History: I melted a turbine when my WI went out and I was running 11.5AFR, -1deg timing 25psi at CMP.

I've since installed an EGT probe in the collector on the inside scroll. I did it there rather than at the port because I feel it will show the highest temps there. (at least my engineering formulas tell me so)

So in the above pic you can see that I'm seeing 1700ish degrees on a WOT pull at reasonable AFR and timing. Now I'm wondering what my port temps would be. I think this supports my theory... but now I dont know what temp to keep my EGTs under. I don't think this 1700 is at the port.

14.7 cruise = 1250deg (egr disabled)
15.5 cruise = 1400deg (egr disabled)

Would you guys post some logs that include AFR, timing, boost, RPM, and EGT for me? Also tell me where your sensor is located. This is my first time using EGT in my tuning. I didn't think it was important till I melted my turbo and turbo gasket.

 

you might not get much data. I believe a majority of people dont have an EGT logging option, only gauge display. I could be wrong though.

Also running -1 timing could have been your culprit. If you advance timing it allows the cylinder walls to absorb more of the heat and thus cooling the EGTs.

 

I agree. Could you guys give me any comparative data that you have though?

You're right, that negative timing was largely the reason, which is why I've increased timing and lowered AFR. In that picture above you see that I'm at 2-3 degrees and my EGT is 1700ish in the collector. I'm going to continue to richen down towards 11.2:1 and try to get timing as high as I can on 25psi... but I doubt it will get much under 1600 degrees...

Edit: looks to me like all the documentation I'm reading is steel and iron should stay below 2000 degrees. I don't think I should be concerned about the aluminum head since:
A: my temp reading is in the collector, therefore higher and not an accurate representation of port temps
B: when I melted the turbine and gasket the head was in perfect shape... so clearly the 2500*F temps were not at the port or the head cooling was sufficient

All that to say... I don't think my max limit should be 1650 degrees F considering the above. I think I will try to keep it under 2K*F. What do you guys think? Please share your experiences.

 

I am also running 25psi and consistently hitting 1600-1650. I ahve spiked 1700 before the tune but i think anything under 1700 is safe for a pull or two. Road racing i would drop the boost a bit to keep egts lower.

 

see... but this isn't the first time I've roadraced with 25psi. Plus the difference here is that I'm CONSISTANTLY over 1650 degrees. what's your peak torque timing and AFR?

 

timing was 2* afrs were 12.7 but this was also at 3312 rpm. Afrs dropped soon there after to 11.5 - 11.3/11.2 by redline.

 

lol crap that doesn't help. 12.7 is way out of the comparison league. Surely someone has a graph that can be posted. Where you at Bryan?

 

here is the best i can give you, hopefully it can help a bit.

 

Well, it seems I'm able to hold 4 degrees at peak torque w/ about 11.2:1 at 24psi. But EGT is still 1700ish. Also something else strange: every now and then during idle it will jump from 1100ish up to 1700 and hang there for 15-30 seconds or so. Nothing changes during that time... Timing is normal, AFR is normal, vacuum varies like normal.... I find it hard to believe I got a bad sensor out of the box... but I'm not sure I can explain things like this. I mean is it really possible that all my WOT pulls are 1700 degrees in the collector? Even at 4deg timing advance at peak torque?

BTW, strange way to do AFR Turco... I'd think you'd want it the opposite. Rich at peak torque allows more timing and lean at the top end helps out where the turbo falls off.

 

Yeah the tune still needs more work (note the timing <100 load). A lot of it has been cleaned up these are just some logs i had from the dyno time. This tune made 290hp/320tq so it isnt all bad.