Modified 6.2 turbo diesel

[NVW]

I'd be interested in a 4-plunger pump and I don't even own a 6.2 or a truck for that matter. If anything is stopping these engines from getting a good bit more of reliable power it's the injection pump, as it has been discussed plenty of times before. If you are going to be hard pressed to install/fit larger plungers in a DS4 that may be the case with the DB4 (but wouldn't know until you tore into one I guess).

Many of these engines self destruct with the available fuel a chipped ds4 will provide. Excess fuel won't provide reliable power. That comes with a good exh.,good cooling, gauges to prevent excesses, etc. The ATT also helps.

 

[Slim Shady]

I have been sitting this one out, but just a little caveat . Making the pump reliable and figuring out how to transfer more volume through the same size orifices in the pump. Can you say excessively high hydraulic pressure, sheared drive pins bearing failure plunger lock up rotor head distortion. Great ideas when someone comes out with a modified pump that is affordable and dependable it will be a shoe in. Maybe someone will get the right combination, would be a nice addition to the A Team Turbo.Yeah would be nice, YEAH who would have thought to do that.

 

[6.2 turbo]

I guess the mechanical pump is the most reliable, I not sure why every body dont just convert their electronic pump to a mechanical. The electronic pump might do better at higher rpms look at Bill Heaths race truck supposedly an off the shelf ds4 , totally blows my mind that he got 500 horsepower , the only way I see it is his motor ,and twin turbos must be extremly efficiant at 5000 rpm, Im suprised the ds4 is up for that. I talked to central penn again, he can get me the head and rotor my only issue is spending that much. Im impressed with response I got at possibly building and selling a db2 pump converted to db4 head and rotor. Do you think Peninsular Diesel would take offence? I think they want like $1800 for a 4 plunger pump,when I talked to them they were unhappy with it and switched to a 2 plunger x.350 Keep in mind Im trying to build max power with my 6.2 for sled pulling . If you over fuel and overboost a stock compression motor you probably will have issues.With low compression you need higher boost. You could over fuel reliably if your motor is built to handle it and watched the pyrometer

 

[SmithvilleD]

Aren't there some everyday driving efficiency benefits from the DS4/PCM having some control over inj timing & fueling rate?

As this is the Performance section, I definitely understand going mechanical, or whatever means to get more fuel when all out performance is the goal.

I've been told by several that the DS4 max fuel rates folks often quote are around 2k rpms, & as rpms rise, the fuel that can be delivered tapers off, regardless of what the PCM is commanding. I'm all ears to hear from folks knowledgeable on the subject.

 

[6.2 turbo]

Thats exactly what I wanted to know, yes you would think you would have more variable timing with the electronic ds4. High rpm fuel is not gotten easily,wonder if Bill got something under his hat, I know he wont give me his timing specs. He is still my hero.

 

[SmithvilleD]

I've noted many stock diesel fuel rate tables where they seem to shoot for a given hp at the peak torque rpm (& actual peak torque they're designed).

Then fuel rates simply taper in proportion to rpm, so hp stays relatively the same as rpms rise.

Obviously that's not max performance effort, but it seems a sort of common theme in some OEM designs.

I wish GMTDScan Tech allowed logging & exporting the raw data into Excel. I haven't spent enough time watching the actual inj timing under the whole range of driving conditions to have a complete understanding/mental picture of what the PCM timing tables must look like.

You can see/interpret how the PCM varies timing in relation to load at constant speed/rpm highway driving. But I would like to see the actual table data & any modifier tables (IAT, coolant temp, etc.).

Buddy, have you cracked enough of the code to have a good sense of the overall timing logic?

 

[6.2 turbo]

Im going to guess the factory timing is close to want you need, fuel dropping of at the top is not ok for max power , could you hook up a throttle switch to the fuel solenoid on the ds4 for full fuel when you floor the gas pedel , might back feed to pcm so you would maybe need a diode , would be a good test of the internal limits of this pump? Also could you program one of these to govern about 1000 rpms higher than you want it so there is no fuel drop off at about 3500 rpm? Wish I knew in real world smoke test what these pumps are capable of especially at full boost do they always clean up ,would give me an idea what Im up against with my db2.

 

[JiFaire]

... a throttle switch to the fuel solenoid on a DS4? Have you been inside one of those things? Just what kind of signal are you planning to input there?

Somehow, I don't think bypassing the gate freq. of the FSD is gonna get you what you're looking for. JMHO, of course.

 

[buddy]

Anything is possible with the right programming, I can post pics of the fuel and timing curves if you like. It is as you say, fuel peaks at 1800-2100rpm, then starts declining. All power tunes will change that to not only increase the peak, but sustain the peak out to 3900rpm. Stock timing also does a similar thing, although I have seen one decent stock program for timing but it was the N/A diesel that took timing out to 20.5° cam timing. Turbo programs all were all more conservative on timing, but I have found the DS4 will go to 22.5° without any effort but programming it to do so. TDCO position has no effect on its ability to do this. It can go further than 22.5°, but its difficult, scanner gets confused too. 22.5° would be 45° crank advance, so theres probably a good reason not to go any further. lower TDCO value does help though for mysterious reasons.

I pushed my fuel table out to 4200rpm, although Ive never been over 3700rpm. It can be programmed out to 4800rpm. There is a speed limiter in the programming as well, power tune will also fix that.

 

[6.2 turbo]

That seems like a lot of crank advance, I suppose you are programing 98 and up. I never had a ds4 to play with so Im limited on the electronics how ever on the mechanical part of the pump its looks similar to the db2. Isnt the fuel solenoid pulse width modulated is it opening and shutting very fast all the time if it is at full load that sounds dumb why not get that to remain open dont it have another little motor for advance, all the fuel solenoid does is regulate fuel input just like the metering valve on a db2. it shouldnt need to open and close exept at part throttle and idle and governor rpm. I am probably getting the wrong picture. Eventially Ill show you some real fuel with my db2.

 

[buddy]

the electronics requires the closure in order to calculate fuel rates and injection commands. The electronics began in 94, thats what I have, OBD1.

45° can be a lot, stock N/A went to 41°. Its a very nice and easy system for controlling fuel and advance from 0-45°.

 

[6.2 turbo]

To me it looks like a db2 with an electric metering valve and timing advance,on the db2 the metering valve does not control injection , only the amount. If I had one it would be fun to take apart and study for a while. I ordered a 4 plunger head and rotor today , should be in on monday ,hopefully I can get you some pics of the rotor head, and maybe a smoke video , still worried it wont be the fuel I need for my big charger it will probably clean it up. Guess there is only one way to find out. There is one major restriction in the db2 that most people dont know about,I might have already said to much, you can get more fuel from this pump than most people realize, since I want to sled pull, I know how much is needed.

 

[6.2 turbo]

I worked on my 6.2 tonight,made some changes to the ip,boost went from 30 to 40 psi, there is still definetly some thing wrong, the only thing I know for sure is that my ip plungers are to loose,it still has a high speed surge/miss, could be the plungers can't pump fuel that quickly and simply leak, when you have such radical mods its hard to know where you are at,good news is my head gaskets must have seated,no more slight gurgle in the over flow.Victor reinz solicor the best head gasket for this motor so far.

 

[SmithvilleD]

Buddy, I for one, would be interested to see any fueling & timing data tables or other PCM programming bits you're OK w/ posting.

 

[buddy]

Buddy, I for one, would be interested to see any fueling & timing data tables or other PCM programming bits you're OK w/ posting.

Here are some stock turbo tables

 

[SmithvilleD]

Excellent. Thanks very much for posting/sharing this info.

 

[Matt Bachand]

I hate to add nothing to this thread but as an owner of a 6.5 for 4+ years and almost 50,000miles, and a forum faithful for 3+ years, this is fantastic reading. Keep up the good work guys.

This internal reworking of the db2 is extremely exciting to read about. Keep up the research 6.2 turbo! You have the attention of many 6.5/6.2 enthusiasts for sure!

 

[Acesneights1]

When I spoke personally to the guys at Peninsular about the DB4 They didn't say anything about it being backwards to a DB2 that I remember. They can build you an IP anyway you want it pretty much was what I got. The only thing he told me that stick out was that the DB4 was very finiky and more designed for use on marine engines where throttle was more constant and something to do with the way the advance works in it. He said you could run one on a truck but probably wouldn't like it and he said they build hi per DB2s that could put out alot more fuel than stock and that is where I left off with them. Best bet is to call them They are very cool on the phone and know alot.. When I bought my CUCV the IP was leaking around the throttle shaft and I had heard about the DB4 and wanted to swap out but after talking to them I decided not to.

 

[SmithvilleD]

Matt seems a very sharp 6.5 guy. They've got an engine dyno & a pretty solid understanding of fueling, brake specific HP, etc., on these engines. Solid, measure things, to understand things approach.

 

[6.2 turbo]

I had talked to them a couple times, think maybe it was Dave?They are definetly great people and very helpfull,Im not worried about the finicky part,what is finiky to some one else might seem fine and all right to me,I will give updates once, Im getting somewere,my card reader still didnt come yet,once it does I at least get a pic of my truck on here.I hope I can also show you guys how to light a turbo,it will take lots of fuel as of now it is spooling mostly from exhaust flow,a little worried about my injectors as I modified some before that didnt work,although these are simply drilled to .065 and relaped the pintles and seats, but they need lots of fuel to pop otherwise they just leak might also be a problem,very low compression just makes every thing seem worse,seems like lower compression needs more fuel to make power, which is why I want more fuel than most people can imagine on a 6.2 or 6.5.