lol i think we all "need" to know

 

Oh you guys will be the first to know... When the decision is made to let you know...

 

Time to resurrect this bitch...

Im having supply issues with Stanadyne on my DB4 stuff, so I am going to open the file back up on this idea, If it works out, it will mean as much fuel, even cheaper, and one standard pump from 100 to 180cc's

I am building two prototypes, and they will be tested by two members of this site... Its up to them if they want to share the results or not, Im just going to observe, and hopefully they hold up every bit as good as factory stanadyne parts....

Being that I can use DB2 core parts, it will cut costs down, AS well as increase the supply of available parts, that means more power for less money. Its a sad issue when stanadyne cant even supply the demands of a few IDI guys who want real fuel out of their pumps, but that doesn't mean Im just going to throw my arms up and give up the ghost.

Everything that goes into the RD4 pump will go into these, the EDM work, bigger cam pin, and calibration... Only difference will be that these will be big bore two plunger pumps instead of .31" 4 plunger pumps.

I am using a 7/16" plunger (Pretty much the biggest effective plunger you can fit), and fueling capabilities will be in the 180cc range. At this point the metering valve is a restriction at these levels, so it makes no sense to go any bigger. Any more useable fuel would require developing a whole new pump.

Anyway, Ill get some pics of the pumps and all the parts before they go out...

Here is a start:




From left to right: .29 plunger, .31 plunger, and .437 plunger

Ill update as the work takes place.

 

That sucks to hear about the RD4. Are the parts on back order or are they not producing them anymore? A built DB2 should be interesting though...

 

Its not that they arent producing anymore, its just I dont know when they are, and I cant supply customers if I have no idea when the parts will be available. If the DB4 parts are available, I will definately build one, but its just that Stanadyne is unreliable.

That being the case, Its time to step up.

 

What's the life if your pumps? Still going to buy one but just wondering?

 

So far its had a trouble free 10-15k on it, and it hasnt been easy either ...

Nothing about it operates outside of stanadynes engineering, it just has increased fueling up top due to the EDM work, and a bigger cam pin to hold it together. The magic is in the calibration, and it wouldnt be possible without the EDM work.

I had my pump in the shop for a check up, and it had a clean bill of health. While it was there, I had them squeeze about 440whp worth of fuel at HP peak, and about 950wtq at torque peak... The only thing that will hold that back is the A3K, due to displacement. Fortunately my cam allows for a substantial drive pressure ratio, so I might be able to get some more out of it than I think. Dont know until its on the dyno.

 

Dude that is cool. In planning a big build in about a year. Need to get some school under my belt first. So ill be watching your post/threads very carefully

 

honest opinion between the rd4 and this new db2?

are they comparable, or even in the same playing field?

 

Only difference in function is that fact that there is two large plungers, instead of 4 smaller plungers. Plunger area is effectively the same, if anything, these bigger diameter plungers should have less leak down, because total bore circumfrence is actually less.

As far as any other differences go, thats the idea behind the two prototypes. It will let me find out the details, and get real world testing from a couple of sources.

 

does the number of plunges affect the fuel curve? does push more fuel faster?

also does the rd4 have the metering issue like the db2?

 

No, the only thing the plungers do is pump the fuel. You will get faster injection events with larger plungers, because more fuel is being pumped with less duration, but that's the only difference bigger plungers have on fueling.

As far as the metering issues are concerned, every DB pump has them, that's the limit we are dealing with. You can only pump so much fuel through the supply orifices at a certain pressure, even with the Gov tuned out of the equation. The way around this is increased lift pump pressure, which is something I'm going to tinker with on these pumps, but at some point, it just isn't going to fuel any further. My goal is to get full plunger travel (~180+cc's) all the way to 4k, and that just may not happen. The faster you spin the engine, the more fuel is demanded by the supply side of the pump, and we are at that limit mechanically right now, the only thing we can change is supply pressure to overcome that. Dynamically there is a few things that need to be played with to get us more than where we are at right now, and that is where my pump is at.

 

[quote=RacinNdrummin;13098989]and fueling capabilities will be in the 180cc range.quote]

are you saying a 180cc capable db2?

 

Wow, what a build. Thanks for allowing me to understand how my pump works a bit better

 

Sweet!! Feeling like a r&d idi performance build will be in the works soon.