DIY Electric Car Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter #1
I recently started considering an electric conversion for my '96 Mark VIII, which has been my project car and casual autocrosser for the last few years.

A bit about the car:

Currently, the car has the original 32-valve 4.6L V8, with some light mods, such as headers/2.5" exhaust, 96-99 Cobra intake manifold swap, underdrive pulleys, and a tune. Oh, and 325,000 miles.

I had been building up the car to put a Vortech blower on it. I had swapped it from auto to manual transmission with a TKO 600 five-speed and re-geared the rear end from 3.27 to 3.73. I initially installed a Ford Trac-Lok (clutch type) limited slip, but am currently running an Eaton TrueTrac torque-biasing unit.

Despite what most people think when they see the Lincoln, it's actually quite a good platform suspension wise, with short-long arm front and rear. With a bit of fabrication, I've been able to get very aggressive with alignment, fit 285 width tires, and run 14" front brakes from the more recent Mustang GT500s. The only downside is the weight; without me in the car, and about half a tank of gas, it's a hair below 3700lbs, after the transmission swap and some lighter seats.

My goal with the Vortech was 450-500hp/400-450ft-lb, which is right at the cusp of what a stock 4.6L crank and rods can handle. With that and the mileage, I was looking at rebuilding the 4.6L. Don't know if any of you have gone down that road before, but those engines are incredibly expensive to rebuild, when you start looking to make big power.

Then, a couple of weeks ago, the fuel pump died when I was leaving work, and I got to thinking about converting. The coworker who gave me a ride home drives a Leaf and that seemed like a sign. We already have a 2012 Volt, that we bought a year ago and are extremely happy with.

So, I'm rolling the idea around in my head and trying to get a preliminary plan together. Here are my goals, in order of priority:

1. Comparable acceleration to a 500hp 4.6L, say around five second zero to sixty
2. Keep the manual transmission for the fun/driving engagement factor
3. Make it legal in North Carolina
4. ~50 mile range
5. Top speed of ~80mph; I don't plan on drag racing and pretty much never exceed 75 in this car
6. Keep the weight under 4000lb. This seems reasonable, since the engine is around 550lb, and I imagine I can drop another 100-200lb between the fuel tank, exhaust, back seat, and other ancillaries. Should give me close to 1000lb to play with.

I primarily drive the car to work a couple times a week in the spring/summer/fall, do a few autocrosses a year, and take some fun drives out in Pisgah National Forest every now and then.

It seems like #2 and #3 pose the most potential challenges; based on reading around this forum, about White Zombie, and some other conversions, it seems like the torque-speed characteristics of DC motors drive most people toward direct drive or two-speed auto transmissions, and those that keep their manual transmissions wind up ignoring first and second gear altogether. It seems like the key to keeping some amount of ICE-like shifting is running a high enough voltage that it makes sense to wind the motor out to 5000+rpm.

So, based on what I can gather, it seems like a WarP 11 HV with a battery pack capable of supplying at least 240VDC and 1200-1500A, and the corresponding controller, make sense to get to around 400+ft-lb and keep the motor making power at high enough speeds that some shifting still makes sense. Using DC seems like the simplest path to get to where I want

I understand that this will take time and money to do; I see it being at least a two year project to spread out the cost. Fabrication doesn't scare me; I've done FWD and RWD auto-to-manual swaps and engine swaps that required fabbing up mounts, made my own control arms, etc. I've dealt with making OE PCMs work with said swaps, so I have no problem with wiring and do have some rudimentary electronics knowledge. I'm a design engineer at a major turbocharger manufacturer with a mechanical engineering background, so really, the electrical engineering, drivability, and legal parts of this are the most daunting.

So, that's a lot of words about me and my dumb car. Here's the feedback I'm looking for:

1. Are there any conversions out there that retained manual transmissions with some semblance of ICE shifting behavior?
2. Is my initial suggestion of a W11HV with 240V/1200-1500A on the right track or should I be looking elsewhere? Open to anything here, as long as it's easily adaptable to a TKO 600.
3. Does anyone have experience legally titling/registering conversions in North Carolina, particularly for '96+ vehicles in emissions counties?

Thanks!
 

·
Administrator
Joined
·
6,111 Posts
Suggestion
Rather than pay for a Warp 11 - just get an 11 inch forklift motor and advance the brushes

They go for about $200 here

Also that is a BIG car for an 11 inch motor - If I was doing it I would use two or even three 11 inch motors joined together end to end and throw away the transmission - it's so much easier to just connect to a propshaft - you could still get the "Gearbox" feel by engaging the motors one at a time - actually NO - you would want to engage all three at once

Batteries - you want modules from a production EV - "New" Lithium batteries are a lot more expensive and much lower quality

My car is a lot lighter than yours - 805 kg

https://www.diyelectriccar.com/forum...ghlight=duncan

I did 0-93 mph in 7.90 seconds at our last 1/8th mile drags
 

·
Registered
Joined
·
4,779 Posts
1. Are there any conversions out there that retained manual transmissions with some semblance of ICE shifting behavior?!
The majority of DIY conversions retain the original transmission, or swap in a similar manual transmission (changing only to get rid of an automatic, or for greater strength and durability than the original, or for adapter availability). Recently, the trend has shifted to using salvaged production EV drive units, which means using not only the motor but the transaxle that goes with it... which is always a single-speed; however, not many conversions of this type are actually completed (you could probably count the ones in this forum on your fingers).

For a recent discussion of the use of a manual transmission, see Ford and Webato unveil all electric Mustang at SEMA 2019.
 

·
Registered
Joined
·
10 Posts
Discussion Starter #4 (Edited)
Hey, guys, thanks for the replies! I thought the forums had eaten my thread, and hadn't been checking back. I've taking the advice, and my plans/goals are now more aligned with Duncan's suggestions, though it is really important to me to keep the manual trans. The plan now:

-Shoot for max speed of 4500-5000rpm with 300ft-lb available through as much of that speed range as possible

-Find an 11"+ forklift motor and advance the brushes
-Find a salvage fist gen Volt battery pack

Seems like the hardest part here will be fabricating an adaptor to go from whatever the motor mounting config is to the 4.6L bellhousing pattern and adapting the shaft for the flywheel/clutch. I'm hoping I can find a motor with a shaft large enough to turn down and key so I can avoid having to deal with splines.

I'm still not resolved a controller; based on some back-of-the-napkin math, if I want to have the possibility of hitting 300ft-lb at 5000rpm, assuming I wind up running ~150 motor volts, I'll need a controller capable of supporting ~1500A at the motor.

Or, looking at it in terms of power, 300ft-lb at 5000rpm is 285hp, what is about 215kW. So it seems like the lowest-cost option that might support what I want is the Soliton 1, assuming that it can support 1500A to the motor for brief periods. I also really like the idea of building my own, for the experience and education, but this seems risky for obvious reasons.

And this is where my knowledge starts to run out and I get a little confused. I understand in principle that a motor controller is basically a buck converter, which reduces voltage and increases current relative to that supplied, using the motor as the inductor. So, when a controller like the Soliton says 1000A/300kW, does that mean battery amps or motor amps, or does the general principle of the buck converter increase current not apply here for some reason?
 

·
Administrator
Joined
·
6,111 Posts
Hi
Controllers drop the motor voltage so the motor current is as demanded

If you have set your controller to 1000 amps - and you are on half throttle the controller will deliver 500 amps

Motor volts x motor current = battery volts x battery current

Couple of flaws in your proposal
As motor rpm rises the back EMF goes up and you need more volts for the same current

1500 amps is far too much for continuous on a forklift motor - mine is rated at 208 amps - more speed means more airflow which means more current is OK - but not that much

My motor needed 110 volts to push 200 amps though it at about 3500 rpm

Even with my current 340v setup the current is dropping off before 3500 rpm

If you have any thoughts about building a controller look up Paul & Sabrina - and send Paul a message - he will sell you a board and instructions

I learned a TON in building my first controller (and in blowing it up)
 

·
Registered
Joined
·
4,779 Posts
-Shoot for max speed of 4500-5000rpm with 300ft-lb available through as much of that speed range as possible
...
I'm still not resolved a controller; based on some back-of-the-napkin math, if I want to have the possibility of hitting 300ft-lb at 5000rpm, assuming I wind up running ~150 motor volts, I'll need a controller capable of supporting ~1500A at the motor.

Or, looking at it in terms of power, 300ft-lb at 5000rpm is 285hp, what is about 215kW. So it seems like the lowest-cost option that might support what I want is the Soliton 1, assuming that it can support 1500A to the motor for brief periods.
"As much of that speed range as possible" will be from stall (zero speed) to only a fraction of the peak motor speed, because you'll run out of voltage.

Yes, 300 ft-lb at 5000rpm is 285hp, or 215kW. The problem, as Duncan mentioned, is that it will take a lot of voltage to push enough current to produce that torque through the motor against back-EMF at that high speed. When the controller is full-on, it is basically just a closed (on) switch, so output voltage and current are the same as input voltage and current; if you could ever get 1500 amps through the motor with a supply voltage of 150 V, it will be a much lower speed than 5000 rpm (and presumably more than 300 lb-ft of torque, but remember that electrical power into the motor does not equal mechanical power out of the motor, because it is far from perfectly efficient, especially at high current).

And this is where my knowledge starts to run out and I get a little confused. I understand in principle that a motor controller is basically a buck converter, which reduces voltage and increases current relative to that supplied, using the motor as the inductor. So, when a controller like the Soliton says 1000A/300kW, does that mean battery amps or motor amps...?
Rated controller current is motor current. The power limit is likely just the product of current and voltage at full-on (when input and output are about the same), so this 300 kW limit would be reached only if the motor characteristics and motor speed lead to 300 volts causing 1000 amps to flow through the motor.
 

·
Registered
Joined
·
10 Posts
Discussion Starter #7
Gents, thank you again for setting me straight. In my mind, I was simplifying everything to P=VI, and thinking that I could calculate the power required for the torque target I wanted at the speed I wanted, then calculate the current required based on an assumed motor voltage. A gross oversimplification!



So, what I really need to know is the current required to produce a target torque and the voltage required to to drive that current at a target speed, correct? I am guessing that these things are just about impossible to find for random salvage forklift motors, short of having your own dyno to measure. I've tried doing some searching, and this stuff doesn't seem to be easy to find even for the purpose-made DC motors like the Warps.



Seems like the most reasonable way to proceed is to build/buy as much controller as I can, advance motor brushes as much as seems sane from reading around here (10-12°?), run as much voltage as seems sane, and see what I get. All with the understanding that the time I can spend at 1000+ amps is going to be a matter of seconds, even with some extra forced air cooling. If I'm not happy with the result, then it's time to look at tying two motors together or a Warp 11HV.


Is Paul still active on here? When searching, it seemed like a lot of the info about their kit was from about 10 years ago. I was also looking at ZEVA's page and the controller projects they did. Seems pretty straightforward from the hardware side; it's the programming side and protecting for failures and runaway conditions that makes me nervous.
 
1 - 7 of 7 Posts
Top