more power

[Soundguy]

Our point is you can TC the bajeebers out of it.. and if it's too light / too small to use it.. it don't help much.. or at least.. that's what my point was. A rider lawnmower with 86hp might be a nice toy.. but if the little 8" soft tires spin while trying to pull a 100# lawn cart... you are not accomplishing much..

soundguy

 

[RobJ]

Our point is you can TC the bajeebers out of it.. and if it's too light / too small to use it.. it don't help much.. or at least.. that's what my point was. A rider lawnmower with 86hp might be a nice toy.. but if the little 8" soft tires spin while trying to pull a 100# lawn cart... you are not accomplishing much..

soundguy

Yeah that's it, in a nutshell. Buy a bigger tractor!

Personally I haven't seen many people add a turbo, gas or diesel. Always a good idea until you have to start buying parts and doing the work. But I would love to see some pics. OEM's are the best, let them do all the plumbing, tuning, etc. I guess a few turbo kits for cars/trucks these days, but mostly I see super chargers and belt driven blowers.

 

[Soundguy]

I see an m&w kit now and then.. and have even thought about adding one to my ford 5000.. but.. just not sure it needs it... it already mows with a 10' mower good... Guess if I had to mow with the 15' mower on the 5000.. then maybee..but not right now.

Soundguy

 

[SPYDERLK]

Our point is you can TC the bajeebers out of it.. and if it's too light / too small to use it.. it don't help much.. or at least.. that's what my point was. A rider lawnmower with 86hp might be a nice toy.. but if the little 8" soft tires spin while trying to pull a 100# lawn cart... you are not accomplishing much..

soundguy

Actually, Jinmans post goes deeper than this by alluding to the fact that torque to the wheels is limited in a HST by the relief valve. The only way to increase this torque in any given range is to increase the pressure. If neither engine bogs at relief setting the stronger engine will give no ground engagement benefit. If the lesser engine bogs a little and the other doesnt then the latter will have a slight power superiority at the wheels since the faster rpm will maintain full flow which will give just a little more pressure holding the relief open wider. So you waste 12 or so of your 15 HP increase in ground engagement. But on the other hand, if you are using 20HP on the pto and climbing a hill, the strong engine is a win-win.
larry

 

[dynasim]

It is more than just the size and weight.

The HST on the TC III's only is capable of adsorbing 35 hp or so(at the rated maximum RPM's). If you ask it to provide more power than its maximum, the relief valve pops. It is the nature of PD pumps to have a hard maximum power adsorption capability(directly proportional to rpm(flow rate) and pressure). This is a good feature to have, as it acts as a "shear bolt", preventing one from over stressing parts through the whole driveline.

If he was willing to increase the RPM, he would be able to add power to the system.

If you have a pto hydraulic pump rated at 2500 psi, and 20 gpm at 540 rpm, it will only adsorb 30 hp at that rpm(that is all the power availiable from 2500 psi at 20 gpm). One can apply a 200 hp farm tractor to that pump, but that pump will only drive 30 hp worth of work, and if hooked to a given hydraulic motor, will only provide the torque that 2500 psi pressure differnce on that motor provides.

Chris

 

[dfkrug]

The HST on the TC III's only is capable of adsorbing 35 hp or so(at the rated maximum RPM's).
.
.
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If he was willing to increase the RPM, he would be able to add power to the system.

I agree you could design the HST axial piston pump to be limited to a pressure/volume that delivered no more than 35hp. But do you know for a fact that the TC35 does that? Isn't it likely that the same HST is used in multiple tractors? JINMAN says the HST is the same as used in the TC45. If indeed the HST pump has that limitation designed in, increasing RPM will not increase the power delivered by the HST either.

 

[dynasim]

Nope, I don't know that(that the drives are the same for all three, and sized for the small tractor), but that has been said here, and looking at them online indicates that it is so.

I have a TC45D, and have never lugged the engine down at full RPM with the HST. The wheels have stopped turning, though. It is a weird experience. Given that observation, the HST is definitely less powerful than the TC45 engine.

For arguments sake(not advice), turning the HST, and therefore the engine, at higher RPM will increase the ability of HST to deliver proportionally more fluid, and hence, proportionally more power. I don't think that would be sensible, though.

Chris

 

[jinman]

I have a TC45D, and have never lugged the engine down at full RPM with the HST. The wheels have stopped turning, though. It is a weird experience. Given that observation, the HST is definitely less powerful than the TC45 engine.
Chris

Chris, you are experiencing exactly the same thing I am. As you can tell by my posts, that's a source of frustration for me too. I can live with it, but I wish it were designed differently.

Larry, you are exactly right about that PTO. While I have not heard of anyone with a TC35DA complain that they stall their engine a lot. Surely, more power available at the PTO would not be a bad thing and it would leave more power for the transmission when the PTO is under load.

Dave, I really don't know if the HST is sized to go into stall/relief at 35hp. I'd love to be able to experiment and find out exactly what the stall point is. I'd also love to increase the relief pressure and see if the transmission could hold that pressure without blowing up. Maybe one of these days when I get really brave I'll increase the relief valve pressure and see if I can get more power to the wheels. If I screw up (and I do that quite often) I'll be splitting the tractor to fix the transmission. That's a big job. The relief valves (one for forward and one for reverse) are accessible from the outside of the transmission casing. I'm very tempted to experiment, but not brave enough yet.

Remember also that the Class III HST is more complex than most other HSTs because of the rabbit-turtle feature. Not only is the swashplate on the pump side adjustable by pedal position, but the motor's swashplate is a two position plate (9 or 15 degrees) controlled by the rabbit-turtle solenoid. If you blow up this transmission, it's likely to be a very expensive repair.

 

[Soundguy]

I'm not sure anyone has said to the contrary? have they?

(edit: I see.. just a clarification..e tc. )

Soundguy

It is more than just the size and weight.

The HST on the TC III's only is capable of adsorbing 35 hp or so(at the rated maximum RPM's). If you ask it to provide more power than its maximum, the relief valve pops. It is the nature of PD pumps to have a hard maximum power adsorption capability(directly proportional to rpm(flow rate) and pressure). This is a good feature to have, as it acts as a "shear bolt", preventing one from over stressing parts through the whole driveline.

If he was willing to increase the RPM, he would be able to add power to the system.

If you have a pto hydraulic pump rated at 2500 psi, and 20 gpm at 540 rpm, it will only adsorb 30 hp at that rpm(that is all the power availiable from 2500 psi at 20 gpm). One can apply a 200 hp farm tractor to that pump, but that pump will only drive 30 hp worth of work, and if hooked to a given hydraulic motor, will only provide the torque that 2500 psi pressure differnce on that motor provides.

Chris

 

[dfkrug]

I have a TC45D, and have never lugged the engine down at full RPM with the HST. The wheels have stopped turning, though. It is a weird experience. Given that observation, the HST is definitely less powerful than the TC45 engine.

That is a valuable observation with your TC45. It seems that NH should
have upsized the HST for that tractor. For the same HST in the TC35,
it makes sense that the engine is losing RPM (bogging) down as power
demand is increased up to the power limit of the engine, without going
to relief or spinning tires. An engine power increase of 10hp in the
TC35 would seem to be quite valuable. If you guys are willing to pay
the premium for the 45 over the 35, it would seem to be nearly THAT
valuable.

I, for one, would love to hear about actual experience with making these
kinds of changes. There will always be people who will say "don't do it"
or "it can't be done", though they themselves have never tried it.