Hi All,
Again thanks fro the great input!
Yes I have read and re read Vsb 14 many times. Regrettably that standard that relates to engine vs weight was written by a team of bureaucrats with little to no understanding of the laws of physics. As such the arbitrary ratios selected for the engine to weight "formulas" in section 2.13 in that vsb 14 standard are baseless and do not comply to any level of sound reasoning, good engineering or scientific standards in general,. They were arbitrarily selected "thresholds" plucked from thin air and then reverse engineered to produce the ever so convenient (and nicely rounded would you not say ?) 3 x, 4x and 5 x ratios vs the tare kg weight. It so poor in what it tries to achieve, so poor.
It cannot be reasoned by any law of physics that the dynamics of the vehicle in question will experience "step function" changes in its behaviour at the magic 1100kg mark. Could it be proven for example by the RMS crack team of "scientists" that a 1093kg car (current official RMS verified max tare weight of an NB MX5 which is the SE model) is incapable of running anything larger than a 4.3L engine whereas an 1100kg car can safely run a 5.5L ? Do they have the physics to prove this ?
Does that make sense to anyone who has any idea how physics and vehicle engineering actually work ? I say no, as this part of the vsb is so poorly contrived that it insults our intelligence.
So let me run that another way..
The RMS is telling me that a 7kg increase in tare weight (from 1093kg to 1100kg) means that a 25% increase in engine capacity is permitted? By what laws of physics did the RMS decide that 4.3L is OK at 1093kg but a 5.0L is not safe..but add 7 kgs and your car is now safe to run 5.5L..WTF ?
If the RMS had any idea at all they would leave "step function" changes alone and use a linear scale for engine capacity vs tare weight. So with every kg increase in tare weight the engine size would increase in proportion. I would be happy to pen a basic algorithm (as would anyone else with year 6 maths skills) for them to use to do just that.
It would simply ask for the tare weight and give you the maximum engine size, every kg change moves you either higher or lower on the engine capacity scale. That is the only way to do it so its correct and in line with sound practice, anything else is gonzo engineering.
The other way is to use power/weight ratio as the determining factor for vehicle safety and drop capacity to kg completely as the measuring stick.
If I had the money I would take the RMS to court and challenge the pathetic vsb 14 section 2.13 on the basis that it is inconsistent with any law of engineering and science in the way that it defines its thresholds or boundaries for engine capacity vs weight. There is no magical event that occurs at 1100kg of tare weight, not a single thing, zippo, nada.
I could potentially challenge the RMS, as the vsb stipulates what the Maximum
Recommended Sizes are. These are defined as recommendations or guidelines and not absolutes in the way the vsb language reads.
I could argue that being off the "magical" 1100kg mark by 7kg at 1093kg (or by 0.7%!!!) warrants consideration for a 5.0l. If the standard is indeed stating that at 1100kg the "recommended" maximum is 5.5L then I do not see how unreasonable a 5.0L is at 1093kg. The car is within 0.7% of the recommended tare weight and 10% UNDER the maximum recommended engine size. Only 0.7% off the target weight BUT 10% UNDER on maximum engine size for that 1100kg target weight.
A case for reason?
Sure, if you lived in the real world....the RMS doesn't live there.
So hence I am sitting on a knife edge with only 7kg separating me from finishing my car and satisfying the pathetically rudimentary and ill reasoned legislation as is.
So I am here, hoping to get a different tare weight from Mazda for the SP so I trip over 1100kg on tare wight and build my car. From everything I know the SP is definitely heavier and must be over 1100kg on tare weight, maybe 1119kg as stated by someone in a previous post. But I don't have that yet on official record...and I need it to build my car without issue.
The alternative is a legal challenge and although I can easily prove that section 2.13 is erroneous on any level of scientific reasoning, I regrettably don't have the depth of pocket to feed the lawyers to work it with me.
But as this has been a running issue with me for a quite a number of years, I would not mind having a crack just for giggles. Imagine the scene as the RMS scientists try to explain the scientific reasoning for why 1100kg was selected as the very important threshold and not any other numerical value of the tare weight.
Grab a bag of popcorn for that one..LOL!
I will keep everyone posted on my progress.
@Bruce: Cheers for the response. I agree and I understand that your Vic Engineer would not approve a 5.0L on the legislation as stated, but any engineer worth a dime would/should have the sense (and balls) to reason against this standard using data and sound scientific methods, because it is nonsensical as it stands today. Engineers are paid and qualified to assess each case on its merits and the legislation should provide the structure to let them do it, otherwise the authorising engineers are doing little "engineering" and more "administration".
@Legume: Faced between the choice of Lexus V8, Nissan V8 or Rover v8...I choose the 1.8L Turbo option. Those V8's are anemic and don't warrant the effort to install.
Thanks so much to everyone for their comments and assistance. As is clear from my language above, Section 2.13 from vsb 14 is a sore point for me because it makes no scientific sense and as a result of its absurdities I cant build my car.
Will keep pressing on with it...hopefully this week will bring it in.
Cheers All!
