Jeremy Parson's Big Block video going 120mph @ Daytona!!!!!!!!!

Bob Drye

New member
There is a Youtube video of Jeremy Parson in his Margay Sprint Kart passing TAG Karts @ Daytona. Try this title

Parsons Racing Supply at Daytona Intl Speedway
 
[video=youtube;nkjQZ4xdNkk]http://www.youtube.com/watch?feature=player_detailpage&v=nkjQZ4xdNkk[/video]

Here you go
 
The gearing used ranged from 30/60 to 30/66. So..... figure an 11 inch tire and engine rpm of 6900 and you get a terminal velocity that kicks a tag's but. The video is from Sunday morning. We didn't use a gopro on Monday because our necks were unable keep our heads straight!!!!!!!!
 
Sceptical...How's 120MPH being worked out here? Considering the shifters arent even pushing that...
30:60 @ 6900 with a typical kart tire (34.75 circumference) is 113MPH, that's a bit more palatable considering the HP requirement to find even an extra 5mph over that. Tire growth is not nearly as big a factor as some have claimed in the past.

Don't get me wrong, 110 is still pretty damn impressive. But 120 seems like a stretch to me.
 
Anything over 100 is good, most karts are doing half of that. And even less than half.

I would have liked to see how it accelerates from a dead stop to 100. Like how many seconds

At the local drag strip no one has done 100 mph. And if your doing 40mph in 3 seconds, that's 100mph in 7.5 seconds. And the best we got with a torque converter is 7.0 seconds @ 90mph
 
Desi, the relationship of motor RPM, gearing and speed does not change with aero.
x Motor RPM / gearing = axle RPM.
That's it, aero has no influence on the relationship.
More speed requires different gearing or more rpm as far as the relationship is concerned.
120mph needs 7300 rpm on 30:60 gearing. Aero will not change that.
It'll change you chances of getting there, but has no influence on the relationship.
 
That assumes there is no air drag though. Air drag increases with the square of velocity, so there is four times as much at 80mph as there is at 40mph.

I'm not sure, but it's hard to believe from a dead stop with only 2.0 gearing that it's accelerating that quick to 40mph.

Without a torque converter, the best we got was a 7.70 E.T. @ 80mph with a kart clutch. This is with much lower gear ratio to get moving and 60 foot quick. But the kart is still quicker, and faster, and with higher gearing.

This 7.70 bike is turning 9000+RPM, and 385cc
 
Desi, the relationship of motor RPM, gearing and speed does not change with aero.
x Motor RPM / gearing = axle RPM.
That's it, aero has no influence on the relationship.
More speed requires different gearing or more rpm as far as the relationship is concerned.
120mph needs 7300 rpm on 30:60 gearing. Aero will not change that.
It'll change you chances of getting there, but has no influence on the relationship.

Correct, if the wind is holding back speed, it's also holding back RPM. Which is why it may be didn't turn 7300 and just turned 6900 instead
 
As the video starts Jeremy is leaving the infield and enters the 2 1/2 mile oval. Notice the kart in front of him that pulls away by 300 or 400 feet. At the end of the video he passes that kart. That kart has a 440. It took Jeremy 2 miles to catch up and pass. On Monday the 440 was faster than Jeremy.
 
As the video starts Jeremy is leaving the infield and enters the 2 1/2 mile oval. Notice the kart in front of him that pulls away by 300 or 400 feet. At the end of the video he passes that kart. That kart has a 440. It took Jeremy 2 miles to catch up and pass. On Monday the 440 was faster than Jeremy.

yeah that sounds like a gearing issue. I figured it wouldn't accelerate that quick
 
I am the kart that was in front of Parsons in the vidieo,the vidieo was of sundays race,I had mised the carb jet by a bunch,way to rich on the top end,thats why parsons caught me,on Monday I hit the jet right on and the kart was a rocket,in the race we left on the 3rd flag,which means that I was 20 seconds behind the first flag group,1st flag 125 tags,2nd flag animal limited mod and then us,by the time I got to the end of pit road and was entering turn one into the infield I had passed all the limited mods and had caught the back of the Tag back,by the time I came out of the infield I had passed all but 6/7 of the Tags,if you want to see how well these engines accelerate watch Tedders tire change vidioe,you can see all the big block karts just fly by,as far as top speed is conserned,I hit an areo wall at 107 mph,in the race on monday I had 11 inch tire,30 driver,63 axel and turned 6900 rpm thats 107.5,now thats by myself no drafting help,I ran a 60,63 and a 66 during the weekend the speed never changed only the engine rpm(areo wall),on saturday in pratice I did have a interesting thing happen,I had a 30/60 on the kart and was going down the back straight when a 125 shifter just creeped by me my tack was at 6600,about 100 feet in front of me he pulled down in line and broke the air,the tack jumped to 7000 and I almost ran into the back of him,the engine was at peak toqure and when the air was broken the kart just lept foreward,the gear change to 30/63 put he kart in a better place when I would run up on a slower kart and get some areo help,the kart pulled up not jumped,much more controled,this kart engine package was faster by itself than 3 Tags drafting,so in closing not 120 mph but 107.5,not bad for a sit up cik(tag) kart,daytona does not do justice to this package,daytona is such a aero track,now on a track with lots of corners and 1 long straight this package will be very fast lap time wise,see you all at NCCAR for the next round,myself Bob Drye and I think Parsons will be there,come by and say hi.
 
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