012, 03:40:00 PM »
Well I was planning on running a data loger as my driver (street roadster) has plenty to do now.
Unless it's crazy, ambitious and delusional, it's not worth our time!

Offline Dean Los Angeles

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Re: EGT or O2
« Reply #3 on: June 15, 2012, 03:45:40 PM »
I agree with Bob. You can never have enough information. Run both.
Well, it used to be Los Angeles . . . 50 miles north of Fresno now.
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It's bigger than life or death! It's RACING.

Offline Bob Drury

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Re: EGT or O2
« Reply #4 on: June 15, 2012, 05:26:20 PM »
  One more thing I might ad, the reason I mentioned using the EGT readings as a backup to reading the spark plugs is because they are not reliable unless you have one for every cylinder which means you don't have time to read them during a run, and they can be thrown off by camshaft duration, overlap and too large or small primary exhaust headers on a N.A. motor.
  The positive thing about a EGT readout of every cylinder is that if you have individual port nossle's you can individually rejet each cylinder to put it where you want it which with a N.A. gas motor would be around 13 to l Air Fuel Ratio, as on a five mile balls out run the climbing engine temp will continue to  lean the motor out the further it is under power.           
  With a mechanical fuel injection, most racers (including me) do not use a high speed leanout (as is typically used in drag racing) for this reason.
                                            Just my opinion,         Bob
Bob Drury

Online manta22

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Re: EGT or O2
« Reply #5 on: June 15, 2012, 08:41:14 PM »
 "With a mechanical fuel injection, most racers (including me) do not use a high speed leanout (as is typically used in drag racing) for this reason."

I did not know this-- thanks for mentioning it.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline fastman614

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Re: EGT or O2
« Reply #6 on: June 16, 2012, 12:31:01 AM »
  One more thing I might ad, the reason I mentioned using the EGT readings as a backup to reading the spark plugs is because they are not reliable unless you have one for every cylinder which means you don't have time to read them during a run, and they can be thrown off by camshaft duration, overlap and too large or small primary exhaust headers on a N.A. motor.
  The positive thing about a EGT readout of every cylinder is that if you have individual port nossle's you can individually rejet each cylinder to put it where you want it which with a N.A. gas motor would be around 13 to l Air Fuel Ratio, as on a five mile balls out run the climbing engine temp will continue to  lean the motor out the further it is under power.           
  With a mechanical fuel injection, most racers (including me) do not use a high speed leanout (as is typically used in drag racing) for this reason.
                                            Just my opinion,         Bob

Like Bob says as above is true... and.... you DO pretty much NEED the information...

We have, for this year, upgraded our data acquisition to be able to read info from ALL 8 cylinders.... ($3000 - but, from another post, I WANT to owe MASTERCARD & VISA a half a million dollars or more and have NO assets when I die!
No s*** sticks to the man wearing a teflon suit.

Offline Captthundarr

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Re: EGT or O2
« Reply #7 on: June 16, 2012, 09:27:18 AM »
Just picked  a digital O2 meter that records and can be down loaded to a laptop. got it from Jegs for 2 bills. neat device.
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Offline Milwaukee Midget

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Re: EGT or O2
« Reply #8 on: June 16, 2012, 09:46:04 AM »
Went with an O2 myself, with a gauge - running a carb, and without the advantage of individual exhaust ports (center 2 shared).  Always looking for information, but I didn't want confusing information.  In my case, O2 will be close enough.
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

We are NOT rebuilding . . . We are reloading.

GOD SAVE MG - The Queen can take care of herself!

Offline kiwi belly tank

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Re: EGT or O2
« Reply #9 on: June 16, 2012, 10:15:43 AM »
Using either or both is still just a safety guide, the whole picture is in reading the plugs.
Start out fat, it's better to waste a run with a fat setup than waste a meet with a burndown.
Digital gauges are too hard to read when you're focused on driving.
To me a tach is a secondary gauge, EGT, low oil light & shift light are primary.
  Sid.

Offline Stainless1

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Re: EGT or O2
« Reply #10 on: June 16, 2012, 10:31:51 AM »
Just remember neither will keep the motor from burning down, they will tell you what and when it happened... if you are recording
Both makes it easier to intrepret the info, a high EGT can be from too lean or too rich... really low makes it easy to find the dead cylinder...
Stainless
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Offline Milwaukee Midget

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Re: EGT or O2
« Reply #11 on: June 16, 2012, 11:26:30 AM »
Start out fat, it's better to waste a run with a fat setup than waste a meet with a burndown.

Gas is cheaper than pistons - at least at the moment . . . :roll:
"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

We are NOT rebuilding . . . We are reloading.

GOD SAVE MG - The Queen can take care of herself!

Offline NathanStewart

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Re: EGT or O2
« Reply #12 on: June 17, 2012, 11:50:42 PM »
I'd say both but most definitely at least AFRs.  Jim, let me know if you're interested in a 4 channel AFR, 4 channel EGT, and data logger setup.  I've got the perfect combo for you.
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Offline jdincau

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Re: EGT or O2
« Reply #13 on: June 22, 2012, 10:10:09 PM »
I'd say both but most definitely at least AFRs.  Jim, let me know if you're interested in a 4 channel AFR, 4 channel EGT, and data logger setup.  I've got the perfect combo for you.
I would like to monitor eng. RPM, front wheel speed, rear wheel speed, oil press., water temp., EGT (4), and O2 (1). What brand do you have in mind Nathan?
« Last Edit: June 22, 2012, 10:13:43 PM by jdincau »
Unless it's crazy, ambitious and delusional, it's not worth our time!

Offline NathanStewart

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Re: EGT or O2
« Reply #14 on: June 23, 2012, 01:10:32 AM »
THIS BRAND.  BTW that's where I work.   :wink:
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