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View Full Version : can i turn up hydraulic pressure to make ztr faster


mowing grass 1111
02-03-2008, 02:33 PM
just like the title states . i have a lazer z that seems to be running a little slower is there any way to speed it up?

Happy Frog
02-03-2008, 03:28 PM
Buy a Bad Boy AOS or a Hustler Super Z, 15 mph should be enough... :laugh:

MowerMedic77
02-03-2008, 04:20 PM
just like the title states . i have a lazer z that seems to be running a little slower is there any way to speed it up?

More info on your mower would help like age,hours,maintenance history but

In short.........No

If your mower used to be fast enough for you but now its sluggish then you should check for exterior issues that may be slowing you down.

1. How old is your pump drive belt? Worn belts will slip and not give you full drive. Also make sure your engine is running at full manufacture rpms.
2.What is the state of your oil? New, old, is the level correct? When the unit is running do you get lots of bubbles in the reservoir tank?
3. Check the hydro levers all the way back to the pump and make sure nothing is loose or causing you not to get full throw on the pump. Also check the set screw on the input of the pump lots of times this is were you will loose alot of your drive when they back out.

mowing grass 1111
02-03-2008, 04:44 PM
ok back to my question ... is there a way to turn the hydro pressure up to speed the mower up

there was a thread were a guy had a lazer z for sale , he said he turned turned the pressure up to make the mower faster
here is the link http://www.lawnsite.com/showthread.php?t=209542 so i know it can be done ..unless the guy who had the mower for sale is full of ****

Restrorob
02-03-2008, 05:08 PM
In short.........No




ok back to my question ... is there a way to turn the hydro pressure up to speed the mower up



Hmmm, I think MM answered your question nicely and right to the point......NOPE !

Think about it...... If it were that easy don't you think EVERYONE would be doing it ?

MOW PRO LAWN SERVICE
02-03-2008, 05:11 PM
Try a scag,i always slow em down coming into turns,but they run with the speed of light..........:usflag:

mowing grass 1111
02-03-2008, 05:25 PM
Hmmm, I think MM answered your question nicely and right to the point......NOPE !

Think about it...... If it were that easy don't you think EVERYONE would be doing it ?
well i am getting two different stories so who knows what to believe

mowing grass 1111
02-03-2008, 05:28 PM
i also had everyone tell me that i could not speed up a gravely pro 300 rider that i had and that was a lie...its a bummer the guy that worked on it has passed away

Happy Frog
02-03-2008, 05:50 PM
Most hydraulic systems are pressure regulated by mean of a bypass valve (usually spring loaded).
Finding the bypass valve on your system and adjusting or replacing it will allow you to change the pressure in your system.
I am not sure if this applies to ZTR and you may encounter another limitation in your control valves, so check for that as well...
I would not mess with this if I were you, if you find your mower too slow, sell it and buy a faster one... Simple enough...

newz7151
02-03-2008, 05:57 PM
well i am getting two different stories so who knows what to believe

Well, I would say believe the repair techs, but I guess if you want to increase your hydro pressure, go right ahead, but don't wonder "why" if your gaskets and hydro filter start having problems.

Landrus2
02-03-2008, 05:58 PM
Was the mower faster at some point. and now is slower or you want to make it faster.
Than when was new. yes you can customize the pump gear but you are going to get a lot of jerking. not worth it leave it original from factory.:drinkup:

GravelyNut
02-03-2008, 06:04 PM
And pressure is not what you always need. It is volume that counts the most. If the pump isn't pushing enough volume at the pressure you need, it will slow down. Pressure gives you torque, volume gives you speed.

MowerMedic77
02-04-2008, 07:25 AM
i also had everyone tell me that i could not speed up a gravely pro 300 rider that i had and that was a lie...its a bummer the guy that worked on it has passed away

And I'm sure if he could talk to you from the grave he would tell you to re-read my post:hammerhead: Good Luck!

Travis Followell
02-04-2008, 08:06 AM
Increasing the pressure would most likely cause some leaks. Either instantly from hoses blowing or over time but if you increased the pressure above spec it would cause you problems. It would also decrease the life of the pumps and motors.

topsites
02-04-2008, 09:17 AM
If your mower is slower than it used to be the problem lies elsewhere and turning up the pressure would be a little bit like starting a fire inside your living room because your heat isn't working like it used to, now once the house is burnt down one wonders about the wisdom of this original concept but by then it's too late.

So... Once whatever is doing it is fixed if you want a faster machine your best bet is to get more powerful motors, there's a thread somewhere concerning this, but afaik you can replace the wheel motors and keep the psi the same.

Because turning up the psi can do a lot more than bust hoses and gaskets and leave hydraulic fluid in the customer's driveway.

It's just generally a bad idea.

mx495
02-04-2008, 12:10 PM
Is your engine still running at the same rpm as new? This could cause the mower to be "slower" than when new.

John Gamba
02-04-2008, 01:00 PM
bigger pulleys on the motors

bruno_rs
02-04-2008, 01:45 PM
i agree with all the other posters telling you to leave the pressure alone. these pumps are designed to run at full load... anything more WILL (quickly) lead to catastrophic failure of the pump AND possibly the entire hydro system. make sure the engine is tuned, all drivebelts and/or linkages are ok, fluids clean and topped off, filters unclogged, etc. not sure what machine you have but, if more speed/rpm's are needed you can "goose" up the gov (alittle) and/or step up to a larger tire. neither will make it a racer however, a difference will ne noticed. i too would think of selling and looking for another machine, if the engine, belts, linkages, etc. are what they should be. gotta love the example of starting a fire in your living room, because the heater no longer works like it used to... very funny stuff!!! good luck, have a good one.

mowing grass 1111
02-04-2008, 03:35 PM
nevermind, i found a shop that can do the job

John Gamba
02-04-2008, 03:52 PM
nevermind, i found a shop that can do the job

GOOD:clapping::clapping:

JimQ
02-04-2008, 04:52 PM
Pumps are rated by displacement or the volume of oil they move per revolution.

Pumps on a Z are “variable displacement” pumps. This means when your sticks are in neutral, the pump does not flow any oil. As you move your sticks forward, the amount of oil the pump moves is increased until it reaches its maximum rated output.

Wheel motors are also rated by displacement but generally rated by cubic inch.

For example - a 10cc pump moves 10cc of oil every revolution

A 15 cubic inch wheel motor requires 15 cubic inches of oil to make it turn one revolution

15 cubic inches = 245cc

That means the pump must turn 24.5 revolutions to move the wheel motor 1 revolution

The system pressure is the result of the “Work” being done.

Moving the mower forward can be described as Work.

It requires a certain amount of work (pressure) to push the mower over flat ground at a given speed.

It requires more work (pressure) to push the mower up a hill at the same speed.

Both conditions require the same oil flow to maintain the same speed but more pressure is developed when going up the hill.

You want to go faster. OK. No problem. You need to increase your flow or decrease the amount of oil that is required to spin your tire.

I’m not going to go into why you shouldn’t do these things, but I will present options and hopefully you will better understand how the components of the system work together.



Replace your pumps with larger displacement pumps

Increase the input speed to the pump
Smaller sheaves on the pump
Larger sheave on the engine crankshaft
Increase Engine RPM
Replace your wheel motors with smaller displacement wheel motors.

Install larger diameter tires



Like I said, I’m not telling you these are good ideas. I’m just saying that this is how you get more speed out of your Z. If you do any 1 of the things I mentioned above without any other system changes you WILL shorten your systems life.

Hydraulic system design is about compromise.

More speed = more pressure = more heat

Be careful.

Q

smokediver
02-07-2008, 10:03 PM
I'd be curious to know how that shop goes about speeding it up...

SILVERSTREAK INC
02-08-2008, 05:27 PM
bigger pump pullies but unless youre running hydro coolers mobile one will break down with heat like that and youll ruin your pumps in no time

if your machine has become noticably slower on one side or both than youve scored up your pump cap so youre not getting the origional pressure casue of bigger than supposed to be clearences...... and at 199 for jsut the end cap plus your gasket kit at 15 bucks its not cost effective to do, so replace the pump

when the arm turns on the pump the spinning drum inside swivels and gives you your directional flow, one time i was able to get about half a mile more per hour out of my turf tiger by messing with linkages to get the arm to pivot father forward..........but.........when i would pull back on the handlebars to go in reverse the drum wouldnt pivot as far backward so i really hurt my reversing speed.