Knocking noise under load
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 421
From: Long Island USA
Biz is backwards, I think 
Either that, or he's talking about "octane dependency". Run a higher octane than necessary, carbon builds up. Static compression goes higher, now you NEED that higher octane. More carbon builds up over time, then you need an even higher octane to keep it from pinging. But this is way off-target at this time.
As to the Superduty/Heavy-duty thing, there was an F-Superduty, really an F-450, back in the 90's. Now, if an F-450 is a Superduty, and after '99 they put that name on the F-250 and 350 too, and heavy-duty is more like F-450/550/650/750, that kinda pins it down.
Anyway, who cares? This is probably a good place to post. On the one hand, you could have posted in the 385-series engine forum. On the other hand the '87-'96 truck forum. If you want the thread moved to one of those, let me know.
Either that, or he's talking about "octane dependency". Run a higher octane than necessary, carbon builds up. Static compression goes higher, now you NEED that higher octane. More carbon builds up over time, then you need an even higher octane to keep it from pinging. But this is way off-target at this time.
As to the Superduty/Heavy-duty thing, there was an F-Superduty, really an F-450, back in the 90's. Now, if an F-450 is a Superduty, and after '99 they put that name on the F-250 and 350 too, and heavy-duty is more like F-450/550/650/750, that kinda pins it down.
Anyway, who cares?
This is probably a good place to post. On the one hand, you could have posted in the 385-series engine forum. On the other hand the '87-'96 truck forum. If you want the thread moved to one of those, let me know.
Lead Driver
Joined: Sep 2003
Posts: 5,844
Likes: 5
From: Albuquerque
Originally Posted by heavyiron
Hey Biz, you may want to check your facts about higher octane and pinging (preignition). You are right that it burns slower, but that helps reduce pinging, not cause it. 
Originally Posted by BareBones
Hmmm. That's what I was thinking though I wasn't sure enough to say anything. I always thought pinging was pre-ignition.... not post-ignition!
Originally Posted by krewat
Biz is backwards, I think
biz
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2003 F250 SD SC 142" XLT FX4 V10 Auto 4x4 3.73s
