We ran a 98 alongside a 97 this fall in corn both with 12 row 20 inch corn heads. The 98 had a geringhoff rota disc and the 97 had a regular deere head. The 98 was consistently at least one mph faster through the field than the 97. The 9870 would hardly ever pull down below 2240 rpm. The 98 has some other features I liked about it. There was a gap between the fuel tank and the top of the chopper which helped keep chaff and stuff from collecting in there. Another thing I liked was to pull up the floor in the engine compartment to clean out on top of the fuel tank it was two pins you pulled and the floor came up. I really liked the 9870. The only problem we had with it was two small oil leaks.
Not really, heavier drives etc. I guess it's hard for someone else to tell you if its worth the extra 25 g's or not but I can tell you in heavy wheat you can use all the horses the 98 has. It has more capacity, more noticeable in heavy straw for sure.
In 150 bu. corn might not see much difference. But in 230-260 corn like we had I could easily run 1 mph faster than the neighbors 97's and I had a 612 chopping head. For those of you who say the only diff. is hp. you are wrong. With the 60 series that was correct but the 9870 is bigger than the 9770 by more than just the engine. Heavier feeder drive, more wind, etc.
You can now get the 5 speed header drive in the 9770's. Also, the fan set up is IDENTICAL, just a adjustment stop is changed and voila...1350rpm. I also added the ICC to my 9770 for very little money so for all intents and puposes it is a weak knee'd 9870 spec for spec. In our conditions, our 97's are not limited for power, but we run out of capacity other places so I went with the 9770 plus ICC. BTW, it bolts right in.
ICC (Increased Cleaning Capacity) is not only the exteneded precleaner.
the wind distribution was changed. all of the smaller machines have a 80/20 split from the chaffer and sieve to the precleaner respectively.
the 9870 gets a 70/30 split, meaning that the precleaner and extension get more air out of the chute to aid in initial cleaning, and also has an extended sieve nose to help with wind distribution
another big difference, this coming right from a customer, they have a 9870 w/ a 612C 30" Stalkmaster. it went down and we got them a 9770 to use with their head until it was fixed. first thing he said was that the 97 was way lighter in the rear end, and that was even with fluid in the rear tires.
another customer with 3 9770's and 612C 22" Stalkmasters had the same complaint
Alot of our wheat straw is wet and tough so we went with the 98 over a 97 mostly because of hp. We push the knife bank all the way in to get the best possible chopping job (half way in makes a noticeably worse chopping job) That chopper takes alot of power and in wheat we are constantly running out of power, we are lower yielding 40-50bpa so we don't run out of cleaning capacity. We feel that whatever Deere did on the 70 series it was able to lower losses compared to our 9860s of the past. And we lift 8000lbs of header in low idle pointed downhill and the machines does it flawlessly (with the Xtra heavy lift cylinders from Deere)
Oh and we ran a 9770 beside our 9870s and it was one heck of a machine, probably would stick beside a 9860, the 9870 was bigger but only by 1mph. One bummer is that the 9770 was a small fuel tank.
ststech, I also put the 9870's fan distribution divider in the 9770. This was also a bolt on job, the side sheets where it bolts to have the holes in it for either set-up.
I believe the shoes have the same stroke but the 98's is faster, I am still looking up these parts.
All the parts for the ICC will bolt on the 97's, it is an easy job. I ran beside a 9870 this season in wheat. My 9760 (the one I had during wheat) was set up identical to the 9870 and side by side the 98 would run faster because it had more cleaning capacity in the wheat we were running. Power was not a problem at all so the extra power of the 98 did not have a advantage but you could run faster before losses were excessive due to the ICC.
I have not run the 9770 with ICC yet, it is in the shop getting the updates...will running it next year.
Who is brochure boy?
And yes it does increase capacity, at least in high yielding wheat it does.
Thanks for the answer and yes jd9600guru is correct. I run two 9770s in wheat and barley. Sounds like installing ICC in the 9770 might be the way to get a cheap 9870. Hp most of the time is not a problem in my conditions. Just curious, how to you have your rotor setup because its seems about half the time my limiting factor is rotor loss.
Next year we will be running 9770's but this year we had 9760's and we didn't have problems with losses it was power that was out problem. When we would set our machines we would run them right were we wanted it for rpm's and then make our adjustments to were it was doing the job we wanted it to do.
The theory on rotor loss is there has to be enough centrifugal force to throw the grain out of the straw. Slow rotor speed will always cause rotor loss. Start with the concaves open at about setting 25. then start increasing rotor speed till cracks start to show up in the clean grain sample. Then start to close down the concave to eliminate unthreshed heads. If operating in really dry straw conditions and shoe losses start to climb, there are seperator covers that can be installed to help reduce chaff load on the shoe. I have found I only have to do this in canola.
I rarely am over 800 rpm in cereals. maybe up to 900 in hrs wheat. you have to get a good crop mat into the rotor. I always tell operators of sts's if the engine isn't working your not going hard enough. too little material through the rotor and it is impossible to set the combine.
Quote:Slow rotor speed will always cause rotor loss. Start with the concaves open at about setting 25. then start increasing rotor speed till cracks start to show up in the clean grain sample.
I always thought the same and used to set STS's up like this for years however this year I experimented a lot, (we had far heavier crops this year than normal, 55-95 bpa). I found I got best results running the rotor about 800 and the concave less than 10. The combines ran lots better than they have before. I came to the conclusion that they seperate far better working more through the rotor at slightly slower speeds and a closer gap. 3 things to note however, our straw was fairly dry, I always run 2 small wire concaves in the front and a large wire at the back and they did burn a little more fuel running like this however I thought the increased capacity more than outweighed it.