Anyone want to take a look at my pfc maps? From the map I think I know why I blew up. I just want to get some more opinions

 

I found a -2 degree timing split at about 10 psi around 7000 rpm. Thats right about where the motor popped when I was passing a car.

 

negative split that adds HP right ??

 

Who knows. I've decided that I am doing all my own work from now on.

 

Send a copy to cewrx7r1@yahoo.com, and I'll look at them tonight. Be sure to list you engine related mods, and miles on engine since rebuilt.

Are you sure you were at 10PSI at about 7000 rpm?

 

Yea It blew up right around there. If you look at my maps, there is a -2 degree timing split in n19, p14

 

Btw, it didn't just blow, it blew really bad. The detonation cracked one of my 3mm seals on the front rotor, causing it to colide with and crack another seal. The seals the got dragged all along the rotor. There were 1/8" chuncks of apex seal imbedded in the rotor face. There was a big dent in the rotor like someone wacked it with a heavy hammer. The front housing, rotor housing, and intermediate housing were also destroyed. The rear rotor looked fine at first but upon closer inspection it had also detonated at some point, possibly at an earlier time. There was a small dent near an apex that was causing that seal to bind. It didn't crack though. All this happened when I downshifted to 3rd gear and reved it out to pass another car. Peak hold on the pfc was about 10 psi. All my tuner could say was that it went lean... I checked everything in the fuel system. Pump, lines, filter, injectors by voltage test.

 

that sucks man.
Just my two cents, but from what i've gathered from the datalogit group, negative split shouldnt be really anywhere if possible, let alone under boost and high rpm's.
I've heard of a few folks being okay with it in lower rpm pre-boost areas though.

 

I'm learning more and more about tuning. I don't know that much yet, but know enough that there shouldn't be any negative split, especially under boost.

 

Sorry to hear about your motor. I do my own tuning now also. The nice thing about doing your own, is if it blows, you know who to blame.
Neg split is one of the easiest things to correct, especially with datalogit, so there is really no excuse for that...
Now if I can only get some solid temp correction numbers.....

 

No kidding...
i think running the default ones is was blew my motor in oct 2001. Now that im finally putting the car back together, i wanna make sure i have that taken care of.

 

I did 8MB of logging tonight and my AirT numbers were all in the 35-39C range under boost when averaged over the map cells. The max single reading anywhere in the whole log was 41C. The min was 29C at idle on startup, and 31C in many other places. The min values are highest along the surge limit when building boost, but that might have just been because I was not in those ranges until I did a long lugging run from low RPM in 5th gear. I would expect much more variation in the actual air temp. Until we find a better air temp sensor, it seems like you just have to program the maps a little rich.

The corners of the boost building curve might be an interesting way to compare turbo spool. The corners of my curve are (P13,N6) (P18,N7) (P19,N9) using the 1-20 number scheme (as opposed to the 0-19 scheme in the log). My MAP sensor won't read high enough for P20. If someone has these numbers, I would be interested in comparing them. My N and P scales are the stock ranges.

-Max