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Forum Index : EV's : Aussie Electric khanacross special

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galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 03:01am 05 Feb 2018
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I had a good weekend, but not quite good enough. I beleive I will fall just short of having the car ready for Sunday Feb 11. Which means I will be looking for another way to do a high speed shakedown (100Kmph) of the car before the first event on March 4.
 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 06:44am 27 Feb 2018
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Hey everyone.

I finally got the car running. Which means I am fairly sure I will be competing in the Khanacross this Sunday. The car is untested and untuned so I wouldn't suggest it will be the fastest on the day but hopefully I can start to dial it in after the first run or two.

On my driveway the car feels really good.

 
Boppa
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Joined: 08/11/2016
Location: Australia
Posts: 814
Posted: 04:34pm 02 Mar 2018
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fingers x'd I'll be there (galderdi you have a pm...)
 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 01:24am 05 Mar 2018
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Well the event was good. But it did reinforce why a practice event would have been an advantage. The car understeers severely and the front brakes lock on anything more than a slight touch. I also blew a fuse part way through my first run.

I went for an extra run after the timing was finished for the day. It was oversteering as normal but then it suddenly gripped and snapped the back around unexpectedly. I over corrected and speared off into a culvert. It made for some gread video though.

I have some work ahead of me to somewhat neutralise the handling.

https://www.youtube.com/watch?v=kT7YvMQiqQY

https://www.youtube.com/watch?v=8lZK1kgPxh8
 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 03:39am 05 Mar 2018
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I managed 24th place outight. On the surface that isn't too impressive. However that included my first run where my fuse had blown. If I just take that run out of the equation I would have placed 10th outright. So for it's first outing I am fairly happy with those results.

Now I just need to work on the brake bias and understeer to move my way up the standings toward the podium.
 
joebog1
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Joined: 07/11/2015
Location: Australia
Posts: 114
Posted: 05:57am 05 Mar 2018
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HHmmmm, I dont know too much, but looking at the wear pattern on those front tyres I will ask two questions
1: How much toe out are you running ?
2: What camber have you set?

The inside of the rubber is worn way down after only a couple of runs.

You are allowed to slap me if I am out of order!!

With my best wishes for a cure
and my best regards for your efforts

Joe
 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 02:57am 06 Mar 2018
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No need for slapping. I am happy to take on board any suggestions.

Although I am not seeing the inside wear you mentioned.Could it be an illusion from the video? The current camber is next to nil. I am seriously considering adding some negative camber as part of the remedy.

I did a rough wheel alignment and believed it to be 0 toe while resting. But I will check it again. Plan to add a touch of toe in anyway, as part of the remedy.

I wish I had a test facility.

My plan includes:

Adding a second aux battery out in the nose.
Softening the front suspension
Adding a touch more negative camber to the front
Speeding up the rack
Adding some more caster
Adding some toe in
Checking and adjusting the ackerman angle
Adding a brake bias adjustment for the front brakes
 
joebog1
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Joined: 07/11/2015
Location: Australia
Posts: 114
Posted: 04:02am 06 Mar 2018
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It could be an illusion from the video!!.

I was a reasonably "fast" runner in a basically stock Alfetta GTV 2 litre.
I had under steer, and it was a result of toe settings, along with tyre pressures.
I know that you already have plenty of experience with tyre pressures, but as you have a very light front end, try a few pounds less.
Another thing I noticed in the video ( and this COULD be camera angle/field of view )
the "inside" wheel is always far ahead of the other, so maybe check the castor.
Add some negative camber, it can only cost a little rubber with increased wear.
Camber is a "magic" thing!! in itself it is an art. I ended up with 3 degrees, wore the tyres but went round corners on rails.

Is your rubber new ? If it is dried up and hard as bakelite it can cause HUGE troubles, consider having them buffed.

I really dont like adding a battery up front, to be nimble you need be light on your feet. Adding weight will make the understeer worse, that brings me back to tyre pressures, age, toe and castor angle.
I offer all these as suggestions only.

My best wishes

Joe

P.S. Dont be too proud to ask an expert at the track!! I have been given lots of advice from people you would never expect to have any idea at all.
SOMETIMES the advice can be negative, but always keep an open mind.
jb
 
joebog1
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Joined: 07/11/2015
Location: Australia
Posts: 114
Posted: 04:47am 06 Mar 2018
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Hmm I just been thinking on what I have already said!!. All really basic stuff, sorry.

Have you got stiffer springs for the rear? Try fitting them.
Can you increase ride height at the rear, OR reduce ride height at front?
Do you have a stiffer anti roll bar for the rear?

As a last resort run a little toe out, say 3mm ( 1.5mm a side).
When doing ALL suspension setups ( even in a road car) I load up the car with concrete blocks to simulate the drivers/passengers weight!! Dont laugh!! it works.
If you sit to the left or right then setup the blocks to simulate WHERE you sit.
Are your shocks adjustable ?? Reduce compression damping, and maybe reduce recovery time.

j.b.
Edited by joebog1 2018-03-07
 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 01:51am 07 Mar 2018
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Don't be sorry. The more conversation I have the more ideas I get.

Prior to the event I thought having very little static camber would be a good starting point. But now having seen the results I can see I need more negative static camber. I think this will be the key change.

I don't want to make anyting stiffer as our venues are fairly rough. The car was already throwing me about fairly badly. So I think making the front a touch softer is a much better option.

I do plan to lower the front a little. But I suspect I can only go a bout 10mm before I will start havign clearance issues under brakes as the nose dips.

Raising the rear height is not so easy but I will work out my options there too.

I don't have any anti roll bars installed at the moment. I had a custom bar made for the front which only arrived yesterday. Obviously putting it in the front would be a mistake. But I will see if there is a way to make it work in the rear.

The extra Aux battery is only about 7Kg so its not like I am totally altering the dynamics of the car. Plus I am not even sure if there is sufficent space for it so I don't know if I will proceed with that change.

I do compete with a few people who know what they are talking about. But as I mention I am grateful for as much conversation as possible. Your suggestions align with the other suggestions so it gives me confidence that I am receiving sound advice.

The results from the day also give me confidence. Aside from the fuse blowing I would have been 10th outright with a poorly handling car. So when I get it to handle well it should be right up at the pointy end.
 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 06:27am 07 Mar 2018
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Oh, I also have to say I get very few truely negative responses. The responses I have had have all either been pure praise or constructive suggestions.

The only exceptions have been on my test video from a week ago and that was about the video/editing not about the car.
 
Boppa
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Joined: 08/11/2016
Location: Australia
Posts: 814
Posted: 06:41am 07 Mar 2018
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  galderdi said   Oh, I also have to say I get very few truely negative responses. The responses I have had have all either been pure praise or constructive suggestions.

The only exceptions have been on my test video from a week ago and that was about the video/editing not about the car.


LOL- sure...
forget about improving the car- spend more time editing videos....



NOT!!!
 
Boppa
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Joined: 08/11/2016
Location: Australia
Posts: 814
Posted: 06:50am 07 Mar 2018
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Im just wondering if a bit more weight in the front mightnt improve the steering, I know the fiberglass vw buggies used to have horrible steering in the front, especially with wide tyres in the wet, they simply didnt have enough weight to allow the tyre to grip well
We picked up on that when they had a full tank of fuel, the handling was better and it gradually worsened as the tank emptied

Have you tried doing a weight distribution check on each tyre? ie front/back balance?
 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 12:30am 09 Mar 2018
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Thanks Boppa.

That test video was pretty bad in hindsight. I just posted it without editing because I was so happy to finally have the car running.

Yes I agree more weight in the front may be part of the solution. All the changes will be a matter of striking the right balance. I am fairly hopeful there will be sufficient space to add another Aux battery in the nosr. It will only add about 7KG but in combination with all the other changes it could be enough. Only time will tell.

I have done a front to back weight check. But not on each wheel. The distribution is/was 44/56 (without driver). With driver I beleive it is more like 40/60.

Adding the extra battery would change the figures to something like 45/55 (without driver) and 41/59 (with driver).

 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 04:18am 19 Mar 2018
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Just a quick update. During the first outing the new car demonstrated noticable understeer, front brake lockups, slow steering and slightly reduced launch speeds. All of these were expected at this stage in the development.
•The understeer and front brake lockups are due to the lack of weight over the front wheels.
•The reduced launch speed was because I have not yet installed a clutch pedal and master cylinder resulting in the need to launch in a higher gear.
•The slow steering is because I have not yet modified the steering to speed it up.


I can't do too much about the weight distribution, although I have added a second auxillary battery in the nose. This adds another 7kg to the front of the car.

This past wekend I altered the front suspension pivots to substantially soften the front. I added some more caster and some more negative camber to the front both of which should increase front grip during cornering.

I still need to:
•Reinforce the panels around the brake pedal to give a stiffer feel
•Add a brake bias adjustment to send more pressure to the back brakes and eliminate the front brake lockups
•Add a steering quickener to speed the steering rate
•Make and install a hydraulic clutch conversion
•Finish and install the replacement handbrake handle
•Make an adjustment to the ackerman angle

The first 5 of these modifications must be complete before my next event on April 15th. I will provide another update before then.
 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 03:39am 05 Apr 2018
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I still have some fairly significant adjustments to complete. I have made some progress but have stumbed on a few items like having a bolt stuck in an awkward spot and needing to "easy out" it. Plus this little issue has meant I needed to order in some replacement bolts. I have also had some clearance and width issues etc with the latest steering rack. I have finished the new handbrake handle. I have also finished the brake bias except I have not filled the fluid, adjusted or tested the system (due to the missing bolt).

I only have one more weekend to sort it all out before my next event. The next event is a motorkhana on Apr 15. Followed by a khanacross hosted by the Lotus club on Apr 29. The lotus day in 2017 was my favourite event so I am really looking forward to this day. But I really need to have the car dialled in to have a good showing. There will be some top end Lotus and Porsche cars competing so I will be very happy with any place in the top 25% of the field.
 
galderdi
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Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 01:23am 16 Apr 2018
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My car was a real handful. I had run out of front steering adjustment during the wheel alignment last week. This left the car with significant Toe in on the front. This made it very twitchy and added to the understeer issues. It also became quite clear the handbrake will not be able to break traction as there is too much weight over the rear wheels. This isn’t an issue for the sweeping style tests but for the tighter ones it makes it very difficult and uncompetitive. You can see this in the 5th video. On the positive side the car’s acceleration was awesome as you will see in the 3rd and 4th videos. Plus I can now see that solving the steering properly may make all the difference to the car.

So the short term plans are:
• Complete the Ackerman angle modification and shorten the steering arms prior to the Lotus Lakeside day on April 29.
• Connect the Clutch pedal so I can change gears for the Lotus Lakeside day on April 29.

Long term:
• Make new upper control arms for the front to provide more caster adjustment and improved range of movement.
• Install fiddle brakes to enable separate left and right braking to swing the car around the really tight corners.

The results from yesterday will probably be released tomorrow morning.


 
galderdi
Regular Member

Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 01:25am 16 Apr 2018
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https://www.youtube.com/watch?v=DHDBpP9fx3Y
https://www.youtube.com/watch?v=uJMca1QEMbk
https://www.youtube.com/watch?v=LqZEdE8aJNc
https://www.youtube.com/watch?v=-zyv8UilDqs
https://www.youtube.com/watch?v=7PaeTOUMCXo
 
galderdi
Regular Member

Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 03:16am 20 Apr 2018
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I placed 21st of 55 competitors (excluding those who did not complete the day). All in all it is obviously not what I had hoped for. But I did manage to beat 6 of the 11 Porsche entries. The result was to be expected considering how bad the understeer is. Plus this is only the second outing for the car so I think it is doing ok considering the stage of it's development. I have a heap of modifications planned for the next 10 days before the next event on April 29. Hopefully I can get the car turning by then.
 
galderdi
Regular Member

Joined: 12/08/2016
Location: Australia
Posts: 99
Posted: 11:32pm 29 Apr 2018
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I had a ball at the Lotus day at Lakeside yesterday. The car was very unstable and not quick. But the main purpose was another opportunity to test the car. The great news is I have gone from massive/uncontrollable understeer to massive/uncontrollable oversteer. This is great because it proves that I can overcome the handling issues and eventually make the car competitive in the autocross/khanacross events at least.

I did have to retire early with a split CV boot. Not a big deal as I already had plenty of information to work with.

Even with the handling issues I managed to place 36th from 55 cars. So I am confident with a few tweaks I can be dicing with the leaders in no time.

https://www.youtube.com/watch?v=AA7EVYUd6F8
https://www.youtube.com/watch?v=V2hsGr94Gb4
https://www.youtube.com/watch?v=rZOJEE3YC-U
https://www.youtube.com/watch?v=lTcVFKXH0Lo
https://www.youtube.com/watch?v=OTfyEgYMCpU
 
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