That's right, both front and back need changed. If not, the front wheels will spin at a different rate than the back with 4x4 engaged. In mud and snow, this isn't a big deal because the tires will slip, but if they grab the ground it will be devastating for your trans. case. Especially aluminum chain driven cases that are used today. This is so critical that even tread wear on the tires becomes an issue.

Gear swaps are fairly easy as long as you know what your doing. If you don't know what your doing, it can take a lot of research and time to complete the project. The shimming and backlash are the big issues here, you put it together if it's not right you take it apart and use more shims.

 

The '07 hemis were rated at 360, so really it should have dynoed in the 250-270 area. 245 is low, but it's not that far off.

If anything, Chrysler is usually pretty conservative with their numbers. The srts always dynoed either right on or slightly higher. They even listed the to the wheel numbers as the advertised numbers on the srt4s when they first came out.

 

I guess I'll add my own story lol.

I was on 16 mile the other day(50mph, 3 lanes). These guys in a chromed out Ford Super Duty were checking out my truck. They honked at me, and I rolled down my window. "hey man, that's the best looking dodge I've ever seen" I said thanks, and we chatted for a second, and the driver said "let's run them."

Ok, so they've got 4 people in a truck that is already twice as big as mine. I thought I saw supercharged on the badge, but I didn't hear any whine. Anyways, I'm not sure what he thought would happen, but it was the quickest roll race ever. We went from 35 to 50 and I stopped at the speed limit already having 2-3 trucks on him.

My buddy has a 2004 lightning, and we ran at the track(actually another friend was driving my truck). He usually runs mid 13s, so I was expecting my truck to get walked. The Ford won, but it was neck and neck the entire length both races. .2 separated them on the final run. Not great times(14.6/93) because of the weather(over 80 degress, rain in the morning and super humid), but the corrected time for my truck was 14.0 at 96. 87 octane, truck full of luggage That was in Thunder Valley on the Hot Rod Power Tour.

I'll update my sig to show the truck.

 

The advertised HP is always at the crank.

All of the accessories, the transmission, and transfer case all require a percentage of the engine's torque. The transmission on the 2009 probably needs 50+ HP to work. So, when you dyno it, you are going to have 390HP minus accessories minus transmission minus transfer case minus spinning a driveshaft minus spinning the axle that has 32" tires on it. That may only equal 275 HP.

Sure, if you compare a 4th Gen at the wheels to a 3rd Gen at the crank. It is not a fair comparison.

 

This is from Truckin'

Keep in mind that different brand dynos read differently too. The two I see the most are Mustang and Jet.

 

Hypertech's dyno is listing the STOCK RWHP of an 09 Hemi Ram at about 340HP:


http://www.hypertech.com/media/dynoc...i_trucksuv.pdf

 

That sounds about right

 

And you have a disadvantage with your 4 wheel drive because of the weight, good kill! I'm much lighter with my 2 wheel drive SWB, and I've been loving smoking all takers so far. Haven't ran any Rams yet, but I'm not interested in beating up on my bros, lol. And I wouldn't waste my time racing a Vette, Viper, Camaro, or Challenger, it's a truck, not a hotrod or a race car. It's a blessing for a truck to run in the 14's as it is, when you all get reflashed, you'll freak at the new power you didn't know you had. I can't wait to send my PCM off to get reflashed, I just have to decide on a cam install or not, and raise the money. I'm not waiting much longer for Diablo to tweak one for the Ram. They've done it for the 09 Charger and Challenger, but seem to be having issues with the Ram for some reason. And guys, we are not only detuned at shift points, but detuned above certain rpms as well, read your manuals. I doubt any of us would see even 350 hp on the dyno until a reflash

 

I started with 11psi and tested to see how much it would take to alarm the knock sensors. That gave me the confidence to move up to the 3.25" pulley for 14psi. That is as high as I will go.

I have an engine compression sheet I build on excel and that is how I gauge my alcohol fuel maps. The only problem with the 09 Hemi's are the current compression ratios. I honestly don't know if boost can safely be ran on them in stock configuration.

 

My concern exactly at 10.5:1 you start adding too much boost and even if you do get the fuel/air mixture right (which i know nothing about) seems like you might start having problem on the bottom end. Does anyone know if the 5.7L Hemi is a 2 or 4 bolt main???? I remember in the early 80's GM took a gas bottom end engine and "adapted" it to a diesel engine in their trucks. To say it didnt work out well would be an understatement. Anyone know how much horsepower someone has gotten a stock hemi short block to reliably produce? There has to be some guys out there hammering on a 5.7L mopar crate engine.
Lee