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#Post#: 4672--------------------------------------------------
Getting the best out of you Torque Converter
By: Adrian Date: September 14, 2021, 6:08 am
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I guess we all install the torque converter (T/C) straight out
of the box after spending some time figuring out the best
position in which to bolt it to the engine for our application.
We try to figure out the best gearing ratios and leave it at
that but Bill Carter in the US CycleKart newletter has just
posted the most interesting little appetite wetter I have seen
for a while. It's on tuning the T/C to get the best out of it
for your Kart given its weight, your weight, driving style and
what you use it for.
My biggest issue with the Renault for example is due to it’s
overall weight which results in poor acceleration out of the
corners, where it really matters. That is why I am tweaking the
engine a bit to take it up around the 10h.p. level.
So here I am spending all this time, effort and money on the
engine whilst totally ignoring the real gains that can be had by
tuning the T/C.
I am not going to lift Bobs article so pop across the Altantic
and read the article for yourself, the least we can do.
Many thanks Bill.
It’s prompted me to look into the subject and when I really know
what I am talking about, I’ll write an illustrated article.
The main thing is to have the clutch bite at around (above a bit
actually) the engines max torque.
A standard T/C starts biting at around 2,200 rpm and since max
torque on a standard GX200 is around 2,600 rpm, we suffer the
engine being pulled down below max torque, resulting in low
acceleration, significantly less then it could be if only the
T/C cut-in at around the max torque. On my rebuilt engine that's
going to be round 3,500 rpm so something has to be done.
Well the good new is that you can quite simply get the T/C
to-cut in at that point by changing the springs within the
clutch for some Blue/silver springs and you can change the
spring in the output clutch (not sure of the correct names for
these parts but I will find out) for a stronger one and you can
change the tension of that spring too.
Also, the weights in the clutch can be changed so there are a
whole bunch of alternatives to have a go at.
I have just ordered a set of blue/silver springs and the yellow
spring for the other end on Gemini's advice. That should give me
a biting start of 3,600 rpm (max torque) and the stronger
yellow spring will hold it down keeping the engine in it's power
band longer but allowing ten thousand rpm so yippe!
In Bills posting he included a spring engagement chart for the
20 and 30 series T/C's and Gemini have promised to send me one
which explains things a bit better.
I must point out that this information is for my use only and
MUST NOT be used by anyone in CycleKartsGB.
It’s not all about winning you know!
#Post#: 4678--------------------------------------------------
Re: Getting the best out of you Torque Converter
By: StefanN Date: September 14, 2021, 7:22 am
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Funnily enough I’ve just machined my Zinc weights to just under
280g (from 340g) which should get them to engage at 2500 on the
blue springs. The torque gain is marginal but thought I’d
give it a go. I have tried Aluminium weights on blue garter
springs (3300 rpm) which kept it in a lower ratio for longer but
didn’t help much with engine and was unrefined when pulling
away.
Will be interesting to see if I’ve machined off anything
important!
I’ve increased the preload on the chain end to keep it in a
lower ratio longer but haven’t tried changing that spring - this
improved acceleration and I suspect increased belt wear.
#Post#: 4683--------------------------------------------------
Re: Getting the best out of you Torque Converter
By: Adrian Date: September 14, 2021, 4:17 pm
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Well done that man.
My engine now has a 1.3:1 set of rockers (pressed steel ones), a
billet rod and flywheel and a 22mm Makuni with jets supplied by
GX tuning and a ten thou head gasket so it should pull in excess
of 10hp and rev a lot higher than the standard engine. I think
around 6,000 rpm with max torque at around 3,600rpm so in theory
at least it sounds like it should pull well off-the-line and
have a good top-end speed to. I hope so.
The engine going in the Wee Beastie is the one supplied by GX
tuning (I put it in the Renault for the speed trial) and that
has a claimed 10+hp. even though it's on a re-jetted standard
carb.
I was going to use it with a centrifugal clutch but i have
changed my mind and I am using a T/C now.
I have a spare 22mm Makuni somewhere, in tricky condition so I
will be sorting that out and fitting it to the Wee Beastie. She
is a cartoon car that is very recognisable but I though it might
be fun at shows in particular to have her pulling wheelies which
she will do. So according to Gemini, there is a set-up of
springs for the clutch and a spring for the driven bit which the
kids use for drag racing (so eat yer heart out Jim lad!
#Post#: 4690--------------------------------------------------
Re: Getting the best out of you Torque Converter
By: jim Date: September 16, 2021, 1:21 am
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I think that engine will make some good power Adrian and would
have easily shown mine a clean pair of heals. I now have a Jimmy
de Fish tail silencer which will go all the way to 11. Your
gonna need a blower to beat the Fish lol.
#Post#: 4691--------------------------------------------------
Re: Getting the best out of you Torque Converter
By: jim Date: September 16, 2021, 1:37 am
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Another pic of the Fish
#Post#: 4692--------------------------------------------------
Re: Getting the best out of you Torque Converter
By: jim Date: September 16, 2021, 1:48 am
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HTML https://www.ebay.co.uk/itm/255104250516?_trkparms=amclksrc%3DITM%26ao%3D1%26asc%3D20140127102845%26meid%3Ddda734f0e11842658597935db6d58e8c%26pid%3D100148%26itm%3D255104250516%26pmt%3D0%26noa%3D1%26pg%3D2506613%26algv%3DOrganicCompBase&_trksid=p2506613.c100148.m2813
These Forward/reverse gearboxes are only just over £50 and could
be a nice addition to your TC
#Post#: 4697--------------------------------------------------
Re: Getting the best out of you Torque Converter
By: peterL Date: September 16, 2021, 8:05 am
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I really hope so!
On the down size it's more weight and drive chain complexity, on
the plus side there's a 1.3 to 1 reduction on the drive.
The biggest issue I'm finding at the moment is that the output
shaft is inboard of the input, so I might be having to put a
layshaft in.
The £50 option doesn't include the cables and lever though, so I
went for the full version, but that still only cost around £119.
#Post#: 5056--------------------------------------------------
Re: Getting the best out of you Torque Converter
By: jim Date: November 14, 2021, 7:26 am
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Adding a forward and reverse gearbox with built in reduction may
help get more from the TC. Here's one I put on an old chassis
recently.
#Post#: 7588--------------------------------------------------
Re: Getting the best out of you Torque Converter
By: peterL Date: September 14, 2022, 2:16 pm
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Wondering if you can steer me in the right direction on the
reverse box Jim, I've hit a small snag as the spacing between
chain drive and TAV belt differs between the engine and reverse
box.
It appears that my input shaft to the gearbox has a shouldered
section at the end, of about 9mm, which pushes the top TAV
pulley out further.
[attach=1]
[attach=2]
Because of the close proximity of the engine to the chain wheel,
I can't just move the engine across, as it will foul the chain.
Thus I think there are three options,
To drill out a short section of the TAV top pulley to fit over
the 20mm section of the shaft.
To take the gearbox apart and get the 20mm section turned down
to 16mm
Or less likely, put a spacer on the engine end of the TAV drive
to push the bottom pulley out the required 9mm, but there's not
a lot of shaft anyway, so this seems the least desirable option.
Did you have a similar issue? Or does your set up allow you to
move the engine across?
Peter
#Post#: 7590--------------------------------------------------
Re: Getting the best out of you Torque Converter
By: jim Date: September 15, 2022, 12:05 am
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Hi Peter, I drilled the tav pulley to fit over the 20mm gearbox
shaft. I also removed a bit in the centre of the engine pulley
to get more purchase .
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