Box Stock

rpm rule

number9 said:
So, when I posted above about the throttle stop screw, I didn't realize how guys may be utilizing them in regards to getting more rpm when dealing with having the gov in place. My boys karts needed a little more rpm, so was messing with them today and see now how guys are using it for those reasons.

I re-bent the loop on the gov spring about .200" shorter - to result in it having more tension. Then I took the throttle stop screw out, removed the spring that was on it, and threaded a nut about 1/2 way down it, reinstalled the screw (without the spring) and added a second nut to the screw. You can use the nuts to lock the screw in place where you want it without risk of it coming out, as I'm not sure how well the weak stock spring would keep it in place if you had the screw backed out real far. A stronger spring would work better and look "legal" if you need it to.

I started the kart on the stand and SLOWLY increased throttle until the lever stopped against the screw and recorded the rpm. Did this several times, with the screw at different positions until I got the max rpm I wanted the gov to allow. I set them at 4280.

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is the governor surging the throttle back or is the screw just limiting the carbs travel?
I'm interested if anyone has gotten the governor to pull back at 5500 rpm, this is something that i can not figure out.Also was wondering if anyone has used a digital rev limiter to solve this problem?
 
hwater85 said:
is the governor surging the throttle back or is the screw just limiting the carbs travel?
I'm interested if anyone has gotten the governor to pull back at 5500 rpm, this is something that i can not figure out.Also was wondering if anyone has used a digital rev limiter to solve this problem?
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I wouldn't want the plastic governor gear spinning at 5500 RPM. The stock springs and stock cam will float the valves near 5500 RPM preventing from revving much higher. It sounds like you want to bypass the governor completely, which I've been told is a recipe for an exploded governor gear.

I'm not familiar with the rules. Guessing you are not allowed to completely remove the governor?
 
THe rules read MAX 5500 checked on stand or rear tires lifted off ground..
They run best at approx. 4500-4700 on the track and perfectly legal..
I'm sure many have played in the no no areas, but not much is helping these motors as for overall performance..
But then again theres good ones and bad ones,, you may have to buy a few to find one..
Claim rule averages 125-150 around here.. NC
 
Its usually easier, and cheaper, to just go to a race and watch who is fastest in the class consistently, and buy their engine since claim is so cheap...that way you know you have a good solid engine and can focus on your setup and tire program
 
W5R said:
Its usually easier, and cheaper, to just go to a race and watch who is fastest in the class consistently, and buy their engine since claim is so cheap...that way you know you have a good solid engine and can focus on your setup and tire program
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I do believe you have to finish 2nd behind the leader to protest/claim the motor
 
Dover Power said:
THe rules read MAX 5500 checked on stand or rear tires lifted off ground..
They run best at approx. 4500-4700 on the track and perfectly legal..
I'm sure many have played in the no no areas, but not much is helping these motors as for overall performance..
But then again theres good ones and bad ones,, you may have to buy a few to find one..
Claim rule averages 125-150 around here.. NC
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We are running on a 1/5 mile track and if your not turning 5400-5500 rpm they will leave you in the dust. From my testing the stock springs float at 5200-5300. So im assuming that most are running cheated springs and governor.
Also I'm curious if there has ever been a class with a rpm rule. This ruling seems to be very hard to manage, as a lot of little thing could affect ur rpm on race night.
 
I will crawl out there with you Jerry. I haved turned my out of box Hemi 4900 on track but it nearly flat lined down straight to do it. 4700 to 4800 is where I keep it. Also our track has a surge rule. That means the engine has to surge before 5500. It you have stock springs and it will only turn 51-5200, you have to set governer under that.
 
I can tell you we won several races and only turned 4800 max RPM , with the tires on the ground , WHILE turning 5200 free revving on the stand ,
 
Kart43 said:
I never realized any track made it so easy to claim an engine. Heck go watch a race buy the winning engine, what a gong show, not my type of racing.
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IN PA ONLY THE TRACK CLAIMES THE ENGINE , AND MUST GIVE THE CLAIMENT A NEW SEALED ENGINE OF THE SAME SKU NUMBER
 
dynoed two box stock predators yesterday our rpm rule is 5000 did one motor and gov surged at 4700 so we backed the screw out second pull was a tad less power draw your own conclusions . also the motors were 1.5 hp difference between the two. never know what your gonna get. some are mean some are duds most are average. be sure to know ALL the rules there are several things that are glazed over. Dagwood allows up to a 42 jet because they run lean at the rpms we turn they also allow pluging the vent tube with a bearing yet the hose has to be attached etc. a up in jet can be worth 3/4 hp fyi
 
J'-remy said:
dynoed two box stock predators yesterday our rpm rule is 5000 did one motor and gov surged at 4700 so we backed the screw out second pull was a tad less power draw your own conclusions . also the motors were 1.5 hp difference between the two. never know what your gonna get. some are mean some are duds most are average. be sure to know ALL the rules there are several things that are glazed over. Dagwood allows up to a 42 jet because they run lean at the rpms we turn they also allow pluging the vent tube with a bearing yet the hose has to be attached etc. a up in jet can be worth 3/4 hp fyi
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What rpm do you have your clutch engage at on the box stock predator
 
Any track that runs the box stock rules should check the rpm on the first three when they come across the scales. Wouldn't take but just a minute. That is their teching point.
 
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