Mach Z not stock king of the lake.

[number1kyster]

I can't help but wonder what kind of clutching was in that SW for it to be bouncing off the rev limiter like that.

Stock clutching with a muffler and tune?

 

[Turboflash]

Agree, especially with that much traction. Something not right.

 

[earthling]

When the Cat 1000 two stroke came out, I can understand that GPS may not have been widely available, but in todays world of GPS, why use radar guns.

Radar guns are more accurate as long as the radar gun operator knows what they are doing. If all you care about is documenting performance with reasonable accuracy then dragy is perfect.

This is simply due to how measurements are taken and the number of factors that have to be proper for GPS to be accurate. A radar gun is bouncing a signal off of an object at the speed of light over a fairly short distance. GPS is receiving signals at the speed of light but they are propagating through the atmosphere which can distort the signals as can any nearby objects (reflections). In some scenarios GPS can just be wrong as low satellite visibility, limited receiver quality (phones), and local conditions can conspire to create erroneous readings. The other issue is that the sample rate on smartphone GPS systems is fairly low, like 1hz (1 sample per second). When I looked into this not so long ago, all smartphones use that 1hz sampling rate to conserve battery life and apple at least did not provide an API (code interface) for changing the sampling rate. For short runs, GPS simply won't be very accurate. That is why dragy which uses an external GPS and better accelerometer is so popular and is considered to be 'accurate enough'.

In the above comparison between dragy and a timeslip you can see that the draggy is off about 5/100ths of a second through 330 and its off by nearly 3/10ths of a second over the run. In a games of hundredths and thousandths how accurate is accurate.

Screen grab from youtube video comparing two dragy units that were mounted side by side. Again, accurate enough for the internet but not accurate enough for meaningful race results.

The real problem is when someone grabs a GPS app on their phone that doesn't have an external unit like dragy and just thinks GPS is GPS. It isn't. Not all GPS systems are equal. A phone app without an external box is going to be horribly inaccurate for short distances and only marginally accurate for longer distances. Ever notice your GPS map correcting itself or how long it takes the system to realize you have turned? This is because the software is constantly having to adjust between system inaccuracy and map errors.

For most purposes but a radar gun can be more consistently accurate, just not convenient.

 

[74Nitro]

Radar guns are more accurate as long as the radar gun operator knows what they are doing. If all you care about is documenting performance with reasonable accuracy then dragy is perfect.

This is simply due to how measurements are taken and the number of factors that have to be proper for GPS to be accurate. A radar gun is bouncing a signal off of an object at the speed of light over a fairly short distance. GPS is receiving signals at the speed of light but they are propagating through the atmosphere which can distort the signals as can any nearby objects (reflections). In some scenarios GPS can just be wrong as low satellite visibility, limited receiver quality (phones), and local conditions can conspire to create erroneous readings. The other issue is that the sample rate on smartphone GPS systems is fairly low, like 1hz (1 sample per second). When I looked into this not so long ago, all smartphones use that 1hz sampling rate to conserve battery life and apple at least did not provide an API (code interface) for changing the sampling rate. For short runs, GPS simply won't be very accurate. That is why dragy which uses an external GPS and better accelerometer is so popular and is considered to be 'accurate enough'.

View attachment 168109

In the above comparison between dragy and a timeslip you can see that the draggy is off about 5/100ths of a second through 330 and its off by nearly 3/10ths of a second over the run. In a games of hundredths and thousandths how accurate is accurate.

View attachment 168110
Screen grab from youtube video comparing two dragy units that were mounted side by side. Again, accurate enough for the internet but not accurate enough for meaningful race results.

The real problem is when someone grabs a GPS app on their phone that doesn't have an external unit like dragy and just thinks GPS is GPS. It isn't. Not all GPS systems are equal. A phone app without an external box is going to be horribly inaccurate for short distances and only marginally accurate for longer distances. Ever notice your GPS map correcting itself or how long it takes the system to realize you have turned? This is because the software is constantly having to adjust between system inaccuracy and map errors.

For most purposes but a radar gun can be more consistently accurate, just not convenient.

How a radar gun is used is very important for sure.
The other problem with a radar gun is that the operator of the machine may hold it wide open throttle past the designated mark, therefore giving a higher reading. Or may let off before the designated mark giving a lower reading.

 

[NYTurbo]

Radar running you run to the gun . Once your by the he gun your speed is irrelevant

 

[Jvji24]

Racing them all

 

[actionjack]

TD Performance meter is 10hz.

 

[74Nitro]

Radar gun story.
The fall of 1997 Palmerston Ontario hosted 4-lane grass drags. Was not a series event, more of a back-yard race so to speak, but a very good turnout. Had my new 98 700sx set up for C stock. At the drivers meeting it was announced that someone had a radar gun and there was a $150 cash prize for who ever posted the highest speed of the day. About half way through the event my bud informs me that I was holding the highest top speed. I thought how is this possible as there was clearly some machines that were much larger in displacement and heavily modded. I looked over at the guy with the radar gun and saw that he was standing near the finish line and following the sleds as they passed.
There were a couple cranky guys with larger sleds when I was handed the cash. I said if you have a problem take it up with the guy running the gun.

 

[VX1R]

Good race for the Polaris Boost! That sled is going to be a force to be reckoned with next season and I hope that everyone who's got one coming gets the most out of it. That being said.....

Just saying. Hey it's the slow season

 

[number1kyster]

I wonder how long it will take Doo to bring a sea level 850 Etec turbo to the market?

Turbo Jamie on this forum had a Turbo 850 Doo Mtn sled that he converted to a Freeride and tuned for sea level last season. I believe he put 3k miles on it without issue.

 

[Motorhead]

Good race for the Polaris Boost! That sled is going to be a force to be reckoned with next season and I hope that everyone who's got one coming gets the most out of it. That being said.....

View attachment 168113

Just saying. Hey it's the slow season

Talk of 15% ethanol fuel to help combat high gasoline price I heard.
Dam ethanol blends and MTB cost me many 2 smokes in my past. That and not keeping any of my sleds stock!

 

[Fords4life]

Talk of 15% ethanol fuel to help combat high gasoline price I heard.
Dam ethanol blends and MTB cost me many 2 smokes in my past. That and not keeping any of my sleds stock!

Ethonel is worthless "filler", i am a self employed mechanic for many decades now, every year i get repeat customers from that worthless crap fuel, i tell people if your engine is used often and fresh fuel moves thru it often you can get by with 10 percent, but if it will sit unused for more than 30 days only use non ethonel fuel. Ethonel atracts water, is highly corosive, turns some rubber type materials to sticky goo, and not to mention you need more of it volume wise to equal the same in pure gasoline, loss of mpg's only gain is some octane and a whole lot of arsh ache!

 

[NYTurbo]

Radar guns are more accurate as long as the radar gun operator knows what they are doing. If all you care about is documenting performance with reasonable accuracy then dragy is perfect.

This is simply due to how measurements are taken and the number of factors that have to be proper for GPS to be accurate. A radar gun is bouncing a signal off of an object at the speed of light over a fairly short distance. GPS is receiving signals at the speed of light but they are propagating through the atmosphere which can distort the signals as can any nearby objects (reflections). In some scenarios GPS can just be wrong as low satellite visibility, limited receiver quality (phones), and local conditions can conspire to create erroneous readings. The other issue is that the sample rate on smartphone GPS systems is fairly low, like 1hz (1 sample per second). When I looked into this not so long ago, all smartphones use that 1hz sampling rate to conserve battery life and apple at least did not provide an API (code interface) for changing the sampling rate. For short runs, GPS simply won't be very accurate. That is why dragy which uses an external GPS and better accelerometer is so popular and is considered to be 'accurate enough'.

View attachment 168109

In the above comparison between dragy and a timeslip you can see that the draggy is off about 5/100ths of a second through 330 and its off by nearly 3/10ths of a second over the run. In a games of hundredths and thousandths how accurate is accurate.

View attachment 168110
Screen grab from youtube video comparing two dragy units that were mounted side by side. Again, accurate enough for the internet but not accurate enough for meaningful race results.

The real problem is when someone grabs a GPS app on their phone that doesn't have an external unit like dragy and just thinks GPS is GPS. It isn't. Not all GPS systems are equal. A phone app without an external box is going to be horribly inaccurate for short distances and only marginally accurate for longer distances. Ever notice your GPS map correcting itself or how long it takes the system to realize you have turned? This is because the software is constantly having to adjust between system inaccuracy and map errors.

For most purposes but a radar gun can be more consistently accurate, just not convenient.

GPS is glitchy, even the dragy and other well known performance meters.

 

[earthling]

GPS is glitchy, even the dragy and other well known performance meters.

I was going to add a sarcastic comment that when people don't trust GPS they have lots of stories about people getting steered wrong by their nav systems but when it comes to performance GPS is the new gold standard.

 

[RobX-1]

Nav systems and simply recording speed are two different things. Not all Nav systems are equal. Sort of like iphone users using Google Maps vs Apple's Maps. Same device but varying results.