Lengths of gokarts/minibikes drag strips???

[madprofessor]

Can't figure out from youtube videos how long a standard drag strip is for gokarts and minibikes, too many, too confusing.
Seems there are 60', 120' and who knows how much longer ones they do drags on. I want to know what my kart builds are doing on a fixed distance from a dead start for stopwatch comparisons when I make a change to something.
Could make something up, but if there's a standard I could compare to also I'd rather do that. Anybody got info on that?

 

[Millwright]

Interesting topic.
Once I'm up and running, I'm very curious to see the benefits of some of the basic performance mods.
I want to get a good benchmark on stock performance before I change anything.
I havnt yet figured out how i might accurately measure performance consistently.

 

[madprofessor]

Well, my setup plan is to use the entrance side of the church driveway to make my measured distances. It's the longest piece of straight asphalt, and I'll walk it off in segments from wherever start line will be with my 25' tape, using my inverted spray traffic paint to make some discreet marks. Going to get a el cheapo stopwatch for the stop button on top, can't trust the touchscreen on my phone for split second timing.
Will still use phone GPS, set to note the top speed, to check that single factor after the test runs. Just need more factors than that, launch time, distance times, etc., with stopwatch measurements.

 

[Bansil]

Years ago there was a paid dragstrip app that did a real good job circa 2010/12 maybe

 

[Millwright]

Not a bad idea! I just searched for an app that records speed and time.
Still relies on an accurate "touch" to start and stop.
I was thinking that knowing the time and distance to reach maximum RPM would be a good measure of performance.
When I say max RPM, I mean a predetermined number, not catastrophic failure. Lol.

 

[Millwright]

A digital tacho might be better than the needle display one I just got.

 

[Bansil]

This used phones gyro/GPS or something to start it

 

[Millwright]

Can't figure out from youtube videos how long a standard drag strip is for gokarts and minibikes, too many, too confusing.
Seems there are 60', 120' and who knows how much longer ones they do drags on. I want to know what my kart builds are doing on a fixed distance from a dead start for stopwatch comparisons when I make a change to something.
Could make something up, but if there's a standard I could compare to also I'd rather do that. Anybody got info on that?

Does this mean schizoballz is in action?

 

[madprofessor]

Pretty much in action, yeah. The 400-piece circlip (E-clips) metric assortment is arriving 2 days early, tomorrow! I'll be clipping the rocker and shaft back on, maybe get some idea why that outside circlip fell off and went down the pushrod passage in the first place. This time the test run will be with all new steering setup, finally puzzled together the dual chain drive setup. BigBonus!: The sprockets spread is accidentally so perfect that chain is plenty tight enough not to need a tensioner at all to keep play out of the left-drive steering. About 1 in 10 chance of that!
This time I'll remember to watch the tach, and to turn on the camera aimed at the CVT, film at eleven. Hopefully be able to do a variety of runs, get the top speed/tach max comparison, some drag runs, other stuff to force changes in the CVT for research on video.
Had to meet the minimum to get free shipping, so there's a 4-piece set of snap-ring pliers coming with it, the 4 in 1 interchangeable heads type are utterly worthless to me. This set has 0.7 mm tips instead of the 0.8mm tips on most others, and reviewers kept saying they had to file the 0.8 tips to get them in. They're for the driven unit on my 30 series CVT, will let y'all know how well they fit. Going to tighten the spring.

 

[gegcorp2012]

Short tracks can present a greater %error on GPS for time to short distances but should be ok for speed.

I tried a few track logging apps to chart my ride and one of the best ones I tried was Track Addict. It uses an aerial view with your runs shown on top and shows times like a 50 foot time for 1/8 or 1/4 mi runs (that's almost the track for a mini though) . I think it relies on the phone accelerometer and GPS too. It can save and replay multiple runs too.

 

[Budget GoKart]

Good idea guys a drag strip test on a 420 china quad would be awesome! I found a chinese quad for 20 bucks i plan to put a 420cc honda in if i cant keep it running on the 110

 

[Joe-405]

Most of them are 1/8 mile for mini bikes.

 

[madprofessor]

Okay, 1/8 mile is 660' long. Fine for acceleration/top speed test that includes time to squeeze out that last 1-2 mph at top end. For a gokart or minibike that's more of a race event.
I was hoping to find a standard length that focuses pretty much on acceleration only, so there might be some empirical data out there from other's motors similar to what I build, at different phases. Since an average builder's gokarts would probably reach top speed in 200' or less, that's the max range I want to test at.
Marking out my "test track" this afternoon at 60' and 120' just because I've heard those numbers mentioned, and however much longer would still be safe on my limited driveway space. Still want to know about length of any official tracks of clubs or other groups.

 

[Millwright]

I've been searching for a "standard" can't find anything geared towards diy goksrts.
Lots of info on karts doing 10second passes on 1/4 ,mile.

Looks like you may have to blaze the trail on this one.

 

[madprofessor]

That gives me an idea for the 3rd length to mark out. Was thinking it would come down to how far I can go at what final speed on our limited space driveway before braking is necessary for safety's sake.
Instead I think I'll base it on watching the tach where it's now mounted right on the dash arch, and when the rapidity of the rise in rpms starts to taper off, that's where the mark will almost be. Measure to that spot, then drop back to a nice round multiple of 10', and make that the 3rd mark.
Film at eleven.

 

[karl]

I was hoping to find a standard length that focuses pretty much on acceleration only, so there might be some empirical data out there from other's motors similar to what I build, at different phases.

Cool idea, just so dependent on vehicle/rider weight and gear ratio/ clutch's , Its tricky to make direct comparisons.

Would be cool to have a DIY standard distance to compare.

Instead I think I'll base it on watching the tach where it's now mounted right on the dash arch, and when the rapidity of the rise in rpms starts to taper off, that's where the mark will almost be. Measure to that spot, then drop back to a nice round multiple of 10', and make that the 3rd mark.
Film at eleven.

That's great for your own results , but every build is different. I would not consider where that lands a "standard"

 

[Millwright]

The question of gear ratio comes up a lot.
Standard answer is always "smaller rear sprocket for........."
A data base of builds in here would be useful.

Info from cart weight, sprocket sizes, engine size etc, etc. And of course performance results.

 

[madprofessor]

Definitely planning on posting results at different distances, with descriptions of changes each time from motor to gear ratios to whatever else is different. Pretty much the only way I can wrap my confused brain around input vs. output for the money and/or effort applied to achieve the changes. Not trying to set any standard for distances, was hoping to find some. Only making up my own as it applies to what I want to find out about this current kart. And future ones.