EGT readings

js72mav · 08-08-2015, 03:24 PM

I am wondering if there is a ball park reading for an EGT reading in my SBF 289, with an automatic trans. When comparing stick shift with automatic and just different engine combos there seems to be a difference in the finally reading. Thanks for your help!

Jamie

Alan Roehrich · 08-08-2015, 05:25 PM

No, not really. There is only a point at which the EGT is telling you that your temperatures are so high as to signal something dangerous is going on, or so low as to signal that little or no power is being produced.

One tool you can use is Larry Meaux's PipeMax software, found at maxracesoftware.com. Enter all of your information into that program, and it will provide you with a general target EGT. Those readings are general readings to compare to dyno pulls, based on Larry's decades of experience with dyno testing.

Adger Smith · 08-08-2015, 05:40 PM

Don't ever try to "target " an EGT as being your "Best". Too many Variables to make EGT what you tune by. BTY I've seen some real cold EGT's melt pistons. Heat in the chamber, not in the ex is what happened!! I have changed the Ex lash and lost power and got higher EGT's. I've added timing and cooled EGT's and lost power...Use EGT as a reference when you tune.

CFMCNC · 08-09-2015, 12:25 PM

WE no longer use EGTs for dyno testing ,We have Wideband O2s on each cylinder and read spark plugs for tuning,EGTs will show high with a over rich condition burning fuel in the exhaust port,Easy to get lost with EGT numbers.Bill C.

James L Miller · 08-09-2015, 01:52 PM

I think that you would look for even EGT numbers in all the cylinders, not for an absolute value. This article is pretty much on target for EGT peaking around the stoichiometric A/F ratio, and then dropping off on either side of it. The wideband O2 sensors are probably the better solution except they get fouled by leaded fuels.

http://www.sdsefi.com/techegt.htm

astikhossw · 08-09-2015, 07:03 PM

Just a curious question I thought having EGT on the exhaust was to follow which way the air fuel mixtures were going like if you had a 2 or 3 cylinder that are high on one side of the engine and lower on the other side you could try to redirect some of the mixture to balance out the cylinders.

Adger Smith · 08-09-2015, 07:18 PM

"If" the mixture is what is causing the EGT difference, yes. There are many variables besides mixture that can cause EGT differences. To list just a few: Rocker ratio differences, cam twist, ignition timing variation, intake air flow & Ex air flow, Compression differences, cam/valve timing & even spark plug heat range differences. What I was trying to say is EGT and now O2's are only part of the tuning equation. Never base a complete tuneup on just an EGT reading & never let anyone tell you you have to have a certain EGT. Find the EGT# where your combination makes the most power. Then when the conditions change record the change and tune around it.

js72mav · 08-09-2015, 09:13 PM

Thanks for the replies.

Jamie

08-08-2015, 03:24 PM	#1
js72mav Junior Member Join Date: Aug 2009 Posts: 31 Likes: 0 Liked 0 Times in 0 Posts	EGT readings I am wondering if there is a ball park reading for an EGT reading in my SBF 289, with an automatic trans. When comparing stick shift with automatic and just different engine combos there seems to be a difference in the finally reading. Thanks for your help! Jamie

08-08-2015, 05:25 PM	#2
Alan Roehrich VIP Member Join Date: May 2006 Location: Murfreesboro TN Posts: 4,969 Likes: 1,136 Liked 1,218 Times in 313 Posts	Re: EGT readings No, not really. There is only a point at which the EGT is telling you that your temperatures are so high as to signal something dangerous is going on, or so low as to signal that little or no power is being produced. One tool you can use is Larry Meaux's PipeMax software, found at maxracesoftware.com. Enter all of your information into that program, and it will provide you with a general target EGT. Those readings are general readings to compare to dyno pulls, based on Larry's decades of experience with dyno testing. __________________ Alan Roehrich 212A G/S

08-08-2015, 05:40 PM	#3
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,399 Likes: 494 Liked 724 Times in 280 Posts	Re: EGT readings Don't ever try to "target " an EGT as being your "Best". Too many Variables to make EGT what you tune by. BTY I've seen some real cold EGT's melt pistons. Heat in the chamber, not in the ex is what happened!! I have changed the Ex lash and lost power and got higher EGT's. I've added timing and cooled EGT's and lost power...Use EGT as a reference when you tune. __________________ Adger Smith (Former SS)

08-09-2015, 12:25 PM	#4
CFMCNC Junior Member Join Date: Apr 2012 Location: Somwhere in NJ Posts: 72 Likes: 4 Liked 3 Times in 3 Posts	Re: EGT readings WE no longer use EGTs for dyno testing ,We have Wideband O2s on each cylinder and read spark plugs for tuning,EGTs will show high with a over rich condition burning fuel in the exhaust port,Easy to get lost with EGT numbers.Bill C.

08-09-2015, 01:52 PM	#5
James L Miller Member Join Date: Apr 2005 Posts: 496 Likes: 6 Liked 25 Times in 16 Posts	Re: EGT readings I think that you would look for even EGT numbers in all the cylinders, not for an absolute value. This article is pretty much on target for EGT peaking around the stoichiometric A/F ratio, and then dropping off on either side of it. The wideband O2 sensors are probably the better solution except they get fouled by leaded fuels. http://www.sdsefi.com/techegt.htm __________________ Mopar 2 Ya!

08-09-2015, 07:03 PM	#6
astikhossw Member Join Date: Jul 2008 Location: moreno valley Ca Posts: 264 Likes: 2 Liked 19 Times in 8 Posts	Re: EGT readings Just a curious question I thought having EGT on the exhaust was to follow which way the air fuel mixtures were going like if you had a 2 or 3 cylinder that are high on one side of the engine and lower on the other side you could try to redirect some of the mixture to balance out the cylinders. __________________ 7015 E/SA Sooner Storm

08-09-2015, 07:18 PM	#7
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,399 Likes: 494 Liked 724 Times in 280 Posts	Re: EGT readings "If" the mixture is what is causing the EGT difference, yes. There are many variables besides mixture that can cause EGT differences. To list just a few: Rocker ratio differences, cam twist, ignition timing variation, intake air flow & Ex air flow, Compression differences, cam/valve timing & even spark plug heat range differences. What I was trying to say is EGT and now O2's are only part of the tuning equation. Never base a complete tuneup on just an EGT reading & never let anyone tell you you have to have a certain EGT. Find the EGT# where your combination makes the most power. Then when the conditions change record the change and tune around it. __________________ Adger Smith (Former SS)

08-09-2015, 09:13 PM	#8
js72mav Junior Member Join Date: Aug 2009 Posts: 31 Likes: 0 Liked 0 Times in 0 Posts	Re: EGT readings Thanks for the replies. Jamie