hi,
i have an '87 t2 that i have built from the ground up myself. mods list:
E6K w/3bar
fuel pres gauge
egt (approx 800 deg C under full load)
j&s knock (stupid thing keep lighting up)
FMIC
full exh.
T78
550 pri
1600 sec
walbro 255
fp reg (44psi static)
street port w/ Hurley 3mm
wideband tuning (cruise=14.4, <5psi=12.5-13.5, >10psi 10.0AFR)

i am writing this b/c i am completely frustrated about the fact that i can still see detonation @ 13psi and up!!! this cost me 1 engine already @ 6000miles!
i think that 93 octane on this set up should be able to support 16-18psi. am i right?? please look at the following and tell me any suggestions that you have:

fuel AFR's= cruise=14.4, <5psi=12.5-13.5, >10psi 10.0AFR

timing= from 3k rpm to 8k rpm- 30deg adv @ 0psi, linerized to 12deg adv @15psi

trail split (>2k rpm)= 10deg @0psi, 2deg @ 5psi, 10deg @15psi (linerized between points listed)

corrections:

timing vs. intake air temp= starting @ 100deg 1deg ret per4-6deg temp rise

fuel vs. intake temp= i have it taking away very little to nothing above 100deg inorder to further richen the mixture

the thing is this engine is NOT leaning out. the detonation is coming from something else. i am baffled. i feel those timing values are already too conservative. can an engine detonate from being too rich? is it possible that small imperfections in the rotor housings/side plates could allow blow-by igniting the next charge? please forward any input that you have. thanks for your time.


justin

513 518 1994

 

Why is your split at 10 for 0psi then 2 for 5psi then back to 10 for 15 psi? Engines can detonate even at 5psi so you could just put the split at 10 all the way across.

At what point did you lose your last engine? At what points are you having problems right now?