Racing Go-Kart Project

Evan Kirkendall

Evan Kirkendall

Senior
Jan 10, 2011
903
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Abingdon, MD
www.harfordsound.com
This is about as off topic as it gets... A few of the ATL crew guys, including myself have decided to put together a racing go-kart for fun. Our goal is to do 0 - 60MPH in 2 seconds on a drag strip. We've got a frame, but it's just a matter of finding an engine to suit now. Anyone have any experience with racing engines? It's been 4 years since I really toyed around with small engines, so I'm out of the loop.



We're trying to keep things as light weight as possible, so we get the quickest acceleration possible.



So, are we crazy, or is this doable?
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Evan
 
Re: Racing Go-Kart Project

I have a buddy whose son races go-carts. I think they are using CR250F engines. They go very very fast but I don't know how quick the acceleration is. Maybe you need to go with a CR450F engine just to make sure you kill youself even faster!
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From talking with my buddy it seems like a lot of the guys around here really like the honda engines over the other manufacturers but they are all so similar that any would work.



The other option is to put a Kawasaki Bruteforce 750 engine on it with Nitrous. That will definitely do what you want. I have a stock Bruteforce 750 and for a big quad it is quite quick!



Here are a couple videos I found that show the Bruteforces with Nitrous. They are quite quick. Keep in mind that the Brutefroce quads are a little over 600 lbs so the same engine on a 100# go-cart chassis would be unreal.



http://www.youtube.com/watch?v=qlzqYYFjdf8



http://www.youtube.com/watch?v=sGGXb4A_sq4
 
Re: Racing Go-Kart Project

Hello Evan,



0 to 60mph in under 2 seconds? I'm sure it's do-able, but you're talking about a comparison of some super performance vehicles.



There's velocity tables available on the web. You'd punch in your hp and vehicle weight and the results will be the time of reaching 0 to 60.... Example:



200hp and a vehicle weight of 500lbs (including driver) will net you a 0 to 60mph time of 1.97 seconds. (Auto or direct transmission)



Slight changes in either the hp or weight will of course, change the time/ acceleration/ velocity.



If you're serious, I'd recommend rethinking your go-cart frame and step up to some stronger/lighter material. Maybe put in a roll cage, and fuel cut-off switch, body panels to reduce air resistance and flight. A big breaking system.



Lots of insurance.



Good Luck, sounds like fun!
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Hammer













 
Re: Racing Go-Kart Project

The acceleration at 2 secs is a bit optimistic but you are looking at a shifter kart. If it's not a racing kart frame, built by pros don't bother. You'll fold up a yard kart with an engine that big. Don't use a cage or belts in a vehicle that small. If something happens you want to be thrown clear and not taking the brunt of a 200# plus machine strapped to you. The kart will weigh around 200# or so. The pros race at 365#, semi pro/am at 385# and the masters, or old fat guy class races at 400-415#. All including the driver and all the safety gear.



Shifters started using motocross engines, two strokes. Don't bother with a 4/, they don't have the right power band, are heavy and don't fit well on a racing kart. Honda has a program for kart racers but over the years the sanctions have gone back to a stock CR125 to reduce costs. A ready to race stock CR125 fitted to a kart with carb to exhaust is about 4 grand new. They keep the resale value well. The mod moto engines after significant mods are quite a bit more expensive. My first in 2001 cost about $6500 to build and about $3500 a year to maintain. The stock CR125 costs a couple hundred a year to maintain. Since then they have built kart designed 125cc shifter engines but they are still up there in price and cost to run, about 4500-5000 new and a grand a year or so to run. They're called KZ right now but in the past were called ICC. Reine Piersen at Swedetech Racing Engines in Elk Grove CA are the ass slappin' daddies of small, high hp 2/ racing engines in the US. They do GP bikes as well.



To get close to that kind of performance it will cost at least around 10 grand for something safe once all is said and done. Might be able to do it for a bit cheap but if you aren't familiar with racing karts I doubt it. You'll need a 32mm shifter chassis with front brakes. You'll cook rears alone and won't be able to stop.



Price/performance wise you get more bang for the buck by building a low end bracket drag car. I'll look at some old data tonight from when I was running the shifter nationally. The shifter was faster than the Miata I'm building now and the stock car I raced the last couple of seasons. The top speed for me was around 107 mph but I was always 70-100# heavy for the class. I'm too damn big to kart. With the little racer size guys you can hit 115 mph or so.



Opps, stock CR125 about 34 rear wheel horsepower, mod CR 125 45ish rwhp and purpose built kart engine, 125cc 2/ 48ish rwhp.



Forgot I had some data with me now, 2008 SKUSA Supernationals running Spec Honda S4 (stock engine, old guy, 405# class) with a scale weight of about 470# I was doing 0-75 in about 7.5 secs. We weren't geared for acceleration, we were geared for a 1200' straight. The pros with the mod engines were doing that same leg in under 4 sec.
 
Re: Racing Go-Kart Project

dear, sweet, little baby jesus

in your fleecy lil' diaper

layin' there...so small and vulnerable

burpin' up Enfamil

please watch over Evan and ATL

and should they learn that most dangerous projects like this start with...''hey dudes...watch this''

may I please have Evans subs?
 
Re: Racing Go-Kart Project

Dave, we got a ''2008 coyote wide track le'' chasis.



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It comes with wheels as well, but I haven't seen them yet.



We were looking at the Briggs and Stratton racing engines. I was trying to avoid doing a shifter kart, as that does add a lot of complexity to the design, but if it's what it takes, than we can do it. I've got plenty of experience modifying engines, and I have access to the machine shop at Clair, so we can do whatever we need.
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We will be adding front breaks, just to be safe.







Thanks!

Evan
 
Re: Racing Go-Kart Project

The Coyote is a real chassis. One of the very few US made. It's specific to circle track but will work for a drag kart. They don't make front brake kits for the Coyote and with a Briggs you won't need them. A new front brake system is about a grand, plus whatever you need to do the the spindles to accept the calipers.



As for the the Briggs, great supporter of karting but in comparison to other formulas isn't going to come anywhere close to that sort of acceleration and some of them won't do 60 mph at all. A clutch kart won't hook up fast enough to come anywhere near your bench mark. It could be fun though. And cheap. Those are only 8-10 hp engines even with the most extreme mods. Depending on the clutch you'll be lucky to hit 60 in under 10 secs.



That package is better suited to circle track racing. You'll have a lot more fun than if you tried to drag race it. You should be able to finish that kart off with a new Briggs for $1200 or so. The engine will be 600-700, tires a couple hun and some misc hardware. Get a kart suit, neck collar, glove and a good helmet.



These guys rock the 4 cycle kart world. Most anything you need for that kart. Comet Karting http://www.cometkartsales.com/



This forum is specific to that style of kart. Bob's 4 Cycle. Bob is an eccentric nut ball but has been around karting a long time. http://www.4cycle.com/



Have fun, race safe!
 
Re: Racing Go-Kart Project

I think several of us would feel better if you go back and edit out the 2 second target, then edit it from your mind. Or consider building a rocket sled, or human rail gun... Getting from 0- anything that quickly is the hard part... Putting the required power to the ground to get moving that quickly in that short a time will be difficult.



The primary attraction of go carts is that they are so close to ground they ''seem'' like they are going faster than they are, from the driver's perspective (of course some modern ones do get up there).. If you really want to accelerate you need to build a dragster or a drag bike, both of which take on a different general form factor (big ass back tires, and wheelie bars.)



Try not to kill yourself or any spectators. Life is not like jackass where everybody lives.



JR



 
Re: Racing Go-Kart Project

Evan Kirkendall wrote on Thu said:
This is about as off topic as it gets... A few of the ATL crew guys, including myself have decided to put together a racing go-kart for fun. Our goal is to do 0 - 60MPH in 2 seconds on a drag strip. We've got a frame, but it's just a matter of finding an engine to suit now. Anyone have any experience with racing engines? It's been 4 years since I really toyed around with small engines, so I'm out of the loop.



We're trying to keep things as light weight as possible, so we get the quickest acceleration possible.



So, are we crazy, or is this doable?
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Evan
Click to expand...



en.wikipedia.org/wiki/Ariel_Atom



www.youtube.com/watch?v=WaWoo82zNUA



THERE ARE BEES IN MY EPI-GLOT-US!



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Re: Racing Go-Kart Project

I spent a fair amount of time at go-kart tracks in Southwest Missouri in the early 90s. I never raced competitively, my family didn't have the resources. But I do remember chasing a little punk around the track a few times who did race. I seem to remember the top speeds being around 50 mph and that was plenty for me.



The kind of acceleration you are talking about sounds like a Darwin Award waiting to happen. Plus, I've never really understood the fascination with pure speed. I'd much race against other drivers than a clock. But maybe that's just me.



As for that ''little punk'' . . . he just had himself a pretty good year.



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Re: Racing Go-Kart Project

I'd go with the Animal. There are more mature mods available. If you really want to do it cheap Harbor Freight sells a similar engine that the racers call a ''clone''. Any of the Briggs engines will be much better made and come as complete kart packages. Hang out for a bit at Bob's 4 Cycle and you'll pick up a lot. Any of the Briggs racing engines should bolt right on to that Coyote. You'll need a clutch, some gears and chain. Also may want to get a new set of brake pads. An Animal on that chassis will be plenty fast for you guys at this point.
 
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