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Who knows Exhaus Gas Temperatures?

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#1
Bench Racer

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We know with a Miata engine cylinder #4 runs hotter than cylinder #1. (There is water temperature data available which provides hotter cylinder head water temperature exiting the rear of head than water temperature exiting the front of the head.)

 

We all monitor our air fuel ratio. (It's a great average to use.)

 

Has anyone checked their EGT using exhaust manifold probes while on track? If you have would you care to share your information.

 

I have a Westech  2DC2-6Dual EGT two probe from my RX7 days. Am going to implement into Cylinder #1 and cylinder #4. Ideal one would implement all 4 cylinders and auto collect data. I fully expect cylinder #4 to be hotter, by how much??? May get on the dyno or may do on track, either way will be frugal eyeball data collection.

 

Ron, the stuff is yours to borrow if you care as long as it's returned by June 1/2017. It's 3/16 hole in header with hose clamp connector. 


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#2
Tom Sager

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We used EGT to tune a 2-stroke kart back when one of my sons was running one.  The kart guys several of which have transitioned to SM understand this but it would take some time to understand the temp data in an SM and tune for any benefit.  Yeah someone has probably done it already. 


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#3
av8tor

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I fly an Extra 330 which is an unlimited acro airplane.  We have the ability to control Lamda with the mixture control lever.  The EGT is used exclusively.  I have also used EGT on my ducati sport bikes to compare the two cylinders.  We always have to run the back cylinder richer than the front cylinder on the air cooled bikes to keep the EGT =.  EGT is great tool for test and tune days, but not something that you can keep up with in a race.  You need a data logger so you can review the data later.  I don't think it is applicable to SM because we are stuck with the stock ECU.  On my ITS car with its Mega Squirt I can fine tune each cylinder, not so lucky on the SM.



#4
wheel

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I fly a Piper Cherokee 180.  Like av8tor, I use the EGT exclusively to set the mixture for altitude.  In the ASedan, I use EGT (two probes, one on each side of the V8) to set carb jetting.  Generally, I will look at EGT during the first practice or test session at a new track.  This allows me to change the jets after a session.  I might glance at the gauges the next time out, but ignore it during the race.  In the SM, I did not see a way to use EGT, since the ECU does the mixture.  

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#5
MPR22

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Only way I could think of to manipulate Idividual cylinder fuel flow is to purposely mismatch injectors to get different flow rates. I'm sure Drago has nothing better to do and if he could get another .5 hp from the tune improvement he would be all over it. Love or hate the guy he has done more to make the class more competitive this. Just about anyone. He is constantly looking for advantages that others are not exploiting. Oh and I hate to admit this but he can actually drive too.
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#6
Ron Alan

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Interesting stuff. My point in the other thread was simply thinking out loud if we can more accurately know if the AFR we see...which is a mixture of 4 cylinders...is in fact 4 equal cylinders and not 3 equal and 1 too lean headed for eventual ventilation! EGT would be one way for sure.


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#7
Tom Sager

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Only way I could think of to manipulate Idividual cylinder fuel flow is to purposely mismatch injectors to get different flow rates. I'm sure Drago has nothing better to do and if he could get another .5 hp from the tune improvement he would be all over it. Love or hate the guy he has done more to make the class more competitive this. Just about anyone. He is constantly looking for advantages that others are not exploiting. Oh and I hate to admit this but he can actually drive too.

 

I'd wager that Jim was all over this 5 years ago.


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#8
Danny Steyn

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David DelGenio, who has forgotten more than all of us combined will even know, tunes his car based on EGT. He tunes it from a sensor in the manifold #2 or #3. Had a very interesting discussion about the relevant merits of this approach vs wideband O2 sensor tuning some years ago. 


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#9
av8tor

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back to the original question about what the EGT of a well tuned motor should be: Most engines will make maximum power at an AFR of between 12.0 and 13.5 to 1 however, the EGT may vary from 1250F to 1800F, The affect of timing in EGT is HUGE on our low compression motors.  The low compression is thermally inefficient and causes high EGTs. To establish EGT the engine needs to be at a steady state, high manifold pressure and rpm.  






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