The White Lightning 818e thread

[Frank818]

You could weld spacers on the FFR mount to even out the fore-aft rack holes issue.

Was the use of a 2015 rack a necessity or the ratio difference was something cool you wanted?

[longislandwrx]

http://forums.nasioc.com/forums/show....php?t=2679348


speedy, see post 2, you need to make that spacer.

also seen in step 15 here:

http://forums.nasioc.com/forums/show....php?t=2681059


then space up you passenger mount to match, once you do that your bellows will likely stop rubbing.


Frank, he had to use all new parts, that's the rack to get if you are paying full price.

[Speedy G]

Mmmm... I thought I'd read and understood the whole thread. I hadn't seen that spacer. Sounds like an easy enough fix and even easier test (with washers). That means longer bolts... find, buy, wait, install...

Well, the choice regarding the 2015 sti rack is a bit of both. This rack was cheaper than new older ones and also I was looking for the better ratio. If the fix is as easy as 3 spacers, then we're golden.

Thanks!

Speedy G

[Frank818]

Yeah that new part rule in Colombia I remember, I thought "new" meant "unused parts from the dealer, no matter the year", but maybe it means "this year new part".

[Speedy G]

Nah, I could've used a 2006 for small parts like the rack, but this one was cheaper. I only need a new unused engine, tranny, and chassis with a bill of sale. Everything else just needs to look new.

Speedy G

[Frank818]

Speedy, almost 4months, were are you at?

[Speedy G]

Hey guys,

I thought I'd update something since I've been MIA for a while. I'm still working on the build, just 3-4 hours a week is all I can spare. Also, since I'm doing and all new parts build, the main time sink has been sourcing the parts. For example, I have the front suspension all set, except for the pinch bolts that hold the ball joints. I also have the steering all set, but I'm missing the pinch bolts for the steering column coupling. I'm also missing the front axles so I can't attach the brakes so I can run the lines. It's been a real pain that some online parts suppliers just cancel the order once they find out it's a non-US card, so I've had to order several parts multiple times. I'm also currently working on the rear brakes. Putting together those e-brakes is no simple task.

In any case, the design is essentially done. AC propulsion really makes it really easy to install their drive. They take care of the brake lights and the reverse lights. I'm thinking the 2 drives will go on top of the tranny, as far forward and as low as possible. Initially the gas pedal will go straight to the drive and the instruments will be connected directly to the drive, the way AC propulsion intended it.

More soon...

Speedy G

[Canadian818]

Glad to see your still working on it speedy. Keep at it!

[Frank818]

I know what you mean Speed! I was and still am having a hard time sourcing many many many different parts. A lot of new parts me too and I've got turned around a few times cuz the nice place with nice prices and nice stuff wasn't shipping outside USA. That's just 350 million people, but you can't do anything when they don't want.

[Speedy G]

I thought I'd looked at all the viable tranny options, but the following link is giving me second thoughts:

http://www.torquetrends.com/e-miata-project

The thing to note is that this is a single motor AC propulsion conversion with a 0-60 under 4s in a car weighing in at ~2200lbs or more. 2200 lbs or less is my goal. He's running a 2nd gen drive and motor, but the torque curve is identical to mine. There's 2 cool things about this miata conversion in particular. The first is that he's using a self-made 2:1 gearbox reduction, which he sells, and a miata rear end. What's awesome about this is that he still gets 135mph max speed. On mine, I'd get 125mph due to the difference in the drive, which is perfect, really. The second cool thing is the battery pack with 100 NMC batteries!!! Now that's not your dad's miata! Those NMC cells alone problably cost like USD50,000!!! All-in-all I'm thinking that might be the most expensive miata ever, probably close to $100,000!! John Rubicon, if you're still watching, this guy sells these for trucks as well. He's also building a transaxle but says he's more than 12 months away. Maybe for Bob's 3rd build...

So, I'm thinking why not just couple the miata diff to his 2:1 gearbox... There's plenty of miata diff ratios and aftermarket lsds... One advantage is that I'd be able to really use the 12,000 rpm without worrying that the tranny's about to explode. If or when I add the second motor, the system could still work reliably since the gear reducer is capable of 800ft lbs. I could then change the miata ring gear and pinion to a lower ratio (higher gear) and gain more top speed. What to do...

Does anybody here know the distance between the miata differential input shaft tip to the axle centers? Can i mount the differential upside down? Those are the only 2 relevant questions to see if it fits. Cost is about the same since miata diferentials are probably available here, second hand.

Speedy G

[Frank818]

Electric really is a different world, a 10" 36lbs gearbox!

Does anybody here know the distance between the miata differential input shaft tip to the axle centers? Can i mount the differential upside down?

I'd guess Andrew and Tamra would have answers to that.

[Speedy G]

So what's a tranny good for if you can do 12,000 RPM? I did a simulation of a ferrari 458 vs an M4, vs 3 818s. The first 818 has a subie tranny with a 3.90 final ratio and shifts at 10,000 RPM, the second has a 2:1 reducer instead of the subie tranny and a miata 3.6:1 rear end. The last one has the subie tranny but shifts at 6,000 RPM. Shifting is simulated at 80ms, like the M4 tranny. My car will probably weigh around 1100kg so that's the number I used. What's interesting is that the fixed gear 818 doing 0-100kph is slower than the ferrari but faster than the M4, but is just as fast as the ferrari at getting to around 120kph and just as fast as the M4 at getting to 160kph. In other words it's geared for the the autobahn. So what tranny should I go with? Here it is:

Simulation818-10kRPMvs6kRPMvsSingleGear-1100kg.png

[Frank818]

Looks like you need to buy a Ferrari. lolll
Aside from that, the MT5 10k seems to have a very nice compromise along the line. Why can't you shift at 12k?

[Martin]

I'd always go for the ratio that gives me the best bang for the sort of driving you intend doing. i.e. If you are going on the autobahn a lot, go for that ratio. If you are going to be driving on regular motorways and will top out at 70mph most of the time, go for a gear ratio that gives you the best cruising experience, and so on.

I went for a gear ratio that gives me the most fun between 30-70mph under acceleration. I will rarely get a chance to put my foot to the floor and hold it there.

[Speedy G]

I actually didn't compromise. I used the motor's dyno, did a torque chart where I have gear and rpm as the axis and torque as the value. I shift when the torque value of the lower gear equals the torque value of the higher gear. It just so happens that with the stock mt-5 the shift point is around 10krpm. Maybe with a diesel gearbox I can get to 12,000 rpm but I think acceleration would be worse. I do have to say that this is conservative, since I put in an 80% efficiency multiplier for the torque value with the mt-5 and 90% efficiency with the 2:1 reducer. Also, the guy that makes the 2:1 reducer has an electric Miata with the same motor as I do. He says he gets 0-60 in under 4s, which is what I'm getting, but I have twice the horsepower than he does, so who knows. Then again, anything under 4s is fast and traction is an issue. Honestly, here my average speed is 9mph due to traffic, at least that's what my beamer's computer says, so it'll be more efficient to be able to choose gears, even if you can only shift when the car is stopped (remember no clutch?). Here's my shifting table:

FFR-818-Shifting.png

[Frank818]

9mph average speed in your neighbourhood? Damn you need the shortest gears in the world to reach 5th at 6-7krpm and 9mph! lolll I run faster than that. Now we know you're not on the Autobahn.

Your torque figures are awesome.

[Frank818]

Updates?

[Speedy G]

Back to work next week... I'm done with brakes, alu panels, steering, and suspension. I'll be working on electrical next, and will start body fibreglass fitting simultaneously. I'll be doing the drivetrain last. It looks like my fellow ev builders are finishing up... that's actually motivating. Back soon..

[Speedy G]

Hey guys, slow progress, but the again, I have 3 year old twins.

I have a few different projects going on simultaneously, but the good news is I got a tranny with 1000 miles on it for 1100 bucks. For some reason, Subaru used to sell the hatchback imprezas locally pre-2008 with low range and in 2008 some customers had expected the low range and they stopped importing them with it. Some customers demanded subaru to provide a low range for their cars, and subaru abliged. They changed the trannies for around 10 customers, and that means they have like 10 5mt trannies with no low range lying around with nobody interested in them, except for me. The bad news? They're meant for 1.5L 110hp engines. The good news? They have a 4.44 final drive. Since I only need 2nd gear initially, this is my best case scenario. These trannies aren't available in the US since the smallest engine available there is a 2.0L. Here's a pic of the tranny:

DSC_1440.JPG

Speedy G

[Frank818]

I have 3 year old twins.

You're in trouble, man. lolll
I mean build-wise.

What's a tranny with low range?
You can't drive more than 50km before it breaks?

Which Subaru uses 1.5L? (I know it's not available in North America)

Will you use 4 gears out of 5?

That's a tiny gearbox!!! They fitted 5 gears into that?
How much torque can it support? On electric power are you sure you won't bust it?

[Speedy G]

Low range is like on a jeep. Usually it's like an additional 2:1 final drive on the output shaft so first gear will have a torque multiple of 28:1 instead of 14:1. Subaru however has a low range on the input shaft. It only multiplies by 1:1.196. That means the tranny has to take the extra torque that the low range multiplies. It's available on Australian N/A Foresters and hatchback imprezas. Actually Euro, Australian and South American imprezas can come with 1.5L engines, or at least they did in2008.

The thing about subaru is that it's all like a lego set. The tranny is the same on N/A imprezas, N/A foresters, etc with engjnes from 1.5-2.5L. The tranny itself is almost exactly in every way to the wrx tranny. The only visible differences are the clutch fork and the stub axles. The ratios are also different as is the final drive. The final drive seems to hold a lot of power, at least that's what the dune buggy crowd says. Some say the gears may not be as strong so there's probably some additional strength from heat treatment or a different alloys since dimensionally they're the same. We'll see, but for the first stage I only need it to hold 150ftlbs at 8,000 rpm, and I only need 2nd gear. Teslas only drive in 2nd gear. Later I'll be buying a PPG 3rd and 4th gear dog set to get a higher top speed. What I do need is an LSD. The factory helical one should be ok but it's expensive. I'm still looking for alternatives.

Speedy G

[Frank818]

150lbs at 8k? I thought electric motors have their max torque at 0rpm?

[Speedy G]

150ftlbs between 0 and 8000rpm. Horizontal line. Max hp is at 8000RPM. It's really not that much torque, but since it's constant to that high an RPM, horsepower is higher numerically than torque. Ideal shifting is at around 10kRPM.

[Frank818]

Is this going to be faster than if you had a WRX engine?

[Speedy G]

0-60 on par with you, probably low 3s, upper 2s. Top speed will suck initially, so yes but no.

[Frank818]

That's very powerful for 150lbs!!

[Speedy G]

Hey I'm not making it up, although I may have fudged the numbers a tiny bit. The original ac propulsion t-zero did it in 4.07 (3.6 with 1 motor and lithium cells). They claimed 336v nominal which is what I'm going for, and their car weighed 2290lbs (1800lbs with lithium cells). I'm still not sure what mine will weigh, but definitely less than 2290lbs. My motors are the same as what they used. With 2 motors the main issue wilk be traction but 11's in the quarter should be doable without shifting, better if I can shift into 3rd and 4th. Hey, after all my motors are the reason why Elon Musk replaced the engine in his 911. It might not be 150ftlbs, more like 177ft lbs, but still... that's les than your original VR6 torque.

https://en.m.wikipedia.org/wiki/AC_Propulsion_tzero

Speedy G

[Frank818]

And 3 years later... loll What's new??