[DodgeMan]

I keep reading that one of the enhancements for the 6.1L powered cars is a reinforced block. Does anyone know if that means it's a different casting than the 5.7L block? Both blocks have the cross bolted mains, so I'm not sure what is meant by reinforced. The dealers I've talked to do not know.

 

[Inferno Charger]

The dealers I've talked to do not know.

And they probably never will unless you find the rare one that knows their $h!t. My take on the 6.1L is that it is not a derivative of the original 5.7L block but then again I keep hearing that all they did was over bore the 5.7L. Which begs the question as to what source is right? Dunno

Later

 

[DodgeMan]

The bore is another reason why I'm wondering if it's a different casting. That's a beefy cylinder wall to be able to go from 345cid to 370cid

 

[Inferno Charger]

Yeah the cylinder wall has to be thicker on the 5.7L to bore it out that much but I think they would need to change the stroke as well with a different crank and rod ratio to achive the 370cid. Otherwise those cylinders would start to get pretty thin.

 

[GLHS837]

(yoda voice) "Sometimes to the past look you must to the present understand")

Anyway, heres some tidbits from an interview Autweek did with Dan Knott, director of SRT.

"Start with the basics: Bore it out by three millimeters to up displacement from 5.7 to 6.1 liters (6.059 actually), bump the compression ratio to 10.3:1 from the standard 9.6:1, install a high-performance camshaft. It goes deeper than driveway hot-rodding, though, and not only because Chrysler can make the electronics work in concert even while keeping it legal in the eyes of the feds.

SRT improves the breathing with larger-diameter, hollow-stem valves and reshaped cylinder ports, fed by a new intake manifold (a thing of beauty under the hood that initially distracted us from the orange block) and steel-tube exhaust headers a quarter-inch larger in diameter than the exhaust manifold in the base Hemi. The SRT-8’s block is reinforced and boasts increased coolant flow, the crankshaft is forged steel, the connecting rods are stronger powdered-metal forgings, the pistons run on floating pins and are cooled by oil squirters, the exhaust valves are sodium-filled, and the oil pan is modified for reduced foaming. With the stronger parts, the SRT version of the Hemi spins nearly 15 percent faster than the base model, putting redline at a respectable 6200 rpm (the electronic cutoff is at 6400) vs. the regular edition’s 5400 rpm. "

From here: http://www.autoweek.com/article.cms?articleId=100555

Another thing we've discussed is exactly what changes the "upgraded rear diffrential" gets over normal cars.

So heres' this bit, note mention of "beefed up halfshafts", which I had not seen in print anywhere.

" Knott also had to draw on corporate knowledge by finding AMG’s supplier of rear differentials and ordered up a part akin to that used on the mighty Mercedes-Benz E500 to couple to his beefed-up halfshafts."

 

[maneval69]

From Allpar

the block changes

The basic, deep-skirted engine block structure was redesigned with reinforced bulkheads to handle higher loads.

Here are the rest of the upgrades.

# To get more air in and out of the cylinders, SRT engineers bored out the diameter of each cylinder by approximately 3.5 millimeters in order to increase the total displacement from 5.7 liters to 6.1 liters. Cylinders are honed with torque plates to ensure a truer bore, to reduce friction and increase power.

# Oil squirters, aimed at the underside of each piston, are added to aid piston cooling for engine durability. A special oil pump pressure relief valve is added to accommodate the squirter oil flow.

# The oil pan and windage tray are modified to manage oil return to the pan sump at high engine speeds and improve power.

# Larger-diameter, flat-top pistons with high-load capability are specified to handle the SRT 6.1-liter HEMI?s compression ratio, which was increased to 10.3:1 from 9.6:1. Connecting rods are redesigned and make use of higher-strength powder metal material. New floating piston pins are introduced to handle higher loads.

# The SRT 6.1-liter HEMI?s crankshaft is forged from micro-alloy steel and rotates in tri-metal main bearings for high-load capability. The crankshaft damper is retuned for higher engine speeds.

# The SRT 6.1-liter HEMI features cylinder head ports designed with larger cross-sectional area. This allows 11 percent higher flow in the intake ports, and 13 percent higher flow in the exhaust ports.

# A billet steel, high-strength camshaft features more overlap and lift for better performance.

# Intake valves feature hollow stems and 2 mm larger heads compared to the 5.7L engine, allowing more air flow. The hollow exhaust valve stems are filled with sodium to dissipate heat efficiently. Premium valve springs with external dampers enhance the SRT 6.1-liter HEMI?s valvetrain and enable higher engine speed operation to 6,400 rpm. The valvetrain system enhancements allow the peak output engine speed to increase to 6,000 rpm from 5,000 rpm ? a 20 percent increase.

# Engine breathing is improved with specially designed intake and exhaust manifolds.

# The cast aluminum intake manifold is designed with shorter, larger-diameter and tapered runners for high-speed tuning. Internal runners are core-dipped to smooth the runner finish and improve air flow.

# Fuel injector flow capacity is also increased by 14 percent over the 5.7-liter engine. Electronic throttle control is shared with the 5.7-liter HEMI, but breathes through a revised high-flow air cleaner box outfitted with a tuned resonator delivering a deep performance sound character (and good for an extra eight horsepower).

# Exhaust headers on the SRT 6.1-liter HEMI are individual tubes encased in a stainless steel shell. Exhaust runners allow increased gas flow while maintaining fast catalyst light-off, while adding 12 horsepower over the 5.7-liter engine?s cast manifolds.

# To control the combustion process, SRT engineers fine-tuned the engine management system using dual knock sensors with premium fuel.

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Leann_Love cam

 

[DodgeMan]

OK....here's some more teasing info supporting a different casting....

http://autoheadline.com/content/view/25/26/

SRT 6.1-liter HEMI Engine Block and Lubrication System
The basic, deep-skirted engine block structure is redesigned with reinforced bulkheads to handle higher loads.

Hmmmmm.......

I'm sorry....I'm just obsessed with this car and these are the things that keep me up at night

 

[GLHS837]

It's okay, DM, no need to apologize, your amongst friends here. We're all sick, but since we're all sick the same way, it's okay

 

[maneval69]

He's got the fever and the only cure is more COWBELL!
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