Not trading in the SS anytime soon. I have thought about a Hemi Durango for the family car. Just curious more than anything. When the hemi first hit the market, everyone said how strong they would be once the aftermarket items hit the street. Well, its been years now and there really aren't any simple kits for making big power (besides nitrous) for the Hemi. I assume thats due to the lack of tuning ability, so I thought I'd become informed and get a good discussion going.

 

From what I've gathered lurking other sites, it's just as stated above. The SD tune and lack of availability of a colder plug prohibits heavy nitrous use. The only thing available for the HEMI tuning wise is handhelds and the Jet chips. We all know that the Jet chips aren't all they're cracked up to be and the HPP3 is mediocre when it comes to tuning in the grand scheme.

I really think once the PCM is opened up, it's gonna be some stiff competition on the street and track.

 

Yeah, the computer front is bleak.
There are two NGK plugs out now, 4306 is a standard length and one colder, while the 4177 is 1/4" shorter and one heat range colder. The NOS guys use the 4306, the F/I folks are using the 4177. The other bad is having two plugs per cylinder, get tiring and expensive!
The CO guy who converted to the stand alone and manual TB with his turbo freed up a ton of power, close to 80 hp/trq over the stock ECU. He did lose cruise control functions tho.
The 5.7L ( some folks are sensitive to the use of the "H" word ) was a big departure from the older 318/360 construction. Electronic throttle control, totally new ECU, and use of a Mercedes transmission are just a few. It can be done, both a stand alone or piggyback, but the cost is super prohibitive. The stand alone conversion is well over $4000 for the parts and labor, and the SMT6 piggyback will probably go close to $1000 when done. Makes HPT and LS1Edit seem cheap by comparison huh?
They also mentioned the processor change from 2003 to 2004 ( 16 bit to 32 bit ). I also hear rumors that even same year ECM's can have up to 8 different programs loaded. The other rumor is how DC coded the algorithms. I can't remember the term but it is similar to an X-Box where the coding is proprietary and not like any other vehicle brand. Makes it very tough to crack and translate. Combine this with DC not coughing up the codes makes life totally miserable from the tuning front.
I hear the stock injector size is 30lb/hr there Richard, with the latest 6.1L having 42lb/hr models. Oh yeah, forgot to mention the 2003 models has lower fuel pressure, 49 vs 58 in the 2004+ models. Go figure....

 

RIP? What did you do to your engine?

 

I think the SRT-10 trucks run the Viper PCM, but don't quote me on that. I didn't realize that the baseline no's on the Hemi's were that low. I thought they'd be higher than that. That's a pretty good driveline loss.

 

I was thinking the same thing about the SRT10, it would make perfect sense.

KTM, that's some good info there. Just look on the bright side though ... there were enough ambitious and knowledgable folks out there to crack the Xbox code and do something with it, so I still say give it time.

 

FYI, the hemi uses the same transmission as the 4.7L dakotas do, and I'm not sure the setup on the hemi, but on the dakota, the trans is 100% electronically controlled, but NOT via the PCM. There's a small "TCM" (transmission control module) that looks similar to a heatsink, mounted up front. This thing controlls the trans completely, the only outside work is the sensor values it reads to know when to shift. So eliminating the PCM might not create issues with the trans as long as you can still give the TCM it's sensor values to read. I think.

 

Aye on the 03 rams the tranny controller is seperate from the pcm. This is how the 03 guys can pull the wire to get the firmer shift. I thought on the 04's the units was merged together and thats why you can't pull the wire on the 04+ like you can on the 03's, though I could be wrong on that.

 

Too much boost + too little tuning = blown pistons and rings.
Another 5.7L tidbit, the upper ring land is veeery close to the piston crown ( ie thin ). Some early F/I guys cracked the pistons under high boost and/or if detonation occurs ( my issue ). DC did this for emission reasons but shoulda installed forged pistons. Well, I guess they live fine when N/A but there is no where near the beefiness of the GenIII motors tho.

 

Can't verify if this is true or not. The Hemi option includes a 5 speed auto tranny, 5-45RE, where all other Ram engine options used the 4 speed. Again I would have to check, especially on the Dakota.
Yes, the 2003 model have the TCM separate from the ECM and the 2004+ have the TCM integrated into the ECM. The TMR ( torque management removal ) was good for a 0.3 second reduction in 1/4 mile times. It only impacts the 1-2 gear shift but is a telltale sign of how "conservative" the DC computers are. Everything was engineered to last for the 7/70 powertrain warranty and up. The engine dyno and chassis dyno numbers show a 25%+ drivetrain loss. The CO guy who went with the stand alone controller is a good example of the restrictive computer. Now we wait for someone to break it open. Seems to me that with my home computer getting virus attacks and worms every day, could someone pay on of these hackers to break into the DC auto computer?!?