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Please don't take it the wrong way, I have immense respect for all you guys experience and knowledge. I just had to do a double take and read it again because of the choice of words, not the concept he was explaining. We can't discuss ideas if we each use words to mean different things. Not trying to teach anyone to suck eggs.Quote:
Originally Posted by isuzurover
Dan
I designed the input adapter shaft for my LT230 to take ~2000Nm. This was back calculated as worst case through my vehicle from maximum traction (at my 29" tyres) through diff gearing and high ratio transfer gears.Quote:
Originally Posted by zkdaz
If you then want to translate that to gearbox and engine torque, you can consider 667Nm engine at 3:1 gearbox reduction (2nd gear in my MSA box). Higher gears mean more engine torque is required.
As you can see. There are very few situations where you are putting this much torque through. The gearbox and clutch also filter out a certain amount more vibration.
If you want more flywheel inertia, just add thickness and move everything before you start the conversion.
NZ conversion rules (LVV Cert) are easy. Your conversion gets checked over by a certifying mechanic (yes, no engineers involved) and the vehicle is put through the standard WOF procedure. If all good then it's plated with the modification details and off you go. The only recent change is a driveshaft safety loop on all turbocharged modifications.
We have no emissions requirements for conversions. However we do for imports. You would need to provide proof of ownership for a certain time period before import. I don't have those details.
It would take a pretty good mind to find gross flaws such as that in Newton's work ...Quote:
Originally Posted by zkdaz
:eek:Quote:
Originally Posted by zkdaz
Edit: Mass x velocity is momentum, not inertia. Mass x acceleration is inertia, not torque. Torque is force x radius.
The following are extracts pasted from Wikipedia. Note that change in velocity (motion) is acceleration.
Quote:
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. The principle of inertia is one of the fundamental principles of classical physics which are used to describe the motion of matter and how it is affected by applied forces. Inertia comes from the Latin word, iners, meaning idle, or lazy. Isaac Newton defined inertia as his first law in his Philosophiæ Naturalis Principia Mathematica, which states:[1]
The vis insita, or innate force of matter, is a power of resisting by which every body, as much as in it lies, endeavours to preserve its present state, whether it be of rest or of moving uniformly forward in a straight line.In common usage the term "inertia" may refer to an object's "amount of resistance to change in velocity" (which is quantified by its mass), or sometimes to its momentum, depending on the context. The term "inertia" is more properly understood as shorthand for "the principle of inertia" as described by Newton in his First Law of Motion; that an object not subject to any net external force moves at a constant velocity. Thus an object will continue moving at its current velocity until some force causes its speed or direction to change.
....
Interpretations
Mass and inertia
Physics and mathematics appear to be less inclined to use the popular concept of inertia as "a tendency to maintain momentum" and instead favor the mathematically useful definition of inertia as the measure of a body's resistance to changes in velocity or simply a body's inertial mass.
This was clear in the beginning of the 20th century, when the theory of relativity was not yet created. Mass, m, denoted something like an amount of substance or quantity of matter. And at the same time mass was the quantitative measure of inertia of a body.
The mass of a body determines the momentum https://www.aulro.com/afvb/images/im...013/05/449.jpg of the body at given velocity https://www.aulro.com/afvb/images/im...013/05/450.jpg; it is a proportionality factor in the formula:
https://www.aulro.com/afvb/images/im...013/05/451.jpg The factor m is referred to as inertial mass.
But mass, as related to the 'inertia' of a body, can also be defined by the formula:
https://www.aulro.com/afvb/images/im...013/05/452.jpg Here, F is force, m is mass, and a is acceleration.
By this formula, the greater its mass, the less a body accelerates under given force. Masses https://www.aulro.com/afvb/images/im...013/05/453.jpg defined by formula (1) and (2) are equal because formula (2) is a consequence of formula (1) if mass does not depend on time and velocity. Thus, "mass is the quantitative or numerical measure of body’s inertia, that is of its resistance to being accelerated".
This meaning of a body's inertia therefore is altered from the popular meaning as "a tendency to maintain momentum" to a description of the measure of how difficult it is to change the velocity of a body. But it is consistent with the fact that motion in one reference frame can disappear in another, so it is the change in velocity that is important.
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AGMA (American Gear Manufactures Association), have a large number of Gear Standards, but I'm only familiar with one - I don't have my copy with me at this moment, and I haven't used it for many years, so can't quote the precise number or title, but it is something like Rating Spur and Helical Gears.Quote:
Originally Posted by isuzurover
This was the standard used around the world for designing these type of gears, but was replaced by the ISO standard when it was introduced - AGMA was the secretariat for the ISO committee that developed this particular standard. The ISO standard was being developed at a time when I had occasional gear design so I kept an eye on what was happening. By all accounts it is a very complex standard intended to be implemented through third party computer programs, i.e. beyond any hope of anyone with a scientific calculator.
Even with the old AGMA standard, for determining the geometry factors 'I' and 'J' I used software that was developed by some BHP engineers (which became an Australian Standard). Those two factors would otherwise consume a lot of time.
As I said, AGMA have a lot of standards, and they probably would have included one for automotive gearboxes.
If there is no specific standard for rating the gears in an automotive gearbox or transfer case, there is no reason why the one for spur and helical gears couldn't be used.
With the rating standard I'm familiar with, common practice is to rate gears in terms of power, as that is generally more useful, but torque could be used as alternative. There are two ratings, 'strength' and 'wear' (both need to be determined and apply to a life of 12000 (or should that be 24000?) hours, whichever is least.
In a gearbox, every pair of gears need to be checked and so should the shafts and bearings. So it is not a trivial exercise to rate an LT230, and you before you could start calculating, you would have to determine a great deal of data for each gear that include tooth details, material and hear treatment (hardness), manufacturing tolerances on cutting precision (gear quality number), lubrication, gear alignment tolerances, etc.
Hey,Quote:
Originally Posted by isuzurover
that's Brutus, it belongs to my mate JL and actually is not a Stage One but an ex-military SIII with some Defender panels.
I drove it in Moab a few years ago, and it's in pieces nowadays, waiting for rebuild and some improvements :cool:
You can find a specs list on my site:
Whitedog Rover, Brutus the 109"...
Just out of curiosity, how would a fairly standard 6x6 perentie driveline stand up to a 6bd1-t?
It has TRB LT95 & 4.7 r&ps. Will be swapping out centers for lockers.
Seeing as I am engineless at the moment, and the truck is very heavy, it might be a good option. Thinking more in terms of pulling up some big hills and overtaking rather that rock crawling.
You would want to swap to 3.54s and a 0.996 t-case.Quote:
Originally Posted by Jitterbug
Unless it's been modified it will have the .996 transfer ratio. And yes the driveline should stand up to the 6BD1 as long as you are not a revhead.Quote:
Originally Posted by isuzurover
I drove an army sixby around last weekend, and 80km/h is the top useful speed. Managed to hit 100 on a downhill, but foot to the floor it wouldn't hold that speed up the slightest of rises.
4.11 diffs or thereabouts with 255/85/16 tyres would be my pick for useful gear ratios-would get cruising speed around 100. A bit more through the turbo would help too.
Go for too tall a final drive ratio and 1st high might be a problem.
The 4BD1T didn't do too bad but we weren't heavily loaded, just troop seats and gear cages. They weigh a fair bit empty anyway!
Were you running out of revs or running out of power?