Evenin everyone!

No question here tonight, just a remark I noticed on my F350.


I'd been straight piped since I been driving it (since Jan. 1st), and 3 days ago I advanced the timing, just by ear, no machine, no light nothing, just by ear with engine sound.



And after advancing the timing, I noticed the exhaust was alot quieter, the straight pipe that is, yes it's still loud, but not LOUD like it was with retarded timing.


Before advancing it. The engine was abit to quite, but the exhaust was VERY loud. And just cruising down the highway at 55-60mph, it had a constant roar from the exhaust.



Now that i've advance the timing, not only does it cold start much better, but cruising down the highway, it's like theres no load on the engine, the exhaust is as quiet as a mouse.


The clatter of the engine is noisier now (more like it should), but the exhaust quieted down. I found that interesting.


It picks up revs much quicker to.



Also, just fueled up tonight, 14.3mpg! Last 2 tanks with retarded timing were both at 13 and 13.2mpg. Exact same driving. I'd say that's not to bad considering everything looks pretty original in the fuel system with 165k miles.



Just taught I might share this, especially for you straight pipe guys, if your exhaust is extremely loud and always sounds like the engine is under load, might wanna check your timing....

 

That's very interesting, thanks for sharing.

I had my 6.9 straight piped when I first got the truck up and running/driving safely. I liked the sound a lot, until I took a 3 hour trip on the highway in the summer (windows down, no A/C). Almost all of the highway I was on had concrete barriers on both sides and the exhaust sound bounced right off it, I could not hear myself think let alone hear the radio. As soon as I got home I slapped on the magnaflow I had laying around.

 

Sounds right up to snuff timing wise, IDK about the straight pipe part, but an IDI should have a healthy clatter in the top end. An engine with retarded timing will be rather quiet. An engine too far advanced will seem to have a lower end knock. Timing by ear is still tricky though. Meters aren't that expensive and well worth the $.

Just my $0.02

Mac.

 

Less combustion exiting the pipe... More being combusted in the cylinder....

This is why turbos like a little more retarded timing than N/A.... the exiting combustion helps spool the turbo, and the more retarded timing on the bigger the housing, the better....

Its all about balance on every particular setup... that's why not one number is correct....

 

I'd love to find one, but never did so far. And I've timed all my IDI's by ear so far, and been pretty successful at it.

 

I time most of my engines, gas or diesel, by ear. I also set idle etc. by ear. Takes lots of practice but you'll get to the point that everything will match up on the tools when you do it by ear... You just know the "feel" of it...