What's the real difference between units?

[RBachman]

I looked around on the site a bit and couldn't find a thread that discussed this---though I'm sure there is one. So my apologies if I am repeating past threads.

I just purchased a JD-4520. Looking at the specs. the 4X20 series all have the same engine, same displacement, same compression ratio, and all else on the tractors seem to be the same. If so, why is there a big price increase between engine horse power? What is necessary to take the same engine and increase it's horsepower? Is it the electronics? The fuel pumps and injectors? Are mechanical components beefed up to handle the load? Do the changes necessary to take advantage of the engine's horsepower really cost this much? I'm not that familiar with tractors and have to be missing something here.

What's the difference?

 

[AKfish]

Congrats on your new 4520! And a hearty welcome to TBN. You're quite correct in that there have been a fair number of previous discussions regarding the various reasons for the HP difference between the 40x20 series tractors.

It's been awhile... but what I recall as the most significant difference between the various models was the fuel injector pump. Several readers researched the part numbers for the turbochargers and the injector pumps for the different models.

The turbos were the same but the injector pumps were different as the HP increased. (I don't recall if there was any difference in lbs. pressure boost for the turbos, though..)

Of course, there was also a general acknowledgement that the computer control (software and hardware - chips, etc.) for the different models was also a primary factor in the different HP ratings.

A search of the archives in the JD owning and operating forum will give you plenty of info and likely clear up anything I've forgotten too!

AKfish

 

[RBachman]

Thanks AK! I'll keep searching. I just hated paying so much more for extra HP when it seemed there really isn't any significant additional costs in the manufacture of the different models. Of course, it is what it is, and they charge it because they can get it.

 

[dfkrug]

Yeah, Kubota now does with GL40s what JD has done for several
years. The L5240 and L5740 seem to be identical, except for 5 hp, and
maybe $1500. I understand that there may be additional fuel delivery in
the 5740 by giving it different pump settings and injectors. What is not
clear to me is if Kubota or JD are using any electronic controls to vary the
fuel settings. Unless the 2 different tractors use heftier components
elsewhere in the tractor, I can not see them costing more to build. I DO
see that the 5240 and 5740 weigh exactly the same, but the hp is specced
at RPMs that are 100RPM diff and the implement pumps differ by 0.4GPM.

Maybe we are just seeing a marketing response to JD?

 

[Reg]

I looked around on the site a bit and couldn't find a thread that discussed this---though I'm sure there is one. So my apologies if I am repeating past threads.

I just purchased a JD-4520. Looking at the specs. the 4X20 series all have the same engine, same displacement, same compression ratio, and all else on the tractors seem to be the same. If so, why is there a big price increase between engine horse power? What is necessary to take the same engine and increase it's horsepower? Is it the electronics? The fuel pumps and injectors? Are mechanical components beefed up to handle the load? Do the changes necessary to take advantage of the engine's horsepower really cost this much? I'm not that familiar with tractors and have to be missing something here.

What's the difference?

In reality; "What the market will bear."

but on a semi-techie basis; fuel maps & "turning up the pump" (the "how ?").

It isn't "cost driven pricing".

 

[skidoo]

I was comparing 4720 vs 4520. It appears the e-hydro comes standard on the 4720 vs optional on the 4520. So, the base price really isn't as great a difference as it first appears.

 

[Cidertom]

From earlier research: The two smaller ones have smaller turbos with less boost. The injectors and fuel is then matched to boost and the owners payment.

Lest anyone think that JD came up with this idea, some of the big engine manufactures have been doing this for years. Same castings, same pumps, just more HP for more $$.

What I found strange is the 4720 (when I bought mine) was not offered in other than Hydro. So 4720 - hydro loss =4520 with 12/12 for net HP.+/- . Even with skidder chains on rear tires, I lose traction short of losing engine power. I bought the 4520 for having enough PTO power at the same time as I'm moving.

 

[Kyle_in_Tex]

If I remember right the boost increases with each model. See the Nebraska tests for accurate info.

I think the boost went from 7 to 9 to 11 psi for the 4320-4720 models.

Hummmm. Makes me wonder if the P/N for the turbos, injector pump, etc are the same???? I'm guessing for sure the "computer" module is different.

 

[jrutherford]

In reality; "What the market will bear."

but on a semi-techie basis; fuel maps & "turning up the pump" (the "how ?").

It isn't "cost driven pricing".

I view it as a 4520 or 3520 is a discounted and detuned 4720 or 3720.
You are paying for the technology and r and d in the highest performing model, any thing else is discounted and detuned to fit peoples budgets or percieved needs. I just upgraded to 3520 because it was available and deal was good; best bang for buck may have been 3720 but how long till delivery? I need the rig soon. I bought 6415 early last december and there was loader shortage, didn't show till February! I am sitting in a 8430 right now. I remember a guy on another forum who chipped an 8320 to make it 8420 and blew the rearend out of it. Yeah, sure look the same outside, but guts may be different!

 

[Kyle_in_Tex]

I view it as a 4520 or 3520 is a discounted and detuned 4720 or 3720.

3520=turbo
3720=turbo and intercooled

 

[Spudland_Dave]

I view it as a 4520 or 3520 is a discounted and detuned 4720 or 3720.
You are paying for the technology and r and d in the highest performing model, any thing else is discounted and detuned to fit peoples budgets or percieved needs

I see it the same way...PERSONALLY, before buying the biggest model of a given series, I'd go to the next series up and a little lower on the foodchain... (I'd get a 4120 before buying a 3720) Reason being, most of the guts/internal parts are the same regardless (Transmission, Pumps, and other important & expensive parts)...so its pretty safe to say a 3320 or 3520 is a pretty bulletproof machine in that it wont have the power to self destruct itself because all its guts are good to 3720 HP levels, etc... True, with good care and careful operation ANY of them should be just fine...but I see it as that little extra buffer.

 

[peter_vii]

If I remember right the boost increases with each model. See the Nebraska tests for accurate info.

I think the boost went from 7 to 9 to 11 psi for the 4320-4720 models.

Hummmm. Makes me wonder if the P/N for the turbos, injector pump, etc are the same???? I'm guessing for sure the "computer" module is different.

If it was just the computer module that needed to be re-programmed, I'm sure
we'd see $300 "upgrade kits" on e-bay.

 

[Reg]

I view it as a 4520 or 3520 is a discounted and detuned 4720 or 3720.
You are paying for the technology and r and d in the highest performing model, any thing else is discounted and detuned to fit peoples budgets or percieved needs. I just upgraded to 3520 because it was available and deal was good; best bang for buck may have been 3720 but how long till delivery? I need the rig soon. I bought 6415 early last december and there was loader shortage, didn't show till February! I am sitting in a 8430 right now. I remember a guy on another forum who chipped an 8320 to make it 8420 and blew the rearend out of it. Yeah, sure look the same outside, but guts may be different!

I doubt that the development costs are counted and shared out to that level of detail.
It was my experience (in a different engineering field) that product development was done for a group (family, "line") of products with the marketeers trying to stretch it every which way they could and twiddle permutations/combinations to fill what they perceived to be potential gaps in the line.
By some ways of doing the arithmetic, sure everything has to be paid for somehow and cu$tomers are the only source of revenue.

At the bottom line every sale subsidizes every activity the company does, including charitable donations.

I still think it is ONE design with minor implementation differences; bore and stroke, pistons, camshafts and balancer shafts, with some smaller changes via fuel maps and turbo boost.

 

[JD3520Turbo]

The 31, 33,35,3720 series tractors are all the same basic tractor. The 33 has a larger engine for some reason than the other 3. The 35 and 37s are turboed with the 37 being intercooled. Also, you will notice that the oil coolers on the top two are larger than the smaller two.
None of those are computer controlled engines that I can tell. The pump on my 35 is mechanical. I am not sure about the 4K series.
Technically, you could put a turbo on the 3120 and turn up the pump, and it would basically be a 35. If you turboed a 33, it would more than a 35. I went with the 35 because of the turbo, and the JD dealer priced it cheaper than any other dealer priced me a 31.

Each series is going to have its good better best products. Some people just want to mow grass, so the 31 is all they need. Others want a cab with all the bells in whistles, and a backhoe and loader, so they get the 37. It all depends what you want the tractor for and what you want to spend.

 

[jcmseven]

Specifically discussing the 4000 series tractors, there is truly little difference between the machines. I have owned 3 3000 series tractors and one can tell a performance difference (engine and PTO power) between the models, making a jump to a higher numbered model seem reasonable. In the 4000 series the tractors are essentially the same, albeit with tuning mods and small parts changes to accomodate these mods safely. Although many claim to know how to "tweak" a 4120 to become a 4720, I have been unable to find someone who has actually done it or recommended it on a personal level. I have had the priviledge of being able to operate every 4000 series tractor, and have owned a 4520. I do PTO work and live in a mountainous area where a low-powered machine will really suffer. I also am very particular about engine performance and have paid close attention to the performance in similar tasks of each of these machines. I have said, even on this forum, to buy to most powerful machine possible, but my usage of these machines has led me to qualify "not in the 4000 series machines". I could tell absolutely NO difference in the 4320,4520 and 4720 in the performance tasks I did, and could only tell the most minute difference between the 4120 and the others. All of these machines are powerful and honestly I think the best "deal" among them is the 4320. I will say the 4720 I used was only in limited time, so it could perhaps impressed me more had I used it longer, but my thumbnail thought was--though nice--it was not worth the additional money unless one wanted to label effect of the 4720.

John M

 

[Kyle_in_Tex]

Here's the nebraska tests for 4320,4520 & 4720. Look at the PTO Max HP and torque. Judge for yourself.

TTL test reports/JD Deere

You will notice the power difference when you are pulling a shredder in deep stuff.

 

[jcmseven]

Kyle, I agree with you 100%. In certain, very difficult situations, the slight additional power of a 4720 v. a 4320 would be notable. In my usage of these machines, though, I have found for rotary cutting, field mowing and heavy pushing/hauling up and down steep grades, etc. that there seems to be little, if any, notable difference between the tractors. Although I am by no means an expert I have suggested to those on the fence to demo both and see if they can tell a difference in power. Most come back saying they can't--or if they can--it is by very little. Those with heavy PTO work or who might be interested in hydro but still want good engine performance and adequate retained power might be better served going a notch up on the power (and pay) scale.

John M