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Discussion Starter #1
Almost every SC in our family had detonation, current car is -93 manual with 2.73 gears. Car is stock, engine rebuilded with balanced internals. Previous owner told that he slightly cleaned intake and exhaust ports in heads during rebuild. No dtc:s and mpg is decent 28, exhaust smoke is dark when accelerating, doesn't look lean to me. No wideband installed. Exhaust gas analyzer test for inspection is good, o2 sensors work, no unburn fuel.
Spark plugs are meant for SC, platinum if I remember correctly. Car works fine but clear pinging is heard when accelerating heavily in low and mid rpms.
We had -90 and 94 automatic sc:s that both had same problem. -94 was modified - 265 hp from crank. I tuned it with Binary Editor and QH and got the pinging to minimal.
I've been told that SC:s factory tune is good and doesn't need adjustment in stock form.

Any suggestions?
 

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more than likely its your fuel out there, the knock sensor will yank out up to 8 degrees of timing, so you would have to be at least 8+ degrees over advanced to get detonation

all 9 of my supercoupes never pinged not once with the stock tunes when they were all near stock

on the countless supercoupes I've tuned/modified/worked on/etc.. not a single one of them had issues with detonation ever

its got to be your crap fuel out there if thats an issue you've been having, there's no other reasonable explanation

best bet is to yank timing in that range since you already have the QH setup
 

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Discussion Starter #5
I claim it's not fuel, this isn't Russia. I've tried low and high octane gas, no difference. My QH comes back from customers car, so I must purchase strategy file for this too, if it's different from -94.
 

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I just did a quick a search and I found that finland 95 octane is in actual RON ratings, that equivalent to about 87 octane in the us, complete junk fuel

supercoupes require 98 RON fuel also known as "premium fuel" which is equivalent to 93 octane in the US based on the different octane ratings used

instead of 95 regular you should be using 98 premium
 

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Had this problem with a 94 Mustang GT. same symptoms. I removed the mass airflow sensor and cleaned it with CRC Mass Air Sensor Cleaner. No more detonation. The wire was dirty enough to fool it into thinking that the mixture needed to be leaner. Try it. It can't hurt.
 
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