# Drag racing go kart



## MalcolmB (Jun 10, 2008)

The Zilla will certainly give you plenty of headroom for the future.

It's probably a good idea to start with lead acid until you get a feel for the technology. Lithium would be ideal for maximising power-to-weight, especially as you've got a heavy motor, but then you have the added complication of needing a battery management system. Those Panasonic batteries will take a real hammering though, as their expected life and capacity is greatly reduced at the high current drains you want. Still, if you can get them for free... How many can you get?


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## MalcolmB (Jun 10, 2008)

I've no experience with drag racing or karting, so I have a couple of questions: With all the torque from that 7" motor, isn't there likely to be a problem maintaining traction in a lightweight kart with small wheels?
Will the kart just be used for a few drag runs or are there other requirements?

I would probably start off with 8 of those batteries to give a 96V system. That should you give you a taste of what the motor is capable of. The voltage will sag considerably under load. This is going to be quite a heavy kart, I'm estimating 220 lbs for motor and batteries alone, but at least that will aid traction


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## albano (Jan 12, 2009)

Is Zilla 1k enough for drag and will it be fine with Panasonic AGM battery?


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## albano (Jan 12, 2009)

My go-kart is coming home tomorrow, can't wait. I believe i will have a bit of work to like motor mounting, axle sprocket, battery tray...........
And soon the Zilla 1k LV.

Hope I'll have a nice power go-kart to impress all the gasses


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## albano (Jan 12, 2009)

Just and update.

Brought the kart home today, got a lot of work to do. Drop the motor in just to have any idea how I'm going to fit it. It look like I'm going to have to do a better homework here as the motor is a monster


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## dimitri (May 16, 2008)

Those batteries are 17AH and according to the graphs you probably want to stay under 30 amps battery current if you want them to last for a while.

See how many batteries you can fit on the kart safely, keeping in mind added weight and weight distribution. Somehow I doubt you will fit all 25 batteries at once.

You really don't need Zilla for the kart , especially with your low voltage and relatively small motor. You'd be fine with any low end controller, but you need to figure out your voltage and current levels.

If you can fit even number of batteries, you have an option of paralleling them in pairs and them connect pairs in series. This will double your battery current, but you will end up with less voltage. This maybe OK depending on your motor specs and sprocket ratio, since you need to balance torque and max RPM. 

In this project it may just be better to have less volts and more amps, contrary to typical EV conversion.

These are just ideas of course, I don't know anything about karts racing, so I don't know speeds, RPMs and torque involved. I do know , however, that its better to do some calculations and pick meaningful combinations of volts and amps before spending money on expensive parts only to be disappointed later when Zilla kills your batteries in 5 minutes.


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## albano (Jan 12, 2009)

Thank Dimitri,

The kart will mainly be just for drag racing 1/8 and 1/4 miles. I will see how many batteries can I fit and also I don't want it to be too heavy.


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## Sutitan (Feb 23, 2009)

Would you consider stretching the chassis a little? Making it a little bit longer would go a long way. you could also mount your batterys where those plastic side bumpers are if you extend your chassis a little.


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## MalcolmB (Jun 10, 2008)

I'm still puzzling over this one. On one hand the idea of a drag go-kart sounds like great fun, on the other I still don't see how you will get enough traction from those tyres to get respectable times. I've watched a few videos of moderately powerful electric karts (20 hp or so) and they all seem to spend most of their time spinning wheels. Since a drag race is all about torque, rather than speed, getting sufficient traction seems to be the weak link in the chain.

The advantage of a go-kart is of course its low weight, but the more lead you add, the smaller that advantage becomes. If you had an unlimited budget I would use a couple of Agni motors, a 1000A controller and 40 of the 20Ah A123 lithium cells that are just becoming available. Total weight (including motors) just over 50 kg. These cells would give you around 40–50 kW, minus losses say 40–50 hp at the wheels. The cells should last a long time if they are only asked to deliver this sort of power in bursts. The downside is that the battery pack would cost around $2000 plus shipping plus the cost of housing and BMS.

Using the lead acid batteries you mentioned, you may be able to pull 200A from them for a minute or so – plenty of time for couple of drags – but the voltage will sag to somewhere around 7V. The batteries will need to be kept warm to do this – 25ºC minimum – and their life will be drastically shortened. Because the voltage sags so much you would need around 16 of them to get the same 100V output as the A123 cells – giving a battery weight of over 100 kg. Because the batteries can only deliver 200A (possibly 300A max?) the maximum power available will be 20–30 kW.

You could go for a lower voltage pack, and add batteries in parallel to increase current delivery and reduce voltage sag, as Dimitri suggested, but then you limit upper range torque and increase losses in the motor.

I guess what I'm trying to say is that starting off with lead acid is certainly a good way to gain experience, but I wouldn't expect the performance to impress a sponsor. I don't want to discourage you in any way, just giving a reality check 

Edit: It would be good to find out from your battery supplier if they can give you a figure for maximum current output over 20 seconds or so.


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## toddshotrods (Feb 10, 2009)

Being that I am basically building an over-sized go-kart, disguised as a street rod , I understand your challenges. It took a lot of effort to come up with a setup that I felt would meet my needs. Honestly, without planning for A123s my project would be little more than an elaborate golf cart. I plan to get it moving (at golf cart speeds) with lead, and then possibly transition to a small LiFePo4 pack to allow more rigorous testing, but the whole thing hinges on having an A123 pack.

Currently, they are the only batteries that allow me to develop the right balance of weight vs performance. Your need is even more critical, due to the diminutive size of your kart. If obtaining an A123 pack is a feasible option for you, I would base everything on that. Suffer through whatever amount of "lesser" battery technology you have to until you get to the real deal. Just use the lower performance potential to deveop the rest of the kart and your driving techniques. I would aim for low-end, at the expense of upper-end performance, to concentrate on learning to launch and control the kart safely. Loading it up with a bunch of lead to gain more performance isn't the answer, because the weight of the battery pack is such a huge element in the overall weight. When you drop back down to a lighter, better, pack you'll have a whole different animal on your hands. That measn wasted time in starting the learning curve again.

Good race efforts require well-planned, incremental, increases. When drag-race vehicles are built it is common place to do shake down passes. You start by trying a low power launch, and work your way up, until a full pass can be made safely. This exposes bugs, and helps tune the chassis and driver. They even do this in the licensing procedures for major sanctioning bodies. I realize you may know all of this, but it could be valuable to the first-timer who decides to follow in your footsteps...


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## albano (Jan 12, 2009)

Thank you all for helping me with advise on my drag go kart.

I just finished to strip the kart to bare and I will start tomorrow with the sprocket and the motor mounting.

I think I'm going to start first with AGM batteries just to get some experience and the feeling.


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## albano (Jan 12, 2009)

One more question.Is there any different mounting the motor in front of the axle or behind the axle.


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## toddshotrods (Feb 10, 2009)

albano said:


> One more question.
> 
> Is there any different mounting the motor in front of the sprocket or behind the sprocket.


Weight distribution. I don't know if you're going to have enough traction to pull the front wheels, but hanging it off the back (behind the axle) will definitely make it more wheelie prone. Are you running wheelie bars?

By default I would say put it in front of the axle if that's possible. The extreme rearward weight bias of having the motor hanging off the back could make your steering light or even non responsive!  Even with wheelie bars, it could ping-pong on and off the bars making for a crazy ride.


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## albano (Jan 12, 2009)

toddshotrods said:


> Weight distribution. I don't know if you're going to have enough traction to pull the front wheels, but hanging it off the back (behind the axle) will definitely make it more wheelie prone. Are you running wheelie bars?


Then I'll have to extend frame so i can put the motor behind the seat (in front of the axle). The frame is chrome molly, will there be a problem if I extend the frame. Must I joint the frame with chrome molly tube or can i use mild steel tube, look like I'm going to nee to extend about 500mm.


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## toddshotrods (Feb 10, 2009)

You should use moly. A nice way to do it is to get some tubing or solid stock that will fit inside the frame rails (tight, tap-in, fit is best) and drilll holes in all the pieces so it can be plug welded to the inner tubing or bar stock. Let me know if this doesn't make sense and I'll explain more. Also, you can google "plug weld" to see some images/descriptions.

One more caveat - you need to have that TIG welded, if you don't do TIG welding yourself. Mild steel can be MIG'd but moly needs TIG. I think there are special processes for welding moly by other means, but I am not familiar with them.

None of this is as hairy as it may seem. If you can't find an inner tubing or bar stock to fit inside the frame rails, you can have pieces turned at a local machine shop. It should be pretty reasonable because it's a quick job to do. Finding someone to TIG weld it for you, assuming you can't do it, also shouldn't be that hard or expensive. Four quick trips around that tubing shouldn't take more than ten to fifteen minutes. Just take the time to do it right the first time, and you'll never have to worry about it.

By the way, I think the stretch is a win-win for you. Better weight distribution off the line - better stability down the track.

Do you have any idea how fast you expect this thing to go (mph)? I would normally weld or clamp braces before cutting the frame to make sure it stays aligned and true, but how critical that is depends on the intended usage. You can make a wooden jig and use pipe clamps to lock it down - it doesn't have to be anything elaborate.


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## albano (Jan 12, 2009)

Thank toddshotrod,

I have already order the chrome molly tube, i will have it at my shop tomorrow morning. It is also better to make the frame a bit longer and put the motor in front of the axle for better center of gravity and better top handling at top end speed. I will take some photo's as I'm doing my project.


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## toddshotrods (Feb 10, 2009)

Cool, can't wait to see the process! We should have a photo shoot of the EV kart on steroids and the mutant EV kart that thinks it's a street rod someday.


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## albano (Jan 12, 2009)

Hi! To all,

Got my chrome molly tube and I`m going to start to cut the frame tomorrow. 

I have to put on roll case cause our local drag strip said I have to put on the case if I extend more than 1.5 meter of wheelbase. The kart will be around 1.7 meter long(wheelbase). 

The reason to extend is because the kart will mainly be for drag and drag is just a straight line. And it will have much better handling at high speed.


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## DC DYNOMITE (Nov 23, 2009)

Have you guys seen this !!! http://www.youtube.com/watch?v=bERjkSTYOdU


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## albano (Jan 12, 2009)

DC DYNOMITE said:


> Have you guys seen this !!! http://www.youtube.com/watch?v=bERjkSTYOdU



Yes I did see it last year, great power hey!


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## albano (Jan 12, 2009)

HI! To all,

IT been a long time since i post here, Was just too busy with the forklift and truck and you know working all the time long hour make you tired and need a bit of rest. Anyway better do the job right the first time than embarrassed yourself at the track.

All i did so far is cut the frame and extend to 1.5 meter wheel base, prepare the controller to the maximum volts and a bit of modification on the motor. As for the battery there is no problem at all we all just have to wait and see the surprise


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## dragster (Sep 3, 2008)

Hi
That kart could not run in the USA at any drag strip you had better look at the rule book before you put any more time into that frame.


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## albano (Jan 12, 2009)

dragster said:


> Hi
> That kart could not run in the USA at any drag strip you had better look at the rule book before you put any more time into that frame.



Hi Dragster!

Yes I know, in USA kart is not allowed on the track.

Did you see my profile from what country am I? I'm in South Africa and here in South Africa they allowed kart on the track, I confirmed with the track before I bought the kart. I just have to put on roll case. 

We even have a ATV (quad bike) with R1 motor on the track, and quad bikes are even more dangerous than go kart.


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## dragster (Sep 3, 2008)

Hi
great go for it, just get yourself a good 5 way safety harness


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## albano (Jan 12, 2009)

Hi all,

Not much done , but at least I'm doing something on the kart. Just been very busy with usually on forklift rebuild.

I just manage to make the motor mounting and I'm going to do a full welding on all the joint tomorrow then I can start with the seat bracket and the roll case. When all the welding and all the,case and and bracket finished....... then I'll strip everything apart and do a nice custom painting on the motor and the kart.

As for the motor I decided to go for 8" inch motor, cause as I was doing some test between the 7" and 8" i found out the the 8" is much better.
It can also handle more volts, amps and it id rated for much higher RPM.

When I did the test, I test it with 10ha AGM battery and the reading was,
7" at 12v 10ha 1560RPM and the 8" was 12v 10ha same battery and the reading was 3650RPM. I test first the 7" then the 8".


As for my plan is to go for at least 144volts+ on this little kart.


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## toddshotrods (Feb 10, 2009)

Sweet! Looks awesome, so far! Are you going to use any body work, or just a tube chassis?


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## albano (Jan 12, 2009)

toddshotrods said:


> Sweet! Looks awesome, so far! Are you going to use any body work, or just a tube chassis?


Hi Tod, 

At the moment i'm going to use tube frame just to test and then if i'm happy with the power then I'll do some body work. Maybe something like F 1 or maybe you can design something for me.


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## toddshotrods (Feb 10, 2009)

albano said:


> ...or maybe you can design something for me.


...grabs his superhero cape and flashes an evil grin


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## albano (Jan 12, 2009)

toddshotrods said:


> ...grabs his superhero cape and flashes an evil grin


Lol, . So are you going to design on not?


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## toddshotrods (Feb 10, 2009)

albano said:


> Lol, . So are you going to design on not?


Absolutely, I'm always willing to let the creativity flow. PM me and we can figure out how to make it happen.


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## albano (Jan 12, 2009)

Hi to all!

Not much done, had a wonderful Soccer World Cup here at my soil and you all knows it winter here but it not that cold. I'm hoping to get my motor back next week as i send it to put some new insulate and some mod on the field coil and also balancing the armature.

Albano


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## albano (Jan 12, 2009)

Hello all,

It been a long time since I touch my project, as it was dead for a very long time. Been too busy with other stuff and couldn't concentrate on my project. 
Now as I starting to get a bit of time and Autumn is here, I feel it time to keep my project rolling.

I had to re-do my motor cause a guys that was busy with my motor only did nonsense and his company close down, I can't find those guys anymore. I have to start all over myself again as you can see how is my motor coming and still have to fit on the field..... I decide to re-do all my custom work on the kart and make it for Show&Shine and drag.


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