Building a better db2

[bbjordan]

Were back to the drawing board on the locked advance, but just broke through 150cc which was the goal for the day.

150cc at what rpm?
A graph of CCs vs RPM would be really nice.

Congrats, and thanks for continuing to push the envelope!

 

[Thewespaul]

150cc at what rpm?
A graph of CCs vs RPM would be really nice.

Congrats, and thanks for continuing to push the envelope!

Thanks man, I’ll go back through my notes and post up the readings through the rpms range, but I believe that was where most db2 pumps peak, around 1500 rpms

 

[Thewespaul]

Your not gonna find much info about it on the internet, it's the way pumps were built for tractor pulling before the inline pumps came to be. Even though it was 20+ yrs ago the pump builders still seem to be tight lipped about it. My research came up with a bunch of dead ends.

Yep a lot of innovation with these older fuel systems were well before the internet, what kind of rotary pumps were you seeing this done to through? The transfer pump does a lot more for a db or dm series than in say a ve style pump, and Inline pumps have been around well before tractor pulling was a competitive sport so I dont think there was ever a point in the pulling world where builders went from rotary pumps to inline pumps, I know in the TTTPA competitions I’ve been in I haven’t seen any rotary powered rigs.

These rotary pumps are really the Achilles heel for our engines, just look at what lagond and hypermax did once they got a better pump on these engines, I know the in-line is the inevitable answer for more reliable power, but it’s not a cheap answer. If we can use some of the modern advances in calibrating equipment and machining these pumps to get more fuel than before I think it’s the most sensible route for the money, but slowly but surely making some progress on the 3208 pump conversion as well.

 

[ifrythings]

I say ditch the db2 and go common rail, then we can chip our trucks, run 400hp tunes, roll coal at idle and run a 12v tune to make the idi sound like a Cummins!

All kidding aside I do believe a common rail setup like that on a 03-05? 24v would be something to try, fuelling wouldn’t be an issues and the theoretical unlimited timing would be there....

 

[Thewespaul]

Haha then we can get the lope tune so we sound like every Cummins owner square dancing on the throttle in their high school parking lot!

I have thought of going with a cr system, it’s actually the most simple swap and there’s already a ton of aftermarket, if I were to do it I would MacGyver a cp3 conversion kit for a 6.6 and use it on our IDIs, but it would really be heretical to take a mechanical diesel and put modern computerization on it, at that point you really loose the best part of these engines which is their lack of electronics, these aren’t particularly well built or designed engines when compared to what modern diesels are like, so i would prefer to keep the dinosaur in the dinosaur so to speak.

I think dynamic timing and fueling control with the db2 is completely possible, and it would be an electrical system that would work in conjunction with all the original mechanics, so the engine would run regardless of if your “tuner” was working on not, but you would still gain some of the features that some of the later rotary pumps like the ds4 and vp44 got, but still keeping the simple mechanical operation. Kind of like the aneroid setup that hypermax sells.

 

[Thewespaul]

Here’s a graph on the final test of the day, not a ton of data points but it gives a general idea

-Updated error when making the graph, note these were taken at 105* fuel temp.

You must be registered for see images attach

 

[IDIBRONCO]

I think dynamic timing and fueling control with the db2 is completely possible, and it would be an electrical system that would work in conjunction with all the original mechanics,

I have no idea what type of pump they used, but the later 6.5s (94 and up IIRC) used a computer controlled injector pump. From my completely biased observations, this didn't really give the 6.5 much, if any, more power. You could put a chip and exhaust on them and get pretty impressive performance. Strictly by the butt dyno.

 

[Thewespaul]

I have no idea what type of pump they used, but the later 6.5s (94 and up IIRC) used a computer controlled injector pump. From my completely biased observations, this didn't really give the 6.5 much, if any, more power. You could put a chip and exhaust on them and get pretty impressive performance. Strictly by the butt dyno.

That was the ds4 pump, internally very similar to the db4 but with computer control, it didn’t do much for performance but it gave the manufacturers much finer tuning of the fuel and timing to improve emissions, a similar but standalone system on a db2 could be used for performance instead of emissions like the manufacturers designed them for

 

[Goose_ss4]

I definitely appreciate the simplicity of these engines. At least me and mine I want to be able to take it anywhere and not having issues. That being said it's a machine and machines break, so I would only say. KISS. keep it simple st****

 

[Goose_ss4]

Could you post some pictures of what was done to the pump for us visual learners??? Like what does a gutted transfer pump look like

 

[Thewespaul]

Sure thing, I’ll pull a core apart and take some pics since this ones all built

 

[Macrobb]

Here’s a graph on the final test of the day, not a ton of data points but it gives a general idea

-Updated error when making the graph, note these were taken at 105* fuel temp.

You must be registered for see images attach

So this is with locked advance and 'tuned' transfer pump?


Personally, I'm more interested in how much fuel you can maintain at 2500-3500 RPM, mainly because that seems to be where the engine does best in terms of airflow. At 1500 RPM, I rarely see anything out of a "stock"/"kit" turbo. I'm sure it might be possible to use a bunch of that fuel down low with enough boost(VGT time?), but for now, high end performance is muck more interesting to me.

 

[Thewespaul]

So this is with locked advance and 'tuned' transfer pump?


Personally, I'm more interested in how much fuel you can maintain at 2500-3500 RPM, mainly because that seems to be where the engine does best in terms of airflow. At 1500 RPM, I rarely see anything out of a "stock"/"kit" turbo. I'm sure it might be possible to use a bunch of that fuel down low with enough boost(VGT time?), but for now, high end performance is muck more interesting to me.

If you read through the above updates as I was running the pump on the stand we ended up not locking the timing because of the advance piston lube orfice. The big fuel at low rpms is not what I’m after either, but it’s jist a side effect of increasing the fuel in a rotary pump, you’re gonna get a lot of fuel down low no matter what really. This pump so far trumps any db2 on the market as far as top end fuel.

Here’s what the transfer pump looks like, imagine this just without the blades

You must be registered for see images attach

 

[typ4]

Your not gonna find much info about it on the internet, it's the way pumps were built for tractor pulling before the inline pumps came to be. Even though it was 20+ yrs ago the pump builders still seem to be tight lipped about it. My research came up with a bunch of dead ends.

I have a local hot rod diesel guy thats older than dirt that informed me of some pump mods and this was one of them.

 

[Chemgrad]

As usual you're an invaluable source of information and innovation. Thanks for sharing your work.