Aussie EV Autocross Special

Agreed, gear changes are an issue. As usual though I am constrained by parts that I can scrounge.

As for the clunking, I have checked the videos (this time with the volumn up) and it is definately the suspension moaning. This is because most of the suspension components aren't running bushings. It groans and moans on anything but the smoothest surface. The driveline only has the standard whir of the motor fan.
 
kiwiev said:
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. ..
Yes 1000+ Nm of Steady torque at the motor, a 9.7:1 reduction transmission, ( so near to 10,000Nm at the wheels!)....and a motor that will run up to 18,000 rpm. will all add up to decent accelleration ! :wink:
 
My next event is a motorkhana and is coming up soon. It will be held at Willowbank on June 18. IF anyone is local feel free to come and take a look. Spectators are free. I'll post another update after the event.
 
I had another competition day yesterday. I was competing in round 4 of the Queensland Motorkhana Championship.
Runs 3,5 & 7 are terrible, My fault not the car. But those 3 out of 12 runs were enough to ruin my chances for the day. I finished mid field.

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My next event is a Khanacross on Aug 27. This one is being hosted by the Lotus club so there should be some interesting scalps to claim. It is to be run on the small circuit at the back of Lakeside and should suit my car. I am really looking forward to it.
 
I had a ball at the Lotus Khanacross at lakeside. The track is quite tricky with a couple of blind corners. It really would help to have track time on this one. My first few runs were average at best but I did improve on my last few runs. I really struggled due to rear end grip. You know it’s bad when you are over steering in a front wheel drive car. I managed to come 34th from 66 competitors. That’s not bad considering the quality of the field. I beat 6 out of 13 Lotuses and 9 out of 16 Porsches. If I wasn’t retiring the car I could put better tyres on the rear and improve the rear geometry and I would be confident of picking up quite a few places. Overall I am quite happy.

I had a problem with my camera and only got 1 video with telemetry. It’s not the fastest run and watch for the plover at about 1:22

https://www.youtube.com/watch?v=XXhOVGg55hI
 
I had a great event on Sunday.

For a while the results were up in the air.....quite literally. We had a mini tornado which flattened our timing tents and associated equipment. The timing tents were thrown about despite being weighed down with concrete blocks. Our volunteers conducting the timing were shaken but unhurt. When I first looked over to understand the cause of the commotion I first thought a wayward car had somehow bowled over the time keepers. I am so glad that was not the case. A handful of timing result sheets were sucked up into the vortex and continued to rise almost straight up until they eventually reached sufficient height to become too distant to view.

But now the results are up in the cloud. So I can confirm I managed 6th place outright. That isn’t too bad, as usual one particular test cost me quite dearly but overall I think that only cost me one place realistically. Looking at the times I am confident all the improvements going into the new car will have me competitive against the guys at the top. I don’t expect to be consistently quicker than them as they will still have a significant size advantage. But I will be closing that gap to some degree and I will have other advantages that will somewhat compensate for the rest of the gap.

Here are a handful of videos from the day:
https://youtu.be/0WW2Wu9H7eA
https://youtu.be/lU-Li3Wa-Mo
https://youtu.be/U6m5F40kJJU
https://youtu.be/_Sh8p1PlSPs
https://youtu.be/LZOc9XA-aSQ
https://youtu.be/PXTGIv1CNE8
 
Here are the pics of my latest project. It is similar to my last one but incorporating a lot of learnings from last time.

I expect it to be about 20% lighter. Plus it is rear wheel drive, narrower, better suspension design, better aero etc etc.

I still have a fair amount of work to complete it and the deadline is looming on Feb 11. I'll provide another update soon.

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Looks sick! What components are you looking to use?
 
Thanks. I am fairly happy so far.

I will be transferring the components from my previous car.

The gearbox is from a nissan N13 Pulsar.
The motor is an advanced DC 8inch.
Controller is a ZEVA 1000 amp.
Batteries are a 144V nominal portion from a Chev Volt.

These components worked exceptionally well in the old car. But I was losing the torque advantage through wheel spin because it was FWD. Plus this car is likely to be around 20% lighter than the old one. Being narrower will make it quicker through slaloms and the like and I expect the improved aero will improve response from about 70kmph (40mph) - 100kmph (60mph).
The improved suspension geometry should result in an ability to hold more speed through the corners.
The improved steering rate should result in better ability through tight corners plus less distraction for the driver (me) frantically turning the wheel from lock to lock.

I have also added passive rear steer. This will be turned to subtly turn the rear end around tight corners. I will tune it to neutral for faster courses.

All in all it should be a very satisfying car to drive. I am getting really excited to give it a whirl.
 
Here are a couple of the latest pics of my new car. I have encountered soem delays on the steering components. We'll see how it goes over the next couple of weeks.
 

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I got the car running last night. This is a huge releif as it means I am fairly certain of competing in the event this Sunday. I do still have a few things to do but they are fairly minor.

I also weighed the car (As best I can). The car came in at 480Kg with weight distribution of about 44/56 toward the back which isn't too bad.

The first drive felt very good. I think it has promise. I just need to do a wheel alignment, brake bleed and some minor additions to be ready for Sunday. I should have some good videos early next week.
 
Hi everyone. Appologies for not posting for a while. It has been a heck of a journey (not implying it is over).



The car is coming along nicely. But it still isn't competitive. I seem to be hovering around the mid field in most results. Not bad in itself as I am usually up against some seasoned competitors in some goo cars. So as I usually say I am happy but not content.



The second last event of 2018 was the Noosa Hill Climb. It was only my second time at the event and I improved by 4 seconds. The car was still understeering but was managable. But the understeer prevents me from gaining too much confidence and holding corner speed. So I am still focused on improving that aspect of the car. Here is a video from that event:



https://www.youtube.com/watch?v=O0FDh_p_rbk



The last event of 2018 was an autocross/khanacross. But it was very very wet which emphasised the understeer to the point where is was not managable. I don't have a video for that event.



I started with a check of all the suspension geometry including Castor, camber, king pin inclination, roll centres, toe in and Ackerman angle.

Castor was about right on the driver side but significantly more aggressive on the passenger side. This will be resolved as I complete the new front contro...l arms.


Camber, king pin inclination and roll centres were about where they need to be.

Toe in was correct but will need to be adjusted again as it will be impacted by all the other changes.

Ackerman angle was a little out on the passenger side but not enough to warrant a change in the short term. The driver side was out by a bit more and I have now replaced the adaptor plate to bring it in line with the passenger side.

I have made some solid progress on a second nose for the car. The first nose is for lower speed events where it is an advantage for the tyres to be in front of the nose. The new nose is sleeker, and will include a wing for additional downforce (maybe). The two noses are interchangeable depending on the upcoming types of events. The nose and wing are structurally complete and just need the panels to be added.

I have created some ballast in the form of a 10kg lump of lead. This can be added or removed depending on conditions. I intend to only include it in wet weather where the understeer characteristics seemed to be pronounced.

I have made new front control arms. These are designed to address the inequality in caster from left to right. They are also designed with a slight bend in the front bar of each arm. The bend is to improve the angle of the rose joint attaching to the chassis mount. I was concerned about the bend creating a weak point in the control arm. So you can see I added some significant reinforcing to ensure it can handle the forces.

I am also part way through a modification of the hydraulic handbrake setup. The existing setup has a single master cylinder serving both rear wheels equally. The braking capacity was insufficient to overcome the grip of the rear tyres. The new setup will have dual master cylinders opposing each other with a handle in between the cylinders. Pushing the handle forward will operate the right rear brake and pulling it back will operate the left rear brake. Operating one of the rear brakes at the same time as some mild acceleration should enable the car to perform very tight turns when required (one of the requirements it has struggled to satisfy in the past). The car will retain the cable handbrake for parking and as an emergency brake. I have created the adaptor brackets required for the modification but I will need a full weekend to install system, rerun all the hydraulics and bleed the system.
 
The weight distribution being a little rear-biased would probably explain part of the understeer, and the lead weight should give some indication if that's the source of the problem. But as for four-wheel dynamics, I'm not the guy :)
Awesome that you've got a reliable rig though. Shame we didn't see it at the expo, but racing it that weekend is a fair excuse!
 
I have made some adjustments to the car. I still have some more to do. Here is the latest photo.
 

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I always figure you've got to be going pretty hard to get a good car racing photo. With motorcycles you can look well 'ard while barely getting a knee down :)

Seems to be running very reliably for you now?
 
jonescg said:
I always figure you've got to be going pretty hard to get a good car racing photo. With motorcycles you can look well 'ard while barely getting a knee down :)

Seems to be running very reliably for you now?

Yes thanks. It is quite good.

At first I thought the new hydraulic handbrake was a bust. But after persisting with it I started to get the hang of it. I'm still not fully on top of it but I was able to get it working most of the time by the end of the day. Car speed, power applied to the handle and timing the sequence of controls is key. The two things I need to work on are how motor power to apply while applying the brake and how much power to apply once the car is pointing in the desired direction. I think what was happening on Sunday was too much power while trying to apply the brake did not allow the caliper to stop the wheel resulting in the car understeering. But a pause of motor power while applying the brake allowed it to stop that wheel. Then a dab of power while still applying the brake operated the other wheel. Then when I am facing the desired direction I was finding an unusual amount of wheel spin before it would grip and take off. So I will need to revise my driving style to ease the power on in that situation.

Some generic improvements I need to make include some new rear tyres and an additional turn or two more caster. I have ordered another steering quickener. The current one is a 1.5:1. The new one will be 2:1. I think I also have some room for improvement on tyre pressures and the rear alignment wasn't quite right.

The event was a bit odd because it was basically a practice day and included both highish speed courses and very low speed courses. So I mostly set the car for the higher speed. So I think there is more room for improvement on the slow stuff.

For the real competition days there won't be a mix. Those days are either higher speed or low speed not a mix.

The next one is on April 14 and is low speed. So I can make some more adjustments to suit those courses. These temporary adjustments will include swapping back to the shorter nose, disconnecting the front sway bar, increasing the passive rear steering.
 
I had a great day at the 2019 Interclub motorkhana. The car was fairly good. I am starting to get the hang of driving the car in this latest format. The new hydraulic handbrake in particular takes some practice. I also think it works best once warm. I did have some issues knocking my switches in the heat of battle resulting in a loss of power. So I will make a cover to avoid this in future. I am waiting for the calculation of the final results but I am hopeful of a solid result, possibly my best ever.

I did capture some video but I am trialling a new camera and the results are not worth posting. I will need to do some more testing before the next event.
 
Well the results are in. I managed 7th from 44 entries. Not quite as good as I was expecting. Still respectable. I also managed 2nd in class, again behind the same competitor. I would have been 6th if I hadn't loaned my car to the 3rd place getter when his car died. The car is heading in the right direction and I have a few ideas for improvements. The next event is the Noosa Hill Climb early June so I won't be facing the same challenges.
 
Very cool stuff mate and glad the 'personality' of the car is generally to your liking.
I'm going through similar things albeit theoretically, that being the anti squat/roll/dive layout in the buggy as it currently sits.
You're not running a locked diff per chance? As this'd obviously have adverse affects on understeer.

The Pirate 4x4 and minibuggy.net forums have some great info on suspension set up that cover most types if you haven't discovered them already.

I'm afraid you'll have to rent out your brain for me to pick in the very near future!

Keep it up bro...this country desperately needs hi perf EV!!
 
Thanks mate. I am always happy to help. I have learned a lot around suspension and handling as a result of this project. I think I am past any significant suspension modifications. I am now down to tweaks and fine tuning. I don't have a "locked diff" but it is supposed to be a viscous LSD. I don't think the LSD function is overly effective in this diff. All in all the car is coming along nicely.

I am seriously considering entering the Mt Cotton Hill Climb on May 11.

I am a little nervous about CAMS saying they will have the first issue of EV specific rules later in the year. There is always a chance they could bring in rules that rule my design out. So I am keen to get as many events under my belt before then.
 
I had a great day at the Mt Cotton Hill climb on Saturday. My results were not all that impressive but quite respectable for a first attempt. I did end up in the Macadamia nuts (quite an effective safety barrier) on my second run. This event has made me realise the "understeer" issue I had been trying to resolve is gone and what I am suffering from now is actually a brake bias issue. On the successful runs during the day I was forced to brake very early for the tight corners and enter at rather conservative speeds. On the second run I left the braking too late for the brakes to handle and as a result continued straight ahead into the nuts. There was no damage to the car or driver apart from some dents to the ego. All in all it was a very successful day as I now know what is required to make the car more competitive. Here are a few photos from the day.59935951_2321590224746903_121309852331933696_o.jpg60414668_2321589608080298_9097743500417433600_o.jpg60058235_2321592084746717_5944682195946831872_o.jpg
 
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