131/181 Hybrid DV

Ken in AZ

Ken in AZ

ill-tempered
Joined
Oct 2, 2006
Messages
358
I want to go over a mod I did this weekend called the 131/181 Hybrid Delivery Valve modification for the P-Pumped 12V Cummins.

First I started with a 913 pump stock on my 98 12V 5spd. I installed a #10 plate ground down to a modified #100 plate. Starwheel all the way forward with Marine 370 Inj. and 4k GSK. With my B1 turbo I could all but clear the smoke at 41psi which has the 62mm compressor to a very slight haze.

I've heard this turbo is good for moving enough air for close to 550hp so I have been in search for more fuel. Having heard that laser cuts are super smokey, 191's are $250 and being the cheap skate I am I I searched for other options. Searching the forums I ran into some interesting threads and found where Smokem recomended that a 131 valve in a 181 holder should produce more fuel than the 181 by itself but he didn't have anyone that has tried it yet. After reading this I set my sights to find a pair of 131's to try and to eventually send out to get custom cut after playing with them.

measurements:

181 shoulder hight = 2.2mm

131 shoulder height = 2.0mm

First driving impressions were believe it or not, better than stock. It almost felt like the smoke was easier to control but when I laid into the throttle that's when things got interesting. Smoke rolled like coal. With the 181's it could roll some smoke, but the hybrid dv's make it really smoke. Performance feels up but I don't really want to coment on that because I have no real measurable data except I can say I have more fuel to burn which now I can up the boost or add a small shot of the giggle gas. It now smokes quite a bit more at 41psi than it did before and feel an honest 10-20hp up than before.

I have no idea if this works going the other way with a 131 holder and a 181 valve nor do I know if this works in other pumps....I only have my one weekends worth of experience on these. :)

thanks and have fun
Ken
 
The holder have nothing to do with fuel delivery. The valve is were the rate is set. The holders have the same size hole in them. So no more fuel can go thru it. We have flow tested just about evey D/V set you can think of and that was one of them. It flowed no more cc's then the stock 131. 131,181,and 191 all have an 8mm (.315) hole. We are work on some billet D/V's that are 9mm(.354) and some 10mm(.393) that will cut down on smoke at lower rpms and load but flow more at higher rpms.
 
BigDodge,
How did you test the flow? In a pump or with another setup outside a pump? Also I don't think that flow is everything here, more how its controlled.


Travis
 
all I know is that I have more fuel now than I did before with no other changes. I also know that shoulder height as measured from the top of the valve down controls fueling. How does it control it? I don't have the answer because I am not a pump engineer but I have a feeling that the shorter the shoulder the more distance between it and the holder durring an injection cycle. This causes a larger opening for the fuel to pass through just like adding lift to a camshaft allows more air to enter into the combustion chamber.

Correct me if I'm wrong....but I also thought that a certain percentage of fuel passes around the holder from the top to the bottom durring the injection cycle thus the difference between shapes from one valve to the other.
 
Smokem said:
The idea is that the 131 delivery valve has less shoulder material than the 181 delivery valve. It was a small gain from my experience.
Click to expand...

Smokem, do you know what the shoulder material equates to in terms of an injection event? In my mind the fuel flows up through the holder and pushes the valve out of the way. If there is less shoulder material there wouldn't the timing be affected too since the fuel would clear milliseconds before a normal valve would? Also since more fuel is able to fill the line wouldn't the durration of the injection cycle change as well or is all this overcome by pressure?
 
Smokem said:
I believe the seat has more to do with the stumbling issues than the valve itself. I doubt the delivery valve seat design was changed for no good reason on the later model pumps.
Click to expand...

so really the swap for the early trucks is the 181 holders, correct?
 
They where tested in a Shiver Diesel 13mm pump on there pump stand. With a 131 d/v if flowed 892cc, with 181d/v it was 921cc,and 191d/v it was 948cc. Changing the holder of the D/v does not change the fuel delivery rate at all. the fuel delivery rate and flow is controled by the valve it self. the shoulder, the od of the under cut,the size of the flutes and the length of the flutes are what controls how the d/v works. Fuel should not flow around the body at all because it's held down the holder that screws in to the top of the pump. so the body shape does nothing.
 
I might just have to try this out with my two trucks. My 95 has had a lowend stumble ever since putting the DDP 1's in, and I'm always looking for more power out of the 97. Will have to see if I can kill two birds with one stone.
 
If you ran the 131d/v with it's holder you will see same smoke as you see know. the 131 with 181 holders will smoke the same as 131 with 131 holders.
 
I've been chasing stumbling issues forever now with my truck and have changed out seats on the delivery valves I was provided by Weston. The 131 seat (seat with the wider bottom then the top) caused more stumbling and bucking then my stock 180hp seats (seats with the machined bottom which is smaller then the top). I still have bucking issues but the seats do seem to make a difference. Not talking about the holders, i've not fulled with those at all.
 
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