Old Briggs engine speed

[Gustafsson16]

Hi, I found an old 5hp Briggs and Stratton engine in our barn.
Will it have enough power to make 30~mph, and have good low end torque? I'm totally new to building gokarts and want to build my first.

 

[Russ2251]

Will it have enough power to make 30~mph, and have good low end torque?

If geared properly, yes.
Most folks would prefer the B&S over anything Chinese.

 

[Unknownkart]

My old Briggs (5hp) did 35 on a cheap homemade yard kart.

 

[Ryafor]

Even a 3hp engine will do the same speed I think. It all comes down to gearing and tire size and if you choose to modify the engine can help but most the engines run at 3600rpm stock so a 3hp in theory is technically as fast as a 5hp just a little less torque. At least that's what I believe. I may be wrong. Just learning myself but if I'm wrong someone will correct me. Altho you've already got the answer you wanted. Just adding a bit for others that may come across this thread in the future

 

[chancer]

Gearing makes top speed.
HP is how fast you get there.

 

[Ryafor]

Gearing makes top speed.
HP is how fast you get there.

3hp engine is just as fast as a 5hp engine at 3600 rpms. So horses get you there faster?

 

[chancer]

Yes. Here is where I asked the same question, and the answers form the Forum:
http://www.diygokarts.com/vb/showthread.php?t=28792

C i only got this smert ferm dis ear Farum!

 

[Ryafor]

C i only got this smert ferm dis ear Farum!

As Red would say. Dumbass

 

[itsid]

Even a 3hp engine will do the same speed I think. It all comes down to gearing and tire size and if you choose to modify the engine can help but most the engines run at 3600rpm stock so a 3hp in theory is technically as fast as a 5hp just a little less torque. At least that's what I believe. I may be wrong. Just learning myself but if I'm wrong someone will correct me. Altho you've already got the answer you wanted. Just adding a bit for others that may come across this thread in the future

Gearing makes top speed.
HP is how fast you get there.

3hp engine is just as fast as a 5hp engine at 3600 rpms. So horses get you there faster?

Uhmmm
almost..

IF the engine has enough torque to get you to the speed at that gear ratio, then YES,
it doesn't matter if it's a 5.5hp, 6.5hp or 7hp engine... except that the more torque (coincidentally hp) the quicker it'll be at speed.

But cutting the torque in half (say comparing a 6.5hp to a 3hp engine)
chances are that with identical gearing the 3hp engine doesn't have enough torque at all.
So you should still account for that by getting a lower gear ratio.

Also -as always- depends on weight wheelsize etc as well;
so in general:
Do the math if you want to know

'sid

 

[Ryafor]

Do the math if you want to know

'sid

Math? Go karts are supposed to be fun. aint nobody got time for math. Would be soooo much easier. If someone would just invent some sorta kartcalc.net that figures all that stuff out

Thanks Sid

 

[itsid]

Math? Go karts are supposed to be fun. aint nobody got time for math.

Well math IS fun, if you're doing it right that is

On the other hand.. if you're doing it wrong.. not even karts are much fun at all, right?

Would be soooo much easier. If someone would just invent some sorta kartcalc.net that figures all that stuff out

Thanks Sid

Now THAT's a great idea!
too bad that url's already registered

'sid

 

[mindymogul]

well math is fun, if you're doing it right that is

neeeeeerrrrrrd!

 

[chancer]

Math is way better than grammar, especially American English.
At least the rules dont change in math.

And I agree with Sid
Cutting the HP reduces the Torque and you may never get moving.

But typically our 6.5 Hp engines on 12ish" tires at 6:1 are great.
Adding engine mods to get to 7,8, or 9 HP just gets the Kart to top speed faster.
It was a quick simple answer.