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Old 08-14-2012, 11:53 AM
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Default Clutch vs. Torque Converter thread: Whats best for my kart?

Lots of guys on this forum constantly claim a Torque converter is always better than any Centrifugal clutch.

That's not always true...

Yes I agree Torque Converters do offer better acceleration, and also allow many karts to be geared for a higher top speed potential.

Torque converters are also a much better choice for most any kart that will be doing a lot of low-speed/stop and go type riding.

They're also a much better choice for Off-road karts that will be climbing steep hills & mountains.

But... you'll hardly ever see Torque Converters used In most any forms of kart racing. Its not because those racekart guys are trying to save money or dont know how to instal a T/C. The reason is a Centrifugal (or disk type) clutch would almost always turn faster lap times. The only exceptions to this would be off-road/Trophy racekarts, or small tracks with lots of tight/low-speed corners.

_______


The reason for this is Torque Converter belts are constantly under tension unless the engine is Idling, this belt tension causes friction. This friction slightly lowers rear-wheel horse power compared to Engine horsepower.

A properly adjusted chain used on a Centrifugal clutch doesn't have this tension/friction issue, so more of the engines power Is transmitted to the ground.

I realise lots of karts experience problems with their Centrifugal clutches overheating, slipping and giving poor acceleration. But many of those problems were simply caused by Improper gearing, lack of lubricating the clutches bushing (or bearing), and/or selecting one of the lower-quality/priced Centrifugal clutch brands/models.

There's lots of very high quality Centrifugal/Disk clutches avalible In the same price ranges of what a Comet Tav2, 30 or 40-series would cost. Those more expensive Centrifugal clutches are made for racekarts, many of them can hold up for years with up to 50hp engines with 4:1 gear ratio's & using 11" tall rear tires. There's also parts avalible to repair most of these racing clutches, so you dont have to buy a whole new one if they ever develop a problem.

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I just thought I'd try to clear a few misconceptions up, Its just not fair to compare a $39 Centrifugal clutch against a $169 Comet T/C. They can both be a very good choice for some applications, but T/C's are not always a better choice for every single kart and budget.

A $169 3/4" bore centrifugal clutch designed for racing would hold up under way more horse power than a 30-series Comet Tav-2... The same is true of the $350/1"-bore racing clutches compared to a 40-series converter system.

There's some 3/4" bore centrifugal race-clutches avalible in the $80 price range, that I feel are much higher quality than the more common $39-$59 models that most funkart owners select and end up having problems with.

The same is true for 1" bore centrifugal clutches, a $160 race clutch model would way outperform the lowest price 1" model (Comet 400-series) that's avalible for around $80.

_______


If you choose to use any Centrifugal clutch, the best way to make it last longer is by getting the kart right up to the speed where you can feel/hear the clutch is no longer slipping. Constant low-speed/stop & go type riding will kill most any centrifugal clutch!
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  #2  
Old 08-14-2012, 02:31 PM
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I feel for my application, around 18hp engine on an off road style cart in the mountains of Tennessee, that a torque converter would perform better. There are a lot of sharp turns and steep hills that I think would burn out a clutch rather quickly.
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Old 08-14-2012, 02:35 PM
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Well written! I hope people will have a read here first, before asking the difference and what they should do.

Sticky?
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Old 08-14-2012, 03:43 PM
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I completely agree with you anderkart. But for most of the people that are on here asking questions, a TC would be better because of where they ride it.

I agree with stickying it too. I think if you added a small section on how the two work it would be perfect
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Old 08-14-2012, 03:54 PM
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Thanks for that.
I think a torque converter would always be better on my kart. Offroad, drifting, lots of corners etc. However, I can see tha a centrifugal or disc clutch is often a good choice if you just ride on asphalt.
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Old 08-14-2012, 04:34 PM
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It's already been said, but I have to agree: This needs to be a sticky.
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Old 08-14-2012, 06:45 PM
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A very informative write-up- Thanks, Anderkart! I do believe I'll get the glue!
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Old 10-06-2012, 12:34 PM
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This is a very helpful post but i am looking into making a race-ish go kart to run whit my friend on his 125 race-kart. To be able to have a competitive kart i need some power, i have the tec to do some mod to a engine like porting an stuff but i don't know what clutch to get, i understand that the maxtorque ones are pretty good but are they good enough?
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Old 10-07-2012, 08:40 AM
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I've got a go-kart/dunebuggy with 14 inch rear tires. I bought a 30 series clone torq converter for my 13 hp clone engine(the engine has done great!!) I have had 2 belts burn in 2 uses so ive decided that i need the 40 series. Ive also learned on the forum that I will need to add a jackshaft to install the 40 series, correct? Since I am adding a jackshaft either way, would it be best if i use a centrifigal clutch with gear ratio system or use the 40 series torq converter?
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Old 10-07-2012, 06:41 PM
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For your application, you must use the 40 series, and yes, you'll need a jackshaft assembly. Whoever told you that a 30 series was going to tolerate 13hp, was misinformed, or intended to mislead you. That said, watch your gear ratio. Even a tough CVT can have problems with an inappropriate final drive ratio.
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Old 10-07-2012, 09:26 PM
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I heard that some Mini Dragsters use TC's. is that true?
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Old 10-13-2012, 12:11 PM
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Thanks for the help!! What are factors do I need to know for the final drive ratio? Also what is your opinion on the off brand 40 series torque converter?
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Old 10-13-2012, 06:40 PM
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No great magic for the overall ratio. The 40 (and clones) boast a 1:1 high range. For the sake of simplicity, calculate gearing as if the CVT doesn't exist. You won't go wrong like that.
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Old 10-14-2012, 11:54 AM
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Quote:
Originally Posted by jhuskers View Post
Thanks for the help!! What are factors do I need to know for the final drive ratio? Also what is your opinion on the off brand 40 series torque converter?
I've never used any of the 'off-brand' converters, so I wont coment on those...

But you'll find some good gear-ratio info in these threads:
http://www.diygokarts.com/vb/showthread.php?t=5438
http://www.diygokarts.com/vb/showthread.php?t=9591
http://www.diygokarts.com/vb/showthread.php?t=10036

Choosing the best gear ratio for your kart is a very complicated subject; It depends on your kart, rear tire diameter, the riders (& passengers?) weight, your riding locations/conditions and your desires between achieving the best acceleration, OR the highest possible top speed.

Sometimes you have to start-out by making the best educated guess you can when selecting your gearing, then you'll end up making final changes after you've actually had a chance to ride the kart for awhile and see how it all works out for you and your kart.
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Old 10-14-2012, 03:21 PM
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Heres a couple pictures of my kart. One passenger, 16" rear wheels, light weight, some offroad and some street, and halfway between fast accelaration and top speed. i am thinking 3:1 but i don't know for sure.
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Old 10-15-2012, 06:45 AM
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With 16" rear tires and your kart, I think 3:1 is way too extreme; unless your planning on doing something like competing at the Bonneville salt flats.

I'd suggest more like a 6:1 ratio. (or possibly 5:1) Then If you wanted a higher top speed, you could always do some engine mods for additional rpm; like removing your engines governor.

One of the cool things about running a Torque Converter is: Its fairly easy (low-cost) to swap-out/try a few different jackshaft-output gears.

So for example; you could buy 2 or 3 gears and have a good ratio for extreme-acceleration/very-steep hill climbing: (7:1)

General-purpose riding: (6:1)

Or re-gear for absolute top speeds when riding at large open spaces w/flat terrain only, (like maybe you could tryout something in the 4:5/5:1 range, and see if your TC belt survives, and if your engine will fully rev to its potential rpm, or not).
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Old 11-23-2012, 06:53 AM
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Hey all I am a newbie at this forum and quite frankly a newbie at messing around with engines. I have already found this site incredibly helpful. So Thanks first and foremost! I have a Subaru robin 6hp on my sons go kart but the clutch is about to go out. I'm thinking of going to a torque converter but what other parts will I have to buy to make this conversion
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Old 11-23-2012, 07:06 AM
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Quote:
Originally Posted by JasonT View Post
Hey all I am a newbie at this forum and quite frankly a newbie at messing around with engines. I have already found this site incredibly helpful. So Thanks first and foremost! I have a Subaru robin 6hp on my sons go kart but the clutch is about to go out. I'm thinking of going to a torque converter but what other parts will I have to buy to make this conversion
to the forum Jason. Start a new thread for yourself in the engine section and ask away. You will get more response that way. To start a new thread, go to the section you want to post in, and then at the top left you will see a button that says "New Thread".
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Old 11-23-2012, 08:27 AM
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Quote:
Originally Posted by JasonT View Post
Hey all I am a newbie at this forum and quite frankly a newbie at messing around with engines. I have already found this site incredibly helpful. So Thanks first and foremost! I have a Subaru robin 6hp on my sons go kart but the clutch is about to go out. I'm thinking of going to a torque converter but what other parts will I have to buy to make this conversion
Welcome to DIY Jason

The Comet Torq-A-Verter is a complete kit.
This online shop has them at a good price: http://www.mfgsupply.com/gomini/gomi...tav30kits.html

It would most-likely come with everything you need to bolt it on, then you'd probably need to shorten your chain. You'd just need to double check your engines output shaft diamiter, (I think yours is the 3/4"size, not 1") and then also be sure to order the kit to match the chain-size/pitch of your karts axle sprocket.

Most karts use #35 or the #40/41 chain and sprocket pitch/size. You could measure the distance between 2-teeth on your axle sprocket to order the corect kit:
3/8" = is the #35 pitch
1/2" = #40/41.


Here's a chart with more chain pitch sizing info:
(you can click on the pic to veiw a larger Image)
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chain sizes.jpg  
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Old 05-17-2013, 03:55 PM
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I am new to this forum and I hope Iam posting im the right area.
I have a old murry go kart with a 6.5hp tucumson engine with a 3/4 output shaft. I believe it has a jackshaft, but im not sure that what i think isa jackshaft isactually a jackshaft. Please read and let me know if im right.
The clutch sprocket is 10, jackshaft input is 25. The output is 10 to axel 35. According to the ratio equation its 9.6:1, I think. It has 16 in rear tires. Currently drive on packed sand and road but wish to drive off road on loose sand up and down hills.

I just bought a clone 11hp engine with a 1in output shaft from harbor freight. I figure I have to change out the clutch for a 1in. For my desired driving would it be better to convert it to a torque converter or stay with the centrifigul clutch? If I switch how hard is it to switch? What type should I get?

Any help would be greatly appreciated.
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