Jump to content
SAU Community

Recommended Posts

Yeh sorry about that Darren. I saw u asking ppl when we pulled over.

I was trying to tell u i had no idea where i was going and ended up following the guys in the magna.

I was thinking of going via eagle on the hill but ended up feeling really tired and couldnt pay attention.

SO i ended up getting home asap and going to sleep.

Yeh you were next on the list to ask, But all good, freeway drive is a freeway drive in the end! yeh eagles would have been good, should have run it! I noticed you must have taken off, Dan slowed down a bit for us to catch up and you were gone!!

All is good! Next time i'll actually say :whoops: properly!!

  • Replies 241
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Just a quick Q:

Following on from some comments in the photography section and in wasteland, does anyone have objections to the no. plates in photo's?

I couldnt be bothered blanking them, but if someone objects I'll take thier photo down

Cheers

Lee

Madaz:

"Luke they have to stop you and fine you thats just a laser gun very inaccurate also 1 moving object cant pin point another moving objects speed"

I have to pull you up on this one buddy. One moving object can determine the speed of another. All it needs to do is correct for the doppler shift introduced by the moving radar. You just need to calibrate for the motion of the radar. I am a physicist that works with radar a fair bit so trust me on that. :(

A lot of those highway patrols with the radar on the roof have cameras built in on them. Sometimes all they do is speed up to get a photo of your plate and then next thing you know you have a surprise in your mail box.

Luke (Heslo): Nice shot of the cop car dude! :whoops:

Aftdrk:

What's the deal with the music video version you posted. It looks like you have bird crap on the lens that isn't there in the other clips you posted.

Hotwire:

I know some people can be a little touchy about having their number plate showing. I know some people voiced their concern to me after I posted pics from the last cruise to mt barker.

Edited by kalel

^ The camera would have an input from the vehicle speed sensor. That way it would know to deduct X from Y to determine your speed.

They have been using them on victorian highway patrol cars for 10+ years. Essentially it knows the speed they are travelling at. Works out how the difference between theirs and your car, and calculates how fast you are coming at them by deducting their speed... so in your example, the difference would be 140kph, they are doing 80 kph, therefore you are doing 60.

Edited by Hotwire
Thanks "R34", "EVIL 34" and the R34 GT-4... now I want a 4 door R34 even MORE now!

Here comes another bank loan :whoops:

We had our own mini SAU cruise back haha

you forgot the R34 4door i was in :)

Madaz:

"Luke they have to stop you and fine you thats just a laser gun very inaccurate also 1 moving object cant pin point another moving objects speed"

I have to pull you up on this one buddy. One moving object can determine the speed of another. All it needs to do is correct for the doppler shift introduced by the moving radar. You just need to calibrate for the motion of the radar. I am a physicist that works with radar a fair bit so trust me on that. :drag:

A lot of those highway patrols with the radar on the roof have cameras built in on them. Sometimes all they do is speed up to get a photo of your plate and then next thing you know you have a surprise in your mail box.

Luke (Heslo): Nice shot of the cop car dude! :(

ok man that might be correct for a ship using sonar as its radar system but were talking very finicky laser guns that when dropped and bumped and with cold and heat will go out of calibration if excuse me farted near i hold very little faith for SAPOL and the way they allegedly calibrate there equipment. PERIOD i spent about 15 months defending myself because they allege i was doing 147 in a 100 zone and there was no way i was copping that on the chin... any ways long story short my expert smoked there calibration procedures and half of them wernt even done the old close enough is good enough and i got it dropped to 90 in a 80 zone dangerous driving dropped no conviction recorded and no loss of demerit points

It would be interesting to know how those cameras asses the speed "your" doing while "they" are doing X amount of speed! Like if i were doing 60 in a 60 zone and they were doing 80 in a 60, how would the camera determin if its me or them speeding??

here here see above rant.... cost me a lot of moo'la

Madaz you are correct in regard to the hand held devices. A guy who use to work for the company that manufactures our radar systems now works for SAPOL fixing speed detection equipment. He said that the guys doing the calibration don't always do a good job.

In regard to the ones mounted on patrol cars as I mentioned above, once they are calibrated with the vehicle, usually they just hook in with cars on-board computer that does all the trip stuff, they are as about as good as they will get and rarely need re-calibration.

Deluxe:

How does one moving object measure the speed of the other moving object? Hotwire is almost there, but they do it with frequencies rather than speed.

Here is how it goes.

1.)the radar works at a frequency F

2.)If the radar moves like when it is mounted on a car then the frequency of the radar beam is shifted by and amount Fd so the new frequency of the radar is:

F_new=F+Fd where Fd=(F x v1)/C where v1=speed of moving radar and C=speed of light= 300000000 metres/second= 1.08 billion kph

3.) when the radar beam bounces off the car being detected which is moving with speed v2 this produces a doppler shift of the signal of frequency F_new

so you get F_new2=F_new + (F_new x v2)/C

= F + (F x v1)/C + v2 x (F + (F x v1)/C)/C

so given that you measure F_new2, you know the values of v1 (from radar moving speed), F, and C you easily work out what v2 (the speed of the detected car is - the only thing you don't know). A computer on board does that calculation in a split second.

if you are still confused google doppler shift,speed cameras and read up. :)

Hope this clears things up for everyone. :D

Edited by kalel

The govt should have their cars impounded for letting lawyers interfere in science and engineering problems, they're so afraid of the fact these systems aren't perfect (nothing ever is but nor does it need to be) they try to hide the mechanics of this shit behind layers of bureaucracy, instead of clearly explaining how this all works, where it can fall down, but also the checks and balances in place to pick up when and where it does... but most importantly doing it in plain english.

Kalel's given you all lesson on the science, and I've worked closer to all this than I care to admit on a motoring forum, the above is tied up in politics and a general disrespect for intelligence of their voters.

But at the end of the day you all know when you've been speeding, personally I've been done three times, and I was in the wrong each time. If you have a GENUINE doubt then pursue it like anything else, but if you KNOW you were speeding take your lumps and stop whining (this isn't directed at any one in particular I must stress), don't fight it coz it makes ratings for Today Tonight.

oh yeah Ash couldn't agree more

i didn't go all the way with it cause i was pushing my luck and trying to get off something i had done i did accept the 90 in a 80 zone because i was speeding just not the amount they claimed, plus a years loss of license was worth $1500 and fighting for

BTW i hoped my comment before about Kalel was taken tounge in cheek go to admire a smart man im only as smart as my google searches :) and spell checks

Just a quick Q:

Following on from some comments in the photography section and in wasteland, does anyone have objections to the no. plates in photo's?

I couldnt be bothered blanking them, but if someone objects I'll take thier photo down

Cheers

Lee

no worries here, ppl who iv pissed off prob already hav my plates an dont read these forums SO MORE PIKS I SAY

But at the end of the day you all know when you've been speeding, personally I've been done three times, and I was in the wrong each time. If you have a GENUINE doubt then pursue it like anything else, but if you KNOW you were speeding take your lumps and stop whining (this isn't directed at any one in particular I must stress), don't fight it coz it makes ratings for Today Tonight.

Too true Ash!

I just was curious thats all!!

Aftdrk:

What's the deal with the music video version you posted. It looks like you have bird crap on the lens that isn't there in the other clips you posted.

Hotwire:

I know some people can be a little touchy about having their number plate showing. I know some people voiced their concern to me after I posted pics from the last cruise to mt barker.

haha sorry kalel i was just mucking around with some trial software that i had to download to put the clips together, that 'bird poop' on the music version was the watermark from the program i was using, oh yeah and i was using my crappy phone camera :)

Edited by AFTDRK

you should try ulead video studio thats was i was using trial software also i think i even first compressed the .mov into mpg in sony vegas pro 8.0 trial :) goto love trial software then formats :D

also http://www.virtualdub.org/ is free

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Nah, OEM washer bottle and brake fluid reservoirs are fine I don't know what it is with the plastic that Mazda used, some plastics, like the washer bottle and brake fluid res are fine, and still look new after 20 years use, where as the coolant expansion tank, and PS reservoir, that I replaced with new OEM items when I first got the car, turned yellow and started getting brittle a few years later If the dirty yellow stained plastics didn't trigger me there wouldn't be an issue, but they did, much like the battery bracket....... Meh As for going back to work full time to support car stuff, nope, why, because I own a Mazda NC MX5, not a Nissan R series Skyline 🤣
    • I've never heard of CJ-motor, so can't advise you on them. I'd just go straight to GCG for a GCG highflow though. Seems no point to use a middleman. I'm somewhat surprised that the price on the CJ site is lower than the GCG retail price. Even though CJ would get a discount of some sort, you would hardly expect them to give up so much margin. Maybe the price is out of date? Having said that "I'd go to GCG"...when I did my highflow, I went to Hypergear. I did this https://hypergearturbos.com/product/rb25dethighflow/#tab-dyno-results with the R34 OP6 450HP profile. With the BB centre (extra $400) and intially with the standard boost actuator, but I eventually got him to send me the high pressure one when I got to the point of being able to actually use it. Ends up costing the same sort of money as the GCG highflow, but this is, of course, the turbo that I KNOW has a shorter length core and so moves the comp cover rearwards. The GCG apparently doesn't do that. My mechanic also swears by the GCG highflow, given that we have another turbo rebuilder who does something essentialy the same as theirs, using Garrett wheels. He says it stands up at really low revs and makes good power. I haven't pushed my HG highflow past ~240-250rwkW yet (should have a little more in it, but unclear how much) and it does have a fairly gentle boost ramp. OK, it's much better now that I have gotten my boost controller tuned up on it.  A lot of my earlier unhappiness was because I couldn't keep the wastegate flap as closed as it needed to be (including some mechanical issues). I'd still prefer it to boost up nearly as quickly as the stocker, and it certainly a bit slower than that. So maybe the GCG one is worth the first look (for you).
    • Ok thanks 🙂 I will higly consider this. Any "known" company for a good reviews and experience to send that off? Is that CJ-motor good one? Or go straight to GCG site? I need to use VPN to even find some of those "shops" let alone access them 🙂 
    • You can literally put in as much WMI as it takes to quench the combustion totally (and then back it off a little, obviously), and it will keep making more and more power. The power comes from the cooling effect of the water (and the meth) and the extra fuel (the meth, which also has massive octane). It is effectively exactly like running E85. One might be slightly better than the other, but they are damn close. But with either you can lean on the boost or the timing (or both) waaaay more than with just petrol and the results are similar. Here's the first thing I googled for an anecdotal bit of evidence. Can't access the attachment without being a gold member, but it is there for the getting if able to, or searched up elsewise perhaps. https://www.hpacademy.com/forum/general-tuning-discussion/show/wmi-vs-e85/
    • Dang, those BBS are so nice! 
×
×
  • Create New...