GT6 GT6+ electric vehicle project. Need Info/Advice.

[Beavis]

GT6+ electric vehicle project. Need Info/Advice.

I'm looking at partially restoring a 1969 Triumph GT6+, and making an electric car out of it. There are some things I would like to know about it to get an idea of what to expect.

I have not been able to find any solid numbers on the drag coefficient of this car. I found a simulation ran online that had the Cd of the Mk1 GT6 at .47, I found .42 for a 1980 Triumph Spitfire(Being a convertable, it seems like it would fare worse than a GT6), and I talked to someone who was selling a GT6 that put the number at .32.

I know the cross-sectional area, 14.9 feet square, but the Cd number holds importance in simulating the car's range per charge, top speed, and 1/4 mile performance.

Also, the car has a TR6 drive axel and TR6 non-overdrive transmission installed. I'm looking at 200 lb-ft of torque from the electric motor, from 0 RPM up until about 4,000 RPM. Could the TR6 tranny/diff handle this amount of power?

How much weight could be lost by removing the GT6 engine and its ancillary components(like all hoses, fuel lines, carbeurators, exhaust, ect.)?

How much weight could be lost by removing an empty gas tank?

How much weight could be lost by removing the spare tire?

How much weight does the car's battery to power its electronics and lights have?

How much does the stereo system and speakers weigh?

How much difference do the TR6 and GT6 transmissions and differentials have from each other, and which weighs more?

Any low-rolling resistance tires that have decent road holding anyone could recommend that fit the car’s 13-inch rims? I know these two variables are mutually exclusive, but I'd like to cut down on losses as much as possible, while maintaining the car's high-performance handling characteristics. There are tires for other rim sizes that have managed good road holding and traction with coefficients of rolling resistance of less than 0.9% of the weight of the vehicle. I’ll also need some traction to make use of that low-end torque.



Thanks for answering.



If you have to ask, I'm looking at building an electric sports car that will go from 0-60 MPH in about 6 seconds(perhaps faster), top at least 110 MPH(Given the TR6 tranny/diff setup and max motor RPM for the series DC motor set at 6,500 RPMwith 13-inch rims, I'm looking at about 120 MPH top speed, about 130 with motor limit at 7,000 RPM), and have a highway range per charge of about 40-50 miles to 80% depth of discharge of the battery pack. Charge time will be about 2 hours from a 220V outlet from 20% state of charge to 100% SoC.

As bad as I feel about doing it, this poor car is going to be butchered all because I want to build a fast and sexy-looking EV to cruise around in(And humiliate unsuspecting ricers at a stoplight with.), and what better choice than one of my favorite types of car, a Triumph GT6? Not only am I going to have to weld in battery boxes and custom fabricate motor mounts to place into the car, but I'm also going to strip out the interior and build into it a custom interior almost bare of any trim, change the seats to a lighter variety to shave off about 45 pounds, and on the exterior remove the chrome strips from the car, shave down the door handles, install leaf springs to increase the GVWR of the vehicle(As a conversion it will weigh about 2,500-2,600 pounds including driver, while stock GVWR is about 2,350 pounds), cover the grille from the inside with some sheet metal, make the toe 0 degrees, machine down the flywheel to reduce inertia losses(Doesn't need to keep the motor revving at a stop, it's electric and has plenty of low-end torque to not need this. Will be like removing 150-200 pounds from the car while accelerating hard), cover all unneeded exterior vents, lower the car closer to the ground by about an inch, build and install a full underbelly, partially cover the rear wheel wells with fiberglass, close any seams, remove passenger-side mirror, and machine the brake disks to be more circular in shape to reduce brake drag. This is all going to be done to maximize efficiency by reducing weight and aerodynamic drag as much as possible, shaving aero drag down by about 20%. A roll bar will be installed to meet SCCA guidelines so I can use it in racing.

Later on after the car is completed and usable, eventual add-ons will be to install an aluminum LeMans style bonnet, fiberglass doors, fiberglass hatch, lighter windows, remove front bumper and install two rounded bumperettes to fit custom bonnet, all to reduce weight even more, perhaps getting the car's curb weight including driver down to about 2,350-2,400 pounds and the LeMans style bonnet would slightly decrease aero drag.

I want to make this look like one of the classic LeMans Spitfires to an extent.

It will have the look of the ADU 4B LeMans Spitfire pictured here(Only with about the top third of the rear wheel well covered, smoother body, no exhaust pipes, won't have the fog lights the LeMans Spitfire has, ect.):

But it won't have that sort of paint job. It's going to be one color through the entire car, the sort of dark green/black paint job Picton Sportscars Ultimate-Spec Spitfire has:

For the interior, it is sort of going to look like that of the electric VW Karmen Ghia pictured here, only instead of red, the GT6 I have planned will have a dark green/black interior color and theme:

After stripping the car's basic sound system out, I'm going to install a 500 or 600 watt high end system from a manufacturer like Bose or some such, but only if it won't weigh more than the car's stock radio system. I want it to be as light as possible, only having creature comforts and such if they don't up the weight too much. An air conditioning system is not initially planned, but may be added later.

Battery boxes will be placed in such a way so to have about a 48-50% weight distribution front, 50-52% weight distribution rear, and placed as close to the center of the car as possible to reduce polar moment of inertia, while keeping as much trunk space as possible. If at all possible, I want to sink the batteries into the floor. The lower the center of gravity, the better. It will no doubt be lower than stock, as long as all the heavy components are placed below the top of where the engine block used to be, as a rule of thumb. Spare tire will be replaced with a can of fix-a-flat. This car won't be going on many long trips with lead acid batteries installed, and as an EV, it won't need tools to repair/maintain a fussy gas engine either since electric motors last over 500,000 miles, entirely maintenance free.

This car will be raced and taken to car shows for display, and be used for my daily commute back and forth to college and work. I want to keep it looking like a vintage racer from the 60s, but give it technology that is not put into the cars sold today (Political reasons, corporate greed, ect. I’ll spare the rant.).

The overall cost I'm looking at to partially restore it and convert it to an EV is as follows, broken down part by part how much this is going to cost me and how much weight each EV part will add to the weight of the stripped GT6:

-1x 1969 Triumph GT6+ in good shape = $1,200
-1x WarP 9’’ series DC motor, $1,395, 160 lbs
-20x Optima D750 Yellow top sealed deep cycle lead acid batteries, $2,760, 900 lbs
-1x Godzilla Controller(72-300V DC, 1,000 amp max), $2,495,
23 lbs
-1x PFC 20 Charger, $1500, 15.5 lbs
-4x Vicor DC-DC converter, $400, 8 lbs
-Steel for battery racks, $100, 50 lbs
-Battery Cable, $100, 20 lbs
-x2 EV200AAANA contactors, $150, 5 lbs
-x2 Feraz Shawmut A50QS600-4 fuse, $80, 1 lb
-x1 Curtis Potbox, $75, < one ounce each
-x1 E-Meter, $235, 1 lb
-x1 Solid-State Ceramic Heater Core(For heating in the winter), $75, 1 lb
-x1 Adaptor Plate, $1000(I will be machining myself, so
don't count cost), 40 lbs
-x1 Set of custom Motor Mounts, $1,000(I will be machining myself so don’t count cost), 20 lbs
-Miscallaneous components(Heat shrink tubing, renting engine crane, restoration tools, ect.), $800,
100 lbs(For stuff actually added to car’s weight)
-Leaf springs, $300
-Battery heaters, $200
-Paint, $1,000

I’m looking at a $13,000 or so initial cost, can go as low as $9,000 if I get motor/controller and other expensive parts used for cheap, and as high as $15,000 if I need a racing clutch and different tranny/differential. Minus stripping the car out, adding about 1,440 pounds to the weight of the car not counting the weight subtracted from stripping out the gas engine and other things. Depending on how much the GT6 engine and other gas-related junk I won’t need weighs, the final car will weigh somewhere around 2,600 pounds including driver. If weight is too much over that after stuff is stripped out of the car, the battery pack will be shrunk down, going no less than x16 Optima D750 for 192 volts in series. The batteries will be arranged in series, with a 240V pack planned out of 20 batteries in series, less than that if not that many can fit, more than that if more can fit and weight including driver is still < 2,600 pounds. The DC motor is rated to 192V and can be taken up to 6,500 RPM with absolutely no damage(I’ve heard as high as 8,000 RPM), at 1,000 motor amps(controller limitation) neglecting back electromagnetic force, produces 380 lb-ft of torque, and counting in bemf losses produces about 200 lb-ft of torque. The 200 lb-ft is what will reach the tranny for hard acceleration. Horsepower counting in bemf will be about 180 at the flywheel, 120 or so at the wheels.

Since I'm a college student majoring in electrical engineering, I'll eventually be building a Lithium Ion battery pack for this car once I gain the know-how, which would store enough energy to give it a range per charge in excess of 150 miles at 70-80 MPH speeds(200+ miles per charge cycle drive or at 50-60 MPH speeds) to 100% discharge and light enough to push the car's weight including driver down to less than 2,000 pounds with planned lightweight bonnet, doors, ect, 2,200 pounds without those upgrades.

I checked the GT6 I'm looking to convert, rocker panels had some rust but was so thin a magnet stuck anywhere on the panels so rust could probably be sanded off, no rust on the bulkhead or under battery area, chassis outriggers were in great condition, gearbox has no worn synchros and works great, master cylinder and brakes function perfectly fine, electrical system is perfect(although will be gutted and upgraded anyway).

Having never done any major work on a car before(Nothing aside from installing a performance chip in my gas-guzzling Ford Contour, changing the battery, and changing the oil), this will be a daunting task. I have planned out the steps I’m going to take for this.

1) Strip the interior
a) Replace the stock seats with lighter seats(-40 pounds
after replacement seats are put back in)
b) Remove all carpets(-15 lbs)
c) Remove all sound deadener(-25 pounds)
d) Remove wood panel dash, replace with custom leather
dash(-5 pounds)
e) Shave down or perhaps even remove bumpers(-15 to -40
pounds)

2) Measurements
a) Drive car up to get weighed
b) Calculate where to position motor/batteries for about a
50/50 weight distribution, battery box needs, ect.

3) Fix alignment and get car to have 0 toe. Remove gas
engine, gas tank, air conditioning, ect. You know the rest
on that part. Weigh each component removed and record its
position. Tow car over to get weighed again and get glider
weight and weight distribution.

4) Restoration
a) Take the newly placed in interior parts and carefully
remove them
b) Clean all grease! There's grease under wheel wells,
around the tranny, around the engine, ect.
c) Strip off the tacky yellow paintjob that was
done to make the car presentable to a prospective
buyer
d) Sand down any and all rust from all parts of the unibody
e) Rustproof everything
g) Re-paint the car. I'm looking at what appears to be a two-tone color that
alternates between Dark British Racing Green and Black
depending on how the light hits it. I want to make the car
scream "I'm an attention whore and I attract crowds of
people that ask dumb questions like what kind of car am I
and how fast do I go while my owner always has to tell them
it's not a Ferrari or Jaguar and then spouts off some track
time that no one understands! Don't even get me started when
he sits there with my hood popped open at the local gas
station, or the time he took me to get ‘emissions-checked’ during the registration process..."
h) Put back in the aftermarket/custom interior pieces I took
out

5) Conversion
a) See if a new racing clutch to handle torque. If it is? Buy and install one.
b) Basic aero mods done to EVs like underbelly, covered
grille, ect.
c) By now, a motor will be bought.
d) Fabricate adaptor plate for tranny
e) Fabricate motor mount. May involve moving cross members to
make room and will not be done if can be avoided.
f) Fabricate battery boxes. Want batteries as low as
possible and want a very low CoG for handling
g) Buy needed EV components that aren't purchased by now
h) Install said components

6) Drive EV, hunt down all sources of unwanted drag, correct
discovered problems

7) Post Conversion(In no particular order and some perhaps
years after EV is on the road)
a) Professional driving course so I don’t kill myself in this thing doing something stupid
b) Experiment with different types of LRR tires
c) Machine down flywheel
d) RACING
e) Aluminum LeMans bonnet, fiberglass doors, fiberglass
hatch, aluminum alloy wheels, lightweight
windows(-200 to -250 pounds)
f) Lightweight but decent power stereo system
g) Transmission upgrade to a Datsun 240Z tranny/diff if the TR6 unit cannot handle the torque well enough
h) Zilla 2k(Higher power controller means more power to the motor. More amps = more torque. With 500+ lb-ft on tap in such an upgrade, I’ll NEED a beefed up tranny/diff for this upgrade)
i) Use my college education in EE to design a management
system for Li Ions and build a Li Ion pack!(Waaaay down the
road)


Does this sound at all the right way to go about things? Any advice? What tools should I look into? I’m certainly no car expert.

If anyone has any questions about electric vehicle technology, I’ll gladly answer them, although the posts might get a bit long.

Thanks.

 

[Webb Sledge]

WOW!! A LOT of information there. Lately I've been working with a EV (electric vehicle) team at our local Govenor's School (kind of like high school or advanced kids), and we currently have a Datsun 240Z that's finished and has been successfully raced, and a Porsche 911 that's is nearly done mechanically, but not cosmetically. The 911 is from about '87.

You mentioned a 240Z tranny/diff. It works fine in our car, but then we're only pushing to about 80V. I don't see why a TR6 tranny and diff couldn't handle 200 lb-ft, though I'm no expert. I've heard of TR6 engines tuned to 250 horses and raced without tranny/diff swaps, but I don't know how often they'd need to be rebuilt.

I'd estimate the GT6 straight-6 at somewhere around 350 lbs, with all the other stuff attached to it, maybe a little more. Again, that's only based on lifting my engine (TR6), and I can't really guess that accurately because a GT6 is 1/2 liter smaller than the TR's.

I'm not sure about the gas tank. An empty one, about 20 lbs

The spare tire, especially if it's original, is going to run about 35 lbs.

I believe that battery is around 30 lbs.

Speakers, 10-20 lbs?

As for the GT6/TR6 tranny/diff, I want to say they are nearly identical. If there is a difference, the TR's is going to be more heavy duty but heavier. I've got no clue as to the weights of either.

As for tires, I have no idea.

Let me just add that ALL of these estimates are just that, estimates. I have actually picked up only a few of these components. Dave Russel or some other member more experienced than me might be able to help out more, and correct my errors, which are probably numerous and overly-general. I do believe they are in the ballpark though.

I will say though, and you probably already know this, mount EVERYTHING as low as possible in the car. Those batteries aren't light, and if you put them high up in that car, it's going to roll like mad. Your car is a different beast than our EV Team cars though. Ours are made only for racing, though they are street legal. Literally everything that isn't needed has been stripped out, and a racing seat and harness was fitted, along with a full roll cage. Its performance is probably on par with what yours will be, considering that our electric cars have less power, but also will weigh a lot less. Hopefully next week I'll get up to the school and work on the car some, and take my digital camera along. I don't know how much you'll be able to tell that you don't already know from pictures since this is a racing car and yours will be a road car, but I'll take them anyway. PM me with your email address, and I'll send them when I've got them.

Sorry I couldn't be of more help.

 

[35thbdaytr6]

Wow, that's a long post. I'm not going to be the one to start a flame was about "displaced emissions vehicles". I respect the fact that you are taking on a project in a field related to your major. One of thee things I always liked to say to the electric car guys at the car show was "does it have to be so ugly?" Not the case in your car.
I ran a search a few months back on component weights and came across a website for scrapyards shipping components. A complete TR6 engine with all accessories weights 470 lbs. If I were you, I'd have some fun with the weight distribution. With how far back the electric motor will be, I'd mount the batteries in the forward area of the spare tire well. Between the lower and further back cg of the motor, and the weight displacement of low rear batteries, that car could have some outstanding handling. A chassis engineer at Lotus once told me the best handling cars in the world would have no antiroll bars - because the cg is below the axle line. Good luck, I'd love to see build up photos. Don't forget to use LED lighting to conserve energy!

 

[Beavis]

Thanks for the advice and info. Webb Sledge, which EV team you working with? Was that electric 240Z you raced named "Sweetheart" by any chance, and then raced at the Power of DC drags at the Mason-Dixon strip? What kind of setups did you have on the 240Z and on the 911? I'm glad to see that there is someone on this site who has been exposed to EVs.

Also, 35thbdaytr6, thanks for that much needed info on the engine weight. Knowing that, my glider weight is probably going to be a paltry 1,150 pounds or so, meaning, if 20 Optimas would put it around 2,600 pounds with my original estimate being a glider weight of 1,380 pounds, in all actualliy, this with specified lead acid battery pack will probably weigh about 2,400 pounds! If there's room for the batteries, I might be able to add 4 more batteries then and go up to 288V for more range and more performance.

I originally intended to put the engine up front, but I have considered a rear engine setup. Might be a bit hard to do though, but the results would be astounding. The transmission could be taken out and just the differential used, so no shifting would be required. Where the transmission used to be, the batteries could be mounted, right smack in the middle of the car and down below the driver/passenger. The only problems would be with top speed, I'd be limited to around 90 MPH or so, and the amps drawn for acceleration with such an low gear ratio would drastically cut range due to losses from the Puekert's effect of the batteries. This would also necessitate a more powerful controller, like a 2,000 amp Zilla, for acceleration, raising the price of the conversion by about $2.5k. But with that setup, I'd be pulling low 13s in the quarter, asuming the differential could handle it! I'd probably be better off with a Ford 9'' rear end if I went that route, although lack of high top speed would be disappointing.

If I kept the transmission and used a zilla 2k, I could keep the acceleration performance, have better range with a transmission, and keep high top speed. But a Zilla 2k is a bit out of price range for right now, and due to the amount of power I'm dealing with, I'll stick with a 1k for now.

I'll probably go with a front engine setup, but i'm going to play with the options I have. I might in fact go for the setup you outlined. I want this thing to handle like a go-kart!

As for LED lighting, LED headlights might be a bit difficult to do. What matters is the raw amount of lumens produced by the headlights and the curvature of the lense used to make it visible and DoT legal. I might have problems accomplishing this using LEDs. The headlights won't make much of a difference in energy consumption whether they are on or off, maybe 50 or so feet in max range perhaps, so going to LEDs might just be an expensive waste for the time being, but the thought of being able to do it is an awesome idea, just to experiment.

With the setup I have planned in my first post, I'm looking at mid to high 14s or so in the 1/4 mile drag. Not fast, but better than the majority of the cars that will pick a fight with me at a stoplight.


I hope I can find the data on the drag coefficient of a 1969 GT6 though. I'll keep looking.

 

[Patton]

Be sure to display many Lucas decals!!

 

[35thbdaytr6]

I would think that you could use a two speed planetary gear set up directly on the motor or diff housing to increase the useability. A CVT system, although it may be pricey, would be perfect in an electric application. It can be adjusted from reduction to multiplication according to amp load. I like the rear mounted motor idea, it allows flexibility in battery mounting locations up front. You could move them around to fine tune the handling. I also suggest you look on eBay for Miata seats, you would be suprised how light they are. I bought a pair of leather ones in good shape for $150 shipped, both seats weigh less than one OE seat in my TR6. Also, consider narrowing a Jeep Grand Cherokee rear, 95 and up already have rear disc brakes, and it's an aluminum Dana 44 on a 4 link set-up. Weak for a V8 Jeep, but strong for your 2000 pound lighter car. I think your stock diff can handle the torque, especially since the electric motor will be smoother than a piston engine.

 

[Beavis]

I ruled a CVT out a long time ago. Reason being, an EV motor's efficiency curve has a much broader peak than a gas engine, and the extra losses from a CVT would more than cancel out any gains made in keeping the EV motor in its peak efficiency band. Performance, on the other hand, would again be astounding, allowing the motor to stay at its peak torque value. But efficiency would suffer by about 5%. With a gas car having a narrow efficiency curve on its engine, it would be a different story with a CVT.

I've considered Miata seats, but I'm also looking at some of the lightweight bucket seats people put in race cars. I'm going to be installing a 5-point safety harness in this car for each seat and a roll bar. I want to make it a lot safer than it was as a gas car.

As for the rear drive setup, I'll look into how much work that would be to do. I wanted to keep this moderately simple so that others could see how this car was done and duplicate the results with a little effort and minimal education. But I still do like the idea. A two-speed gear setup is also not a bad idea, and many an electric dragster has used the setup. Such a thing, might again, be difficult to place without doing a complete overhaul of the car's body, but it will be looked into.

 

[jeff3113]

Beavis,
Sounds like you have certainly put alot of thought into this. It did cross my mind before I went to the dark side and a 300Hp v8 engine.
I would have figured a DC motor mounted where the differential is - directly to the rear shafts would be my start. Cut out the losses in the old gear box. Reverse is changing polarity in the motor. Without motor, tranny and gas tank there's quite a bit of weight capacity to use for batteries.
Of course I'm chatting without doing any research into the idea being feasable as you defined. Anyone can build a EV to go around the block 2x. It's building it to really perform that takes talent.
Good Luck and please send along pics!

Jeff

 

[W Sledge]

[ QUOTE ]
Thanks for the advice and info. Webb Sledge, which EV team you working with? Was that electric 240Z you raced named "Sweetheart" by any chance, and then raced at the Power of DC drags at the Mason-Dixon strip? What kind of setups did you have on the 240Z and on the 911? I'm glad to see that there is someone on this site who has been exposed to EVs.

[/ QUOTE ]

Yep, that's the one!!

 

[78Z]

Re: GT6+ electric vehicle project. Need Info/Advic

GT6 uses a slightly beefer version of the Spitfire tranny NOT the TR6 one. Its pretty fragile with the stock motor ...

 

[W Sledge]

[ QUOTE ]
Beavis,
Sounds like you have certainly put alot of thought into this. It did cross my mind before I went to the dark side and a 300Hp v8 engine.
I would have figured a DC motor mounted where the differential is - directly to the rear shafts would be my start. Cut out the losses in the old gear box. Reverse is changing polarity in the motor. Without motor, tranny and gas tank there's quite a bit of weight capacity to use for batteries.
Of course I'm chatting without doing any research into the idea being feasable as you defined. Anyone can build a EV to go around the block 2x. It's building it to really perform that takes talent.
Good Luck and please send along pics!

Jeff

[/ QUOTE ]

Jeff,
The only problem with mounting the electric motor where the diff is, is space. Those motors are HUGE, and probably wouldn't mate up well. It's remotely possible that enough fabrication could be done to make it a mid-motored GT6, but with that much work it'd probably put you out of your price range. And I can say from experience that moving that much metal is NOT an easy job, nor a short one. If it were me, I'd just stick with the front motor rear drive setup. Given that an electric motor is much shorter than a GT6 engine, it could be moved back far enough to make the car mid engined, which would work wonders for handling.

 

[Beavis]

Re: GT6+ electric vehicle project. Need Info/Advic

78Z, this particular GT6 doesn't have the stock tranny/differential installed; the non-overdrive TR6 units have replaced what was stock in this particular car.

I'm guessing data on this vehicle's coefficient of drag is unavailable though. Ah well.

 

[UltimateQuestion]

Re: GT6+ electric vehicle project. Need Info/Advic

Wow, sounds like quite a project. Removing the "Stock sound system" from a Gt-6 involves only a AM/FM radio and a single speaker, /ubbthreads/images/graemlins/lol.gif both together can't be more than 10 lbs. The big sound system you plan will definately be adding weight to the vehicle.

 

[Beavis]

Re: GT6+ electric vehicle project. Need Info/Advic

Ahh. If it won't add more than 20 lbs then, it should be ok...

Lack of weight is more important than creature comforts in this idea, to an extent.