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Discussion in 'Heavy Equipment & Pavement' started by AWJ Services, Oct 13, 2013.
Looks good. Were you satisfied with the mini x/mower performance?
what was on the grill ? they were the pictures i looked at .. lol
Yes and no. LOL
What I have found is that the mini ex flows are rated at 1000 psi. So if you do the math you will find that usually the rated flow will equal the actual hp available at boom. My Kubota makes about 19 GPM so that equates too 19 actual usable hp available. Not alot and it is just on the verge of being not enough. It uses a 21 cc motor and the KX080 machine uses a 28 cc motor and the KX080 is more efficient and really about as small(flow wise) I would recomend for this type of head. The KX080 makes about 26gpm. This is a mulching head not a flail mower so it is completly different and I would guess performs different than a Flail mower. Not saying it is better just clarifying that I have no experience with flail type mowers n my Mini ex. So The TB260 I am hoping to buy is rated at 27 gpm and I was given the actual flow of the machine at 3000 psi and it makes about 27 hp at the boom. So in theory it will give me about 42% more power over the Kubota KX161which is a dramatic increase.
Chuck Roast and ribs.
horsepower = (psi * gpm) / 1714 so none of your math works out. 19 gpm @ 1000 psi = 11 HP and 27 gpm @ 3000 = 47 HP. Someone is lying to you.
No one is lying too me. I never said that the machine would only make 19 gpm at 1000 psi or that the TB260 would make 27 gpm at 3000 psi. I said that the manufacturer rates there flow at 1000 psi and that the flow spec will be all the hyd hp you will have too work with. The TB260 makes 15gpm at 3000 psi which works out to about 27 hp. My Kubota makes about 10 to 11 at 3000-3100 psi. That equals about 19 hp. My point was too help people be able too have an understandable way too compare these machines. Most of these machines will make the rated flow up into the 1500 to 1900 psi range before the machine starts taking power away from the aux circuit. I got this informatioon from someone who actually has put a flow meter on these machines and others.
something doesn't seem right but maybe excavators are different on the aux circuit than skid steers. I've put flow meters on several skids to see the flow/psi at different rpms and watch pressure spikes, flow drops, etc. Most of the time the machines came stock out of range or on the low side. Same thing for RPM range, i've seen several machines not make enough rpms on the motor.
The hydraulic formula assumes 100% efficiency. We all know that's not the case at the quick couplers and from my experience, manufacturer rated flows and psi are off at the quick couplers, too.
I try and have each machine I buy tested before I put it in service especially when I am going to run high flow attachments. Out of about 8 or 9 skid steers, only one was set within the spec range but it was on the low side.
Why should you lower the rated flow because of a restriction in the connection? The manufacturer rates the machines with no restrictions. It's up to the owner to take advantage of it.The Aux circuit is electronically adjustable on most all of the new min ex's. The ones that are not it is easy to turn them up to max flow. The only other thing is to check the relief pressure on the aux circuit. It is usally less than the main pump relief. I also verified my machines flow with the cutters rpm.
I wanted too elaborate on what i was saying. Regardless of the carrier( skid or ex) the manufacturer rates the flow. There is no standardized way of rating flow so ultimatley you will have too check flow ( like Yellow dog ) said to verify actual performance. Fow rating and adv psi rarely are rarely meant to be used togethor. The manufacturer rates the max psi and the max flow. So if put a flow gauge on the machine you will find that max flow is not usually at max psi. Flow and psi together make hyd hp so you can have less flow and more power depending on psi. If the manufacturer will not give you a flow chart from 0 too max pressure then it is near impossible too compare machines. As Yellow dog said expect to lose 20 to 40% of that hp after it goes through the attachment.
Keep in mind the different hose sizes (think blood pressure higher when vessels constricted) can affect psi and flow. Valve blocks, diverters, and coupler restrictions on both sides (machine and attachment) also play a part. The local CAT dealer, a big one, was drilling out couplers to reduce flow restriction on XPS skid steers but then I started wondering how that affected psi?
I've seen relief valves kick in too early, flow rates decrease significantly with RPM drop, etc. It is really hard to have a one-size fits all scenario.
I'd like to own a flow meter (anyone know where to get one for a Bobcat?) just for the hell of it. I'd like to flow test my excavator (supposed to be 19 gpm at 3000 psi) as well as my toolcat (26 gpm at 3000 psi on high flow) just to see where they are at. I don't run much more than a grapple and mower on the toolcat and a thumb on the excavator but I'd still like to see where they line up with Bobcat's specs.