Drag race gocart help

[Aarogance]

hi guys I'm building an off road drag racing go cart. Will be raced on pretty flat ground but none the less still off road.

My setup will be as follows
Large offroad dunebug style go cart
18hp duromax go cart engine
18-22 inch rear wheels (weighing pros and cons)

My question is should I run a torque converter or a clutch. I have been assuming torque converter until recently seeing other people's builds. This go carts only job is to a straight line 200 ft race. So we need all the acceleration we can get. And yet still a good top speed. Any input would help tremendously. Also pros and cons of tire size would be appreciated. Thanks guys

 

[anickode]

If you haven't already bought the engine, I'd definitely reconsider, unless you're planning on building the snot out of it anyway.

The duromax 440 is in reality closer to 13.5 hp. The 18hp rating comes from taking peak torque number (which does not happen at 3600 rpm) and calculating the HP at 3600 rpm.

Don't get me wrong, It's a good engine for the price... Electric start, and a little beefier than the predator 420, but it is NOT a contender against an actual 18hp engine.

Have you considered snowmobile engines at all? Very high power density, and wouldn't need much if any modification. You can undoubtedly find a used, complete fan cooled 440 for what a Duromax 18 costs. Shoot, by the time you throw money into modding the duromax, you could buy one heck of a sled engine and STILL come out way ahead on power and top speed.

As for gearing, depending on your tire size, you'll still want to be in the normal range... Maybe 7:1 or 8:1 with the big tires. What you'll really want is a torque converter that you can really tune and get dialed in to shift out optimally. I think a Comet 780 would be a decent choice for the duromax.

 

[Smerft85]

Where are you located? I've got a liquid cooled artic cat 440cc I'd sell pretty cheap, the clutch is present as well.

 

[Aarogance]

Thank you anickode I didn't realize. Smerft85 I live in Texas my number is 2547227410

 

[mckutzy]

Dude... dont put your Phone number on line like that.. do that in a PM...

 

[Smerft85]

Yes, please edit your number out of that post. P.m. me and I'll see what shipping would be to your zip code.

 

[Joe-405]

Torque converter and NOT a cheap knock off ebay one.

 

[anickode]

Thank you anickode I didn't realize. Smerft85 I live in Texas my number is *removed from quote so it's not still here when you edit your post*

Yeah snowmobile engines might be a touch harder to come by there. But still probably one of your best options for a high revving, powerful light weight motor.

You WILL have to jet the carbs leaner though.

 

[Brianator]

*kart* fyi. Lol. Tire size (and gearing for that matter) you'll need to experiment and play with to figure out what's best... what I learned of car drag racing and tire size is as follows and SHOULD apply just the same to your situation : whether 18 or 22 inch tires your MPH at the trap should stay roughly the same (unless you top out too soon) but your ET will change. The goal is to have the motor at its top RPMs JUST as you hit the trap, that means you've accelerated the WHOLE way down the track, as much as possible and you're not going to get any faster than THAT! Just my 2 cents.