Mechanical vs Electronic

[JeepSJ]

Discussion regarding injection pumps and flow. DB2-4911 is (or was) considered sort of the gold standard on a build. If I have read correctly, the electronic pumps can flow more fuel. From a theoretical standpoint, if someone was doing a build up with low compression, big turbo, etc... would electronic be a good option over the 4911, or is there some other mechanical pump?

[DickWells]

John Kennedy would go with the electronic setup, if I'm not mistaken. Certainly would conform to regulations a lot better. But, I've never regretted putting a 4911 in our Suburban. I just got sick of chasing down flaky grounds and other intermittent skips and misses. I had done a DIY remote mount of the PMD, which seemed to have fixed those issues, but never did trust the electronics over the long haul. Now, with just one wire to the pump, the only thing I ever have to think about is how to keep the 4L80E shifting right, and these days, even that seems to be a non-issue. Still, from what I read, John's tunes are a good bet with the pump that's on there, and your emissions are bound to be a lot cleaner. Someone else will have to tell you how that would work out with low compression and big boost, since I've never been down that path.

[JeepSJ]

I'm going to bring this back up because the discussion never really got going the way I hoped it would. Can anyone else chime in on this? As I'm gathering parts to get the DieselSJ back together, I'm strongly considering the electronic option over my 4911. I could sell my freshly rebuilt 4911 to fund the parts for the electronic. Whatever I do here, will also be what I do with the dually (with the exception of the dually also getting a 4L80E and letting the ECU control it as well).

So, considering things such as 18:1 compression, TE06H/HX-35 turbo pushing 20psi (intercooled), driveability, mileage, etc... Oh, and definitely a Kennedy tune if I go electronic. Mechanical vs EFI?

[trbankii]

I could be interested in your 4911 if you decide to go EFI.

[Robyn]

A 4L80 with a Stand alone controller is a great idea.

As far as the DS4 injection goes ...... Go lay down with a cold compress on your forehead until the notion passes.

20 PSI IS WAY MORE THAN A six and a half can stand.
There is simply not enough mass in the block/heads or enough bolts to keep the lids on.

12-15 is about all the head gaskets can take.
Above this point an aftercooler is a must have, but then there is the gasket issue.

Even with a stud kit it's not gonna live.
300 reliable HP is about the best the 6.5 can give ya and it can do so without 20 psi boost

I can't be more to the point.

You have a little gold mine in the 4911.

It will shove enough fuel into the 6.5 to melt it, and the 4911 won't leave you stuck between nowhere and a dark place on a cold night.

:):)

[arveetek]

I would never, ever, ever consider purposely installing a DS4 pump on a rig that didn't come with one. I despise the DS4. One of these days, when I can gather enough change for a quality 4L80E controller, my Tahoe will lose the DS4 and go with a DB2. The DS4 is the weakest link on my rig, and I never leave home without a spare PMD. I just don't have the confidence in this system that I did with a DB2 setup on my other rigs.

The DS4 is one of the reasons the 6.5L has such a poor reputation to start with.

I agree with Robyn; let that idea flee from your mind! :D

I think I read recently that the DS4 is also going to be (or already is) an obsolete item from Stanadyne, meaning they won't be manufacturing anymore pumps or continuing to support them in the field.

You might do a search on the DB4, which is a mechanical, marine, 4-plunger pump. I don't know much about them, though.

I would stick with the 4911 myself if I were in your shoes. Most guys with the DS4 dream of having a 4911 instead!

Casey

[Kennedy]

I favor the electronic pump IF it was built that way. I do not favor mechanical swaps in electronic trucks. If you are doing a swap into a non standard vehicle mechanical would make it much simpler. Just be sure that there is a good way to communicate TPS/APP to the trans controller if automatic.

[JeepSJ]

OK, ok, ok...I think what you are telling me is to stick with the 4911.

DB4 could be interesting...

Yeah Robyn, I know...even with my Navistar block and head studs. But there are guys doing it. Honestly I'll be happy if I can get 15psi below 2500 rpm and have it stay there through the rest of the range. I wasn't ever able to even get to 10 below 2500rpm in the past. And yes, it will be aftercooled.

[Dvldog8793]

Howdy
Just an FWI-
I had a 2002 6.5 block NEW DS4 with all the good stuff and a cooler. someplace in the neighborhood of 290HP. It last for about 120,000 miles and the crank went south. This was with incredible maintenance and do everything I could think of to keep it for a good long time. The lesson I learned is that as HP goes up longevity goes down with the 6.2/6.5. IMHO...having pulled some large heavy loads with that engine, I think I would have been just fine with about 250hp, and maybe the engine would have lasted.
just my .02

[JeepSJ]

I'm not trying to build a 300hp engine. I am however trying to get as close as I can to 500ft/lbs of torque.

[JohnC]

I'm not trying to build a 300hp engine. I am however trying to get as close as I can to 500ft/lbs of torque.
No problem! All you need is 190 hp at 2000 RPM! ;)

[RustyAC]

I had '92 K3500 6.5 Turbo prior to my current '95 C1500 Suburban.

The biggest advantage I have noticed with the electronic DS4 pump is starting and idle quality when cold. Yes, the DB2-4911 in my '92 was a fresh rebuild and the engine ran great, also cold starts were not bad. It is the lukewarm engine conditions (shut off for 30min-2hrs depending on ambient temperature) that always bugged me. Sure it always started, but if it wasn't quite cold enough to trip the fast idle/timing advance temperature switch, it was a rough idling and white-smokey experience until it was warmed up again.

With my current '95 DS4 rig- no matter what temperature the engine is, a puff of smoke during the initial start is all that ever comes out the tailpipe. It always idles at the optimum speed and timing for its temperature. The ECM control over the glow plugs also seems to be a major advantage, as it compensates for temperature a lot better as well.

For these advantages alone, I would never consider swapping the DS4 on my '95 for a DB2. I just packed a spare FSD and allen wrench in the glovebox for piece of mind- they are easy to change when remote mounted anyway.