Hummer is making a comeback, but this time it's electric

[LE BARON]

This gives new meaning when you say to the missus "Honey, I'm going out for a whiz"
Or if you go for a whiz around town, as long as you don't have it hanging out the window. Otherwise people might say you are marking your territory.

GM gave only a few details about the truck, which will be unveiled officially on May 20. It will have a huge battery to generate the equivalent of 1,000 horsepower, and will be able to go from zero to 60 mph (97 kilometres per hour) in three seconds. The Hummer also will produce 11,500 foot pounds of torque

 

[frankmp]

Derek....going to trade in your Hummer? Might need to spend some $ for a charger plug-in....Welcome back!!!!!

 

[ddgermann]

Derek....going to trade in your Hummer? Might need to spend some $ for a charger plug-in....Welcome back!!!!!

The Canadian Hummer forum was dying a slow death until recently when this news came out Frank. I have had all 3 models and they were great for what they were intended to do. Sold the H2 and H3 due to keeping the fleet modern and under warranty (Actually, it was garage space for a new Corvette and Caddy) but there is no chance (well little chance) I will be selling or considering the new electric. The quoted numbers are really impressive, to say the least. I will be curious to see what this thing is actually capable of though. If it is like the beast below .. maybe ... otherwise likely I won't be interested to have a pretend offroad machine. I am scared to see the price of the thing as well.

The H1 is a unique machine and does what it was designed to do very well. Plus it's just really fun to drive.

 

[YFCvii]

What a gorgeous ride that H1 is
... the only thing I get close to in my stable ...
is 4x4 and the color Black.

 

[Rruuff Day]

And it's diesel....

 

[Tourmax]

And it's diesel....

Yep, but its a 6.5....garbage engine. Total garbage.

The only saving grace is if it’s an optimizer 6.5. Then it at least has a chance at surviving.

P400 was even better (redesigned 6.5 by general engine products). But it had nearly nothing in common with the regular 6.5. It was redesigned to go into the up armored HMMWV, since the “gm” 6.5 no longer had enough “umpfh” to drag it around, at least not with any authority. But those are almost like finding a unicorn: impossible to find, crazy expensive to buy.

Yes, I used to have a 6.5 TD:

It died a horrible death when the main webs let go. Replaced it with an Optimizer 6.5 TD (10 grand all said and done). That was still running when I sold the truck, but it was one heck of a dog. Even after I went through it, gave it all the supporting modifications it needed and even went so far as to buy tuning software for it. Never got it much over 300 hp/400 tq. My 2016 ecoboost 3.5 would eat its lunch and burp back up a couple bucks change. Chuck a trailer on each and the 6.5 TD wouldn’t even be able to keep up. I know that for a fact because I once was on the highway and a 1st gen ecoboost left me for dead pulling the same sized trailer.

Don’t even get me started on what an abortion the DS4 pump was. Several Pump driver modules (even the “upgraded” ones), couple shut off solenoids and even an optical sensor. Garbage. Total garbage.

The best part of that truck was the 4L80E, the rest was junk. Total, complete junk.

6.5’s were horrible engines (and the NA 6.2 before it), no two ways about it. Worst IDI ever made....I’m glad mine is gone.

An electric Hummer might be interesting. Range will be the big question.....

 

[Rruuff Day]

lol.... I'm guessing Derek's Hummer isn't much of a dog... He may chime back into this thread again and discuss his take on what 6.5 mods he has done. I run a 7.3 Powerstroke 6spd manual. Had it aftermarket chipped at a diesel Hperf shop when new in 1999 and I know it's definitely not a dog... Still runs and looks like new after 21 years, other than a new water pump this winter, has never given me a lick of trouble, and pulled my 9000lb fifth wheel like it wasn't even there until I sold the trailer last year. And it will still roll enough coal to drown a Prius if necessary.

 

[Tourmax]

lol.... I'm guessing Derek's Hummer isn't much of a dog... He may chime back into this thread again and discuss his take on what 6.5 mods he has done. I run a 7.3 Powerstroke 6spd manual. Had it aftermarket chipped at a diesel Hperf shop when new in 1999 and I know it's definitely not a dog... Still runs and looks like new after 21 years, other than a new water pump this winter, has never given me a lick of trouble, and pulled my 9000lb fifth wheel like it wasn't even there until I sold the trailer last year. And it will still roll enough coal to drown a Prius if necessary.

View attachment 35917

Powerstroke is a DI diesel, very different beast from an idi, even a 7.3 idi.

With a DI, you basically just feed it fuel and timing and it will just keep making more power until you blow it up. You’re not even working hard to get big numbers from a DI until you get over around 700-800 hp and stupid amounts of torque.

An IDI is limited (mostly) by the precups that are built into the heads. You can only pound so much fuel and timing to it before it just flatlines on the dyno. It comes down to pumping losses and heat retention in the heads themselves. Work an idi too hard and you’ll just melt it down. I’ve seen it happen several times in a frantic dyno session to get more power than they can make. I’d start tuning a guys truck and when it would flatline (usually around 250-280 ho peak) the owner would want us to push it harder. I lost count of how many times I heard; “thats it? Its a diesel, it gotta make more than that!!! Keep working on it”. At that point, I’d tap out because I knew it was going to turn the pistons or block into scrap. But, at an owners insistence, I’d hand my laptop off to another guy there who would be willing to push it further and shortly after you would get oil firing out the dipstick tube (caved piston crown), a snapped crankshaft or the main webs would let go and it would turn itself into a paperweight. Once, we shut it down when we heard a metallic “tinging” noise. On teardown, we found the “2 cylinder precup had cracked so badly a chunk had been blow out and was bouncing around and destroying the head, cyl walls, piston crown, valves, etc. that engine didn’t even top 275hp...

I used to keep my egt’s below 1200 F and it would still send the ect into the stratosphere towing hard.

The hottest 6.5’s (when I was working on them) top out around 350 hp, and that was a pretty radical 6.5 TD. Thats a dog for the amount of money and work you need to pour into it. I used to build them with Bill Heath and my truck had a lot of his custom parts on it. Still couldn't get it much past 300hp. Bill holds the land speed record for the 6.5 IDI trucks, officially. He also used to drag race them in old square bodies. He knows what he’s doing on these old hacks and he even doesn’t get much over 300 out of them.

keep in mind; those were all engines NOT hamstrung with the H1 center mounted turbo. It’s relatively easy to swap and modify turbos on a “side saddle” 6.5 Turbo. You’re MUCH more limited by the center mount turbos...

 

[ddgermann]

Yep, but its a 6.5....garbage engine. Total garbage.

The only saving grace is if it’s an optimizer 6.5. Then it at least has a chance at surviving.

P400 was even better (redesigned 6.5 by general engine products). But it had nearly nothing in common with the regular 6.5. It was redesigned to go into the up armored HMMWV, since the “gm” 6.5 no longer had enough “umpfh” to drag it around, at least not with any authority. But those are almost like finding a unicorn: impossible to find, crazy expensive to buy.

Yes, I used to have a 6.5 TD:

View attachment 35915

It died a horrible death when the main webs let go. Replaced it with an Optimizer 6.5 TD (10 grand all said and done). That was still running when I sold the truck, but it was one heck of a dog. Even after I went through it, gave it all the supporting modifications it needed and even went so far as to buy tuning software for it. Never got it much over 300 hp/400 tq. My 2016 ecoboost 3.5 would eat its lunch and burp back up a couple bucks change. Chuck a trailer on each and the 6.5 TD wouldn’t even be able to keep up. I know that for a fact because I once was on the highway and a 1st gen ecoboost left me for dead pulling the same sized trailer.

Don’t even get me started on what an abortion the DS4 pump was. Several Pump driver modules (even the “upgraded” ones), couple shut off solenoids and even an optical sensor. Garbage. Total garbage.

The best part of that truck was the 4L80E, the rest was junk. Total, complete junk.

6.5’s were horrible engines (and the NA 6.2 before it), no two ways about it. Worst IDI ever made....I’m glad mine is gone.

An electric Hummer might be interesting. Range will be the big question.....

You are blowing a bunch of smoke. The 6.5 TD had a couple of years of bad castings. (97-early 99 which I had and it failed) Otherwise once replaced; performed as designed. Mine is replaced with the newer optimizer block and agreed the P-400 is a somewhat better engine, but that also has as much to do with the CAT control system as anything else. Certainly not worth the cost; especially in a Hummer. The factory did put them in the Hummers in 03-04 models If I remember right. No H1s were built in 05.
The 6.5 TD in the H1s are a great fit as the power and torque are designed to move the truck at 55 MPH and the weak point built into the driveline takes 15 minutes to replace if you stress it to it's the breaking point. As designed.
I do agree that I would have not wanted this engine in a pick-up that's expected to do 100 MPH and tow big loads with that gearing. However, in my Hummer it tows fantastic and has an abundance of power for a 9000 pound truck.
THE PMDs did get hot and fail but that is easily remedied with a remote mount (which I did) As far as the rest... I put in a manual wastegate controller, set for 12-14 pounds of boost which is nice and safe according to the pyros on the cylinder temps, then upped the fuel delivery with a #7 chip in the PMD, custom-tuned PCM, new lift pump and fuel lines with increased capacity, put on an air to air intercooler system, added Evans Waterless coolant, and a ton of refreshing on the cooling system and all the driven components on the engine. The injectors and pump I left stock. The truck is reliable and runs safe and strong.
The 4L80E transmission which is also in the H1 is really good so we completely agree there.

I have heard so much of the slagging of the 6.5 over the years it always makes me laugh. It simply was a bad fit for the highway pickup but there are 1000s of happy owners to this day. It is unfortunate the Duramax didn't come out earlier as the only Hummer with one in it is the 2006 H1Alpha...unfortunately the last year is was made.

 

[Tourmax]

You are blowing a bunch of smoke. The 6.5 TD had a couple of years of bad castings. (97-early 99 which I had and it failed) Otherwise once replaced; performed as designed. Mine is replaced with the newer optimizer block and agreed the P-400 is a somewhat better engine, but that also has as much to do with the CAT control system as anything else. Certainly not worth the cost; especially in a Hummer. The factory did put them in the Hummers in 03-04 models If I remember right. No H1s were built in 05.
The 6.5 TD in the H1s are a great fit as the power and torque are designed to move the truck at 55 MPH and the weak point built into the driveline takes 15 minutes to replace if you stress it to it's the breaking point. As designed.
I do agree that I would have not wanted this engine in a pick-up that's expected to do 100 MPH and tow big loads with that gearing. However, in my Hummer it tows fantastic and has an abundance of power for a 9000 pound truck.
THE PMDs did get hot and fail but that is easily remedied with a remote mount (which I did) As far as the rest... I put in a manual wastegate controller, set for 12-14 pounds of boost which is nice and safe according to the pyros on the cylinder temps, then upped the fuel delivery with a #7 chip in the PMD, custom-tuned PCM, new lift pump and fuel lines with increased capacity, put on an air to air intercooler system, added Evans Waterless coolant, and a ton of refreshing on the cooling system and all the driven components on the engine. The injectors and pump I left stock. The truck is reliable and runs safe and strong.
The 4L80E transmission which is also in the H1 is really good so we completely agree there.

I have heard so much of the slagging of the 6.5 over the years it always makes me laugh. It simply was a bad fit for the highway pickup but there are 1000s of happy owners to this day. It is unfortunate the Duramax didn't come out earlier as the only Hummer with one in it is the 2006 H1Alpha...unfortunately the last year is was made.

We disagree on many points.

But thats ok, we can disagree and still be amicable. That just makes it a healthy debate, not a distasteful disagreement.

Blowing smoke?

Hardly.

Lots of experience with these engines. Certainly a lot more than one H1 installation.

6.2 in the square-bodies right on up to the optimizer. I’ve had or worked on all of them at on point.

It’s just a bad engine design that they just pushed even harder with the turbo application. 6.2’s would crack and break main webs just as a NA engine. But because they were only pushing in the 120-150 hp range, they could live a long time with those faults. You have to remember the orginal intent of this design was MPG, and only MPG. The 6.2 was penned in the early 70’s as a way for GM to post big MPG numbers during the gas crunch, which it did nicely. But Detroit Diesel cut everything to the bone to do it, part of that was weight out of the block, which made it crack prone everywhere. It didn’t help that GM spec’d it as being able to fit in The same space the SBC fit in. That also limited DD in designing the engine. If you know diesel engines and how compact a package the SBC is, you start to see where the problems came from. Then they grew the 6.2 into the 6.5 TD in the 80’s, but they didn’t do anything to change the basic design. The added power just made things worse.

I’ve never taken a (running) 6.2/5 apart (nor has anyone that I know) without finding cracks in the webs. Sometimes you could pin them. Stop drill or even “lock and stitch” the cracks, but 99% of the time they are just scrap. Even repaired ones would eventually come back, having suffered a catastrophic failure of some sort. Most scrapyards won’t even sell the 6.2/5 becuase they know its going to fail. They go as scrap weight. I’ve seen (and built) 6.2/5’s with everything from main girdles to splayed 4 bolt caps. Doesn’t matter, they all fail. Its just a matter of when. It’s an under spec casting for what its asked to do. Thats why they upped the main web thickness, changed the block metallurgy and had the IH foundry cast the optimizers. Well, that and the fact GM had no interest in servicing/replacing a design they had determined as “discontinued”. Thats where AMG and GEP take over.

The turbo only sped 6.2 failures up (and made the failures bigger). The Turbo was a “stop gap” measure where GM was trying to keep up with its diesel competitors at the time and the duramax/isuzu was too many years away (design phase). Gm saw the writing on the wall for the coming diesel HP wars with the DI Cummins/Dodge and Ford/IH , but just couldn’t get a DI deisel design off the boards fast enough. So they punched out 6.2 to 6.5, cobbled on a turbo and electronic emissions controls and set it loose on the unsuspecting public. It was all a bad idea. 120hp design pumping out 212hp by putting it under boost and no other changes? Bad idea. Full stop.

But again: GM had to get something out into the market to carry their banner, even if it was waaaaay outgunned. .

They also changed from the db2 pump (mechaical) to the ds4 (electric over mechanical). That didn’t help the 6.5 TD either. As I mentioned, I’ve seen multiple failures of the ds4 and they’re not all pmd related. But almost all of them were electrical component failures, not mechanical.

I also remote mounted my pmd/fsd. Still ran hot as hell (Bill Heath relocation kit), but it was working when I sold the truck. Pmd was another bad design, no two ways around it.

I’ve got a “turbo master” up on the shelves somewhere.That’s Bill Heath’s design. Ran it for a while and went back to vacuum control. That was key to making more than 300hp. You can calibrate the turbo behavior in the ECM if you leave it as vacuum controlled. When its on, when its off and how much boost it makes and where. Belive it or not, there are points in the rpm range where you actually want the turbo to back off in order to make more hp. It counter intuitive, but dyno graphs don’t lie. Turbo masters are pretty primitive. Thats why none of the oems are using mechanical wastegates and haven’t since the early/mid 70’s. Even Cummins (which was a mechanical hold out on the 6bt turbo) vacuum referenced the Holset wastegate “spring control”. A good “tuner” doesn’t just turn up fuel and timing, they “tune” everything in the pcm, from the tailshaft to the cooling fans. Mechanical turbo control just limits you that much further. I suppose theres the argument of “less to go wrong” since its just a threaded rod and a spring, but the vacuum system works perfectly fine, if you take care of it. Same as any other system in a vehicle.

Bill sent me a couple “tune in a can” calibrations. Some worked well, others not as much. I always got better results brainstorming with Lindon and tuning my own truck. Bill’s were good, if you didn’t know better could be had if you put in the time and money to learn. I use John’s “Tunercat II” along with VDF’s from Lyndon Wester. At least I do for odbII gm’s. Tunercat is an awesomely power piece of software, it’s too bad he sold the rights to JET for their diesel-tuner. They charge by vehicle for tuning and lock you in. Point blank: JET sucks. The original TC is wide open: buy a vdf and tune as many of that vehicle as you like. Lyndon is also great and he sells his own version of a diesel tuner (essentially: tunercat II with a few graphics changes). You CAN still get TunercatII, but tou have to by it from Moates.net and it has to be packaged with their “road runner guts kit”. You’ll spend near a grand to get it. But if tou tune 6.5’s, its pretty much the only game in town. Unless you want to get up into the 2 grand range for Lyndon’s software/hardware package.

Also for consideration: I was military until this past Apr. I’ve been on lots of joint exercises with the US army. Every one of thier EME guys (military mechanic) I’ve ever talked with absolutely DESPISED the 6.5 in the hmmwv’s. Yes, they had to endure abuse from combat and somewhat.....ummm....”careless” operators. But they saw the same things I saw on civvy side: cracked precups, cracked main webs, fractured cranks, etc. thats both 6.5’s and optimizers, although the optimizers were less troublesome. Not a lot less, but less.

you do know that upping the calibration resistor really does nothing for you, right? The resistor is matched to a pump at the oem to compensate for production differences in the pump. Tossing in a higher number DOES get you more fuel, but only at WOT. The resistor calibrates the maximum fuel delivery point. It has no effect on anything besides WOT.

Thats not just my opinion, I’ve tested it on a chassis dyno. Running a #5, we switched to a #9 and changed nothing else. Absolutely zero effect on the hp or torque curves. Despite what the resistor is supposed to do (according to internet lore), it didn't even change WOT. We tried it on my truck and then two others that were in the shop. Results were always the same: zilch. Better off to just stick with the oem resistor card it came with.

yep, I’ve got lots of experince with them. In fact, I’m one of 5 people (that I know of) who have ever been able to make more than 300 hp out of them. Getting past 250 requires pretty serious work. Not the least of which is a grand to buy the tuning software, more hours than I can count learning the ecm’s code and many, many, many dyno sessions.

oh, and pickup applications were NOT intended to run 100 mph on the highway. That, my friend, IS blowing smoke. They were designed to run at torque peak at the national (us) speed limit. Which was 55.....

Because you have one truck with a 6.5 and its given you good service, that doesn’t mean they all do. Just like someone, somewhere eventually gets a “lemon” in an otherwise reliable design, someone, somewhere will also get a “jewel” from a line of lemons.

So as you can see, I’ve had several (and I’ve fixed/modified even more) so when I say they’re “junk” I’m basing that on a pretty large sample size.



iI’s just a bad design. Start to finish. Whether you’re talking 6.2, 6.5 or optimizer (yes, I’ve seen one with cracked mains and cylinder bores). Even the “fabled” 599 casting has failed on me. there are no exceptions to the GM 6.x curse.

It’s really quite surprising from a design firm like detroit diesel, who did the work for GM in the beginning. Surprising in the way that DD would even let it off their drawing boards with the compromises GM demanded. Oh well, “money talks” I guess...

 

[LE BARON]

We disagree on many points.

But thats ok, we can disagree and still be amicable.

Blowing smoke?
Hardly.

Lots of experience with these engines. A lot more than one H1 installation. 6.2 right on up to the optimizer. Bad engine design that they just pushed even harder with the turbo application. 6.2’s would crack and break main webs just as a NA engine. But becuase they were only oushing in the 120-150 hp range, they could live a long time with those faults. I’ve never taken a 6.2 apart (nor anyone I know) without. Finding cracks in the webs. Most scrapyards won’t even sell the 6.2/5 becuase they know its going to fail. They go as scrap weight.

Turbo only sped those failures up. The Turbo was only a stop gap measure where GM was trying to keep up with its diesel competitors at the time and the duramax/isuzu was too many years away (design phase). Gm saw the writtong on the wall with the cummins dodge, but just couldn’t get a DI deisel design off the boards fast enough. Hense: we got the punched out 6.2 with a turbo and electronic emissions controls.

They also changed from the db2 pump (mechaical) to the ds4 (electric over mechanical). That didn’t help the 6.5 TD either. As I mentioned, I’ve seem multiple failures of the ds4 and they’re not all pmd related. I also remote mounted my pmd/fsd. Still ran hot as hell (Bill Heath relocation kit), but it was working when I sold the truck. Pmd was another bad design, no two ways around it.

Also for consideration: I was military until this past Apr. I’ve been on lots of joint exercises with the US army. Every one of thier EME guys (military mechanic) I’ve ever talked with absolutely HATED the 6.5 in the hmmwv’s. Yes, they had to endure abuse from combat and.....ummm....”careless” operators. But they saw the same things I saw on civvy side: cracked precups, cracked main webs, fractured cranks, etc. thats both 6.5’s and optimizers, although the optimizers were less troublesome. Not a lot less, but less.

you do know that upping the calibration resistor does nothing for you, right? The resistor is matched to a pump to compensate for production differences in the pump. Tossing in a higher number DOES get you more fuel, but only at WOT. The resistor calibrated the maximum fuel delicery point. It has no effect on anything besides WOT. Thats not just my opinion, I’ve tested it on a chassis dyno. Running a #5, we switched to a #9 and changed nothing else. Absolutely zero effect on the hp or torque curves. Despite what the resistor is supposed to do (according to internet lore), it dodn’t even change WOT. We tried it on my truck and then two others that were in the shop. Results were always the same: zilch.

yep, lots of experince with them. In fact, I’m one of 5 people who have ever been able to make more than 300 hp out of them. Getting past 250 requires pretty serious work. Not the least of which is a grand to buy the tuning software, more hours than I can count learning the ecm’s code and many, many, many dyno sessions.

oh, and pickup applications were NOT intended to run 100 mph on the highway. That, my friend, IS blowing smoke. They were designed to run at torque peak at the national (us) speed limit. Which was 55.....

The DS pump was just an extension of previous mechanical pumps with electronic controls. The main problem with the DS were the electronics and the vast majority of the time it was the PMD on the side of the pump housing. The Encoder sensor and the solenoid were fairly problem free although with time the solenoid was subject to "normal" wear. Don't forget guys and gals that that pump was working like crazy.
1/2 engine speed so lets say 1500 RPM pump speed X 8 (number of cylinders) = 12,000 injections per minute. So a little "normal" wear and tear is understandable, at least to me.
One other problem was the heat generated by the engine as the DS sat in the "V" of the engine. So good potential for heat build up there and that was problematic for the PMD
The electronic problems were solved to a large extent with the advent of the DE model pump - no PMD - but new engines were changing over to common rail injection. Basically individual electronically controlled unit injectors supplied by a high pressure pump. So timing and injector output was completely controlled by the ECM. Just about all engines in N. America are now common rail mainly because of pollution (EPA) mandates on Nox and particulates. Nothing against controlling pollution however what was a $450 pump repair in 1980 has turned in to an injector change out that can cost several thousands depending in large part as to how well the repair facility sharpens their pencils and how good they are at diagnostics.
Rruuff! You have a 7.3L - keep it. Compared to the 6L it is a tank. When they got in to the 6L repair times skyrocketed as anything involving the engine was quite often a cab off repair.
A lot of problems with any diesel fuel system is water related. If it were not for water there would have been a lot fewer fuel shops. Common rail has lead to the demise of fuel shops since proper diagnostics can now be done on vehicle and the defective part R&R'ed in the garage. Water is still the main culprit with fuel injection systems. It just costs you 10 times as much now.
Clean fuel, clean fuel filters, clean air filter, clean engine oil and filter and your engine should last a lifetime, however long that is.

 

[Tourmax]

The DS pump was just an extension of previous mechanical pumps with electronic controls. The main problem with the DS were the electronics and the vast majority of the time it was the PMD on the side of the pump housing. The Encoder sensor and the solenoid were fairly problem free although with time the solenoid was subject to "normal" wear. Don't forget guys and gals that that pump was working like crazy.
1/2 engine speed so lets say 1500 RPM pump speed X 8 (number of cylinders) = 12,000 injections per minute. So a little "normal" wear and tear is understandable, at least to me.
One other problem was the heat generated by the engine as the DS sat in the "V" of the engine. So good potential for heat build up there and that was problematic for the PMD
The electronic problems were solved to a large extent with the advent of the DE model pump - no PMD - but new engines were changing over to common rail injection. Basically individual electronically controlled unit injectors supplied by a high pressure pump. So timing and injector output was completely controlled by the ECM. Just about all engines in N. America are now common rail mainly because of pollution (EPA) mandates on Nox and particulates. Nothing against controlling pollution however what was a $450 pump repair in 1980 has turned in to an injector change out that can cost several thousands depending in large part as to how well the repair facility sharpens their pencils and how good they are at diagnostics.
Rruuff! You have a 7.3L - keep it. Compared to the 6L it is a tank. When they got in to the 6L repair times skyrocketed as anything involving the engine was quite often a cab off repair.
A lot of problems with any diesel fuel system is water related. If it were not for water there would have been a lot fewer fuel shops. Common rail has lead to the demise of fuel shops since proper diagnostics can now be done on vehicle and the defective part R&R'ed in the garage. Water is still the main culprit with fuel injection systems. It just costs you 10 times as much now.
Clean fuel, clean fuel filters, clean air filter, clean engine oil and filter and your engine should last a lifetime, however long that is.

Not to be contrary, but the ds4 and db2 share nothing except the mounting pad and the general shape. Nothing interchanges and thats not because they put electronic controls on the ds4.

Ds4 was an entirely new pump, made by the same company as the db2 (stanadyne).

military HMMWV’s got the db4, mostly for “ruggedness”, but also because the ds4 had such a bad track record. Also, they couldn’t “harden” the ds4 to emp. Important consideration in a military environment...

anywho, thats enough for me. I’m out of this discussion.

 

[LE BARON]

Not to be contrary, but the ds4 and db2 share nothing except the mounting pad and the general shape. Nothing interchanges and thats not because they put electronic controls on the ds4.

Ds4 was an entirely new pump, made by the same company as the db2 (stanadyne).

military HMMWV’s got the db4, mostly for “ruggedness”, but also because the ds4 had such a bad track record. Also, they couldn’t “harden” the ds4 to emp. Important consideration in a military environment...

anywho, thats enough for me. I’m out of this discussion.

I didn't bother to get in to the parts breakdown but that is not relevant.
The DS4 (4 plunger) is just the standard DB pump with electronic controls. It may not have exactly the same parts but the operation is the same.
D= Model D pump
S= solenoid
B= basically the second generation with a bigger rotor.

There was a model "A" pump was back in the 50's. In fact if you can find an old DPA made by CAV in England you can see "made under licence" from Roosa Master. Vernon Roosa was the inventor of the rotary pump hence the Roosa Master pump and also Roosa Master filters way back then. That eventually morphed in to Stanadyne over the years. Roosa Master model "A" pumps are quite rare to see but they do have a couple down at Stanadyne in Hartford in the show case.
CAV is really the company responsible for popularising the rotary pump on the diesel engine. One hell of a lot of Perkins with them

Any way, we digress from going for a whiz in the soon to be EV Hummer.

 

[ddgermann]

We disagree on many points.

But thats ok, we can disagree and still be amicable. That just makes it a healthy debate, not a distasteful disagreement.

Blowing smoke?

Hardly.

Lots of experience with these engines. Certainly a lot more than one H1 installation.

6.2 in the square-bodies right on up to the optimizer. I’ve had or worked on all of them at on point.

It’s just a bad engine design that they just pushed even harder with the turbo application. 6.2’s would crack and break main webs just as a NA engine. But because they were only pushing in the 120-150 hp range, they could live a long time with those faults. You have to remember the orginal intent of this design was MPG, and only MPG. The 6.2 was penned in the early 70’s as a way for GM to post big MPG numbers during the gas crunch, which it did nicely. But Detroit Diesel cut everything to the bone to do it, part of that was weight out of the block, which made it crack prone everywhere. It didn’t help that GM spec’d it as being able to fit in The same space the SBC fit in. That also limited DD in designing the engine. If you know diesel engines and how compact a package the SBC is, you start to see where the problems came from. Then they grew the 6.2 into the 6.5 TD in the 80’s, but they didn’t do anything to change the basic design. The added power just made things worse.

I’ve never taken a (running) 6.2/5 apart (nor has anyone that I know) without finding cracks in the webs. Sometimes you could pin them. Stop drill or even “lock and stitch” the cracks, but 99% of the time they are just scrap. Even repaired ones would eventually come back, having suffered a catastrophic failure of some sort. Most scrapyards won’t even sell the 6.2/5 becuase they know its going to fail. They go as scrap weight. I’ve seen (and built) 6.2/5’s with everything from main girdles to splayed 4 bolt caps. Doesn’t matter, they all fail. Its just a matter of when. It’s an under spec casting for what its asked to do. Thats why they upped the main web thickness, changed the block metallurgy and had the IH foundry cast the optimizers. Well, that and the fact GM had no interest in servicing/replacing a design they had determined as “discontinued”. Thats where AMG and GEP take over.

The turbo only sped 6.2 failures up (and made the failures bigger). The Turbo was a “stop gap” measure where GM was trying to keep up with its diesel competitors at the time and the duramax/isuzu was too many years away (design phase). Gm saw the writing on the wall for the coming diesel HP wars with the DI Cummins/Dodge and Ford/IH , but just couldn’t get a DI deisel design off the boards fast enough. So they punched out 6.2 to 6.5, cobbled on a turbo and electronic emissions controls and set it loose on the unsuspecting public. It was all a bad idea. 120hp design pumping out 212hp by putting it under boost and no other changes? Bad idea. Full stop.

But again: GM had to get something out into the market to carry their banner, even if it was waaaaay outgunned. .

They also changed from the db2 pump (mechaical) to the ds4 (electric over mechanical). That didn’t help the 6.5 TD either. As I mentioned, I’ve seen multiple failures of the ds4 and they’re not all pmd related. But almost all of them were electrical component failures, not mechanical.

I also remote mounted my pmd/fsd. Still ran hot as hell (Bill Heath relocation kit), but it was working when I sold the truck. Pmd was another bad design, no two ways around it.

I’ve got a “turbo master” up on the shelves somewhere.That’s Bill Heath’s design. Ran it for a while and went back to vacuum control. That was key to making more than 300hp. You can calibrate the turbo behavior in the ECM if you leave it as vacuum controlled. When its on, when its off and how much boost it makes and where. Belive it or not, there are points in the rpm range where you actually want the turbo to back off in order to make more hp. It counter intuitive, but dyno graphs don’t lie. Turbo masters are pretty primitive. Thats why none of the oems are using mechanical wastegates and haven’t since the early/mid 70’s. Even Cummins (which was a mechanical hold out on the 6bt turbo) vacuum referenced the Holset wastegate “spring control”. A good “tuner” doesn’t just turn up fuel and timing, they “tune” everything in the pcm, from the tailshaft to the cooling fans. Mechanical turbo control just limits you that much further. I suppose theres the argument of “less to go wrong” since its just a threaded rod and a spring, but the vacuum system works perfectly fine, if you take care of it. Same as any other system in a vehicle.

Bill sent me a couple “tune in a can” calibrations. Some worked well, others not as much. I always got better results brainstorming with Lindon and tuning my own truck. Bill’s were good, if you didn’t know better could be had if you put in the time and money to learn. I use John’s “Tunercat II” along with VDF’s from Lyndon Wester. At least I do for odbII gm’s. Tunercat is an awesomely power piece of software, it’s too bad he sold the rights to JET for their diesel-tuner. They charge by vehicle for tuning and lock you in. Point blank: JET sucks. The original TC is wide open: buy a vdf and tune as many of that vehicle as you like. Lyndon is also great and he sells his own version of a diesel tuner (essentially: tunercat II with a few graphics changes). You CAN still get TunercatII, but tou have to by it from Moates.net and it has to be packaged with their “road runner guts kit”. You’ll spend near a grand to get it. But if tou tune 6.5’s, its pretty much the only game in town. Unless you want to get up into the 2 grand range for Lyndon’s software/hardware package.

Also for consideration: I was military until this past Apr. I’ve been on lots of joint exercises with the US army. Every one of thier EME guys (military mechanic) I’ve ever talked with absolutely DESPISED the 6.5 in the hmmwv’s. Yes, they had to endure abuse from combat and somewhat.....ummm....”careless” operators. But they saw the same things I saw on civvy side: cracked precups, cracked main webs, fractured cranks, etc. thats both 6.5’s and optimizers, although the optimizers were less troublesome. Not a lot less, but less.

you do know that upping the calibration resistor really does nothing for you, right? The resistor is matched to a pump at the oem to compensate for production differences in the pump. Tossing in a higher number DOES get you more fuel, but only at WOT. The resistor calibrates the maximum fuel delivery point. It has no effect on anything besides WOT.

Thats not just my opinion, I’ve tested it on a chassis dyno. Running a #5, we switched to a #9 and changed nothing else. Absolutely zero effect on the hp or torque curves. Despite what the resistor is supposed to do (according to internet lore), it didn't even change WOT. We tried it on my truck and then two others that were in the shop. Results were always the same: zilch. Better off to just stick with the oem resistor card it came with.

yep, I’ve got lots of experince with them. In fact, I’m one of 5 people (that I know of) who have ever been able to make more than 300 hp out of them. Getting past 250 requires pretty serious work. Not the least of which is a grand to buy the tuning software, more hours than I can count learning the ecm’s code and many, many, many dyno sessions.

oh, and pickup applications were NOT intended to run 100 mph on the highway. That, my friend, IS blowing smoke. They were designed to run at torque peak at the national (us) speed limit. Which was 55.....

Because you have one truck with a 6.5 and its given you good service, that doesn’t mean they all do. Just like someone, somewhere eventually gets a “lemon” in an otherwise reliable design, someone, somewhere will also get a “jewel” from a line of lemons.

So as you can see, I’ve had several (and I’ve fixed/modified even more) so when I say they’re “junk” I’m basing that on a pretty large sample size.



iI’s just a bad design. Start to finish. Whether you’re talking 6.2, 6.5 or optimizer (yes, I’ve seen one with cracked mains and cylinder bores). Even the “fabled” 599 casting has failed on me. there are no exceptions to the GM 6.x curse.

It’s really quite surprising from a design firm like detroit diesel, who did the work for GM in the beginning. Surprising in the way that DD would even let it off their drawing boards with the compromises GM demanded. Oh well, “money talks” I guess...

You know what? Definitely keeping amicable but remember you were doing the heavy slagging of the engine. I just offered a different perspective. So go ahead and be the 6.5 superhero.

I didn't even read the rant above as I really don't care.

Have a great day and ya... smoke

All good man.