Expected EGT readings using Laust probe kit?
09-29-2016, 11:05 AM
#1
Rennlist Member
Thread Starter
Expected EGT readings using Laust probe kit?
Which temps are you "Laust probe kit" users reading?
Please advise!
Please advise!
09-29-2016, 05:30 PM
#3
Rennlist Member
Thread Starter
10-01-2016, 01:15 PM
#4
Addict
Rennlist Member
Rennlist Member
See post #49 here
https://rennlist.com/forums/944-turb...ml#post3607772
and Duke's comments following.
My engine can be considered stock for "stock" boost.
Laust
https://rennlist.com/forums/944-turb...ml#post3607772
and Duke's comments following.
My engine can be considered stock for "stock" boost.
Laust
10-01-2016, 03:19 PM
#5
Rennlist Member
Thread Starter
See post #49 here
https://rennlist.com/forums/944-turb...ml#post3607772
and Duke's comments following.
My engine can be considered stock for "stock" boost.
Laust
https://rennlist.com/forums/944-turb...ml#post3607772
and Duke's comments following.
My engine can be considered stock for "stock" boost.
Laust
/Peder
10-02-2016, 03:34 PM
#7
Rennlist Member
Thread Starter
Get back to you soon, present soon to be finished
Trending Topics
10-10-2016, 01:08 PM
#8
Rainman
Rennlist Member
Rennlist Member
Has anybody tracked EGT vs AFR in cruising conditions?
I don't have an EGT probe but am thinking about playing with cruising AFR as an economy experiment.
*edit* of course Laust did...
https://rennlist.com/forums/944-turb...ml#post3607772
I don't have an EGT probe but am thinking about playing with cruising AFR as an economy experiment.
*edit* of course Laust did...
https://rennlist.com/forums/944-turb...ml#post3607772
Last edited by V2Rocket; 10-10-2016 at 01:24 PM.
10-12-2016, 01:42 PM
#9
Three Wheelin'
10-12-2016, 02:58 PM
#10
Rainman
Rennlist Member
Rennlist Member
not something i really care to monitor but just wanting to know how hot the 944 engine runs at lean AFR to not go too extreme.with the old rogue tune setup i could change cruising afr and watch my WATER temp gauge go higher or lower on the same route based on cruising AFR.
03-23-2018, 11:45 AM
#11
Three Wheelin'
I have an EGT sensor mounted in the CO2 test port of the stock crossover pipe, and I have been datalogging the results with the VEMS ECU. I have the engine tuned well but safely with an Evergreen K27/26 hybrid turbo (with ported hot side housing and larger/lighter turbine wheel), but I am concerned that my engine's EGTs are way too high. I am seeing 1000 degrees C (1,800+ F) at the end of a 4-5 sec pull in 4th or 5th gear at 1.2 bar of boost (I only plan on running 1.0 bar at the track). Even at the wastegate spring setting of 0.7 bar/10 PSI I am seeing 800+ celsius during a short pull. Again, the engine is tuned safely to run at 0.80 lambda (~11.76:1 AFR) on 91-octane pump gas, and timing is perhaps 12-15 degrees BTDC at full boost, so both of those factors could be raising EGT.
I initially suspected that the sensor reading might be skewed, but the EGT reading with the key on, engine off agrees with the ambient temp, but even while idling when warm at lambda 1.0n, EGTs are at ~650 degrees C, which seems awfully high. Is there an EGT sensor calibration feature in VEMS?
I know that EGT is a result of numerous factors (such as AFR and ignition timing as mentioned above), but is there a correlation between EGTs and exhaust back pressure? Measuring back pressure was next on my list, because while I love the spool of my new turbo, I am afraid that the hot side is a bit too restrictive. Sadly, my car is down for some body work at the moment so I won't be able to test this for a bit, but I would like to hear what others (especially those of you who race/track your 951) have seen in terms of EGT and what is safe.
I initially suspected that the sensor reading might be skewed, but the EGT reading with the key on, engine off agrees with the ambient temp, but even while idling when warm at lambda 1.0n, EGTs are at ~650 degrees C, which seems awfully high. Is there an EGT sensor calibration feature in VEMS?
I know that EGT is a result of numerous factors (such as AFR and ignition timing as mentioned above), but is there a correlation between EGTs and exhaust back pressure? Measuring back pressure was next on my list, because while I love the spool of my new turbo, I am afraid that the hot side is a bit too restrictive. Sadly, my car is down for some body work at the moment so I won't be able to test this for a bit, but I would like to hear what others (especially those of you who race/track your 951) have seen in terms of EGT and what is safe.
03-23-2018, 11:54 AM
#12
Drifting
Edit: at 20psi for three seconds on a 26/8 will break every stock exhaust piece on the engine along with melt the turbine tips and catylitic converter mainly because the 55lbs injectors duty cycled out 100% at 18 psi. But it was super fast for three seconds maybe less. I have done this test. I think your still good. Just run your engine on rich best when your accelerating, meaning 12:1 pound: pound air fuel ratio. 13:1 is lean best and 14.7:1 is stoichiometric (meaning that's what the catylitic converter wants to be fed in order to do its thing). At least that's what my collage books stated. This is a good read on that. http://www.endtuning.com/afr.html. Also I recommend you get a fuel injector duty cycle monitor. You don't want to take the injectors over 80% duty cycle. It's not good for them. I found that out too.
Last edited by Humboldtgrin; 03-23-2018 at 12:32 PM.
03-23-2018, 12:56 PM
#13
Three Wheelin'
Edit: at 20psi for three seconds on a 26/8 will break every stock exhaust piece on the engine along with melt the turbine tips and catylitic converter mainly because the 55lbs injectors duty cycled out 100% at 18 psi. But it was super fast for three seconds maybe less. I have done this test. I think your still good. Just run your engine on rich best when your accelerating, meaning 12:1 pound: pound air fuel ratio. 13:1 is lean best and 14.7:1 is stoichiometric (meaning that's what the catylitic converter wants to be fed in order to do its thing). At least that's what my collage books stated. This is a good read on that. http://www.endtuning.com/afr.html. Also I recommend you get a fuel injector duty cycle monitor. You don't want to take the injectors over 80% duty cycle. It's not good for them. I found that out too.
My concern is high EGTs and the long-term affect on exhaust components, turbine wheel, O2 sensor, etc. A rich AFR will actually raise EGT (some of the unburned fuel that is so helpful in controlling combustion temps/detonation will ignite as it exits via the exhaust port), and retarded ignition timing will also raise EGT. I have not dyno-tuned the engine to play around with this, only road tuning so far.