speed difference

[tgus3]

Hi all,
I changed from a clutch to a torqueconverter on my my kart. With the clutch I could hit 48.8mph.Now with my tc i can only do 45. Is this range about what to expect between a clutch and tc?

Thanks

 

[Felineman]

Clutch=Speed Torque Converter=Torque or it could be all the snacks your eating lately

 

[gr8hairy1]

Swapping only a clutch can give unexpected results. In other words, it's very very rare to change clutch types and have the exact same performance. Neither good or bad. Just different. Most times people change sprockets when they change clutch types.

Questions that need to be answered first:

What kind of kart is this on? (Do you know the model? If not post pictures).
and
What ratio does it have and what size sprockets? If you don't know, tell us what the axle sprocket tooth count and clutch sprocket tooth count is.

Telling us tire size may be useful, but as of right now it's not that important.

Also, for kicks, what engine does it have?

 

[anickode]

I betcha get to 45 a whole lot quicker though...

Torque converters have an inherent inefficiency due to slip ratio. Belt drives simply chew up power because of friction. You might see some improvement once the belt is broken in, however.

Why do you think racing karts run $500+ clutches instead of torque converters?

 

[65ShelbyClone]

Yeah but junior dragsters use $1000 torque converters instead of $500 clutches.

Hi all,
I changed from a clutch to a torqueconverter on my my kart. With the clutch I could hit 48.8mph.Now with my tc i can only do 45. Is this range about what to expect between a clutch and tc?

Did you use a sprocket on the TC with the same number of teeth as the clutch it replaced?

 

[anickode]

Yeah but junior dragsters use $1000 torque converters instead of $500 clutches.



Did you use a sprocket on the TC with the same number of teeth as the clutch it replaced?

True, but drag racing is all about the hole shot and acceleration.

There is also a big difference between a $1000 custom built torque converter and a $57 Chinese knockoff from fleabay.

 

[tgus3]

Yeah but junior dragsters use $1000 torque converters instead of $500 clutches.



Did you use a sprocket on the TC with the same number of teeth as the clutch it replaced?

Yes I know thers going to be a difference. But is 3-4
mph the average between the two?heres pics:
might have been an 11t on the clutch..but either 11 or 12...

 

[anickode]

And what is your torque converter sprocket? Is it 10t 41p or 12t 35p

 

[tgus3]

And what is your torque converter sprocket? Is it 10t 41p or 12t 35p

12t. 35 chain

 

[gr8hairy1]

What was the sprocket tooth count on the original clutch sprocket?

What is the sprocket tooth count on the torque converter sprocket? It looks like you have a 30 series and usually, they are 10t, but others can be chosen.

Your go kart looks like a Dingo. They usually have 18" tires, which often measure 17" top to bottom with a measuring tape.

In those pictures it looks like you have a 60t sprocket on the rear axle and you have upgraded the exhaust, to get those numbers you've probably also had to do something to the intake, but who knows. If that's the case, I'm guessing the governor has been removed.

With upgraded (or modified intake) and exhaust you might be getting a little over 5000rpm.

Based on that, if you have a 12t sprocket (like you said you thought it was) and are driving around 45mph, you likely have about a 60t rear sprocket.
60 divided by 10 equals 6:1 ratio. With 17" usable size tires you chould get 54mph when over 5krpm, but that is assuming your engine has the power to get it there and your kart is not small(read: a little heavy for the engine). I'm going to guess you have a Predator 212cc, as I don't see a starter on your engine. While you have upgraded parts of the engine, with the size/weight of your kart and only having a 212cc, it likely can't quite hit the top speed and with torque converters, you lose a little on top speed (but gain a ton of low-end acceleration), thus the 45mph you are currently getting.

I would guess your centrifugal clutch (original clutch) also had a 12t sprocket.
Everything is the same, thus the 48mph, because centrifugal clutches are a little more efficient on the top-end.



All of this would have been much easier if you could've given us all the measurements we had asked for, but I teach English online and a number of my students didn't show up, so I had WAY too much time on my hands.

All these guesses are perfect world scenarios (assuming your kart has no issues and drives great). Most likely I'm wrong on some details, but.... I don't care. I had my fun lol. And for that, I thank you

---------- Post added at 10:13 PM ---------- Previous post was at 10:02 PM ----------

Looks like while I was typing my overly lengthy response you confirmed the T/C sprocket 12t.

To gain the 3mph back (which is very small - as in the difference of a very slight slope), if you haven't already, upgrade the valve springs and do something proper with the intake...if you haven't already. Also, see if the carb needed to be re-jetted to a larger size........again...if it hasn't been already).

TL : DR
Same sprocket setup between a torque converter and centrifugal clutch will be close, but the T/C will have more acceleration and the centrifugal clutch will have slightly higher top speed (aka you are correct). But there are a number of other factors that can change things.

Update

See itsid's post

 

[anickode]

What was the sprocket tooth count on the original clutch sprocket?

What is the sprocket tooth count on the torque converter sprocket? It looks like you have a 30 series and usually, they are 10t, but others can be chosen.

Your go kart looks like a Dingo. They usually have 18" tires, which often measure 17" top to bottom with a measuring tape.

In those pictures it looks like you have a 60t sprocket on the rear axle and you have upgraded the exhaust, to get those numbers you've probably also had to do something to the intake, but who knows. If that's the case, I'm guessing the governor has been removed.

With upgraded (or modified intake) and exhaust you might be getting a little over 5000rpm.

Based on that, if you have a 12t sprocket (like you said you thought it was) and are driving around 45mph, you likely have about a 60t rear sprocket.
60 divided by 10 equals 6:1 ratio. With 17" usable size tires you chould get 54mph when over 5krpm, but that is assuming your engine has the power to get it there and your kart is not small(read: very light). I'm going to guess you have a Predator 212cc, as I don't see a starter on your engine. While you have upgraded parts of the engine, with the size/weight of your kart and only having a 212cc, it likely can't quite hit the top speed and with torque converters, you lose a little on top speed (but gain a ton of low-end acceleration), and limited by the power of the engine, thus the 45mph you are currently getting.

I would guess your centrifugal clutch (original clutch) also had a 12t sprocket.
Everything is the same, thus the 48mph, because centrifugal clutches are a little more efficient on the top-end.



All of this would have been much easier if you could've given us all the measurements we had asked for, but I teach English online and a number of my students didn't show up, so I had WAY too much time on my hands.

All these guesses are perfect world scenarios (assuming your kart has no issues and drives great). Most likely I'm wrong on some details, but.... I don't care. I had my fun lol.

---------- Post added at 10:13 PM ---------- Previous post was at 10:02 PM ----------

Looks like while I was typing my overly lengthy response you confirmed the T/C sprocket 12t.

To gain the 3mph back (which is very small - as in the difference of a very slight slope), if you haven't already, upgrade the valve springs and do something proper with the intake (if you haven't already). Also, see if the carb needed to be re-jetted to a larger size (if it hasn't been already).

DO NOT TOUCH THE VALVE SPRINGS UNLESS YOU HAVE A BILLET ROD AND FLYWHEEL!!!

Unless you like a shotgun blast of cast aluminum bits to the back. Then go ahead.

 

[gr8hairy1]

DO NOT TOUCH THE VALVE SPRINGS UNLESS YOU HAVE A BILLET ROD AND FLYWHEEL!!!

Unless you like a shotgun blast of cast aluminum bits to the back. Then go ahead.

Very very true. Thank you for that. Valve float can save the unprepared lol

 

[itsid]

in fact the series 30 has a 10% overdrive.. so you GAIN top speed (gearing untouched)


Most common issue with a newly installed series 30 is a friction issue (belt or chain too tight)
maybe an alignment issue causing friction and thus additional powerloss.

Now the bad news is.. a series 30 looses a good amount of power because of the belt (20+%)
usually that's not an issue at all, since it being what it is, it compensates for that in almost all situations with adjusted gearing ratios.

BUT in case your engine barely had enough power to reach that top speed,
you might just not have that 20% extra the TC eats away
(in which case you indeed loose a tiny bit of speed)
you can regain some (most.. sometimes all) of it by adjusting the gear ratio,
sometimes you could alternatively just install a 4° timing key to shift the powerband slightly upwards.

Hard to tell.. but frankly.. an ungoverend free breathing 200cc clone on a Dingo should work
without adjusted gear ratios and without any further engine modification...
(check the TC belt and chain, alignment and tension)
See if the bearings of the jackshaft are in good condition
(driven should spin freely and evenly without the belt attached)

'sid

 

[gr8hairy1]

I stand corrected. I seem to always forget about the overdrive on 30 series....

 

[tgus3]

Thanks guys...the rear sprocket is a 95t i know..its massive.However its getting worn;what t should i replace it with? The engine is predator with straight pipe, ungoverned.Im planning on getting airfilter too .What size should i jet it with?
Tires are 18 in.

 

[anickode]

18" tires... 80 tooth would be a nice compromise. Trade a little torque for more speed. With the torque converter, you'd still have plenty of grunt for climbing hills.

Engine me get not have the power to fully utilize an 80 tooth however, and further modifications would be necessary.

 

[gr8hairy1]

Thanks guys...the rear sprocket is a 95t i know..its massive.However its getting worn;what t should i replace it with? The engine is predator with straight pipe, ungoverned.Im planning on getting airfilter too .What size should i jet it with?
Tires are 18 in.

95t? Something is off. To hit 45mph on 18 inch tires with a 12t sprocket and 95t sprocket ....... the engine would have to be doing 8,000rpm. With your predator only being ungoverned and straight piped, I don't think that's possible.....

If you're right, it sounds like you have a phenomenal 212!!! Take care of that thing and upgrade some internals for longevity.....

Each engine is different. You could have 3 engines with the same intake and exhaust but have different sized jets on each one. Best recommendation is to watch some YouTube videos on people doing it. Some choose to drill out the jet, some choose to buy larger jets. Just keep in mind if you drill it out, remember what size drill you used in case you go too big. It's easy to forget what you used when you've drilled it a few times and aren't organized with your drill bits.

 

[tgus3]

Well im pretty sure its 95..counted 2-3 times.Shall i get another 95 or a 80 or 85t?

 

[gr8hairy1]

It's more based on personal preference. I like the idea of a smaller rear sprocket for reducing the chance of something I drive over hitting the sprocket/chain. I plan on using a jackshaft to do that, because I like my current ratio.

Going smaller decreases acceleration and increases top speed. You go too small you run the risk of the engine not being strong enough to accelerate to the top speed it could theoretically reach. Plus the lower the ratio the more strain it puts on the belt and chain (usually not an issue with the chain, but 35 chain is a little weaker than most).

If you want to continue using it off road, don't go too small.

I don't have much knowledge about good ratios for a predator 212 on an off road go kart. From what I do know, I would say you won't want to go below 5:1. Optimal is usually 6:1 (73t) to 7:1 (85t).

I still don't understand how your 212cc can make 45mph on a 8:1 ratio. Very impressive.

 

[tgus3]

this is with the clutch