Which Engine Should I Buy?

[SamWhittle]

Please forgive the vague question, after two afternoons of googling all I know is that this stuff seems complicated and I need more info than none, but! I don't know where to start so I figured the engine was the best place to start.

I am torn between really fast and off road. I am torn because my budget is about 400 dollars starting with nothing but a MIG welder.

From what I understand, the average 6.5HP Predator Engine is fine for cheap offroad beginnings. And from what my dad(who has no personal experience) says a good chainsaw engine is good for high speeds because they have a very high max RPM.

I weigh roughly 150lbs, and my kart weighs... well, I haven't gotten that far, what other information do I need to start this project? Where is a good starting place in general?

 

[Poboy kartman]

Buy a 6.5 Predator and call me in the morning.

 

[chancer]

Buy a 6.5 Predator and call me in the morning.

(817) 501-

 

[Bbqjoe]

(817) 501-

867-5309

 

[Hellion]

Wise man say you must always start with frame first.

 

[chancer]

Find a cheap used Frame on Craigs list. Might even find one with an engine.
Rebuild from there.
That is really the best place to start.

 

[B_Bimmer]

After you find or build a frame, the correct engine is the biggest one that will fit.

 

[pRoFiT]

$400? yah if you have mig and the metal already. then maybe 400. Thats about how much im into mine and i picked up an engine for $50! Otherwise id be at $500.

Texas huh... Craigslist is your friend. find one there for no more then $200. Put $200 into repairs and mods and be good to go

Probably find a nice manco dingo for 200 i can find #$%#^ in california@#$!@#$!@#$ sorry for cussing.

not sure where in texas. Dallas?
https://dallas.craigslist.org/ndf/snw/5846572790.html

houston?
https://houston.craigslist.org/for/5835373923.html

Austin? this one is good
https://austin.craigslist.org/snw/5841423833.html

brownsville. this one needs work
https://brownsville.craigslist.org/snw/5831166311.html

san antonio. i love this one
https://sanantonio.craigslist.org/cto/5831983856.html

 

[chancer]

Yup No Karts in Cali! @##$%
Have a look in PHX Craigs list. Its like a candy store!

 

[SamWhittle]

Thanks for the Craigslist links I was only looking in my immediate area and didn't see any of those! However, I originally started this project because I want to build a kart not buy a kart, so I think I'll stick with some plywood and some 4130 steel and me welder. If I could only find a huge engine on Craigslist xD

 

[bob58o]

Since I heard plywood and big engine....
I thought PD420 16HP Powerland 420cc Shipped to your TX door for $170.

But then I couldn't find it on eBay. Says sold out?
She gone.

 

[Bwdeaton]

Since I heard plywood and big engine....
I thought PD420 16HP Powerland 420cc Shipped to your TX door for $170.

But then I couldn't find it on eBay. Says sold out?
She gone.

They just switched over to their own website to sell them.

Here is the link.

The website advertises free shipping to anywhere in the lower 48 states.

 

[KartFab]

A honda gx390 (rated at 11.7 hp) has a max power output (torque) of 26.4 Newton-Meters
The powerland "16 hp" has a max power output of 23.1 Newton-Meters

Thats a good deal for a motor but its definitely not 16 hp, probably more like 10.2 hp. Take that for what its worth. Also, it says the engine 'will not operate above 3500 feet'.... weird.

 

[ezcome-ezgo]

Making false HP claims will get you sued.

 

[Joe-405]

Mine made 18.3 with exhaust and jetting and air filter so................. I believe it makes that stock.

 

[KartFab]

Mine made 18.3 with exhaust and jetting and air filter so................. I believe it makes that stock.

I'm going off the numbers the manufacturers provided for torque because anybody can jack with you and say oh its 16 hp, but at what RPM? What is the torque like? This is just plug and chug (can anybody verify this is correct?)

So given the following

H=horsepower
T=torque (lb/ft units)
N=speed (RPM units)

H=(T x N) / 5252

Powerland has supplied max power output, but conveniently left out RPMS
H=16
T=23.1 newton meters aka 17.04 ft/lb
N=unknown rpm

(5252 x H)/T=N (speed in rpms)
(5252 x 16)/17.04=4931

So at 4931 RPM the powerland produces 16 hp theoretically? Puts things into perspective a little bit better now doesnt it?

So what about net torque at 2500 rpm?, or net power at 3600 rpm? All that information is ABSENT... all we see is "MAX POWER OUTPUT" on their website...which I am interpereting as max HP (hp=power, torque=torque, we were given max hp with the associated torque at that hp) if you were to use the same formula and assume that they were really saying 17.04 ft/lbs torque at 3600 rpm, you would not get 16 hp as an answer, instead, 11.7 hp @ 3600 rpm. Or if they were really meaning to say max torque, max torque happens around 2500 rpm, so you would get 10.9 hp at 2500 rpm. You cannot fudge torque or HP at a given RPM, but you sure can fudge hp by omitting the RPM.

Its my opinion, that powerland engine runs a theoretical hp of 16 at 4931 rpms, and an actual HP of above 11.7 at 3600 RPM, but it is unknown because it (torque at 3600 rpm, torque at 2500 rpm) is not provided. The numbers don't add up.

Also, looking at the predator 670, you know the one everyone is saying is "22 hp", you look at their specs and you get 45 nm at 2500 rpm, which is 15.7 hp, obviously is going to go up as the rpms go up, but not to 22 hp, more like 17, then you look at the cars and cameras dyno run here and you see just over 17 hp max hp
https://youtu.be/6aK7ZDlBisk?t=16m3s (yes parasitic losses blah blah)

Im just saying hp ratings are crap because the chinese made ones are using hp, and leaving out HP at a certain rpm.

 

[Poboy kartman]

Making false HP claims will get you sued.

Wonder how many FR has pending?

 

[Joe-405]

If you look in the powerland manual it tells you the tq @ what rpm stock. Fyi.

I can't find my manual or else I would tell you. I seem to recall peak torque was around 25-2600 at more then hp tho. So alot of manufactures take peak tq and hp and split the 2 to get max power.
Or so I've been told. Which would make more sense.

 

[Keithc64]

Building cart for 5 year old son

I just purchased a silver streak mini cart. It has a 50cc motor that's trash. I like the frame and want to make it something he can enjoy for a few years. Thinking of putting 212 predator on it. After readin up I think I'm going to have to do a lot of work to make it right. I have access to a welding shop at work and the skills necessary to build . I'm just looking for the most affordable way to swap the motor move the sprocket upgrade the axel. And what motor clutch/torque converter/axel/sprocket combo to get. I would start new thread but can't figure out how to.

 

[mckutzy]

Keithc64-Hello and welcome....
The New thread button is at the top of the Heading frame labled - Threads in Forum : Engines & Clutches.....