Oil Analysis for Pinging / Detonating Engine?

Messages
331
Location
San Jose, CA
I have a 2004 Subaru WRX with a modded ECU (Cobb AccessPort Stage 1). It has a 2.0L turbo engine. And since I live in CA, I get crappy 91 octane gas only. With the ECU upgrade, my car sometimes gets some slight pings / knocks / detonations during full throttle. I have the following questions which hopefully someone can help: 1) If the pings are doing damage to my engine, what can I expect to see if I do an oil analysis? Elevated lead? What should I look for? 2) My car has about 7000 miles on it now, oil has been changed 2 times and is currently on dino Chevron Supreme 10w-40 (~1200 miles on it now). I planned to wait until 10k miles for it to fully break-in before I switch to synthetic. Is it still a fine path in my situation? Or should I dump the oil at once and go to a stout synthetic like Mobil 1 T&S 5w-40, 0w-40, or even Redline 5w-40/10w-40?
 
Messages
2,602
Location
The Tropics of Antartica
No engine oil can protect against detonation and analysis will not show the ring frett nor ring land damage . You might see lead/copper from the pounding along with the problems due to blowby from excessive cylinder pressure that causes to rings to loose their ability to seal but in all it's best to fix the problem . Detonation really does leads to a early engine death [crushedcar]
 
Messages
3,094
Location
Metro Detroit
In addition to what Motorbike said, the pinging sound is coming from your valves rattling around inside their guides. This also won't show up in the oil, but will wear away the valve stems and seats.
 
Messages
232
Location
Aviation Capital
Tell a little more about your mods. Did your kit include a new thermostat? What kind of plugs are you using. Do you often run a injector cleaner? And have you tried any octane boosting products? Also ping is a lot different than detonation the ping is a timing a little off. Detonantion is your piston cooking off the gas like a glow plug. Also how many miles on your current odometer? [Freak]
 
Messages
308
Location
Houston, TX
quote:
Originally posted by Matt_S: In addition to what Motorbike said, the pinging sound is coming from your valves rattling around inside their guides. This also won't show up in the oil, but will wear away the valve stems and seats.
how are the valves rattling if they're seated? "pinging" from detonation is literally the sound of flame fronts colliding explosively. -michael
 
Messages
57
Location
South Jersey
go to colder plugs. most vehicles today use too hot of a plug for EPA. a hotter plug reduces warm-up time which helps get the engine up to operating temp faster which reduces overall emmisions. Although all of this helps mostly in testing not in the real world except a small %. Going to a colder plug most times will increase power and MPG. And with MPG getting better does that not reduce emissions better than the testing?
 
Messages
3,094
Location
Metro Detroit
quote:
Originally posted by Michael SR: how are the valves rattling if they're seated? "pinging" from detonation is literally the sound of flame fronts colliding explosively. -michael
My understanding of detonation is that the gasoline ignites too early, usually before the intake valve is completely closed, causing it to rattle back-and-forth in its guide.
 
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