So tomorrow im going to tune my afc to the right specs of a stock motor. I already have the star wheel turned to the correct position. For a stock motor and turbo. How many turns should I turn the smoke screw in? I'm also installing a #10 fuel plate.
That depends on how much smoke you want.:thumbsup: I set mine to where it was contacting a little. I slid my afc housing forward after tuning, and also my fuel plate. It drives pretty good now.
A lot of people say, you'll have best fuel mileage by leaving it stock. I plan to advance my timing to about 16.5 degrees which should help make it more fuel efficient. Its hard to say what my mileage is right now as I have a couple fuel system problem that I'm tracking down (lift pump is needing replacement). I've so far hit about 17mpg with mine and it has 4.10s along with 285/75r17s (about 33.5") that's mixed city and highway. I'd like to go up to a 35 to help the mpgs too.
When I had my stock sticks in and I found the sweet spot, the pre-boost smoke was imperceptible.
Going to bigger injectors made my truck dirtier. Certainly better than most of the other tweaked out diesel trucks I've come across, but still not as clean as it was. Oh well. My truck back when it ran clean couldn't hold a candle to itself in it's current config.
As I understand it, 60psi is the commonly accepted safe limit for pressure on P7100s, however there are also tons of people out there who are claiming to run much higher (some even as high as 100+ psi) without pushing fuel past seals.
There is no issue with 40psi on any P7100. However, you're unlikely to get a gain on a 215 pump because of the camshaft profile.
The 160 (and I believe 175) pumps benefit from higher pressure because the cam only allows the plunger to remain at bottom dead center (where the barrel fills with fuel) for a short time, therefore more supply pressure results in a more complete fill. The 215 (and 180?) pump cams keep the plunger at BDC for a much longer period, so more supply pressure doesn't do much as the plunger fills more completely anyways.
I agree with you on all of that, exept that the 180/215 do benefit from higher pressure, just not as noticeably as the 160/175. Yes, 160/175 and 180/215 have the same cam profiles respectively. Also, the 160/175 can have the barrels shimmed up higher to allow a longer fill.
Also, assuming my odometer was fully accurate with the stock 245s, my odometer would now be reading 3.9% low. This means my current average calculated mpg of 19.3-ish might really be more like 20-ish.
Wow, I was thinking a matter of 10 or 20 thousandths. 5mm would make a hell of a difference...
First, I should probably focus on getting enough air to see full rack travel without instantly pegging my pyro, lol.
I have fueling limited with a stop bolt on the AFC arm, at about 60% of full rack. Before I moved my timing to 20*, I still could hit 1500 if I stayed in it long enough. That 4* of timing lowered my EGTs enough I could probably stand to add a little more top end fuel, but I'm hesitant to put it to the floorboard... a popped head gasket is not an option, at least not for the next few months.
Oh, yeah, his isn't very high last I heard. There may be more going on there than meets the eye. He may have increased it, found an improvement from stock, but then stopped advancing it only because he didn't want to stress his head gasket.
At any rate, he found what worked for him and advocates others to do the same. His needs from his truck as a hotshotter are going to be different from most everybody elses, and since optimal timing isn't as much of a science as we'd like, anything short of controlled testing is going to ultimately be speculation.
That notwithstanding, just because one highly experienced person says it, doesn't mean "everyone" does.
Cylinder pressure is the enemy of a head gasket. Lots of things contribute to pressure, but primarily it's a factor of timing, boost pressure, and delivered fuel.
Dauntless is right but by only bumping timing and not touching the pump you can very easily blow a hg. Boost and delivered fuel only serve to speed up the process.
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