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DC Plasma - Build Thread - 10Sec Fiero

74290 Views 95 Replies 17 Participants Last post by  John Metric
Nine (9) Second Fiero now

Well, I thought I would start a thread on my build as it is rather unique car. (and someday someone else may try to do the same crazy thing)
I documented the entire thing with pictures, that are all over in various locations, I will try to link them all in here if anyone has a specific request for a particular shot. This is the best video link
http://www.youtube.com/watch?v=5LR-BZcIuC0&feature=share&list=PLA3E4F9ED20798E34
I was originally going to build a Diablo kit and bought an Oklahoma car that had sat dead in Austin for a long time (17 years?) 88,000 miles Red 2M4 for $1000 on ebay. I finished thrashing the leaky 4 cylinder for about 30 minutes until the heads blew all the way through and the bulk of the radiator fluid got in the oil system. Right after that I spent 8 months in Alberta and watched them racing electric snowmobiles and became convinced that the off the line torque of an electric motor was tremendous. I then saw some electric car drag racing in Vancouver/Portland area and I was hooked. Very easily you can have sub 4 second 0-60 mph times and like my car we do 0-60 in 2.4 seconds with the drag radials.
I decided to build to the National Electric Drag Racing Association classification called MC which is Pro-Modified Street Conversion.
I also occasionally race in SCCA slalom racing courses but they haven't found a category for me yet.
From the beginning we targeted putting the batteries in the trunk do to the nice "water tight" nature of the compartment.
Our target was to beat the White Zombie at 10.25 seconds.
Here is one of the more recent shots someone took at the Texas Mile in Beeville TX.


you can see a video of the build here...
http://www.youtube.com/user...98E34/10/Hh_9irEYFJ8

Some of the main modifications:
Replacement of the engine cradle with a Lincoln Mark VIII rear end and suspension.

Removal of the gas tank and substitution of a slightly wider (1" each side) torque tunnel into which we inserted two Netgain Warp9 motors, each capable of sucking 400 battery HP. Fiero was amazing this way in that the large what looks like a transmission tunnel down the middle is the gas tank area (A lot of people are surprised to learn that) worked out perfectly for the motors. Everything is to the rear of the original front "firewall" so we can maintain "mid-engine" status.

Nearly direct coupled, (really a short coupled DANA Spicer 1350 driveshaft) the motors to the differential. Installation of a 1200HP Gear Vendors overdrive so we have two gears (really 1.5).
Installed a five point roll cage.

Firestone Air bag rear suspension
12" Corvette brakes in front by West Coast Fieros thanks Chris West
Two motor controllers, good to supply 425 battery HP to each motor by Cafe Electric
Controller cooling system
LiPo battery pack by Lithium Start 2400A 375V (peak ratings) 6P90S
LiPo Battery Management System by Elithion
KYB shocks all around
Sport Edition CD 16X7.5 wheels 5X100 on the front, 5X108 on the rear
BFG Drag Radials 255/50R16
Eagle GT's 225/60R16 for running around town and the slalom courses

Catchin some rear wheel air...on the slalom course in the Macy's mall parking lot in Hagerstown MD




Catchin some front wheel air at Houston Motorsports Park in Houston




More front wheel air at Royal Purple Raceway in Baytown Texas.




One of my favorite shots index racing in the 7.0 1/8th mile Brandt Nationals at Lonestar Motorsports Park in Sealy TX



Best times so far...
60ft 1.551
1/8 mile 6.321 112mph
1/4 mile 9.898 134mph
1/2 Mile 134.5mph
1.0 mile 155.0mph
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...I will have a new chart with a little more data using the Helwig brushes. I am putting up to 199V on each warp9 now....
Which reminds me... it would appear that in exchange for much higher zorch-resistance, the new Helwig brushes seem to wear down at an alarmingly fast rate* - have you noticed a lot more carbon dust around the brush assemblies since switching over to the Helwigs?




* - which I have dutifully filed under the category, "TANSTAAFL"
 

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Discussion Starter · #22 · (Edited)
Thanks for the detailed answer.
How much do you expect the 199V to push the peak power rpm out too?
I am not sure that I will find out with my current pack. 199V and 2000amps is 400kW or about 536eHP each motor. See below. You can extrapolate the charts below. perhaps 2500rpm???? I would be well into the nines there and my car will need a major overhaul, roll cage, certification, parachute, competition license, etc....
Another point, I have been finding that the higher my voltage MV setpoint, the quicker I go up in rpm. For example. I can just get to 199V by the end of the track and the car is still accelerating like mad. See data below.

http://www.youtube.com/user/dcplasmaracing?feature=mhee#p/c/1/fIkIWUOEByQ
This has the seat of the pants feeling of actually moving the peak power point up rather than to the right. As I went from 170V to 180 and 190 I found the shift point around the same rpm. I just get there quicker. It may have something to do how the zilla approaches peak voltage.

Some cars, reach their peak voltage and peak rpm about the same time.
Some cars reach peak power at a point well below peak voltage. For example, here is Waylunds latest curve from mid '10, showing he doesn't reach peak power at peak voltage. Raising his peak voltage wouldn't help with his peak power point.




You can see his peak power is limited by battery sag around 3300rpm. My pack is now suffering at this point as well. My power curve would like to continue up and to the right but I truncate this by controlling the LBV setpoint in the hairball.
I project that if I let the pack sag a bit more or I add some more batteries (26Ahr now) I would push the peak power point up rather than to the right. If it does go right maybe 100rpm? Near the the same 3200rpm as Waylunds Impulse9s. Except we will be making around 850 battery HP at that point.

I would like to re-clarify the dyno sheet projection was using real data, was the input to the motor not the output and theoretical knee point with unlimited pack and controller. I am there with one motor, one zilla and my pack. When I use two motors and the overdrive, my pack is starting to show its limits, and I am below the knee point near 2800rpm. I was trying to create something that was truly only the motor limits. For real life, the peak rpm knee on the Warp9 motor dyno sheet may be closer to 2800rpm.
 

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Discussion Starter · #23 · (Edited)
Which reminds me... it would appear that in exchange for much higher zorch-resistance, the new Helwig brushes seem to wear down at an alarmingly fast rate* - have you noticed a lot more carbon dust around the brush assemblies since switching over to the Helwigs?
* - which I have dutifully filed under the category, "TANSTAAFL"
No extra dust, probably vaporizing it, but if you look at the difference between power output between the top two lines, 170V and 190V figures, it doesn't seem in line. I don't think all the extra power is going into the driveshaft, I would say I am making about 50eHP in heat at the brushes. In my favor, with the overdrive, I am only at 4100rpm at 128mph. I have a viewing window into my motors while racing, I have yet to see any arc flare brightening the cab(I mostly race at night). I am thinking of putting a camera on them during a run.
 

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Discussion Starter · #24 ·
We will be racing against Shawn Lawless S11 Lemonjuice on Thursday at Bradenton Motorsports Park, FL. You may witness the fastest EV race of all time between two electric conversion cars.

We are racing Pro-Modified Street Conversion. Both currently 333V. he has run a 9.8 I have a best time of 10.4

I will try to let it all hang out and see if we can take him.

Metric
 

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Discussion Starter · #25 · (Edited)

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Discussion Starter · #26 · (Edited)
Here is the run chart for the 9 second run.
We made a peak battery HP of 862
We crossed the line at 134mph and 4300rpm (torque calculation is based upon inputs and needs to be multiplied by estimated motor efficiency to get motor output torque.)


 

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Re: DC Plasma - Build Thread - 9Sec Fiero

holy shit you launched like a bat out of hell! The Fiero just took off!
Solidly into the 9's, wow congratulations John.



Can you help me read the graph and say why the Zilla data is adding up the motor amperage (4000A) but not the motor volts (only 200V)...Unless motor volts are on the secondary axis on the right-side of the graph...
 

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Discussion Starter · #30 · (Edited)

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Discussion Starter · #31 · (Edited)
Re: DC Plasma - Build Thread - 9Sec Fiero

Can you help me read the graph and say why the Zilla data is adding up the motor amperage (4000A) but not the motor volts (only 200V)...Unless motor volts are on the secondary axis on the right-side of the graph...
This chart is a summation of two zilla logs.
The two motors are in parallel, with each zilla providing power to one motor.
The motor volts are limited to 199V, that doesn't add together. There are actually two voltage lines nearly on top of each other, but I hid one to make the chart a little clearer. But the current is 2000amps each and that does add together for 4000 amps total.

The other tricky thing is the motors make 4000 amps (2kX2) and about 170V when the pack is around 250V and 2500Amps.

I had the battery limit here set at my previous setting of 2500 Amps. I will try 2800amps next (approx. 90C factory rating)
Also, I am tempted to play with the 199V setting.


Metric
 

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Discussion Starter · #32 ·
Re: DC Plasma - Build Thread - 9Sec Fiero

holy shit you launched like a bat out of hell! Can you help me read the graph and say why the Zilla data is adding up the motor amperage (4000A) but not the motor volts (only 200V)...Unless motor volts are on the secondary axis on the right-side of the graph...
It is also not adding the torque calculations together, I just noticed.
That is the calcs(pre-motor efficiency) for one motor.
 

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Discussion Starter · #34 ·
Great run.
Can you comment on the current dip at about 1.5 seconds? did you lose traction?
Also, can you PM me the raw data for further analysis?
Gerhard
Yes, that is a bad habit of mine, I lifted my foot around the 60 foot mark because at my home track in Baytown, that is where you switch from a deep concrete slab to a shallow one and the dew builds up there and I have broke traction at that exact spot DOZENS of times. So I tend to lift a little there to try to get through that area. You can see this on the line labeled "pedal" where it drops from 100%. I also slightly lift the pedal during when I am looking down for the overdrive shift button. I have already broken one pedal due to bracing myself for the acceleration by standing on the pedal so now I have this ultra light touch on the plastic.

I will send the hex dump if you want. Can you interpret it?
 

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Discussion Starter · #35 ·
Great run.
Can you comment on the current dip at about 1.5 seconds? did you lose traction?
Also, can you PM me the raw data for further analysis?
Gerhard
Here is a run chart of what a traction break looks like at that exact spot from mid summer. Followed by one without.


 

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Discussion Starter · #39 · (Edited)
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