Ram vs Dodge/Chrysler - how complete is the separation?

[Renze]

And the really cool thing is with turbo(s) you open up the availability of a exhaust/compression brake.

And why is that ? A compression brake is called compression brake for a reason... and so is an exhaust brake.

When Clessie Cummins invented the Jake brake after he sold his engine company (And had the Jacobsen drill chuck company produce it, hence Jake brake) it was 1957 and turbocharging wasnt common yet.

It disappeared because its a diesel, not because its an in-line.

It wasnt, it was an Italian V6

They still show one on their website, yet under "special products"

SPECIAL APPLICATION ENGINES[col=279]

www.vmmotori.it

Under "on-road" they only list a 3 liter 4 banger and a 4.5 liter inline six. Which off course would be great in a 3/4 ton pickup..

INDUSTRIAL ENGINES ON-ROAD

www.vmmotori.it

 

[DarkBlack]

Cool story, but they forget the most important reason:
Apart from the lower thermal efficency inherent to a lower compression ratio, the other big factor in efficiency difference with a diesel engine is, that a diesel controls its speed by adjusting the fuel delivery, and gasoline engine controls its speed by choking off the air.

Fair enough, but I don’t think the article even mentions diesels. Diesels vs gasoline wasn’t in the scope of comparison. It’s strictly about the gasoline inline 6 vs gasoline V engines.
For all of diesel’s attributes, we all know our government is pressuring hard to eliminate them.

 

[DarkBlack]

Now at partial load conditions, the old V8 gas engine with mediocre power output is constantly working to suck a vacuum between the pistons and the throttle valve.

So, more efficient would be to use an engine displacement that can cruise with a wide open throttle, whilst keeping a turbo at hand to push more air into the engine when accelerating or towing.

That’s the goal of modern cylinder deactivation that many modern V engines employ. Keep the cylinder valves closed on half the cylinders during partial load, so you have 1/2 the pumping losses. You also gain dynamic compression gains on the active cylinders by having a higher charge pressure than you would if the flow was shared across all cylinders.
Still.. 4 and inline 6 cylinder turbo engines make more sense for meeting ever stricter regulations

 

[Renze]

Fair enough, but I don’t think the article even mentions diesels.

It should have. Because it totally misses the point of the trend of replacing a V8 by an iine 6 which is downsizing + turbocharging to partially eliminate throttle loss.

I used the diesel reference to illustrate throttle loss (which a diesel doesnt have) and that downsizing and forced induction is the only way of eliminating it at partial load conditions in spark ignition engines.

 

[Renze]

That’s the goal of modern cylinder deactivation that many modern V engines employ.

Guy i know has a Ram 1500 Hemi. He had cylinder deactivation, deactivated, because he says its a source of expensive breakdowns...

And its not near as efficient as downsizing + forced induction because that piston is still displacing air when its slamming up and down 25 times per second at 1500rpm.

 

[DarkBlack]

Guy i know has a Ram 1500 Hemi. He had cylinder deactivation, deactivated, because he says its a source of expensive breakdowns...

And it’s not near as efficient as downsizing + forced induction because that piston is still displacing air when it’s slamming up and down 25 times per second at 1500rpm.

I agree. That’s part of why Ram is dropping the cylinder deactivation hemi V8. A turbo inline 6 is more logical than a cylinder deactivation V8. My personal experience with it is it’s better on paper than in actual execution. I don’t know if I’d go so far as to state with a certainty, that cylinder deactivation is a source of expensive breakdowns though.
The 5.7L has had an unenviable track record of wiping out cam lobes. I’m not aware of it ever being proven linked to the lifters deactivating. I believe just as many non-active lifter lobes have failed.
Improperly hardened camshafts, and perhaps an inadequate oil migration path in the lifter valley, at lower rpm’s may have been the cause

 

[WinterDeere]

Guy i know has a Ram 1500 Hemi. He had cylinder deactivation, deactivated, because he says its a source of expensive breakdowns...

I always disable it in my car (Charger SRT 392), and usually in my SUV (Durango R/T 5.7 Hemi), but more often than not just leave it on in the truck (Ram 1500 5.7 Hemi). It is an annoying feature, especially in a sporty car, but I've never heard of it causing breakdown issues for anyone I personally know. Ram's are easily the most popular truck here, maybe even more than all other brands combined, probably due to a unique combination of nepotism and a very large dealership with strong community ties.

 

[Renze]

The 5.7L has had an unenviable track record of wiping out cam lobes. I’m not aware of it ever being proven linked to the lifters deactivating. I believe just as many non-active lifter lobes have failed.
Improperly hardened camshafts, and perhaps an inadequate oil migration path in the lifter valley, at lower rpm’s may have been the cause

After i bought it, i found that i bought the right year of Volvo D5 diesel. They prescribed 0w/30 low friction fuel saving engine oil from 2006 onwards, had cam wear problems, and they increased the lobe hardening from 2007 onwards.

It used quite some more oil with 360.000km than my previous 1999 S70 TDI with 560.000km, which i solved by using 5w/40 engine saving oil. I dont know how much fuel this oil is intended to save, but the oil i kept filling every 6 weeks was pretty expensive too.

 

[Mtsoxfan]

Back in the 80's I remember working on Cadillac 8/6/4 engines. In theory, it made sense as a fuel saver, shut down valves when cruising. In reality, there were many carbon buildup issues.
Back to truck engines...

 

[Wombat Ranger]

My 2005 Daimler-Dodge Ram pickup had a Getrag 6-speed manual transmission. But they've all been ZF 8HP70's for the last 10 years or more.

That's "ZF Friedrichshafen AG"... so I'll give you one guess where they're based.

Your 2005 must have been a 1/2 ton. I just recently sold an NOS Getrag 238, maybe the last one out there. Unfortunately they're obsolete and parts entirely unavailable.

I think Ram also used a manual 6 speed that Benz builds for their European Atego distribution trucks ?

Yes. Mercedes G56. Direct takout from those trucks, until the 6.7 rolled around and Chrysler wanted to reduce cruising RPM. They changed the drive pair by one tooth to increase the overdrive ratio. It also changed all the rest of the ratios, so the early G56 gearing has nicer splits, but all the pickup guys want the later one for the lower top end RPM.

I have that transmission in my 2009 Ram 4500 seen somewhere back in this thread hauling the 450B. It's served me well, I opened it up this winter for the first time in it's life (at 330k hard working miles), it got a new (used) input shaft/gear (pilot bearing wear from a badly machined flywheel), bearings, syncros, thrust washers, and seals. That 4000 mile trip in 4 days bringing back the dozers was the shakedown run, it did great.