Torque Converter Upgrade?

[HULKSMASHNOOBSGOTIT]

Hello. I recently picked up a predator 212 swapped Carter Brothers kart off of OfferUp for $450. It has a somewhat strange drivetrain. It has a V belt drive centrifugal clutch which goes to another V belt pulley in what appears to be a 2:1 gearing. (not a torque converter) It then goes through a shaft to a chain connected to the axle in what looks to be a pretty high torque gearing. I haven't counted the teeth yet but I will tomorrow morning and post an update. The kart tops out at 25mph with a bypassed governor. The engine revs fairly high at that point. It FEELS like 5000 RPM or so. It is enough to backfire when I let off the throttle. My idea is to put a 30 series torque converter on by rotating the mounting plate 90 degrees up and replacing the old driven V belt pulley with a 10t sprocket to connected to the torque converter. The setup would have a total of 2 chains. Should I do it and would it improve my initial takeoff and/or top speed and if so, how much?

 

[panchothedog]

it will increase your take off speed for sure because it sounds like you have a belt drive centrifugal clutch. Hard to determine top speed. You don't give us enough information. What is the diameter of your rear tires,and then the tooth count of your axle sprocket. Post some pictures of the drive train and the rear of the kart. Not at all advantages to run two chains, especially with a torque converter

 

[Denny]

Unless they are splitting the ratio to use smaller sprockets!

 

[HULKSMASHNOOBSGOTIT]

Sorry for the delay, but it has a total of a 9:1 gearing. 2:1 belt drive into 12t to 54t (4.5:1) sprocket ratio. It has 145/70-6 tires (14 inch diameter). I put it through an online calculator, and at 25mph it does 5200RPM! I want to mount the torque converter in the 90 degrees upwards position, pull off the old (gokart) belt driven pulley, and replace it with a same sized sprocket as the torque converter. So a chain would come off of the torque converter and go to the stock jackshaft, which would then go through the 4.5:1 gearing to the axle. I will most likely get a 10T sprocket for the jackshaft to up it to a 5.4:1.

 

[HULKSMASHNOOBSGOTIT]

I also take it mainly off-roading. Steep hills, slow bumpy areas, and high speed smooth, wide straights.

 

[panchothedog]

Most karts with a torque converter run at 6:1 ratio and do really well. It has become the industry standard. SO you might want to underdrive it just a little bit from the converter to your jack shaft in order to lower that 5.4 to 1 closer to the desired 6 to 1.

 

[Denny]

Pancho gave you the best answer. How tall are your tires in the rear by the way?

 

[Karttekk]

Here is his setup. Maybe changing the current sprockets would do the trick with less work.

https://www.bmikarts.com/PDF/Carter-Bros/CarterBros/Model-1235-3015/1235-3015.pdf

 

[Karttekk]

it will increase your take off speed for sure because it sounds like you have a belt drive centrifugal clutch. Hard to determine top speed. You don't give us enough information. What is the diameter of your rear tires,and then the tooth count of your axle sprocket. Post some pictures of the drive train and the rear of the kart. Not at all advantages to run two chains, especially with a torque converter

Here's the belt driven clutch.

3/4" Bore, AB Belt Clutch, 200182

The 3/4" bore AB Belt Clutch is a reliable and durable component designed to provide smooth and efficient power transmission. This clutch features a friction surface that engages with the belt to transmit power from the engine to the driven equipment. It is made of high-quality materials to...

www.gopowersports.com

 

[Karttekk]

Swapping out the current 54 tooth sprocket with this 60 tooth will get it closer to 6:1. Should end up with 5:1 anyway. It will bolt right up to that proprietary hub.

NOS Carter Sprocket. Part G572. 60T. See pic. | eBay

Find many great new & used options and get the best deals for NOS Carter Sprocket. Part G572. 60T. See pic. at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[Karttekk]

My guess is with a new belt and that bigger sprocket you'll be happy. Spend more time riding instead of working!

 

[Karttekk]

Here's your belt.

Drive belt ( V-belt) 5L-300

The Drive Belt (V-Belt) for 5L-300 is a durable and reliable replacement part designed to ensure smooth operation of your vehicle's engine. Made from high-quality materials, this belt is designed to resist wear and tear, and provide long-lasting performance. It is also easy to install, ensuring...

www.gopowersports.com

 

[HULKSMASHNOOBSGOTIT]

it will increase your take off speed for sure because it sounds like you have a belt drive centrifugal clutch. Hard to determine top speed. You don't give us enough information. What is the diameter of your rear tires,and then the tooth count of your axle sprocket. Post some pictures of the drive train and the rear of the kart. Not at all advantages to run two chains, especially with a torque converter.

Just scavenged the old listing for it. Has some photos. My phone is currently broken so I unfortunately cannot take my own.

 

[panchothedog]

Nice looking kart.

 

[HULKSMASHNOOBSGOTIT]

Nice looking kart.

Yeah, it was a steal for $450. My first kart.

 

[HULKSMASHNOOBSGOTIT]

Here is a VERY crudely drawn idea on how I would do it.

 

[BrownStainRacing]

View attachment 136707Here is a VERY crudely drawn idea on how I would d

You can buy the driver and 7" driven w/o the backing plate, no need in all that unnecessary extra chain. Jus order a belt to match.
Measure the big pulley and see if you can put a 7" driven in its place.

 

[HULKSMASHNOOBSGOTIT]

You can buy the driver and 7" driven w/o the backing plate, no need in all that unnecessary extra chain. Jus order a belt to match.
Measure the big pulley and see if you can put a 7" driven in its place.

Might give it a shot when I save up enough. (I'm a highschool freshman so I don't make that much money.)
Also, would China clone pulleys work fine?

 

[BrownStainRacing]

Yea they work good.
You may need a longer jackshaft, as the drivens are much wider. Still, I think that would work better for you. The last short 5/8" jackshaft and bearing kit a had to buy was only $40, had to use locking collars and cut it down a little bit. Jus have to shop around.
That 7" driven is night and day difference compared to the 6".

 

[Denny]

We need to teach you the proper terminology first! What you are looking at with the back plate is a 30 series TAV II cvt system.