Torque

[propain37]

I want to know how can I increase torque without increasing rpm. I did a top speed run and the steering was very fidgety. It made the kart shake a lot. Because of this I am scared of removing the governor.

 

[Kartorbust]

Gear change for starters. Go either up on the axle sprocket tooth count or down on the clutch/cvt tooth count. You'll lose top speed, but gain a bit out of the hole.

 

[itsid]

exactly!

a lower gear ratio (higher toothcount on the axle) is maybe the easiest.
the same effect can be had by reducing the rear wheel diameter
(since that too is part of the overall gear ratio essentially)

If you do NOT want to mess with the gear ratio
you would have to mess with the engine itself..
(which is not recommended really to solve your problem at least)
you could retard timing a hair (say 2 or 3°) yes RETARD, not ADVANCE,
that'd shift the peak torque towards lower rpms
(as opposed to advanced timing which shifts it towards higher rpms)

that and a mildly increased compression ratio (thinner head gasket)
to actually increase peak torque a hair could do the trick.

So, gear ratio it is!

BTW fix your steering issues.. it's not too complicated,
a piece of string and a good set of tools is all you need.

Correct Ackermann geometry on the kart
a perfectly straight line [string] from the center of the rear axle to the kingpins of your spindles.
The linkage MUST be on that same straight line
see below.

ideally the caster is ~10° and there is zero camber on the front wheels (on a non suspended kart)

And voila the best possible corner handling for your kart is achieved

'sid

 

[propain37]

Thanks but I don’t really want to lower the top speed. Would putting a higher flow filter and exhaust help? Also would this steering help at high speeds? I don’t have a welder.

 

[Kartorbust]

There might be some extra power when doing a K&N air filter, but not much. When you do air intake, you should also do a high flow exhaust and re-jet the carburetor. You don't want to lean it out a lot, as these are already running pretty lean for emissions, top of that they run a bit hotter. So you'll need to richen up the carb jet, do a spark plug read to see if its good.

 

[landuse]

Thanks but I don’t really want to lower the top speed. Would putting a higher flow filter and exhaust help? Also would this steering help at high speeds? I don’t have a welder.

You cannot have the best of both worlds....Sorry. You have to sacrifice one for the other

 

[itsid]

I want to know how can I increase torque without increasing rpm. I did a top speed run ... It made the kart shake a lot. Because of this I am scared of removing the governor.

Thanks but I don’t really want to lower the top speed. Would putting a higher flow filter and exhaust help? Also would this steering help at high speeds? I don’t have a welder.

As landuse said you can't have both.. BUT you could cheat here.

remove the governor and kick your rpms to 5500 rpms..
NOW lower your gear ratio by a factor of 1.5..

Say you have a 11" rear wheeled 5hp kart
with 6:1 ratio governed to 3600 rpm... std cent clutch. *

your torque and speed is about'ish:
Max Wheel Torque: 59.34 (43.77 ft lbf)
Top Speed: 31.6 km/h (19.63 mph)

you change the gear ratio and remove the governor
assuming still 11" wheels, 5hp engine but governor removed (5500rpms) and a 9:1 ratio instead (1.5:1 jackshaft installed)

Max Wheel Torque: 89.01 Nm (65.65 ft lbf)
Top Speed: 32.18 km/h (20 mph)

See, you drastically increased the wheel torque, giving you the additional torque you asked for,
without decreasing the top speed
(in fact it increased ever so slightly with my assumed 1.5:1 increase)

Other than that there is absolutely nothing you could do.
And yes that requires high flow filter and exhaust to not have the engine choking at higher rpms,
but increased flow doesn't help (in any noteworthy amount) in lower rpms by itself.

Also the steering geometry fix would certainly help at all speeds.

'sid

* The numbers will change for different setups of course, but the ratio of growth (torque and speed) are still the same.. (~50% more torque, ~2% more speed)

 

[propain37]

Thanks a lot. Do you know if I can buy custom spindles that are already at an angle.

 

[Kartorbust]

GoPowerSports sells spindles that already have it set. However they are just generic ones. To get optimal steering, you could cut it off, then measure the angle and weld them in.

 

[propain37]

Would a Harbor Freight Welder be strong enough to weld on spindles or am I looking at a much higher quality welder?

 

[landuse]

Would a Harbor Freight Welder be strong enough to weld on spindles or am I looking at a much higher quality welder?

HF should be fine

 

[anickode]

Would a Harbor Freight Welder be strong enough to weld on spindles or am I looking at a much higher quality welder?

Depends on which one, and how good you are at using it.

You could spend $5000 on a top-of-the-line Miller, and still lay down crap welds that break off when you hit the first bump.

Whatever you buy, take the time to learn how to use it before you start doing stuff that can get you hurt.

 

[itsid]

No need to buy custom spindles really...

usually the spindles you have are only off by a few degrees.

It's enough to cut a small fillet in one side (the one it should move towards)
hammer it to the correct angle and then weld the seam shut.

'sid