• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

DS4 pump mods

You could,but they might seize,aren't the ds4 plungers ceramic. I did bigger plungers on a db2 but they seized,next time I will get some oil grooves cut in them,maybe this would do the trick. There is also some shops that re chrome plate head and rotor,and plungers, and then machine every thing for precise fit,I thought of getting this done after,the plungers and rotor are custom edm machined. It would be a lot easier to custom grind or cut the pump cam, 4 .310 plungers can pump a lot of fuel,I think the fuel solenoid and cam ring are probably the restrictions,I still can't understand why the fuel solenoid can't simply stay open at full throttle,this is how I would want mine . I have only db2 pumps and its a struggle to get enough fuel past the metering valve,I have tried some radical modifications ,in desperate attempts to get more fuel to the plungers, I even tried a full throttle bypass that eliminated the metering valve at full throttle. For a while I ran a 2 plunger .310 pump with only a locked governor,locked cam ring,and modified metering valve hole,and it pumped enough fuel to make 50 psi boost,but it refused to idle,it would lope as high as 2500 and back down to 1000,then back up again.
 
thats what i like to see backyard engineering. but i wish heath or kennedy would look into flowing more fuel. i was talking to the cummins guys over at competition diesel about the vp-44 pump which is similar to the ds4 but i havent gotten any specific info on how they got more fuel other than bigger plungers
 
All the little tricks are often kept secret . It seems there would maybe be a market for a modified ds4, maybe more so than a db2,I should get one just to see what the ds4 is like. One thing to remember with 4 plungers they almost hit each other so plunger size will be limited,on a 2 plunger I believe I could go to 14 mm,if the hole is made off center,I did 1/2 inch,and that opened a hole that had to be plugged ,next one will be welded at that spot before machining.
 
6.2 turbo said:
I still can't understand why the fuel solenoid can't simply stay open at full throttle,this is how I would want mine .
Click to expand...

No, yoy dont want.. when solenoid is open pump doesnt deliver fuel. Injection happends as long as solenoid is closed...
 
The only way I would change my mind,would be if the fuel solenoid does not feed the plungers,and is a return valve instead,which I doubt it since it would not have very good control and probably wouldn't idle very well.
 
I dont know if the DS4 needs to be modified so much as just told to deliver more fuel.

What would be awesome is a diesel enthusiast well versed in reading and writing assembly language to be able to actually redefine the programming rather than just manipulating within the boundries of the current program.

I think even just manipulating the current program the DS4 will provide more fuel than a DB2.
 
I would think the obd II ,especially 98 and up could be tuned with efi live or hp tunners,but I don't know if they are setup to do so.
 
Well not with those setups, but they can be tuned and are from pletny of vendors, but only within the parameters of the computer software. The software has max and mins and you can vary things within those parameters, but if we could rewrite the whole program or pieces of it you could completely redefine the limits.
 
Does Bill Heath's program produce more fuel than any other program,that is set up for max fuel?
 
Any programmer is capable of commanding the max amount of fuel. I know how how they manipulate it but without a tune from each person to compare I dont know which ones are programmed to output the most. From the selection of programs I have seen from most of the players, none of them did get the max they could have out of the DS4.
 
6.2 turbo said:
Does Bill Heath's program produce more fuel than any other program,that is set up for max fuel?
Click to expand...

Bill must have some way of getting more fuel that he isn't releasing probably due to smog police restrictions and liability in a commercial offering, I don't think he'd be hitting 158 mph at Bonneville without some push on the max fuel limits using an off the shelf DS4 IP, last push I did with mine I maxed out @ 121 mph, this was in 2008 before my current program I'm playing with now, that is supposed to be more matched to the ATT. I just rolled over 200K on odometer, I won't be exploring the boundary of how fast will it go until I put my new engine in it, and have a run through the rest of the running gear, hopefully sometime this winter after I finish up at GE steam turbine U here in Ny in Aug.
 
He told me his program maxes the pump on the race truck,but how are you to know if the program is maxed,and the pump has more left. I guess somebody could put a ds4 on a test stand,and somehow bypass the fuel solenoid and measure cc's of fuel from 1000 revolutions ,if it wouldn't cost so much I would check some of mine,think its like $80.
 
IIRC max output is 92^3mm/1000 max flow, but advertised as 80^3mm @ Stanadyne's site, on my scan tool @ WOT 100% engine load the display just shows 80+, I have no idea how much plus is out there he's enabling with his reflash. When I was stock S (L56) GM program max was 56^3mm, with stock F (L65) limit was 65^3mm
 
Most of the stock S tunes I have been seeing actually peak at 62mm3 and the F ones at 67mm3, but its only momentary at 1800rpm WOT. They drop off at any pedal amount after 1800rpm.

Doing mechanical modification like larger plungers may not help at all, if you dont increase the amount of fuel put into the plungers. To get more fuel into the chamber you need longer pulse width (on DS4) or more transfer pressure. The meterning valve opens for the pulse width and so much fuel goes into the chamber then gets put into the plunger to be injected. To get more fuel into the spill chamber you need more time or more pressure. Whatever meters the fuel in the DB2 and DB4 is like the DS4's pulse width (time).

6.2 turbo, have you determined how much internal transfer pressure there is and is this regulated or increasing with RPMs? i assume it increases with RPMs, with the way its mapped in the program.

Does it make sense that it would work this way and larger plungers may not help you until the metering of the fuel is addressed?
 
What is per 1000 strokes? Is that revs of the IP rotor or cam compressions ???? If you do the rough math the 4 plungers are capable of 120 mmm "perfect pump rate" I think in one rev of the rotor (as in volumetric pump displacement due to cam stroke x plunger dia.). So it must be something else limiting the fuel output of 92mmm/1000 strokes. ????


Bison posted the transfer pump pressure does go up with RPM. Logical since pump rate/time as in gpm is driven by function of RPM and restriction to flow stays the same for the most part depending on fuelrate I guess.

But what exactly goes on I don't know. I think the plungers will pump a certain amount per rev whether its injected or not so the transfer pump pressure is not linear in reality I would think.

reference Bison thread on DS IP build and Smithville's max out put threads
 
I wonder if the Optic Bump is in a way reducing the a restriction to the fuel metering valve so more fuel is getting pushed in for a given pulse width. And an IP builder is supposed to measure the output and put the correct resistor in the PMD to make up for the slop in OS placement and IP tolerances.

Im not so clear on what the 1000 strokes means, becuase 80mm3 is not a large volume and the truck can suck through quite a few gallons. Unless thats just a tolerance thing, and it takes a 1000 strokes to average it out to the commanded rate, given the feedback it gets.
 
On the DB2,I have a charge pressure gauge,it increases pressure with rpm,stock was about 100 psi,I modified the regulator,for about 130 psi,with my big pump it would drop to 70 psi at full fuel,my new pump didn't drop past 100 psi. The db2 has a varible regulator that wastes fuel,mine is made to be completly closed at any thing under 130 psi..
 
Thanks 6.2Turbo

Then the charge pressure appears to be the key to increasing fuel output in mechanical pumps, and will do the same in electronic pumps.
 
buddy said:
Thanks 6.2Turbo

Then the charge pressure appears to be the key to increasing fuel output in mechanical pumps, and will do the same in electronic pumps.
Click to expand...

Even with a set fuel rate? Or would you need to do both?

If the pulse remains the same length, but pressure is higher, then it should inject more fuel than the PCM knows about, similar to optic bump, but maybe more-so?

I can see this working at high rpm, but may cause driveabliity issues at low rpm? DS4 uses alternative method to idle I believe so it may idle fine, but light throttle may become super sensitive, maybe possibly accelerate while trying to cruise?
 
You must log in or register to reply here.
Back
Top