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Hello,
for some reason im getting very high egts on my 88 T2 S4.
when i go over 4k rpm at about 9psi they go to 900C and i believe it would keep climbing even further if i keep my foot on the gas.
cruise at 3-4k is anywhere from 800-900C aswell.
Intake and exhaust is Streetported.
The EGT probe is installed in the manifold as shown here. http://fc3spro.com/TECH/HOWTO/EGT/manimod.jpg
Base timing is set correctly.
This is my map: https://anonfiles.com/vdF7i5vcy5/202...3-03-10_nexmap
Been trying to figure this out for a while now. hopefully someone can help me out here.
Last edited by MetalSkinGaming; Jul 5, 2022 at 10:33 AM.
here is a logfile from today https://anonfiles.com/L5J7ldv9y4/PCL...-05_0334pm_zip
i dont have a logable egt tho. but pretty much whenever i hit boost at over 3k rpm it goes to 900C
and when im at over 4k rpm it even does it at about 0 psi
Some things that jump out to me are you intake air temps rising quickly and falling slowly which appears to indicate that the intercooler is not working well. A higher IAT will cause a higher EGT but in this case likely only by 25-35 degrees C. What was the outside temp during this data log and was the drive on a major heat soaked highway or out in the country?
The injector staging is set to a high duty cycle switch over point, 88%. This trace shows the secondary injectors coming in as programmed. While the fuel is being delivered you may be able to gain some fuel cooling if the secondaries were coming in sooner. But this cooling is likely minimal. Also many people suggest keeping duty cycle below 80% so you may wish to research this and find your preference.
Another thing, possibly related to IATs, is knock signals are exceeding the knock threshold at times. I had to enable Ignition Tuning > Knock Control to be able to see the knock settings so unless it was a map copy artifact you map not have knock control enabled.
Sadly I don't see a smoking gun data point regarding 900C EGTs when in vacuum but at boost you may have the ignition timing to low which would dump heat into the exhaust and raise EGT. Here is an ignition trace of one of the 9 psi pulls. Your 17.0 @ 0.0 psi is similar to my setup but the 5.1, 5.9, 5.7 @ 9 psi is much lower as I'm in the low to mid teens. I'm not familiar to the setup of EGT sensors in your manifold type so I can't help there. Does your EGT sensor have an option for providing a 0-5V signal out and if so do you have the skills to wire in a sensor input to the Haltech? Seeing the EGT trend relative to the other data points would really be helpful.
some things that jump out to me are you intake air temps rising quickly and falling slowly which appears to indicate that the intercooler is not working well. A higher iat will cause a higher egt but in this case likely only by 25-35 degrees c. What was the outside temp during this data log and was the drive on a major heat soaked highway or out in the country?
Thats because i still have the shitty tmic. Will change to a v-mount this winter so this problem goes away. The drive was out in the country
the injector staging is set to a high duty cycle switch over point, 88%. This trace shows the secondary injectors coming in as programmed. While the fuel is being delivered you may be able to gain some fuel cooling if the secondaries were coming in sooner. But this cooling is likely minimal. Also many people suggest keeping duty cycle below 80% so you may wish to research this and find your preference.
Ok ill change i to 80%
another thing, possibly related to iats, is knock signals are exceeding the knock threshold at times. I had to enable ignition tuning > knock control to be able to see the knock settings so unless it was a map copy artifact you map not have knock control enabled.
Yea i dont have it enabled as im not even sure if the knock frequency i set is correct. How would i set knock frequency when you dont want a rotary to knock at all?
Also do you think that the threshhold is too low or that its actual knock?
sadly i don't see a smoking gun data point regarding 900c egts when in vacuum but at boost you may have the ignition timing to low which would dump heat into the exhaust and raise egt. Here is an ignition trace of one of the 9 psi pulls. Your 17.0 @ 0.0 psi is similar to my setup but the 5.1, 5.9, 5.7 @ 9 psi is much lower as i'm in the low to mid teens. I'm not familiar to the setup of egt sensors in your manifold type so i can't help there. Does your egt sensor have an option for providing a 0-5v signal out and if so do you have the skills to wire in a sensor input to the haltech? Seeing the egt trend relative to the other data points would really be helpful.
Sadly the egt sensor doesnt have a analog output signal.
Would advancing the timing be safe in terms of knock? Im running 100octane eu fuel which is 95-96 octane us
i'm running the same manifold (it may literally be the one in those pics), and i have seen EGT over 900c at 7psi, and in my case it was a bit lean. mine wants AFR to be in the low 11's and timing is in the high teens, i was tuning as well.
that being said, EGT at peak power once it is tuned; i am looking to be around 900c
i'm running the same manifold (it may literally be the one in those pics), and i have seen EGT over 900c at 7psi, and in my case it was a bit lean. mine wants AFR to be in the low 11's and timing is in the high teens, i was tuning as well.
that being said, EGT at peak power once it is tuned; i am looking to be around 900c
what does your timing map look like right now?
are you running a streetport aswell?
my afrs at 9 psi are between high 11s and 11,4
what does your timing map look like right now?
are you running a streetport aswell?
my afrs at 9 psi are between high 11s and 11,4
right now, i'm running the default PFC map, except the cell where the autotune corrected it. when it hit 900c, I was tuning it, so had pulled a couple/few degrees so maybe like 16btdc? going from 11.5 to like 11.3 fixed it, the stock map is like 19
its just a stock REW with the FC turbo, and keep in mind my EGT target is around 900c, i was a little surprised it happened at such low boost
The standard settings Haltech recommends for Knock Detection and Knock control are good. You have a good opportunity to learn about relationships between AFR, timing, EGT and knock signalling. I suggest you look at the various rotary maps, including Haltech's base map recommendation. I believe you will find the ignition map will have larger values than what you are using in the boost area. Since you said you are using a 95-96 octane us fuel then you should also have a bit wider knock tolerance.
I suggest making some small incremental ignition changes in the 3500 to 5000 rpm / 3 to 9 psi range then go for a short drive and once the engine is warmed up do a few pulls in that rpm/boost range, noting your EGTs and then come back and analyze the logs. I would think you will see the knock signal values slowly drop and eventually not exceed the threshold and possibly you may be able to see some difference on your EGT gauge. If you have a GoPro video camera or similar it may be worth an attempt to do video logging of your EGT gauge and if you could get the tach and EGT in the same view then you would be able to get into the ball park for matching EGT values to other log values, Pay attention to the IAT values as a log starting at 90 IAT will likely look different than one starting at 140 IAT. When looking for improvements you will have to try to match up similar situations.
Observe all the cautions that are repeated often in this forum such as ensuring your AFR numbers stay within reason, don't go to high to fast with ignition values without good justification, watch your knock readings, etc.
