'04 4320 performance chips?

Rob52 · Nov 13, 2006

Anybody know where to find performance chips for JD 4020 series? Do they may them? Are they worth it?

joebobharley · Nov 13, 2006

Ahh, the Holy Grail. Instant 4720 in a box. Doesn't exist in this world and probably never will. However..... there is always hope.

papafoxtrot · Nov 13, 2006

joebobharley said:
Ahh, the Holy Grail. Instant 4720 in a box. Doesn't exist in this world and probably never will. However..... there is always hope.

Does anyone know what JD does to make the incremental changes between models? All the specs seem to be the same between my 3520 and the 3720, yet the "7" has more HP. More boost to the turbo? Or has it been "chipped" in some way to get those few more HP's? They're doing something. Its plain they add the turbo between the 3320 & 3520, but the same situation holds true between the 3120 and 3320.

NoMo · Nov 13, 2006

The 3720 has an intercooler whereas the 3520 does not.

papafoxtrot · Nov 13, 2006

NoMo said:
The 3720 has an intercooler whereas the 3520 does not.

Wow,

So if can scoop an intercooler someplace, I can gain 7HP? I mean that's worth the quest. I didn't think there was that much gain to be had, but keeping things cool is an honorable pursuit.

Do you know what the boost pressure is and is it the same on both (37xx vs 35xx) - or do they play with that too?

NoMo · Nov 13, 2006

The cool(er) air by itself won't do much by itself- you need more fuel too. I don't know if they are getting the extra fuel by increasing pressure or via injector duration.

My guess is that the turbos are the same and the extra power comes from the intercooler/fuel changes. Maybe someone with more/better knowledge will come along and give us some facts vs my speculation.

joebobharley · Nov 13, 2006

There is a good deal more complication in the difference in engine set up other than just an intercooler. Additional fuel, timing differences as well as "chip" or computer changes that would control all sorts of other different engine parameters. There are a couple of other threads on the site that have documented some of this. Although I am sure that there is a path that could be taken, no one so far has admitted to having the know how. John Deere is very protective (and rightly so) of the actual differences between the machines and how they bring it about.

papafoxtrot · Nov 14, 2006

joebobharley said:
There is a good deal more complication SNIP. John Deere is very protective (and rightly so) of the actual differences between the machines and how they bring it about.

Thanks for the info. I popped for the 3520, over the 3320, just because the HP jump/$$$ seemed well worth it. I'm just a HP (actually torque) junkie from way back.