shm21284

Sometimes, intelligence sucks!!

GTORX7 was talking to me about why my engine was possibly detonating. Ignition timing and spark was good. Fuel was more than ample (i used his innovative motorsports AFR guage and wideband). Boost at knocking was at 10 lbs, ive had no problem with knocking at 18psi before (only ran the 1/4 twice with that, was on old engine hehe).

I have overheated my engine, and my old engine cracked the rear cast plate from detonation due to lack of fuel, both involving extreme heat. This could cause the springs (apex seal, side seal, corner seal springs) to become weaker, correct? I had my engine compression tested and it was about 56psi (below the bare minimum), evenly, on all rotors, BUT IT WAS FLOODED (lack of lubrication to the seals) AND MY BATTERY WAS SOMEWHAT LOW!! According to a 30 year rotary mechanic, the compression was fine when taking into consideration these problems. Its got an engine rebuild on it with 4000 miles, and a monster street port, but those springs have been through hell.

My question for the experieced rotary gods is: could these low compression numbers mean weak springs? Could the low compression be causing blowby under boost, making a hot exhaust charge blow back onto the intake side and therefore igniting it too early, causing detonation? Has anyone seen this or heard of this happening before?

brandon davis

iTrader: (3)

i am no roatry expert but i have had a few turbod cars and by what your explaining it makes perfect sense. combustion in one rotor face is leaking past the seals due to such high presure from forced inductoin causing early combustion in the next combustion cycle which i think any one could tell you that detonation is just an early more violent cumbustion cycle. now you have two combustions happening out of timing cycle. just my 2 cents good luck fixing it.

Directfreak

iTrader: (2)

What you are stating makes sense.

Are you getting Oil Blow-by as well? Have you checked your intake to see
if you are getting Oil into the intecooler or intake?

That will also help detonation.

shm21284

dammit, well i guess i will continue installing the fuel injection and get her running and tuned. If its tuned properly and still detonates (i will have to buy a pyrometer-exhaust temp guage), then i will buy ANOTHER gasket kit, and new springs, and do it all over again

shm21284

for the record, it was GTORX7's intelligence that brought this idea forth....