Best pulling gear for ford 9700

mark in boonville ny · Jul 22, 2014

Im going to be pulling my 9700 at the local tractor pulls. Im not sure what the best gear would be. It has dual power but im thinking 3rd or 4th. I pulled it in 3rd several yrs ago but seemed like it had some power left but dont want to not have enough if i go fourth. I think it will be pulling in the 13500 lb class. She is heavy but still needs weights to get it heavy enough. I cant get it down to the next class lower.

RodinNS · Jul 22, 2014

You can look up the Nebraska tests and find the drawbar component of the test... but I suspect you will find 6L to be the gear where maximum power is delivered. Maximum pull will probably be in 2L or mabey 3L....

Rod

showcrop · Jul 23, 2014

Mark, where have you been? The heaviest I pull my 9000 is at 11,500 but I do pull 13,500 weighing 11,500. I wouldn't go lower than 5th unless it is a very tight track. I think that it was my second time out with it that I was in fifth and ran out of power. I had number one pulling position so I had the option of trying again. I went down to fourth and ran out of power again but at about forty feet shorter! Momentum is everything!!!! Don't go lower than fifth.

Bern · Jul 23, 2014

Theoretically you'll get more power out of 4th high since the power transfer through the trans is in more of a straight line. Having said that, for a juiced up pulling tractor, I'm sure the difference is negligible.

mark in boonville ny · Jul 23, 2014

Right momentem is key for some of these guys but ya the 9700 weighs almost 12000 so i gotta go 13500 class. So your saying 5th. I know if i stop before 50 ft i can try again. So maybe ill try 5th. It does have dp so im sure it will help some. The pump is not getting touched. Its litteraly coming straight off the spreader to the fair grounds. I wish i could fit it in a 11500 but idk where theres 300-500 lbs i can cut. Rear tires are loaded but its got heavy rear wheel weights on the inside and that will be an all day job to remove a couple of those. So i gotta find somewhere i can add weights to the rear.

showcrop · Jul 23, 2014

(quoted from post at 12:35:17 07/23/14) Right momentem is key for some of these guys but ya the 9700 weighs almost 12000 so i gotta go 13500 class. So your saying 5th. I know if i stop before 50 ft i can try again. So maybe ill try 5th. It does have dp so im sure it will help some. The pump is not getting touched. Its litteraly coming straight off the spreader to the fair grounds. I wish i could fit it in a 11500 but idk where theres 300-500 lbs i can cut. Rear tires are loaded but its got heavy rear wheel weights on the inside and that will be an all day job to remove a couple of those. So i gotta find somewhere i can add weights to the rear.

How about removing your three point hitch? between the upper and lower arms and links, it should take just a few minutes. The stay blocks would come off quickly too. I bet that it would all add up to over 400 lbs. You need to open up your pump. Turn the screw all the way out!! Every body that you are competing against will. Momentum was huge for me between 4th and 5th so I know that it will be for you. I pretty much always start with the DP in low, then when the RPMs come up I shift it up. Depending on the track, sometimes I need to shift back down as I get down the tack and sometimes not.

RodinNS · Jul 23, 2014

In theory that is correct... in practice, perhaps not. I know I spent some time looking at the drawbar tests for my 7710 about a month ago and 6L was it's highest performing gear in terms of power delivery... and various others were the same, although I didn't look at any of the larger chassis tractors. Some of the differences in power delivery are also quite striking... like probably 20% off in the lower gears.
Interestingly enough... the 16x8 transmission performs better in underdrive rather than direct drive which is somewhat counter intuitive and certainly the opposite of what you're suggesting. I would not have expected that either..

Rod

Bern · Jul 23, 2014

Just for kicks one day, I took the rear tires and front driveshaft off of an 8970 Genesis tractor and hooked it to a PTO dyno. I took a baseline PTO HP reading with the trans in neutral. I then proceeded to check HP after throwing it in gear. Mind you, the trans is only turning the rear axle shafts and the transfer case output shaft, that's it.

In top (16th) gear, I lost over 20 HP with cool hydraulic oil. The loss decreased as the oil warmed up, as expected. Also, as expected, the loss decreased proportionately when downshifting into the lower gears.

The 20 HP surprised me, but the highest loss in high gear did not. Spinning those brake discs and ring and pinion at high speeds definitely causes some parasitic losses due to oil churning.

Applying this to the Nebraska tests, I can't see how you'd have 20% less power in the lower gears. That makes absolutely no sense at all. About the only thing I could think of that might even remotely cause this is more tire flex under higher torque loads, but not 20%. That kind of heat generation would destroy a tire I would think.

Something to think about for sure.

RodinNS · Jul 24, 2014

I think wheel slip and higher parasitic losses in the transmission itself account for the lower output in the lower gears. A 7710 will basically achieve spinout in most field conditions in 5L if it's sufficiently loaded so there's really no gain in hp below that. On a concrete track obviously it will be slower than 5L...
I should go back and look at the tests again... I just use 20% as a rough figure but it seems like it ranged from a low of probably 57-58 hp up to a high of just over 73 hp... so that's a fair swing. It's also worth noting that slip is at 14.9% in that test in 3L... so that would be a major impediment to power transfer. Also remember that the Nebraska drawbar tests are done by measuring pull between the tractor and test car at a measured speed so it accounts for just about every loss you could get in the equation...
It's an interesting test that you did with the dyno. Must have been a slow day?

Rod
Test 1433

RodinNS · Jul 24, 2014

I'd second that... three point should drop a few hundred anyway... run with a near empty fuel tank as that's going to be a couple hundred pounds, etc. I'd certainly turn it up some though I don't know if I'd turn the screw all the way out... 1.5-2 turns is about all you'd gain on it I think... the injectors will only flow so much and after that it's just smoke you're making.

Rod

showcrop · Jul 24, 2014

(quoted from post at 04:35:36 07/24/14) I'd second that... three point should drop a few hundred anyway... run with a near empty fuel tank as that's going to be a couple hundred pounds, etc. I'd certainly turn it up some though I don't know if I'd turn the screw all the way out... 1.5-2 turns is about all you'd gain on it I think... the injectors will only flow so much and after that it's just smoke you're making.

Rod

I started out with about two turns then a couple more, then finally all the way then back 1/2. I gained appreciable power every time, and never got a whole lot of smoke.

Rod, ever gone to pulls at Crapaud or down to Skowhegan?

mark in boonville ny · Jul 24, 2014

I figured 3 point hitch but i can get the lower pins out. Anyone got any tricks. And yes the bottom tank is full shoulda drained it some. I just weighed and i was way off. Its 14000. But i got in the 13500 class. There used to be 16 or 15500 class but not anymore.

RodinNS · Jul 24, 2014

No, never been to crapaud, but sometimes think about going. Went to college with a guy from there... It just seems that we're always flat out busy when the pulls are going on over there.

Rod

showcrop · Jul 24, 2014

(quoted from post at 09:28:33 07/24/14) No, never been to crapaud, but sometimes think about going. Went to college with a guy from there... It just seems that we're always flat out busy when the pulls are going on over there.

Rod

ten years or so ago my wife and I were in Nova Scotia for a few days so we went over to PEI for a day. Our friends there told me about the pull at Crapaud so we stopped there for a few minutes. I watched some guys find out where to set their throttles while getting dynoed so that they wouldn't open it too far while getting checked after pulling.

RodinNS · Jul 24, 2014

Indeed. My bud over there used to talk a bit about their tricks, turn the air on, etc... They used to pull with 1086's I think.. Where were you in NS?

Rod

Bern · Jul 24, 2014

Thanks for the link. After looking at the data, you're right, wheel slip is the major reason why the power is lower in the lower gears. I would imagine that the same dynamics apply in pulling competitions as well. I still maintain that 4th gear in an 8-speed Ford is more efficient.

As for the test I did, I did it after hours one day when I was off the clock. It was just something that I was really curious about. It was spurred in part by trying to figure out how to get hydraulic temps down in the Genesis tractors, which had issues with that problem. Brake drag was a major factor, as noted by the brake cooling kit NH came out with on the later tractors.

I also suspect that reverse clutch pack drag figured highly into the high gear HP loss. This is confirmed also by the efforts Funk made to prevent reverse clutch pack failures when roading.

showcrop · Jul 24, 2014

(quoted from post at 10:04:14 07/24/14) Thanks for the link. After looking at the data, you're right, wheel slip is the major reason why the power is lower in the lower gears. I would imagine that the same dynamics apply in pulling competitions as well. I still maintain that 4th gear in an 8-speed Ford is more efficient.

As for the test I did, I did it after hours one day when I was off the clock. It was just something that I was really curious about. It was spurred in part by trying to figure out how to get hydraulic temps down in the Genesis tractors, which had issues with that problem. Brake drag was a major factor, as noted by the brake cooling kit NH came out with on the later tractors.

I also suspect that reverse clutch pack drag figured highly into the high gear HP loss. This is confirmed also by the efforts Funk made to prevent reverse clutch pack failures when roading.

Yes Bern, Essentially the same dynamics apply. In lower gears it is very easy to overpower your traction and spin out. As I said in the earlier post momentum is huge. In a pulling competition you are dependent on traction but momentum makes you less dependent on your traction. This is why speed limits are now the norm in tractor pulling.

showcrop · Jul 24, 2014

(quoted from post at 09:51:27 07/24/14) Indeed. My bud over there used to talk a bit about their tricks, turn the air on, etc... They used to pull with 1086's I think.. Where were you in NS?

Rod

We stayed the first night in Chester. We live in Chester NH. The second night we stayed somewhere around New Glasgow. We never made it out your way. I would like to get back and get out to the east end. If we get snow we may do it on snowmobile LOL.

RodinNS · Jul 24, 2014

My reason for looking at the test data was more real world... I'd hooked the old blue lady to a 16' Salford RTS 1100 vertical tillage tool... and I wanted to know what her best pulling gear was because it needed all she had... and I wanted to know what her efficiency numbers were. Salford recommended a minimum of 90 DB hp and the 7710 is rated for 74 on radial tires. I ended up running her in 6L at 2200 continuously. She was working 9 ac hour steady at a fuel consumption of 6.7 gph. Based on the efficiency numbers that would extrapolate out to a continuous average output of 91 db hp... or about 108 on the PTO... which is perhaps a bit hotter than I thought I had her set. She could also be a bit tired given there's 8100 hours on the clock... I thought it was a fairly impressive show of force for the old girl.. Another guy tried the machine on a TL100 and he could make the speed as long as he didn't drop the machine. As soon as he did... he said it was like a boat anchor behind him. LOL. I always get a chuckle from the tales of all the 100 hp tractors around... that might make 80, be they blue, orange, green or red.

Rod

RodinNS · Jul 24, 2014

There's probably still snow in the highlands... why wait LOL.

Rod

showcrop · Jul 24, 2014

(quoted from post at 14:36:53 07/24/14) My reason for looking at the test data was more real world... I'd hooked the old blue lady to a 16' Salford RTS 1100 vertical tillage tool... and I wanted to know what her best pulling gear was because it needed all she had... and I wanted to know what her efficiency numbers were. Salford recommended a minimum of 90 DB hp and the 7710 is rated for 74 on radial tires. I ended up running her in 6L at 2200 continuously. She was working 9 ac hour steady at a fuel consumption of 6.7 gph. Based on the efficiency numbers that would extrapolate out to a continuous average output of 91 db hp... or about 108 on the PTO... which is perhaps a bit hotter than I thought I had her set. She could also be a bit tired given there's 8100 hours on the clock... I thought it was a fairly impressive show of force for the old girl.. Another guy tried the machine on a TL100 and he could make the speed as long as he didn't drop the machine. As soon as he did... he said it was like a boat anchor behind him. LOL. I always get a chuckle from the tales of all the 100 hp tractors around... that might make 80, be they blue, orange, green or red.

Rod

I was helping my cousin once and went out to smooth between chiseling and corn planting with some kind of cultivator that was probably 14 feet and probably had about 16 shanks. I was surprised at how quickly it pulled the TW-30 down if I got it too deep.

mark in boonville ny · Jul 24, 2014

So i pulled. I went with 4 low started off with dp low then bumped it up and got idk 200 ft or so started loosing power kicked it back down made it about 6 more feet and thats as far as she made it before it almost stalled out. Guess 3rd is where its at.

RodinNS · Jul 24, 2014

There's no shanks on this thing. It's got probably 30-35 coulters on it. The first couple rows are 1.5" and the next couple rows are 2", IIRC... Then it's got a rod harrow followed by a crumbler. It only works 2-3" deep. It's actually fairly light to pull considering... but it is still 4 tonne of dead weight and 16' working width.. so it takes some snort from that standpoint.

Rod

Best pulling gear for ford 9700

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