Monthly Archives: September 2014

Mustang Project – Week 1

Much tinkering was done. This week I placed an order for an [ingersol rand impact drill and the associated hardware]. While waiting for that, I began work on the vehicle body. I started fabricating the front bumper (note I’m building the chin spoiler separately). I completed the bumper’s shell and should only have to reinforce/layer the part in order to get it into working shape. I also removed the radiator and began shaping the hood.

Lesson learned this  week: fiberglass burns! Don’t dump it on yourself (it also turns your jeans into plastic)

Tools used this week:

  • Dewalt Power Drill
  • Orbital Sander
  • Fiberglass Kit
    • Respirator
    • Fiberglass cloth (6oz)
    • Bondo Resin
    • Cheap Brushes
    • Fiberglass Roller
    • Latex Gloves
  • Molding Clay (terra cotta)
  • Insulation (blue) foam
  • Various Screws

The Endeavor

Fiberglass’d

I began by ripping the bumper off with a ratchet. I think it’s safe to discard. It looks bad, is heavy, and I’m not sure it’s structurally necessary. The front pegs it was attached to are still there providing support. Furthermore, once I remove the engine, the engine compartment won’t need as much protection… I think. Anyway it will look cool!

bumper

Next I began work on the replacement bumper. Originally, I wanted to build the whole thing out of clay to form the mold, but that turned out to be prohibitively heavy. The bumper came apart under its own weight, dang gravity!

For my next attempt I purchased [insulation foam] from Lowes. I used this with my [power drill] and some hardware to build the shape. I then sanded it down to allow the clay to better grip the surface. Finally, I covered the thing in clay to form the final shape.

clay_bumper

I now covered the thing in aluminum foil, waxed the foil with a mold release, and applied resin. Next I chopped up the fiberglass cloth and began layering it. I waited for the first layer to be about halfway dry before adding the second, and I applied additional resin after each layer. I only layered it twice for now to give the piece a semi-rigid form but will add additional layers to get the part to where I want it.

Bumper_Fiberglass

The final step will be to sand it until happy. I’m also not sure what it will look like until after I add the chin spoiler so I intend to fabricate that before going much deeper into the weeds on the bumper itself.

Other Work

I ripped out the radiator:

under_the_hood

And I began working on the hood mold:

clay_hood

Alright! That’s all for this week. Next week I should be receiving my air drill, and I intend to buy an engine hoist. The plan is to finish the hood, drain the engine, and get the engine out! Lots of work gotta get ‘er done!

Mustang II Conversion – The Body

In this second post about my 1976 Mustang II project I’m going to discuss the vehicle’s body, and the modifications I either have to or want to make to it. Most people hate it, but the 70s Mustangs are my favorite in the long line of pony cars. Whilst trolling the Internet for sexy hot rods, I stumbled upon this saliva inducing beauty put together by the folks at A-Team Racing. I’m using that vehicle as the reference and target for my own project. Note that not only do I have absolutely NO experience working on cars or with composites, but I also do expect to spend most of my time stepping on my tail and failing. Best way to learn right? At least I’m realistic…

Conversion

Rough Design

The vehicle I’m starting with has some significant bodily differences from my target so I did a quick mockup of what the vehicle should look like before and after. This allowed me to really get a feel for how large the project I’m taking on actually is. It’s pretty big…

Slide2Sorry the bottom image didn’t scan well. I’ll try to spruce it up in the future.

You’ll notice that the biggest issue is that hatchback problem. My donor vehicle is a notchback, not cool. The part that I’m most worried about there is the glass. I intend to fabricate the rear panel out of fiberglass and use a lexan sheet for the window. I think I can drill holes through these layers and bolt them together, then grind off the bolts and fiberglass over top of them to get a smooth finish.

Fabrication Plan

The basic idea is to pull off most of the body panels and replace them with fiberglass replicas. This allows me to cut weight while also giving me the opportunity to adjust the vehicle’s appearance to better suit my ego.

Here’s the general layout of my plan:

  • I will be using foam to build the general shape of the body panels
  • I plan to overlay that with clay in order to mold a more defined shape
  • Next I will cover that with aluminum foil and spray it with a releasing solution
  • Then I plaster fiberglass on top of that and let it harden into the part
  • After reinforcing the piece I should be done

In some cases I may have to take the positive and pull a negative form off to get the actual desired shape, but that is generally speaking what the process should be to build virtually every part of the car… I hope…

Let me know where the wrinkle is in my plan! No, it’s not the whole plan, Jeez!

Mustang II Restoration & Conversion

I’m beginning a new project and this one is a touch out of the ordinary for me. I know absolutely nothing about cars, but I’m going to be taking an old 1976 Ford Mustang II, modernizing it, restoring it, and converting it to electric power or die trying.

My first objective is to establish the technical requirements for my project. The purpose of this vehicle, once built, is going to be taking me to and from work on a daily basis; however, I would like to maximize the vehicle’s acceleration where possible in order to yield a more pleasurable driving experience.

1310-1978-mustang-ii-evolution

Dialing in the Project Requirements

My daily commute is 16 miles each way. I want to have at least a 30% mileage buffer but would prefer a 50-60% buffer due to additional battery drain caused by auxiliary systems like HVAC, the stereo, power steering, etc. This all totals out to:

Range Calculation:

Screen Shot 2014-09-14 at 9.19.49 AM

This means my minimum range is 42 miles, and my target range is between 48 and 52 miles from. The next step is to determine how much power it will take to drive my car each mile. This metric is known as Watt-hour per mile or Wh/mi. This number can be extremely difficult to determine prior to producing the finished product. It is further muddled by the driving efficiency over speed curve. That is to say my base requirement is a function of the vehicles weight and aerodynamics, but my electric motor will also have a different efficiency based on the speed I am traveling at and the gear ratio of the vehicle’s transmission/rear axel. This means that I have to begin making assumptions and over-engineering my system in order to develop an adequate product.

The most important controllable variable in this equation is the vehicle’s weight. 1973-1978 Ford Mustangs had a gross curb weight of anywhere between 2600 and 3400lbs based on the year model and trim package. By ditching the major vehicle components required for an internal combustion engine (ICE), we shed a bunch of the car’s flab. My donor car is a 1976 notchback body style 2.3L v4. This makes it a muscle car wussy! Fortunately for me, it also makes it one of the lighter Mustang IIs weighing in at 2600lbs. The vehicle also suffers from some rust and is in need of a facelift so I will be constructing my own paneling out of fiberglass and carbon fiber. These modifications should allow me to shed additional weight over the existing sheet metal.

Component Weight
Engine 400
Exhaust System 200
Fuel Tank 50
Sheet Metal 150
Total 800lbs
New Weight 1800lbs

This is of course just the vehicle’s weight without the new electric drivetrain and batteries to propel it forward. Once I factor those pieces in the car will be much heavier, though still lighter then it was as a stock ICE. Since we won’t know how much battery we need until we solve for wh/mi and we need the to know vehicle performance data in order to calculate that we will make some assumptions. Wh/mi for most light vehicles tends to be around 250-300 and for small trucks it is 350-400. I was able to find that amp draw for a small miata is 90amps at 50mph. We will use this number as our low end. For our high end, since the Mustang II will be much heavier we will assume 170amps at 70mph. For all of these calculations we will assume a 144V battery system, though our file setup might differ. We’re just eyeballing and overestimating here.

Range Calculation:

Screen Shot 2014-09-14 at 8.52.25 PM

The last thing we need to do is solve for our power requirements. In order to preserve the lifespan of our batteries we must factor in a depth of discharge (DoD) limit. If we deplete our cells by greater then 80% it will greatly shorten the life expectancy of the EV. This means that we will need an additional 20% on top of our power requirements. For this conversion I will be using lithium ion batteries (LiFePO4). However, if using lead acid batteries it is important to also factor in the Peukerts effect. This effect causes lead acid to output at only 55% efficiency meaning that we need almost twice as much power for the same effect. All right! Power is in watts so let’s solve for it!

Power Requirements:

Screen Shot 2014-09-14 at 9.24.22 AM

Value Power Requirement DoD Factored
Minimum Power @ 50mph 10811.84 12974.208
Base Target Power @ 50mph 12475.2 14970.24
Top Target Power @ 50mph 13306.88 15968.256
Minimum Power @ 70mph 16219.84 19463.808
Base Target Power @ 70mph 18715.2 22458.24
Top Target Power @ 70mph 19962.88 23955.456

This means that peak power for my rig is 24,000 kW. Now it’s time to take a look at equipment and gauge the kind of power I am going to see.

EV Setup

I want my “muscle” car to handle with the same level of growl you would expect out of a small block v8 like the 302s Mustangs are famous for. A little bit of tire squeal is appealing, especially on a bad day! In EV speak we have a couple values to work with. What is somewhat counter intuitive, is that they are each predominately controlled by different components of the car. That means that horsepower isn’t as simple as a big motor.

Value Result Control System
Volts (V) Horsepower (Top Speed) Battery Pack -> Motor Max
Amperage (A) Torque (Acceleration) Motor Controller
Amp hours (Ah) Range Battery Pack

 

An electric car is a system. High voltage means high top speed, but only if both your motor controller and your electric motor can support it. Your controller can always output the max amperage it is rated for; however, the voltage sag that it can place on your batteries if they aren’t rated for it can be catastrophic. What is similar to an ICE vehicle is that the more fuel (Amp/hrs) you pack into it the farther it can go in one straight shot.

I found that I could get a really good deal on certain pieces of equipment by buying used. Since EV components are typically rated to work for a long time without breaking I felt safe buying certain parts like the motor and controller second hand. The current rig I am planning to build with associated specs is:

Parts List Specs Notes
NetGain WarP 9 Motor 156V continuous Should handle like a small block v8 when fed properly
Manzanita Zilla 1KHV 1K Amps/300V HV controller is powerful enough to handle dual WarP 9s if I upgrade in the future
PWN Real Force 3.2V 100AH/170V Not sure about these yet…

Reading around online I’ve found that the WarP 9 should be able to run at 170V fairly stably given that it is still run within its holistic power guidelines. The controller is also capable of adjusting the true voltage/current seen by the motor thereby shielding it from the battery pack. This means that as long as my pack is not over 300V it should be within limits, but in order to hit near max voltage for the WarP 9 (to maximize the top end speed) I will need to be careful about choosing batteries with too much AH opting instead for higher voltage (more on this in a future post).

OMG!!! What did I sign myself up for!

That is the general details regarding my conversion project. I decided to just jump right in and start working on this car because I’d otherwise never actually get around to it. The most difficult part of the project might not actually be the EV conversion. I have three major goals in mind:

  1. Make a cool electric car
  2. Make said car actually look cool too
  3. Create a sick car computer system to jam out and hack the planet!

I’m not too worried about that last part… it’s my forte; however, that second bullet might give me some trouble and will be the focus of my next post. I want to make the whole thing look very different than stock. This is going to involve a LOT of fiberglass and carbon fiber fabrication work! I have NO idea what I’m doing, but I can’t wait to get started! I’m glad to have you along for the ride. Please comment below if you have any questions or want to provide suggestions/encouragement. Most importantly please comment if you think I’m and idiot and have a better idea or a flaw to point out! You’re dumb and this is why are the best comments out there!

2014-09-14-2

P.S. Sorry about the exclamation marks… I get excited