I am very NEW here but not a stranger to the Commander world. I have had my Jeep Commander "Baby Birtha" since 2012 and just cannot let it go. I have big plans in the near future for my vehicle and looking to possibly place an LS at some point. In the meantime, I do like to play around with it and try things out. For example, the "Viper" TB swap on the 3.7L V6 motor. So, I just wanted to clear a few things up on what I found out on my end.
Not sure about the 2006 Models but if you have a DBW Jeep Commander from 07-10, the 4.7L TB will bolt right up to the 3.7L intake manifold. Just make sure you are getting the electronic DBW and not a cable driven TB. You can purchase them on car-parts.com. The 4.7L TB I have is from a 2010 Jeep Commander (P/N: 53032837AB) at $70.00 out the door with 20k miles on it. So, it was a nice clean deal...why not right!?!? Either way, I wanted to get rid of that BIG black box that was a pain to tighten the clamp to the TB. PLEASE know that the 4.7L TB may bolt up to the 3.7L Commander or Grand Cherokee but that doesn't mean it's going to be a clean swap. Just a few things to look over...There is a tab/notch on our intake manifold that lines up and goes into the 3.7L TB indent/insert. The 4.7L TB has the same indent/insert but the 4.7L TB will not line up with the 3.7L intake manifold. Do not force it on and just bolt everything down. It may look like its down, but it will not be fully flushed. You will have to trim that tab on the intake manifold off to have the TB fully flushed and sealed. Everything will bolt right up and do not forget about the connecter. Make sure you torque down to spec.
Now what I really like to talk about is the size differences of the TBs between the 4.7L and the 3.7L. Yes, the 3.7L TB is a 2.5" opening vs the 4.7L TB being at 3" opening. What I do not see people talking about too much about is the opening to the intake manifold. Measure the intake manifold on the 3.7L carefully and you will see there might be a slight air restriction. The 4.7L and 3.7L intake manifold opening are NOT the same size which I see people are saying that they are. The 3.7L intake manifold measures at 2.75" opening. So, the 4.7L TB opening is bigger than the 3.7L intake manifold. Let us say you have the 4.7L TB on your 3.7L intake manifold. Open the butterfly valve and you will see the round edges of the intake manifold. This does not mean it is not sealed but that will cause air restriction...at least in my book.
As for power differences or torque gains...nothing. I honestly do not feel any difference but lose in MPG. I went from 13MPG to 11.5MPG. The ECU will adapt to the new TB and will act normal at some point but just know that there are no gains on the 3.7L V6. This motor is just maxed out completely. You can try to place a tune and see what it does but the tuning maps on our 3.7L motors are very extremely limited to nothing at all. You are more than welcome to give it a try which I did, but I thought some information I found out would help some peoples decision making a little easier.
If you do want your 3.7L to feel almost brand new I suggest changing all the sensors on your vehicle if it has high mileage. Clean things up a bit…I did, and it sounds and drives GREAT. I also placed a catch can on my vehicle just to see what happens and it works wonders. Catch can do work on our vehicles and I think it is worth it. Here is a link to the catch can I have (Ruien Polish Baffled Universal Aluminum Oil Catch Can Reservoir Tank Black). If you have any questions just let me know. Hope this helps!!!