Delivery valve affect on timing?

tune your afc and leave the plate in it and grind it. dont worry about timing and changing dvs if your worried about low end smoke....
 
I swapped my stretched stock AFC spring for a stock 180 pump gov spring set for full fuel at 40-45psi. I will let you know how it runs after some tuning tomorrow.
 
cumminstroked said:
My guess is it would change a degree or two. You have to take into consideration your injectors the fuel is going to and the pump that is pushing the fuel through the DV's. When I changed my holders out I saw a pretty big change when checked with the light but what it changes on my truck wouldn't be the same as your truck. An injector with a lower pop pressure would be different than with a higher pop because your line wouldn't be pressurized as much befor the injection event in the cylinder. A higher pop on average will run a higher timing than a lower pop since it takes more fuel pressure in the line to inject. I would think a DV works the same way. The easier it is to push the fuel through the less timing. The harder to push the fuel through the higher the timing but Even with a timing light I think it would be hard to get an accurate reading because the pulse is picked up after the DV so its hard saying what is happening with timing before the fuel gets to your lines. I may be completely wrong but that is a few thoughts I put together.
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Opposite. The higher the pop pressure will retard timing.
 
Gasoline Sucks said:
I swapped my stretched stock AFC spring for a stock 180 pump gov spring set for full fuel at 40-45psi. I will let you know how it runs after some tuning tomorrow.
Click to expand...

If your setup reacts like mine you will need a little more spring tension. I have the 215 gov spring in there and with full fuel at 40ish PSI I still have low RPM part throttle smoke. Tightening the wheel up only delays the topend to over 60PSI but kills the smoke down low on moderate acceleration. You may get lucky with the 180 spring as it is a little stiffer. I have one I plan to try myself so that I can dial my WOT fueling in a little earlier. Good luck.
 
AHall said:
Opposite. The higher the pop pressure will retard timing.
Click to expand...

I was thinking of it as the higher the pop pressure the higher the timing retard.

EX. a 280 bar injector will be at 25 degrees where as a 260 bar injector would be 22 degrees???
 
The 180 gov spring really cleaned up the way it drives except for the 0-5psi haze when normally driving it, I might be able to get rid of that with some pre-boost adjustment not sure. I set the afc for full fuel at what the compressor regulator said was ~45-50psi but the spring is too heavy for my current setup as it takes what feels like foreverrr to push it forward when you mash it. If feels laggy like the truck's acceleration is limited solely on that spring moving forward. I know its limiting fuel because even wide open there is zero smoke now. Im going to try taking a few clicks out of the star wheel once I get the pre-boost closer.
 
cumminstroked said:
I was thinking of it as the higher the pop pressure the higher the timing retard.

EX. a 280 bar injector will be at 25 degrees where as a 260 bar injector would be 22 degrees???
Click to expand...

The two statements contradict each other :doh:
 
No they don't. They may not worded perfectly, but they are in agreement.

Epically post by a dumb phone.
 
cumminstroked said:
I was thinking of it as the higher the pop pressure the higher the timing retard.

EX. a 280 bar injector will be at 25 degrees where as a 260 bar injector would be 22 degrees???
Click to expand...

The higher the OP the more retarded the timing. Even tho im sure it's on a very minut level. An extreme example would be if 260bar was the 0* mark, then 300bar might retard 1*, 220bar might advance 1*.

The disadvantage is the pressure will be lower and atomization will go down. I experimented with a set of 5/12's. Set to 350bar to lower timing and increase atomization, and increase pump static to 25* in hopes to get a highly atomized charge and a dynamic streetable timing. It didn't work well. Although the injectors are still at high OP in a different truck and seem much cleaner than any other 370 i've seen.
 
SHughes said:
No they don't. They may not worded perfectly, but they are in agreement.

Epically post by a dumb phone.
Click to expand...

Are not in agreement.

280bar at 25* would be saying injecting earlier compared to 260bar at 22*.
 
AHall said:
The higher the OP the more retarded the timing. Even tho im sure it's on a very minut level. An extreme example would be if 260bar was the 0* mark, then 300bar might retard 1*, 220bar might advance 1*.

The disadvantage is the pressure will be lower and atomization will go down. I experimented with a set of 5/12's. Set to 350bar to lower timing and increase atomization, and increase pump static to 25* in hopes to get a highly atomized charge and a dynamic streetable timing. It didn't work well. Although the injectors are still at high OP in a different truck and seem much cleaner than any other 370 i've seen.
Click to expand...

AHall said:
Are not in agreement.

280bar at 25* would be saying injecting earlier compared to 260bar at 22*.
Click to expand...

I was backwards.
 
X2 as said there is not a significant amount of change to really worry about it. there might be one or two degrees difference in the combination of injector and dv's
 
AHall said:
Are not in agreement.

280bar at 25* would be saying injecting earlier compared to 260bar at 22*.
Click to expand...


Sorry, it's clear now. Appearantly not while I was at work, failing at mutitasking. LOL
 
AHall said:
The higher the OP the more retarded the timing. Even tho im sure it's on a very minut level. An extreme example would be if 260bar was the 0* mark, then 300bar might retard 1*, 220bar might advance 1*.

The disadvantage is the pressure will be lower and atomization will go down. I experimented with a set of 5/12's. Set to 350bar to lower timing and increase atomization, and increase pump static to 25* in hopes to get a highly atomized charge and a dynamic streetable timing. It didn't work well. Although the injectors are still at high OP in a different truck and seem much cleaner than any other 370 i've seen.
Click to expand...


I was once told, no evidence to back it up but from a very experienced builder, that the difference between stock p7100 and VP pop-off pressure could delay timing as much as 9*. But not a hard and fast rule by any means.

This was in conversation about my p-pumped 24v using standard VP pop-offs at the time. At 30* of timing it was right on the edge of coming out of the bowl.
 
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