suzuki SV650s top speed......? (117.3 aparently).

[younggunns]

i have bin with my eyes anyway 132mph, and felt i still had some more to go.
all i have modded is a leo vince full exhaust.
surely the digital speedo on the k6 pointy can't be out that much..

can it........?
http://i195.photobucket.com/albums/z16/element155/IMG_0732.jpg
(http://i195.photobucket.com/albums/z16/element155/IMG_0732.jpg)

[Samnooshka]

Aren't Dyno runs done in 4th or 5th, or did I dream that?

[younggunns]

Aren't Dyno runs done in 4th or 5th, or did I dream that?
i'm having this argument with someone else and they sent me the pic....
they didn't believe me when i said i hit 132mph.
i'll hit them with your info now. see what they say to that..

[TSM]

Indicated, indicated, speedo error

[yorkie_chris]

Dyno run and top speeds are completely useless.

I could quite easily gear my bike to do 190mph on an inertial dyno, it wouldn't mean a thing though.

[Steve_God]

I had my car on a dyno run today (well... yesterday now... it was Saturday!), and it was fully explained:

They run it in a high enough gear to get an effective reading at each RPM point that the machine reads from, and rarely (if ever) do they use the top gear.

On my car, they used 3rd gear to measure the torque, and 4th to measure the BHP. And along with the stats, it also gives 'Maximum road speed reached in test" - which I think is what yours 'should' also say!

[Blue_SV650S]

As mentioned, that will be in whatever gear it was tested .. but as you bought it up ...

Mathematically an SVS is geared for 148mph with stock gearing at 10500rpm. I am not sure it'd red line in top mind with stock gearing.

With 14, 44 which is what I have on my track SV is mathematically geared for 138 mph.

I had that out at Silverstone about a week ago and I can tell you for nothing it was on the red line in top down the back straight (and through the left kink before 'bridge' 8)).

So I know for sure that an SV will do at least a mathematical 138mph and it would probably pull slightly taller gearing. So lets round that to 140mph. - lets not guess to much from this point, but Silverstone straight is a finite length long ... if you had infinite length, there is a good chance it'd pull taller gearing still and do 145+ ... but again, we are hypothesising a bit to far at that point to make the numbers have any real foundation ..

Points to note:-

That flat out in top with 14 44 is a bike with a full race fairing, rider fully 'prone' and no mirrors.

I say mathematical as I am using the know gear ratio reductions, RPM and rear tyre circumference as my input. There are 3 obvious things that could make the numbers inaccurate in reality.

1. Clutch slip - at that sort of speed there is massive air resistance
so it is possible that the clutch is overcome at high speed and you are getting at least some slippage (i.e. rpm higher than should be).

2. With centrifugal force the tyre will expand/balloon increasing the circumference.

3. Rev counter error.

I have no hard data to ascertain the amounts of clutch slip and ballooning that would occur at those sorts of speeds, but as one would increase the speed and the other would reduce, lets for arguments sake (and for want of accurate data) say the effects equal out and we are back at our mathematical and road (track) tested ~140mph figure ;)

[gettin2dizzy]

With a fully open exhaust you can rev out an SVs in top :)

[Dangerous Dave]

Oh... god... we are back to top speed of an SV650 again, the speedo is inaccurate and gets worse the faster you go! There was a thread a few weeks back about what was your highest recorded top speed on the SV, 9/10 seemed to believe the speedo which is so obviously exaggerated!

As 'Blue SV650S' said above, SV is mathematically geared for 138 mph, but realistically it won't get there! The manufacturers estimated top speed is actually a lot closer to the real top speed than that is!!!

[Blue_SV650S]

As 'Blue SV650S' said above, SV is mathematically geared for 138 mph, but realistically it won't get there! The manufacturers estimated top speed is actually a lot closer to the real top speed than that is!!!

No, I said in stock it is mathematically geared for 148 ... my track SV has 14/44, which is mathematically 138 at 10500rpm (red line) ... and mine DOES pull to (and slightly in) the red line in top with 14/44 ... if we argue clutch slip and tyre expansion cancel each other out (and believe the rev counter) I KNOW my bike will do at least 138mph - and it does it lap after lap!! ;)

So I am saying that with appropriate gearing I am pretty sure a faired SV with no mirrors and a 'prone' rider will do 138mph. However to get that extra 10mph* to attain 148, you would need different gearing! And bearing in mind I am not sure the SV can pull 15/44 all the way to to the line ...

Phoenix, which had 15/45 (145mph mathematical) would NOT get to the red line in top before I had to hit the brakes at silverstone - it might have done given a long enough straight, but it was certainly not going to get there any time soon if ever!! ;)

So by my calculations and experiment, I really don't think even a 'slipy' SV will do much over 140 in the real world ...

*10mph doesn't sound a lot, but at that speed it takes more and more BHP to get every extra 1mph

[yorkie_chris]

Air resistance vs power is a cube relationship. To double speed you need 8x the power. Add rolling resistance to that too. Also maybe gearbox losses.

[G]

I think my speedo is way out, you can be doing 100 down the motorway and only be going slightly quicker than all the traffic around you, I'm pretty sure that they arnt all doing 100 lol

It accurate at 70mph mind as i was following the girlfriend down south the other day and she has a digital speedo and gps all of which were saying 70.

[Blue_SV650S]

I think my speedo is way out, you can be doing 100 down the motorway and only be going slightly quicker than all the traffic around you,

I think you will find that most people do 80-90 down the motorway these days, so you will only be going slightly quicker! ;)

[Alpinestarhero]

I've had 105 mph on my speedo. Dont tell me it was any slower, I saviour the joy of going that fast on my restricted SV

Gets a bit weavy at that speed :D

Matt

[Sharka Zulu]

The Most Ive seen on my speedo is 148mph
But I was sitting behind two R1s and a ZX12 so that helped :p

with no slip stream assistance i can get about 135mph

[flymo]

only way to properly measure this is with speed guns or good quality gps I reckon. There are too many variables that could introduce error.

I left the speedo connected for my first test session around Anglesey and I was seeing indicated speeds of 145mph at the fastest sections, how accurate that was is anybodys guess. The speedo is now removed as it's too distracting on a track.

[northwind]

Yep, even the tyres deform a wee bit at high speed. Mine has no clocks at all today, that's the only way to get no speedo error :cool:

[leatherpatches]

Just after I got my sv (now gone) it had about 800 miles on it. At this time I had a readout of 142mph from the speedo. This was completely stock and down a very slight incline.

My friend was next to me in his car with a GPS unit which was reading 129/130/131 mph for this stretch. This would seem to indicate that it was over-reading by about 9% of the true value. Put another way the true value was about 8% less than what was reading on the speedo.

I was quite impressed with the bike at the time! Pretty good from a 650 v-twin.

All the above experimentation was conducted, of course, on private land and not the public highway.

[rowdy]

I have an sv650s 53reg and in standard form managed to get a speedo reading of 131mph on the road. As a surprise 30th birthday present my wife organised for me to take my bike to steve jordan suzuki where a full race m4 system was put on and then we went down to a friend of hers who has a dyno in his garage and three speedway world championship titles to his name. his friend Mark Dent (Dynopro co-founder and dyno tester of the mini twins race series) came down to dyno my bike. before running it he estimated that it would be producing around 65bhp but after testing and leaning it of a bit it was producing 72 which he said was a very good figure for it. Kelvin (dyno owner) asked him how hard to rev the bike without blowing it up and Mark told him that my bike had a rev limiter set at about 10400rpm. I told him that my bike reved nearer to 11400rpm and he told me that a handful of them left the factory with a higher rev limit setting and I must be one of the lucky ones. The long and the short of it is a bike with standard gearing (only other mod apart from exhaust is k&n filter element) that revs way past 10500rpm in top gear and has achieved 141mph on the road on more than one occasion.

[yorkie_chris]

104000rpm.

revs way past 105000rpm in top gear and has achieved 141mph on the road on more than one occasion.

That's a high revving SV :-P

141mph indicated that is, not true.

[Dangerous Dave]

141mph indicated that is, not true.
+ 1, this debate will come and go over the years. For some unknown reason people seem to believe the speedo is 100% accurate, and get so upset when they find out that there SV won't do 140mph!

He,he... I know how fast they will actually go, thats why I enjoy these threads/posts... \\:D/

[rowdy]

:):rolleyes::rolleyes:
That's a high revving SV :-P

141mph indicated that is, not true.
you re quite right if it did rev that high im sure id be picking bits of piston out my backside

[rowdy]

+ 1, this debate will come and go over the years. For some unknown reason people seem to believe the speedo is 100% accurate, and get so upset when they find out that there SV won't do 140mph!

He,he... I know how fast they will actually go, thats why I enjoy these threads/posts... \\:D/
fair enough im not saying the speedo is 100% accurate but they will rev to the red line with a little bit of mods

[OldBoy]

:):rolleyes::rolleyes:

you re quite right if it did rev that high im sure id be picking bits of piston out my backside

About 10k revs according to http://www.gearingcommander.com/ for an s on standard 15/44 sprockets, rev counters don't appear to be any more accurate than the speedo.
One of the bike magazines, can't remember which one, recently tested one of the latest crotch rockets and found the rev counter to read way over the top.
Perhaps someone has the article close to hand and can fill in the details.
As soon as I have the time I will measure the actual revs and see just how much the SV is out and post the results on the forum.

I can understand why its best to have the speedo reading high but why the rev counter? There is no excuse for it with modern digital electronics.

Can't take credit for the useful gearing site link but it was in a post some where by someone on this forum.

[lloyd_christmas]

I can understand why its best to have the speedo reading high but why the rev counter? There is no excuse for it with modern digital electronics.

Can't take credit for the useful gearing site link but it was in a post some where by someone on this forum.




I can remember when Yamaha brought out the 06 (07?) R6. They claimed it revved to something silly like 19,000. They were exposed when it was found out that they actually revved to more like 15,500.

I would imagine that the sold a few bikes on the back of it though.

[Dangerous Dave]

fair enough im not saying the speedo is 100% accurate but they will rev to the red line with a little bit of mods
Oh, yeah I agree. In fact I know that a 650 with JHS cams can rev to the limiter and pull all the way, my 750 has an extra 1400 rpm's, but this required the limiter to be altered (I don't know how it was done).

[yorkie_chris]

I've heard the SV400 has a higher limiter but same ICU connector.

[Dangerous Dave]

I've heard the SV400 has a higher limiter but same ICU connector.
I have heard that too, but I have also heard the engine won't get you that far up the rev range anyway. I haven't worked on an SV400 yet though so this is all based on other peoples comments and not my own experience.

[Blue_SV650S]

I have heard that too, but I have also heard the engine won't get you that far up the rev range anyway. I haven't worked on an SV400 yet though so this is all based on other peoples comments and not my own experience.

Indeed, the power tails off after what 9.5k?? ... so it is not like it'd make you go any faster even if it wasn't rev limited until say 16,000 RPM ;)

[yorkie_chris]

Yes, but dangerous daves engine is modified up to the nuts, so it might benefit from more revs?

[Quiff Wichard]

only got 80mph out of mine!


but then I do weigh 44 stones .



now THERE'S a variable.

[Frank]

only got 80mph out of mine!


but then MY B**** do weigh 44 stones .



now THERE'S a variable.
is that you in the other thread Mr Quiff

[rowdy]

Oh, yeah I agree. In fact I know that a 650 with JHS cams can rev to the limiter and pull all the way, my 750 has an extra 1400 rpm's, but this required the limiter to be altered (I don't know how it was done).
looking at getting mine bored to 750 is it just a rebore and pistons or do the barrels need changing aswell

[rowdy]

Yes, but dangerous daves engine is modified up to the nuts, so it might benefit from more revs?
you only need a full race exhaust to get some benefit from the extra revs in top gear , my bike struggled to rev higher than about 10300rpm in top without it but will go past that now its gained another 10mph top speed (speedo reading not true reading)

[supervtwin650s]

So just reading through these posts makes me wonder where, when, and whose riding these bikes. I personally have had my sv650sk6, up to 149, at 5200 feet. This was with a Yoshi TRS, worn rear tire, and me tucked as tightly as I could be. It took about 2 and 1/2 miles to do this. On flat land. I also have a fender eliminator, flush mounts, lots of unnecessary weight gaining pieces, hugger, Metzeler Sportec M3 in the rear, modified airbox, forced induction, and no reflectors, all weight and drag components. So that's the deal. I will try to record this at some point, if not, just ride your bike hard! Real HArd! Shift it high, 11,800 is what the rev limiter will kick in at. I also run Mobil 1 4T Racing synthetic. Give it a try.

[DarrenSV650S]

So just reading through these posts makes me wonder where, when, and whose riding these bikes. I personally have had my sv650sk6, up to 149, at 5200 feet. This was with a Yoshi TRS, worn rear tire, and me tucked as tightly as I could be. It took about 2 and 1/2 miles to do this. On flat land. I also have a fender eliminator, flush mounts, lots of unnecessary weight gaining pieces, hugger, Metzeler Sportec M3 in the rear, modified airbox, forced induction, and no reflectors, all weight and drag components. So that's the deal. I will try to record this at some point, if not, just ride your bike hard! Real HArd! Shift it high, 11,800 is what the rev limiter will kick in at. I also run Mobil 1 4T Racing synthetic. Give it a try.
You obviously haven't read all the posts

[Lozzo]

So just reading through these posts makes me wonder where, when, and whose riding these bikes. I personally have had my sv650sk6, up to 149,

Impossible. The average American's brain cannot stand the air pressure at those sort of speeds - something to do with it rattling around the skull like a baseball in a dumpster.

[MattCollins]

:) Who cares... So long as the bike accelerates smartly from 50-90mph to get me around 175ft road trains and will cruise all day at 75-80mph then all is good. A bike that tops out at a real 120mph without coming apart is usually fairly good at doing what I ask of it.

Cheers

[MattCollins]

Lozzo, everything American is bigger. BS factors of 20-100% need to be applied.

Cheers

[husky03]

Impossible. The average American's brain cannot stand the air pressure at those sort of speeds - something to do with it rattling around the skull like a baseball in a dumpster.


:winner:

[Biker Biggles]

[quote=supervtwin650s;1731851]So just reading through these posts makes me wonder where, when, and whose riding these bikes. I personally have had my sv650sk6, up to 149, at 5200 feet.

I reckon you would reach terminal velocity at 5200 feet and actually be going slower than that by the time you hit the ground.:smt115:takeabow:

[Dangerous Dave]

only way to properly measure this is with speed guns or good quality gps I reckon.
Nope, for a start civilian available SatNav's are not accurate and even the top spec military equipment isn't fantastic either.

looking at getting mine bored to 750 is it just a rebore and pistons or do the barrels need changing aswell
Whoops I missed this but as the thread has been dug up from the grave....

You can just re-bore the barrels and fit bigger pistons, to be honest boring out the SV engine isn't worth doing unless you do the bottom end too.

[yorkie_chris]

Measured mile for top speed.

Depends how you mean worth doing, the stock crank won't last long bored out that much.

[davepreston]

well i was lucky enough to have an runway and a speed gun ay work (warton for them in the know) and i clocked 136 and suzi wasnt enjoying it to much at the top i think 140 would be possible with some serious tinkering. i did for the i wonder factor but my bike is for town work and the 70 - 100 on the motorway it is all i need it for and more so dont see the point in adding to the top end acceleration possibly but again its quick enough for me

[rowdy]

Nope, for a start civilian available SatNav's are not accurate and even the top spec military equipment isn't fantastic either.


Whoops I missed this but as the thread has been dug up from the grave....

You can just re-bore the barrels and fit bigger pistons, to be honest boring out the SV engine isn't worth doing unless you do the bottom end too.
Oh aye, the bottom end would be strengthened.

[yorkie_chris]

Big money.

[Dave20046]

Isn't it mathematically capable of 148mph if it was a perfect surface, no wind and no rider? I would've thought the sv'd do 120ish standard.
Who cares anyway if all you want to do is brag about top speed get a busa or sommat. may aswell just have fun on the torquey mofo :cool:

[yorkie_chris]

Mathematically? What does that mean? Rev limiter in top? If that is what you mean, then yes, 143mph would give 10,200rpm in 6th with stock S model gearing (iirc). But that means sod all, because it won't reach the rev limiter in top!

Air resistance vs power is the main thing that matters for top end. (rolling resistance is pretty small by comparison)

[rowdy]

Mathematically? What does that mean? Rev limiter in top? If that is what you mean, then yes, 143mph would give 10,200rpm in 6th with stock S model gearing (iirc). But that means sod all, because it won't reach the rev limiter in top!

Air resistance vs power is the main thing that matters for top end. (rolling resistance is pretty small by comparison)
I have near as dammit hit the rev limiter in top and my rev limiter kicks in at 11400rpm(tis true,tested on dyno). Speedo reading 142mph (means f*** all I know) on a private road of course.
Anyhoo, away from the top speed bs (I know I'm slightly highjacking the thread but it is an old one) what is a ballpark figure for a billet crank, for I am toying with getting an rsv1000r but like the idea of keeping mine and modding it as it'll be more bespoke.

[Dangerous Dave]

speed gun ay work (warton for them in the know) and i clocked 136
What is the likely hood of that being accurate?

Depends how you mean worth doing, the stock crank won't last long bored out that much.
Exactly, why tune the top end when the bottom end is the weaker part.

But that means sod all, because it won't reach the rev limiter in top!
Most SV's with a full system and filter will hit the limiter in top, but as stock they won't.

what is a ballpark figure for a billet crank
The Falicon billet crank I have cost me around £1200, my engine would pop without it for sure!

[-Ralph-]

My speedo is consistantly 10% over at any speed according to my sat nav (which is doing a straight distance/time calculation so should be accurate at a steady speed). I have a K6 pointy. So my indicated 134mph max was actually only about 121mph. Which I think is realistic for a stock SV. At and indicated 33, I'm doing 30. Indicated 44, is 40, etc, etc.

I have lowered the gearing now and have an aftermarket exhaust can, it definately quicker since, but still never tried it flat out since. It gets to an indicated 130mph with less effort and as it will be revving out at higher revs now and hence probably producing more power, it may be a few mph quicker, but still not more than a true 125mph I wouldn't expect.

[BigFootIsBlurry]

I dont understand what the fuss is about with top speed, especially on a bike. I've driven at 175mph in a car and while it was fast it wasnt half as much fun as chucking it throught the corners at less than half that. The only difference with bikes to me is that 175 wasn't scary in the car but would have me reaching for new pants on a bike. I've not been up to any speeds worth talking about on 2 wheels but to me its the twisties that matter.

[kwak zzr]

exactly that, 100 is fast enuf, i rarely exceed it :) but a nice corner at 60 is far more rewarding, if all roads were built straight id pack in biking.

[MattCollins]

You would hate the Northern Territory, Au. Around 3000km of (sealed) highway in an area 6.5x bigger than the UK and it is all straight. Sometimes my biggest challenge is staying awake.

Cheers

[-Ralph-]

Nope, for a start civilian available SatNav's are not accurate and even the top spec military equipment isn't fantastic either

I looked this up recently after a conversation with Kilted Ginger where he had been told by somebody not to rely on his Sat Nav speed reading.

It would appear you are quite right but accuracy is of course relative...

http://gpsinformation.net/main/gpsspeed.htm I like this link becuase it's a direct quote from Garmin, rather than something written on a forum by Joe Bloggs, the local village "know it all". The person who wrote it should know what they are talking about, so not being a physicist myself, I'm going to work on the assumption its correct.

Accuracy to within 0.5 mph is good enough for me when compared to my 10% too optimistic bike speedo that is about 25 times less accurate at the SV's modest top speed.

Even my cheap as chips unbranded Sat Nav has a SirfIII 20 channel GPS receiver, old 5 channel devices may be more inaccurate, but anything with 12 channel or more should be damn accurate if you are to beleive what I have read about them on various GPS websites (not forums).

Of course you can have as many channels as you like but if you can't see that many satellites its useless, but I've never seen less than 10-12 satellites on screen when on a open motorway on the bike. Being "open air" and not having the car bodywork and glass seems to make a big difference to the strength of the signal.

[Dangerous Dave]

Civilian SatNav's have to comply with the same specs as vehicle speedometers, they have to over read. When driving a Landrover at an indicated 80mph a civilian SatNav actually reads an indicated 77/78mph. Even the top of the range military kit is not accurate (this includes the equipment used in laser guided war heads), accuracy of these weapons is prove enough and only the skilled pilots in F-117's actually scored a 100% hit rate in GW1 with the same equipment as F-16's.

[yorkie_chris]

Huh? Laser guided weapons are guided by laser. Isn't it the JDAM that's GPS guided?

Surely the F117 getting better accuracy is down to them not worrying about evasive action while guiding bomb.

[speedplay]

Crashes seem to feel like 140mph when your sliding down the road on your face!!

[Nutter]

Civilian SatNav's have to comply with the same specs as vehicle speedometers, they have to over read.

Really? Are you sure about that? I don't think that's the case. Satnavs don't come under Construction and Use regulations or anything like that, so I'm pretty sure the speed display isn't governed by the same rules as speedometers.

Besides, I think the rules with speedometers is that they may over-read by up to x%, but must not under-read - it is entirely legal for them to display the correct speed.

[TSM]

Civilian SatNav's have to comply with the same specs as vehicle speedometers, they have to over read. When driving a Landrover at an indicated 80mph a civilian SatNav actually reads an indicated 77/78mph. Even the top of the range military kit is not accurate (this includes the equipment used in laser guided war heads), accuracy of these weapons is prove enough and only the skilled pilots in F-117's actually scored a 100% hit rate in GW1 with the same equipment as F-16's.

Have you considered that the Landrover speedo is the incorrect one as most cars/bikes are?

GPS is realy realy acurate, ok its not exact if you speed up to 80 and then look at the GPS and see it says 70, give it a few hundred meters at a constant speed and the GPS will be exact, if it was wrong then the system would never know where in the world we were, ie you travel 100miles but if it had 10% inacuracy then it would think you had been 90miles.

GPS speed is only calculated from position its covering, so the higher the sampling rate of the GPS receiver the more acurate the speed will be.

[Dangerous Dave]

Huh? Laser guided weapons are guided by laser. Isn't it the JDAM that's GPS guided?
Not all smart weapons are laser guided, a few other devices also operate via SatNav.

Surely the F117 getting better accuracy is down to them not worrying about evasive action while guiding bomb.
For a start a F-117 isn't actually capable or undertaking evasive action, and secondly the air defences were down before the aircraft entered enemy skies. The accuracy came from the pilots skill and experience, when the F-117 was in service it was only piloted by the best pilots (as the US would claim) and also bear in mind it has the same systems as the F-16 which also operated in GW1 when the air defences were down and did not score to well.

Besides, I think the rules with speedometers is that they may under-read by up to x%, but must not over-read - it is entirely legal for them to display the correct speed.
I don't think vehicle speedo's are allowed to under read at all, after all you could then blame the manufacturer for recieving a speeding ticket

Have you considered that the Landrover speedo is the incorrect one as most cars/bikes are?
Yes, Landrover speedo's are famous for being exaggerated hence why I know the SatNav also over read.

GPS speed is only calculated from position its covering, so the higher the sampling rate of the GPS receiver the more acurate the speed will be.
Yes, but is always a few steps behind you. Trust me, SatNav's are inaccurate and for proof I recommend you do a timed mile and see how far they are out.

[kwak zzr]

my satnav's poo at estimating my speed, its always wrong.

[Nutter]

I don't think vehicle speedo's are allowed to under read at all, after all you could then blame the manufacturer for recieving a speeding ticket

Oops, got over-read and under-read the wrong way around! I've edited the original to make more sense.

[TSM]

Yes, Landrover speedo's are famous for being exaggerated hence why I know the SatNav also over read.


Yes, but is always a few steps behind you. Trust me, SatNav's are inaccurate and for proof I recommend you do a timed mile and see how far they are out.

Trust, i dont know you..
They are not inaccurate, they are accurate in the information they have. Look at what i wrote and i did say that if you quickly accelerate then look at GPS it will read wrong, but if you stay at a constant speed its will get a true speed. Also the issue is not to do with GPS, its to do with the unit thats receiving the signal. There are proper units to track speed and they use several receivers to get a quicker and even more accurate speed/location at any given speed.
Even a digital speedo on a bike is a bit slow at updating when you accelerate or decelerate.

[MattCollins]

GPS is realy realy acurate, ok its not exact if you speed up to 80 and then look at the GPS and see it says 70, give it a few hundred meters at a constant speed and the GPS will be exact,

Consumer grade GPS is not really, really accurate. There are so many enviornmental factors contriving to mess things up that it is a technological marvel that they work at all.

...if it was wrong then the system would never know where in the world we were, ie you travel 100miles but if it had 10% inacuracy then it would think you had been 90miles.

Not too sure where that is coming from... GPS doesn't count up all the little shifts to determine its position (like INS), but it does do that (caveats likely apply) for the built in odometer and that sort of inaccuracy is not uncommon.

GPS speed is only calculated from position its covering...

No, modern GPS also uses phase shift to calculate speed which is a big improvement on solely position based calculation. There is a lot of averaging, fudging and smoothing going on and the speed readout can be somewhat fuzzy. Under adverse conditions (satellite geometry, shadowing, multipath, electronic interference etc) both speed and position accuracy really goes down the crapper.

...so the higher the sampling rate of the GPS receiver the more acurate the speed will be...

...give it a few hundred meters at a constant speed and the GPS will be exact...

These last two statements contradict each other.

Cheers

Matt

[TSM]

Consumer grade GPS is not really, really accurate. There are so many enviornmental factors contriving to mess things up that it is a technological marvel that they work at all.

Since Bill Cinton signed the act that means that GPS is no longer crippled as much as it was before, its accurate for nealy everything we need to do and in the case of Car/Bike SatNav its considered very accurate. Depending on the receiver you have it can more or less accurate.


Not too sure where that is coming from... GPS doesn't count up all the little shifts to determine its position (like INS), but it does do that (caveats likely apply) for the built in odometer and that sort of inaccuracy is not uncommon.

No, modern GPS also uses phase shift to calculate speed which is a big improvement on solely position based calculation. There is a lot of averaging, fudging and smoothing going on and the speed readout can be somewhat fuzzy. Under adverse conditions (satellite geometry, shadowing, multipath, electronic interference etc) both speed and position accuracy really goes down the crapper.

Grant you the phase shift for speed, it was based on the assumption that forced inacuracy is put into the speed it shows.
Make sure yr receiver has WAAS/EGNOS support, then the interference problems are reduced, most nowerdays have it included.



These last two statements contradict each other.


no they dont, one says a higher sampling rate gives a better acuracy, the 2nd says travel some distance at a constant speed and the speed will be exact, how apart from the word exact (which in this instance means it does not fluctuate massivly from accelerator) are these contradicing each other?

We are talking about satnavs on cars or bikes. For the most part they are very very acurate, limitations tend to be introduced though slow receivers and software.

If we are saying that GPS in its simplest form when SA was enabled, then yes its bad, but SA days are over and with the way receivers are today they are more than accurate enough for all civilian uses.

[MattCollins]

Make sure yr receiver has WAAS/EGNOS support, then the interference problems are reduced, most nowerdays have it included.

Thanks for the advice, but I use a ground and satellite based DGPS plus a reference station. Take note of my location.

WAAS/EGNOS has absolutely nothing to do with correcting the types of inaccuracies that I mentioned. Just to refresh...
satellite geometry, shadowing, multipath, electronic interference

You go from "exact" to "very very acurate". Now you say "Depending on the receiver you have it can more or less accurate". I'll ask again, which is it? I'll go with the last seeing as it is the closest to the truth.

[TSM]

Thanks for the advice, but I use a ground and satellite based DGPS plus a reference station. Take note of my location.

WAAS/EGNOS has absolutely nothing to do with correcting the types of inaccuracies that I mentioned. Just to refresh...

WAAS/EGNOS/DGPS do give corrections to the inaccuracies you mentioned,
WAAS/EGNOS give these corrections via sat while DGPS does it via ground based radio transmitters and most peoples receivers dont have DGPS but its increasing, and also as with all other methods it suffers from 'electronic interference'. Are you a marine person, as they tend to have DGPS equipment as it was part replacement to the Decca and Loran systems.

You go from "exact" to "very very acurate". Now you say "Depending on the receiver you have it can more or less accurate". I'll ask again, which is it? I'll go with the last seeing as it is the closest to the truth.
You know exactly what it means and what its trying to say.

[yorkie_chris]

For a start a F-117 isn't actually capable or undertaking evasive action,

Huh? Explain that. (maybe PM to stay on topic!)

[TazDaz]

Huh? Explain that. (maybe PM to stay on topic!)

This thread is already on the verge of offtopic with purely GPS malarky which I don't understand at all! :batman:

F-117 was a bomber and because of it's stealth capabilities the manoeuvrability was hindered I believe!

They call it a fighter but I have no idea why as it can only carry either 2 or 4 bombs (i forget exactly how many!)

Obviously it can take evasive action, a 747 can take evasive action, but it won't be as quick to manourvre as something like a Raptor, which is also a hell of a lot faster!

EDIT: forgot to say, apologies for going completely off topic, I just like planes! :)

[-Ralph-]

Come on guys, stop arguing googled b*llo*ks and lets get real. I can't believe that everyone on this thread suddenly became satellite positioning experts overnight!

I'd like to know if my sat nav is accurate or not. Is there anybody here who REALLY knows what they are talking about? If so, then please show us your stuff and type something considered, substanciated and reasoned with some explanation of why what you are arguing is true. Not just a statement that says some GPS acronymn is an inaccurate techonolgy! I may be stupid but humour me anyway and explain to me WHY it's not accurate. You could blind me with science and it all be b*llo*ks, but so long as you appear to know what you are talking about instead of making one line statements based on something read on google, I'll believe you! I know sh*t about sat nav, but I'm pretty good at smelling BS.

What about Garmin claiming 0.1% accuracy in the product specifications. Are they lying?

[yorkie_chris]

OK, here's something definately not just b0llocks from google. V = D/T.

Get an OS map, measure 2 points on a road and time how long it takes to get between them at an indicated speed of "whatever".

[-Ralph-]

OK, here's something definately not just b0llocks from google. V = D/T.

Get an OS map, measure 2 points on a road and time how long it takes to get between them at an indicated speed of "whatever".

Now I think thats probably the most accurate thing posted so far :p.

You know I think I might just do that, I have a stopwatch on my trip computer in the car, and I can use the shadow from the bridges on any two motorway junctions and measure the distance on the map afterwards.

Cops used to convict people on the same evidence did they not with the old VASCAR system?

Measure it on cruise control over 5 miles or so and it'd be pretty damn accurate.

Thanks YC, the simple answers are always the best! I'll post up the results and let you know how accurate my speedo and my sat nav are.

[northwind]

Get an OS map, measure 2 points on a road and time how long it takes to get between them at an indicated speed of "whatever".

Ah, but remember that leaning the bike makes the speedo accuracy vary because the rolling radius changes ;) So does high speed as the tyre deforms. So even if you do a timed mile and then use a speedo healer to correct it, it'll still vary slightly in use.

My conclusion is that it's best just to not give a **** how accurate your speedo is, as long as it doesn't leave you getting speeding tickets, and just lie about your top speed- everyone else does it after all. My SV does 190mph.

[yorkie_chris]

Oh you must have fitted a TRE :-P

[northwind]

Mine goes at 70mph even sliding along the track, just imagine what it's capable of when it's upright!

[Bluepete]

My TomTom one gives the same speed readings as the calibrated speedo in my job cars and the same speed as the provida video. That's good enough for me.

Both bike and my own car's speedo over read. I prefer to use the TomTom in my own car for setting the cruise control speed on long trips.

Dunno what my bikes top speed is, certainly no more than 70mph surely?

Pete

[Jester666]

...Dunno what my bikes top speed is, certainly no more than 70mph surely?...

The most sensible answer yet! :thumbsup: :lol:

[-Ralph-]

My TomTom one gives the same speed readings as the calibrated speedo in my job cars and the same speed as the provida video. That's good enough for me.

Both bike and my own car's speedo over read. I prefer to use the TomTom in my own car for setting the cruise control speed on long trips.

Dunno what my bikes top speed is, certainly no more than 70mph surely?

Pete

Excellent! Thats good enough for me too! I want to know sat nav accuracy for exactly the same reason, to set my cruise control at the maximum speed that I can, without having to worry about speeding tickets.

Pete, what speed would you set your cruise control at (send me a PM if you prefer ;-) )? I am currently using 77/78 mph on the sat nav (depending upon uphill or down hill) thats about 82/83 mph on my car speedo. I still have to watch for and brake for camera vans and police cars though, because I wasn't sure that my sat nav was accurate and that I wouldn't get a ticket.

I set it at this because I'm counting on it being below the ACPO guideline 10% plus 2mph, so I'm staying below a sat nav indicated 79mph. Should this be OK (lets assume my sat nav is accurate!) or would you be setting it lower?

Before everyone says, "just drive at 70 and you won't have to worry," I've done over 4000 miles this month, all motorway and my average journey is 4 1/2 hours non stop, so a 10mph increase on my average speed does get me 45 miles further in the same time, the difference between a speedo indicated 70 and a speedo indicated 82 is significant, so it's worth finding out what speed I can drive at without getting tickets. I don't want to drive slower than I have to, but I don't want to have to watch for police cars and camera vans all the time.

[-Ralph-]

OK, here's something definately not just b0llocks from google. V = D/T.

Get an OS map, measure 2 points on a road and time how long it takes to get between them at an indicated speed of "whatever".

OK came back up from Leeds tonight and did these tests to alleviate some boredom.
On cruise control with the sat nav reading 71mph, with the occasional flick back to reading 70.

First bridge after M74 J21, until the first bridge over J17 northbound
13.0 miles in 10 min 56 sec = 71.34 mph

Bridge over M6 J43, until Bridge over J44
3.8 miles in 3min 12 sec = 71.25 mph

Mileage from the sat nav itself and checked afterwards with google maps, both of which agree.

So my sat nav is accurate enough for me. :thumright:

So back to the original topic and why we went off on this tangent in the first place. If you wanna know the true top speed of your SV650, come and borrow my sat nav (or just use your own, chances are it has the same SirfIII receiver).

[Paul the 6th]

I've had 170 out of my sv. My mate on his hayabusa couldn't keep up :razz:

on a bit more of a serious note, vehicle type approval (the tests which certify vehicles as being safe for use on the road) state that speedo's can over-read by upto 10% but must never under-read. Generally, the faster you go the more innaccurate the speedo becomes. So when I was doing 170 on mine, it was over reading by upto 17mph (so I was probably actually only travelling at around 163mph)...

[MattCollins]

Paul, 153mph methinks. :) Curious to know what you did to get the SV moving that fast.

Cheers

PS. First 50km break-in and oil change on a new SV today. Lots of stop go working the range on a little used road - trailered it out there. I know that it does at least 70mph indicated.
......................
TSM, believe what you want.
Ralph, is derision how you deal with something that you do not understand?

[Paul the 6th]

Paul, 153mph methinks. :) Curious to know what you did to get the SV moving that fast.

Cheers

PS. First 50km break-in and oil change on a new SV today. Lots of stop go working the range on a little used road - trailered it out there. I know that it does at least 70mph indicated.
......................
TSM, believe what you want.
Ralph, is derision how you deal with something that you do not understand?

Nah it was actually 163 - not because I'm bad at maths but because of my magical jet pack supa doopa boosta thingy. :razz: about 140ish indicated on mine iirc :)

[MattCollins]

Aha! :)

[MiniMatt]

Given that time is relative, and therefore speed (as a time/distance function) is also relative, before we even begin to consider that distance is a three dimensional variable but legislated as if it were in two dimensions.... is there some kind of existential argument I can use to weazle my way out of speeding tickets?

[Frank]

Given that time is relative, and therefore speed (as a time/distance function) is also relative, before we even begin to consider that distance is a three dimensional variable but legislated as if it were in two dimensions.... is there some kind of existential argument I can use to weazle my way out of speeding tickets?
no

[Bluepete]

Given that time is relative, and therefore speed (as a time/distance function) is also relative, before we even begin to consider that distance is a three dimensional variable but legislated as if it were in two dimensions.... is there some kind of existential argument I can use to weazle my way out of speeding tickets?


Nope, and if you started babbling like that, you would get locked up for being unfit through drugs! ;)

[northwind]

Given that time is relative, and therefore speed (as a time/distance function) is also relative, before we even begin to consider that distance is a three dimensional variable but legislated as if it were in two dimensions.... is there some kind of existential argument I can use to weazle my way out of speeding tickets?

There was an episode of ally mcbeal where someone tried to get off running a red light by claiming that because of his speed, the light was invisible due to redshift. Then they did the maths and discovered he'd have got a bit of a stiff speeding fine if that were true :mrgreen:

[MattCollins]

There was an episode of ally mcbeal ....

Please, you don't actually watch that rubbish... there goes any credibility you might have had.

Cheers

[-Ralph-]

Whats the upper operating range of a gasto? I knew guys when they first came out who tried to beat them on the superbikes of the time by riding past flat out with the theory that they were out of range of the camera before it flashed! Wonder if you could do it on Paul's SV?

[rowdy]

Whats the upper operating range of a gasto? I knew guys when they first came out who tried to beat them on the superbikes of the time by riding past flat out with the theory that they were out of range of the camera before it flashed! Wonder if you could do it on Paul's SV?
Believe this was done on top gear a few years back, around 150mph I believe, bound to be on Dave again somewhen.

[northwind]

Please, you don't actually watch that rubbish... there goes any credibility you might have had.


I was in training to be a homosexual, it was research, but in the end I failed the practical test.

[MattCollins]

I was in training to be a homosexual, it was research, but in the end I failed the practical test.

Too much info!:shock:

[adgsv650]

ive had 130 out of my sv 650 with a blue flame exhaust and a kn filter

[SV650Racer]

Just out of interest we built two SV650's for the NW200 in 2008 (seems strange saying last year!). One was clocked at 139MPH through the speed trap which on most bikes at the NW is flat out in top well and truely!!. Another one was clocked at 144mph.

Ok these bikes are tuned SV's id expect to be running 1 tooth down on the road gearing on the rear. The one we built has just come back for a refresh and was making 187bhp on the dynapro dyno so gives you an indication of what true top speed would be possible on a road going mostly stock SV which would make no more than 68-72bhp in the majority on the same dyno as the above.

Pretty cool..:mrgreen:

File with top speeds is here BTW:

http://www.northwest200.org/files/NW200_%20Race4b_McKendryFabrications400.pdf

Page 8 has speed trap readings. Numbers 51 - 56 - 70 - 72 - 74 - 87 are all on SV650's.

[SoulKiss]

Too much info!:shock:

He lives in Edinburgh - which is like Brighton, only more so.......

[Viney]

Just out of interest we built two SV650's for the NW200 in 2008 (seems strange saying last year!). One was clocked at 139MPH through the speed trap which on most bikes at the NW is flat out in top well and truely!!. Another one was clocked at 144mph.

Ok these bikes are tuned SV's id expect to be running 1 tooth down on the road gearing on the rear. The one we built has just come back for a refresh and was making 187bhp on the dynapro dyno so gives you an indication of what true top speed would be possible on a road going mostly stock SV which would make no more than 68-72bhp in the majority on the same dyno as the above.

Pretty cool..:mrgreen:

File with top speeds is here BTW:

http://www.northwest200.org/files/NW200_%20Race4b_McKendryFabrications400.pdf

Page 8 has speed trap readings. Numbers 51 - 56 - 70 - 72 - 74 - 87 are all on SV650's.Holy mother of god! Whats it running? Methanol with quad turbos and a supercharger?

[SV650Racer]

Holy mother of god! Whats it running? Methanol with quad turbos and a supercharger?

LOL..at my female fingers:-D

[Viney]

LOL..at my female fingers:-DYou..You mean it isnt true :cry:

[SV650Racer]

You..You mean it isnt true :cry:

:mrgreen: