Aussie EV Autocross Special

Ahh come on. Don't deny me my only source of exercise.


I do agree the steering is way off. This rack was sold to me as a quick rack. But that was clearly a lie. I am not sure I will bother on this car though. It will never be super competitive in motorkhana due to the size and weight. I plan to retire it from motorkhana and keep it for khanacross which is what its suited to. But I will certainly be installing a better rack in my new project.
 
Cool
So we are the agent for HPEV motors on the east coast of Australia if you want to go with a AC 50 in the new project nice and light and flick a switch to go from forward to backwards without a gear change.

Cheers Kiwi
 
I am happy to consider all options. I have been tending towards an 8 inch ADC just because I have one already and it would mean many of my parts would be interchangable between the cars. I will do some more research. I still have some time before I am committed. Is there a site with local prices?
 
Does yours come with the Curtis controller?
Does the Curtis controller invert from DC to AC? Or would I also need an inverter?
 
galderdi said:
Does yours come with the Curtis controller?
Does the Curtis controller invert from DC to AC? Or would I also need an inverter?
Yes comes with the Curtis controller wiring harness, hour glass readout and contactor.

The controller is the inverter

Cheers Kiwi
 
I was competing in Rounds 1 & 2 of the Queensland Motorkhana Championship in Gladstone over the weekend.

In preparation for the event I had a trailer brake pad seperate from it's backing plate. So I replaced that before leaving as travelling for about 18 hours round trip with no trailer brakes didn't appeal to me.
I tried to adjust my clutch cable, but in the end the cable gave way and sunk into the sheath. Luckily I didn't need the clutch for this weekend anyway.
Then when loading the car on the trailer I realised the throttle was playing up. I eventually reverted to an older throttle I had as a spare.

Luckily the weather held out despite the looming tropical Cyclone further north.
The first day the car was running very well and I was positioned in 3rd for most of the day.
But later in the day the heat got to me and I had a brain fade moments.
I still managed to place 6th outright which isn't bad considering I got 3 tests wrong out of 12.
At the end of the last run on day 1 it was apparrent I had developed a significant vibration. I beleived it to be a loose bolt from the flywheel or clutch plate putting the flywheel out of balance. Or potentially a worn gearbox bearing. The motor itself still seems to spin smoothly.
With little time and without my workshop facilities I could not risk separating the motor and gearbox to inspect the problem.
At the end of day 1 I was faced with the decision to protect the vehicle or continue with day 2. If the event didn't figure in the season standings I would have pulled out.
But as it was Round 2 of the Motorkhana season I decided I would proceed with caution.
I figured I would coast through the day with the aim to complete at least 50% to at least earn some more points towards the season championship.

On day 2 I found the vibration was worse at low revs. I was hoping it was just the clutch out of centre, but my clutch cable was out of action so I could not release the clutch to help it re-centre (if that was the problem).
But I pushed on. For any medium to long tests I selected 2nd gear from the start and turned the current up.
This was my attempt to keep the revs at a managable level and not do any further damage. I also periodically cooled my head with ice, which I think helped me concentrate, resulting in better results.
In the end I managed to achieve 3rd outright for day 2 which was about my target coming into the weekend and well exceeded my expectation after developing the vibration.

I have packed the car away as we have some really bad weather looming for the next few days. Hopefully this weekend I will be able to pull it apart and identify the problem.
My next event is a khanacross on April 9th (2 weeks). Hopefully it is a quick fix other wise I will miss my second khanacross in a row.
That would be devastating as the car is much better suited to khanacross and I have been really looking forward to seeing the car's true potential.
 
Having now seen the full results from the weekend I can report that I only missed 2nd place by 0.27 secs on Sunday. One less hesitation or a little more power or a little more grip and I could have had it....Yeah I know coulda, woulda, shoulda. I am still very happy with the result.

I have also now had the chance to pull the front of the car apart and diagnose the vibration. It turns out there were two issues. I am sure one caused the other but I am not sure which came first. Two of the four springs from the clutch plate popped out. The other is retainer bolt that attaches the flywheel/adaptor to the motor output shaft snapped.

I suspect the bolt came lose ever so slighty and then this allowed the flywheel to vibrate enough to continually wack the head of the bolt until finally it gave way. Then the vibration was able to get worse and combined with a stint of higher than usual revs shook the springs lose. The main reason I suspect this is because the remains of the retainer bolt were way too easy to remove.

The other thing I found as a result of last weekend was a surprising amount of under steer. I had expected the big sticky tyres on the front to resolve the understeer, but that wasn't to be. I plan to address this with a couple of adjustments.
I think the toe out on the front wheels might be a touch too extreme, so I will wind that in slightly.
I think the negative camber on the front is a touch too much (3 degrees). That doesn't sound like much but the geometry is designed to add more negative camber as the wheel loads up. So under load it would be more than 3 degrees. I think I will adjust it back to be 2 degrees.
Last weekend I was runnign with semi slicks on the back. I think for motorkhana I will return to running with my old/hard/cheap tyres on the back which should cause the rear to want to break lose a bit more.

So the good news is this is all quite easy to resolve and I am confident I will have it all back together by the end of this weekend ready for the event next weekend (in time to beat some more Porsches and Clubmans).
 
In the last event I only managed to complete the first 3 runs before my suspension broke. In hindsight there was a flaw in my design. The mount for the lower control arm was flexing over the past 18 months. Eventually the flexing weakened the steel enough to snap off entirely. Then without that support the other control arm mounts ripped off under extreme load. Its not a big deal other than the need to dismantle the car entirely so I can get at the welds.

On another note I went for a test Drive in the Teslsa yesterday. OMG it was awesome.
 
galderdi said:
In the last event I only managed to complete the first 3 runs before my suspension broke. In hindsight there was a flaw in my design. The mount for the lower control arm was flexing over the past 18 months. Eventually the flexing weakened the steel enough to snap off entirely. Then without that support the other control arm mounts ripped off under extreme load. Its not a big deal other than the need to dismantle the car entirely so I can get at the welds.

On another note I went for a test Drive in the Teslsa yesterday. OMG it was awesome.
You know you need a Tesla power plant mate and your left nut sack to boot.

Got a interesting project to do over the winter, should be a weapon btw

Cheers Kiwi
 
Yes I have had many thoughts jump into my head how I can shoe horn one of those into some project. Potential projects aren't the problem, funding is. I recently realised there was a fundamental flaw in my home budget. As a result I am having to significantly cut back my spending indefinately. This means my next project will stall, I will only be able to proceed with the bits that don't cost much.

Any hints on your new project? Will it be an extension of your old thread or a new one?
 
By the way I have completed the majority of the repairs from last weekend. I had to totally remove the entire front of the car and the floors so I could weld in the repairs. But it is back runnign again. I just have a few minor things to finish up with eg passenger seat, more rivets etc.
 
galderdi said:
Yes I have had many thoughts jump into my head how I can shoe horn one of those into some project. Potential projects aren't the problem, funding is. I recently realised there was a fundamental flaw in my home budget. As a result I am having to significantly cut back my spending indefinately. This means my next project will stall, I will only be able to proceed with the bits that don't cost much.

Any hints on your new project? Will it be an extension of your old thread or a new one?

May upset some people lol but I want to prove the car before I stick 420Kw in its ass.


Cheers Kiwi
 
I like that approach. I did the same thing with my 240z. I built it with a low HP motor first so I could sort out the brakes, suspension etc.
 
kiwiev said:
galderdi said:
Yes I have had many thoughts jump into my head how I can shoe horn one of those into some project. Potential projects aren't the problem, funding is. I recently realised there was a fundamental flaw in my home budget. As a result I am having to significantly cut back my spending indefinately. This means my next project will stall, I will only be able to proceed with the bits that don't cost much.

Any hints on your new project? Will it be an extension of your old thread or a new one?

May upset some people lol but I want to prove the car before I stick 420Kw in its ass.


Cheers Kiwi

How about putting it in this???

http://www.graysonline.com/lot/0004-7016844/transport-trucks-and-trailers/race-car-frame-and-fibre-glass-body?spr=true
 
As tempting as it is it really isn't suitable for my purposes. It souldn't be elligable for my categories without modification. And the amount of cost and modification required make it unviable. Plus the end result would be way too heavy for my needs. But I did give it some serious thought.
 
galderdi said:
oatnet said:
I am looking forward to someone else telling you that your Curtis controller is too weak to drive a 9" brushed motor, and that a $75 power supply will charge your pack in hours instead of days, so you can start enjoying what your build really has to offer. :mrgreen:

Oatnet, you were right again. The controller was too weak to drive the motor. At least I am man enough to admit when I was wrong. My resistance to accept the facts was more about budget than anything else. It has been a painful experience from a financial point of view. But I am confident 2017 will provide some excellent results now that I am running the Zeva 1000amp unit.

I am glad you found a way forward so you can get the most enjoyment from your car. 1,000a is plenty - as long as it actually pulling 1,000a and you can verify it on a meter like the cycleanalyst. My 500a Kelly only delivered 88a - I haven't worked with a Zeva controller, so I hope it performs more like the Zilla than the Kelly.

-JD
 
Thanks, yes the car is excellent now. Power is nolonger a weakness. Plus I haven't even turned it up past about 850amps. Now it's just a matter of finding ways to increase the grip. May 21 is D day. I should have some interesting results to share.

On a side note I am slowly progressing on the next project. I am copying my existing drivers seat this weekend. I have already removed it and stripped all the material etc off it. I have started waxing it. I will at least get to the point of completing the fiberglass mold this weekend. I will finish the new copy next weekend at the latest. I am still undecided on the drive train, but my latest thinking is a thick drive belt between the motor shaft and an R180 LSD diff from a WRX STI. At least this way I end up with a good LSD between the front wheels. The biggest issue with this approach is space for mounting the motor and Diff. But I am thinking of mounting the motor along side the diff but offsetting the motor forward enough to clear the CV drive shafts.
 
I had a khanacross yesterday. I didn’t quite get the results I was hoping for yesterday.

The car was fairly good but not quite the fastest on the day. I obviously still need to find a little more performance. I have a few ideas. I wasn’t far off the pace but I was aiming to be top three so being slightly down the leader board is a bit disappointing. I have a few ideas for some improvements to bridge the gap.

Aero is one big consideration. Currently the car has a very flat nose so effectively I am pushing a lot of air in front of the car at speed. I think I will change the design to get the air flowing around the nose better.

On this particular occasion the driver was an issue too. I had three significant issues that impacted my results. The first was as a result of running late for my turn I thought I was changing a setting to increase my power, but I was changing the wrong setting (reflection from the sun also didn’t help). So when I took off the power was woeful. The second was not noticing that my she was damp, which caused my foot to slip off the brake twice. That gave a few people a heart attack including me. Lastly I was just launching when I heard the time keeper say “Wait for it” I thought she was talking to me so I stopped. It turned out she was talking to someone else. That cost me about 2 seconds on that run.

All in all though I am fairly happy as the car was solid and predictable, I just need to find about 5% to start winning.

The next one is a motorkhana on June 18 and then another khanacross July 19.

Here are a few of the videos from the day:
[youtube]Kb_TR1vTK9M[/youtube]
[youtube]5QKFux4Py90[/youtube]
[youtube]0K4EeR4FK_Y[/youtube]
[youtube]pSW2TtCgI1s[/youtube]
[youtube]mITwJPNXGI8[/youtube]
[youtube]tJ7h19VpIfA[/youtube]
 
At the speeds, and time at speed, that you run at, i doubt any aero mods will get you the gains you are looking for.
Fix the issues with that control unit attached to the steering wheel first!.... (the driver !)
PS.. What is that "clanking" sound as you run slow .?
 
Changing the driver would defeat the purpose. I'm in this for the fun not to watch someone else go quicker. But I know I can improve. Part of the problem is the front suspension is too hard. It is very difficult to pick the right lines when you are getting knocked about so much, particularly with my helmet hitting the roll. So softening the suspension is #1, that will help me concentrate on driving rather than hanging on. I know I can drive better because I achieved better results with my previous car.

As for aero, I don't suggest for a minute it will bridge the entire gap. But I think it has to be part of the solution. You can see from the speedo it goes great from 0-70kmph then is ok from 70-95. The only reason for the difference in acceleration is aero. Pushing a square meter of air along in front is always going to hurt performance. So I believe a relatively small aero modification will make a difference. Even if it only makes 0.1 of a second per run then I am 10% towards my target. Plus it has 0 chance of hurting performance.

I'm not sure what clanking sound you are referring to. Is there a particular video/time you noticed it in? Off the top of my head I suspect it is either the control arm joints (metal on metal) or its just the roughness of the surface. The surface is getting really really bad. We even had to cut a section out of one of the courses due to the surface breaking up.
 
No No, i was not surgesting recruiting Mark Webber ,....just making sure you eliminate those errors you know you are responsible for as stated.
Aero may make a small difference, but it will also definitely add some weight which could offsett that benefit somewhat under accelleration....which you do a lot of
I suspect your reduction in accelleration above 70 is more likely due to the reduction in torque at that rpm level.
The "clanking" or "rattle" can be heard in several of the videos as you roll up to stop at the start line, and as you roll away from a stop at the finish. Sounds like it may be something in the drive line ?
 
I agree regarding the driving. There were some quantifiable errors on Sunday. They cost me 32 seconds. That alone would have moved me up to 5th or 6th. Then there are unquantifiable errors (not taking ideal lines, braking too soon, holding the gears too long etc). Some of these will improve when I soften the suspension plus more time behind the wheel learning to drive again.

Ah yes, torque reduction. I wasn't thinking of that.

Regarding the aero my main plan is just to add a wedge out in front so I'm not pushing a flat panel through the air. The construction will be similar to my side panels, a metal skeleton with polycarbonate panels. Based on past experience I think it will only add about 1.5 kg. I will consider removing the passenger seat which will offset the weight increase and will also slightly improve the aero. I might look at some other improvements too, like covering the passenger side, like they do in some convertables, to stop the wind swirling in that void. I think this would be almost entirely Polycarbonate so next to no weight increase.

I did briefly consider putting some contours out in front of the wheels and suspension to shift the air flow around the tyres. But in this case I do think the weight increase would be greater than any aero gain.

I also want to look at a little flap in front of my front springs. At the moment the air flowing up the front of the car hits some significant resistance when it gets to the springs. Again this would just be poly carbonate.
 
Just another thought for your next car is gear changes the reason Tesla is the fastest acceleration car is no gear changes and good constant torque.

Cheers Kiwi
 
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