# 1993 RX7 Conversion!



## dougingraham (Jul 26, 2011)

The least expensive way to get to under 6 sec 0-60 would be with a warp 11-HV and a Zilla Z2K EHV. You get about 300 ft-lb at 1000 amps and you can probably run it that way with the street brushes for a long time.

You need a battery that can do 1000 amps without sagging below 280volts. That will be the trick. At 1000 amps and 280 volts this is an input power to the motor of 280000 watts which is 375 hp. You get that 300 ft-lbs from zero rpm up to around 4500 rpm.

Without a transmission and with the normal differential ratio (4.1 I think) with 255/50 R16 tires an rpm of 4500 would be a full torque speed of 85 mph. This is not going to be the top speed. It will continue up to the rpm limit (113 mph at 6000 rpm) or air drag limit if that happens to show up first.

You would improve the 0 to 60 times with a little higher numerically rear end ratio. The RX-8 rear end is 4.77 which changes the redline to 97 mph and the 4500 rpm torque band limit to 73 mph.

The above is what I would do if I were to convert a third gen. On my first gen I chose poorly with my batteries from a performance standpoint. They just can't put out the power. But from a street car daily driver standpoint I made good decisions.

With a Zilla 2k you can turn up the current to increase the torque to the point where you will start to break stuff. 1400 amps is probably a good stopping point and that should give you around 450 ft lbs. I am pretty sure you would not have enough tire to prevent wheel spin.

I have a simple drag racing simulator. Using 2600 lbs and 1000 amps in the guesstimates give a 60 ft time of 2.93 and a 0-60 time of 6.28 seconds. The 1/8 time time is 9.72 seconds at 90.66 mph. The 1/4 mile numbers are 14.19 seconds at 108 mph. These numbers are a little optimistic because they don't take into account the air drag or rolling resistance.

If you go to 1400 amps then the numbers look like this.

60 ft time [email protected]
0-60 time 4.19 seconds
1/8 mile [email protected] mph
1/4 mile [email protected] mph

The car could really use a transmission. The numbers would be better with a couple of gears.

If you go to 1400 amps with the Rx-8 rear end:
.
60ft [email protected] mph
0-60 time 3.6
1/8 mile [email protected] mph
1/4 mile [email protected] mph

Your downside would be three contactors to get reverse. The Zilla with the correct hairball knows how to do this.

It all depends on what you really want to do.


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## nimblemotors (Oct 1, 2010)

All I can say is what a waste as you could have bought my Boxster
and had one beautiful kickass car. But no. 




rp0029 said:


> OK gang. I am the owner of a 2014 C7 Corvette. It is a beautiful car. It rides like a dream. But all four tires (even if you drive relatively mildly) need to be replaced at between 5,000 and 7,000 miles (Pilot Super Sport ZPs are super soft soft), which means $3200 per year on tires alone. Gas is expensive.
> Insurance is expensive. Before I even start on my monthly payment, I'm out more than $600/month. I wanted the Tesla but it is way overpriced, and I do not like the style of any of the other electric cars out there, and I don't really want to wait for the model 3.
> 
> So I just yesterday I bought a really rough 1993 rx7 for 2700 bucks with a gutted interior, rebuilt title, spray painted exterior, and no engine/transmission. Hooray!
> ...


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## dougingraham (Jul 26, 2011)

rp0029 said:


> I assume that a higher performance car with the voltage cranked up gets less mileage. Is there a way to "de-tune" the vehicle somehow to get better mileage when I don't feel like going fast?


You would think so but it isn't really the way it works. I have experimented with turning down the motor current in an attempt to maybe get better mileage. Yes it does detune the vehicle but my mileage does not go up. It makes it easier to drive smoothly in the lower gears but in your case you would not have gears so all you need to do is turn down the motor current limiter until you reach the point where you don't like driving it and then turn it back up to an acceptable level. You could probably put this on a switch (the valet switch or the spouse switch).

I don't see any increase in range when I turn down the fun factor. I am sure that turning down the fun factor on a massively overpowered car would make it a better daily driver though. And help keep you out of trouble.


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## rp0029 (Jun 8, 2015)

Thanks for the response! So basically I need a z2k to get a 13 second quarter mile car, and a z1k to get a 14-15 second car.

The tires are aftermarket, 18 inch.

So for a street driven can would you recommend a built powerglide, the FD tranny, a t56, or just a direct drive? 

What are the advantages/disadvantages of each?

And which batteries would you buy?
Thanks!


dougingraham said:


> The least expensive way to get to under 6 sec 0-60 would be with a warp 11-HV and a Zilla Z2K EHV. You get about 300 ft-lb at 1000 amps and you can probably run it that way with the street brushes for a long time.
> 
> You need a battery that can do 1000 amps without sagging below 280volts. That will be the trick. At 1000 amps and 280 volts this is an input power to the motor of 280000 watts which is 375 hp. You get that 300 ft-lbs from zero rpm up to around 4500 rpm.
> 
> ...


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## rp0029 (Jun 8, 2015)

nimblemotors said:


> All I can say is what a waste as you could have bought my Boxster
> and had one beautiful kickass car. But no.


How much? Is it an ev?


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## rp0029 (Jun 8, 2015)

Here are some pics.


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## dougingraham (Jul 26, 2011)

rp0029 said:


> Thanks for the response! So basically I need a z2k to get a 13 second quarter mile car, and a z1k to get a 14-15 second car.


I guess you can think of it this way. Or put in 2 motors and then one 1k zilla for each motor. There is a bit more to it than this but in essence yes. Or you can get to 10 seconds with two zilla 2ks and two motors. But without the right batteries you won't make it there. Also there is the mass of the car to consider.



rp0029 said:


> The tires are aftermarket, 18 inch.


It wasn't in my notes about the FD wheel sizes. This is going to increase the diameter of the tires so it works against a higher numerical rear end. I was guessing the tire size based on 16 inch rims.



rp0029 said:


> So for a street driven can would you recommend a built powerglide, the FD tranny, a t56, or just a direct drive?


For street driving I mostly just leave it in third gear. I shift into 5th on the interstate. A two speed with carefully selected ratios would probably be enough. Having a reverse would be a plus. Running brushed DC motors with advanced timing backwards is hard on the commutator and the brushes.

If you actually plan to do some drag racing or autocross with the car then you need to do a lot more planning up front. If you are going to daily drive it 99.9% of the time then the stock manual transmission and a single WarP 9 motor will give you a nice driving car if you give it enough batteries. And most of the time you will just leave it in third or fourth gear. I do use second gear when I am heading up the hill in my neighborhood because it spins the fan in the motor a little faster and keeps it cool. I could make it in third or even fourth but the RPM would be low and the fan would not move as much air. Tradeoffs.



rp0029 said:


> What are the advantages/disadvantages of each?


I don't know anything about the powerglide or the T56. The stock transmission has enough widely spaced ratios that you can pretty easily find a gear that will work out. For direct drive you would put the motor in the transmission tunnel with a little longer drive shaft back to the diff. Reverse the motor electrically. You don't drive much in reverse so it isn't much of a problem to run it backwards minimally.



rp0029 said:


> And which batteries would you buy?


This is where most of the money goes. For street use just get CALB CA series. The 100 AH cells will do 1000 amps for a little while. With a WarP 9 motor you could get by with around 50. This would give a range of 45 miles to a reasonable 80% discharge level. If you strip as much weight off the car as possible the range goes up. I have been estimating a 2800 lb weight with driver. If you use a warp 11 HV then you want around 92-96 cells to get the voltage up. This would be about twice the range but twice the cost as well. To do the drag racing you would need more exotic batteries. I am building a drag racing pack which will give me full power at the motor and weigh about 50 lbs. This lightens the car by 350 lbs. But my range will drop to 8 miles with the drag pack in the car.

You really need to figure out what your goals are.


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## dougingraham (Jul 26, 2011)

rp0029 said:


> Here are some pics.


That looks to be in fairly good condition. Is that a carbon hood?


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## rp0029 (Jun 8, 2015)

Yes it is a carbon hood, sort of. I believe it is fiberglass underneath.
So if I buy a warp 11 HV, and 96 calb batteries (302 volts) a zilla 2k EHV, I can crank it up to 1400 amps at get 450 lbs of tq?
What batteries are you using for your drag pack?

Thanks!


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## rp0029 (Jun 8, 2015)

Could I buy the warp 11 hv and drive the motor with only 50 batteries until I have them all?


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## dougingraham (Jul 26, 2011)

rp0029 said:


> Yes it is a carbon hood, sort of. I believe it is fiberglass underneath.


The easiest way to make a mold is to pull one off of a good hood. This is not the way to make the lightest structure though. You actually have to engineer the structure to take advantage of the materials. So if the hood is a carbon and fiberglass structure it is probably just fine.



rp0029 said:


> So if I buy a warp 11 HV, and 96 calb batteries (302 volts) a zilla 2k EHV, I can crank it up to 1400 amps at get 450 lbs of tq?


You can run 10C on the CALB CA cells for a little while. What you would end up doing is setting the motor current to 1400 amps and the battery current to 800 or maybe 1000 on special occasions. The controller will sort it all out and give you 1400 amps at the motor while limiting the battery current to 800. What you will see when you drive it is full torque over a narrower RPM range. It might start tapering off at 3000 RPM. This would still be a terribly fast street car. The problem is that unless you go with exotic batteries you end up with a lot of them in order to get the power. 100 cells at 3.2 volts nominal is 320 volts nominal. At 100 AH this is 32kwh. And about the most power you will get out of them is going to be 272kw. If you pull more current then the voltage will drop and the power will remain the same. The Tesla battery pack is 85kwh which is almost three times larger. They have to make it that large in order to get the power levels they are demanding.



rp0029 said:


> What batteries are you using for your drag pack?



I am going to use the ampahaulic.com packs which are much higher specific output cells. About 50 lbs worth. This is just enough to give me 1000 amps at 190 volts. But I will only have 8 miles of range. To fully feed a WarP 11 HV at 1400 amps you would need 14 of these (22.1 volt) modules in series and 4 in parallel for a total of 56 modules. This would give you about a 19 mile max range. Cost would be over $6700 if you do all the pack assembly yourself. This would be a little less than 100 lbs of batteries. The downside of this kind of battery is they only have an expected lifespan of perhaps 300 cycles. For drag racing this is not too bad because you would have to make at least 10 runs down the track to get the equivalent of a cycle. The pack has essentially unlimited life in this respect. (3000 to 5000 trips down the drag strip is a lot!) So you can see that this kind of pack is completely wrong for a daily driver where you would probably use more than half a cycle per day.


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## rp0029 (Jun 8, 2015)

You are very infornative. Thank you for your help.
I'm still trying to get a handle on the battery situation. You mention exotic batteries. What is the lightest battery I can get that will do say a 50 mile range and allow me to run 1400 amps? Are there higher voltage batteries which have less storage capacity such as the ampahaulics, that give more cycles?


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## dougingraham (Jul 26, 2011)

rp0029 said:


> Could I buy the warp 11 hv and drive the motor with only 50 batteries until I have them all?


Yes, but the voltage will determine the speed where you run out of torque. Lowering the voltage will narrow the torque band and limit peak power. With 50 batteries the motor will feel like it runs out of poop at around 2500 rpm. Peak power would be limited to 1000 amps * (50 cells * 3.2 volts * 0.85) = 136 kw (182 input HP). Without a transmission it would feel ok up to a fixed RPM and then feel like all the power went away. Probably around 40 mph. Adding more batteries just moves this point up until you reach the voltage limits of the motor.

With a transmission, you just shift up when you get to that point.


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## dougingraham (Jul 26, 2011)

rp0029 said:


> You are very infornative. Thank you for your help.
> I'm still trying to get a handle on the battery situation. You mention exotic batteries. What is the lightest battery I can get that will do say a 50 mile range and allow me to run 1400 amps? Are there higher voltage batteries which have less storage capacity such as the ampahaulics, that give more cycles?


What seems like a simple question encompasses a lot of topics.

There are four figures of merit that are normally given to batteries.

Cost/Kilowatt Hour (Lower number is better)
Watt Hour/Mass (wh/kg Higher number is better)
Watt Hour/Volume (wh/liter Higher number is better)
Discharge rate which is usually given as some multiple of capacity (called C).

The last one is pretty important but usually only to drag racers or driving enthusiasts. The reason for this is because generally we want to go more than 1/2 mile on a charge. Drag racers need the battery to put out the highest possible power while weighing the least. People often bring up Super Capacitors. And while this will someday work, it doesn't even come close today. Let me describe C ratings to give you a feel for them. If you want to drag race at the top levels you would want a battery that only lasts just long enough to get you to the end of the track. Lets say you are a slow drag racer and can only do the 1/4 mile in 15 seconds. A 15 second discharge would be 3600 seconds per hour / 15 seconds = 240C. If you are in the 8's then you need an 8 second battery which is 3600/8=450C. The fastest batteries that are being sold to mere mortals are rated at 150C. But usually those numbers are an exaggeration. They might be able to do that once and only for a couple of seconds and then you see excessive voltage sag. 100C is attainable for the time needed for a drag race. So today the 8 second guys need to carry about a battery that is at least 4.5 times heavier than they want. Those batteries are the ones most commonly used by the Radio Control hobbyists and are typically called LiPo. The Ampahaulic batteries are a good version of these. I did a lot of research and these $120 packs are a less costly and better built than the ones the Hobby guys are buying. For twice the work using the hobby packs you might save 10% over the ampahaulic packs.

Lets look at a car you plan to daily drive. In your example you want 50 miles range. Assuming you drive the whole way at 75 mph your 50 miles will take 0.667 hours or 2400 seconds. You only need a battery with a (3600/2400) 1.5 C rating. It is tough to find a battery that won't do 1.5C. Actually this is an average rating and you need more than this for your acceleration up to 75 mph. Any average speed less than this and the C rating needed goes down. What about acceleration? Assume I am a lead foot and I only know three speeds, those being off, cruise at 75mph and full on. If we take the max value of 1000 amps and assume you have a perfect transmission (CVT) that can hold the motor at the max rpm where it will still put out full torque (this is the peak HP point) you will be pulling 1000 amps * 280 volts = 280000 watts or 280 kw. It depends on the rolling resistance and the air drag but it takes approximately 20 to 25 kw to hold 75 mph. This means your short term power requirements are 280kw/20kw are a little more than 14 times your average requirements. If your car gets about 300 wh per mile and you want to go 50 miles then you need a battery that has a capacity of at least 15 kwh. To reach your peak 280kw motor input value this would require a peak C rating of 18.7C. With CALB CA's your peak is about 10C. That means that to use CALB CA's ( or any of the large prismatics) you need more than a 50 mile range. To meet your peak power with the CALB CA series you would need at least 28 kwh pack. Such a pack would be expected to take you about 93 miles. With such a pack I would limit the normal range to somewhere between 70 and 80 percent of that or between 65 and 74 miles in order to extend the life. A 20C rating is a no brainer for the RC liPo batteries. Even the cheap ones will do this. This leads into other considerations and the other figures of merit.

Figures of merit for CALB CA 100 AH

$390 per kwh
94.12 wh/kg
157.94 wh/li
4C/10C peak

A CALB CA100 pack that would take you 50 miles would cost $5850. It would weigh 351 lbs. It would take a volume of 95 cubic liters and it would only be able to make a peak of 127kw instead of the 280kw you want.


Compare to the Ampahaulic pack.

$830 per kwh
139.9 wh/kg
312.0 wh/li
50C/100C

An ampahaulic pack that would take you 50 miles would cost $12450. It would weigh 236 lbs. It would take a volume of 48 cubic liters and it would have zero problems making your power requirements. But its expected life is no better than 1/3 of the CALB CAM cells.

I was going to do a comparison to the cheapest Hobby King RC packs that can do 20C. You might be able to do something here but it will end up being between the two in price.

The best deal cost wise would be salvage Volt or Leaf packs. I don't know that you can get 1000 amps out of these without paralleling them. Neither vehicle comes close to those demands so they didn't design for it. I think both cases the peak currents expected are 400 amps for the Volt and 300 for the Leaf.

For a daily driver that you might take to the track you might consider doing what I am doing which is have a pack for the drag strip and one for daily driving. I didn't plan for this when I did my conversion so my pack swap takes over an hour, probably closer to two. If you design for it you can probably do it in 15 minutes.

Best Wishes!


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## rp0029 (Jun 8, 2015)

So the c rating is how quickly the battery can discharge all its energy, and by using 3600/C I can get the seconds to drain the battery? I read through the wiki, is there a place w a little better explanation of the technology involved? Thanks!


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## rp0029 (Jun 8, 2015)

I'm not really a track guy, I am just looking for a dd that will haul the mail. You have been a tremendous help.


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## rp0029 (Jun 8, 2015)

A few more questions. Why an 11 hv instead of two warp 9s? And does a transmission/gearing effect range in an ev, and how so?


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## Moltenmetal (Mar 20, 2014)

If you're after a daily driver that can haul the mail, you can compromise on power a bit and save money on the pack. There is no point in going with dual motors if you don't have a pack capable of feeding them with the peak current they can draw. The single 11 in motor would more than do in that case.

Gearing allows you to match the torque band of the motor to the driving conditions. Too few speeds and you either give up on top speed or off the line performance, unless you have a motor capable of very very high rpm. Keep the transmission and you have options, including an easy reverse. The clutch is another matter. There are lots of clutchless conversions out there which seem to work flawlessly. I kept my clutch and don't regret it. I also am having a blast with my AC conversion even though it is limited to only 500 A and is relatively low voltage ( only 32 series, 105 V nominal). With a light small car and that torque at low rpm that the IC engine never had, it's so much fun to drive! Depends on expectations.


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## rp0029 (Jun 8, 2015)

OK here is what I want, and perhaps you guys can help me make the calculations and/or point me to the correct battery. I want enough battery to feed the Warp 11 HV with 1400 amps for the amount of time it takes me to get to say 100mph (say ten seconds). I am hoping for the car to have the original 2800 lb weight (or less) and 50/50 distribution, and so the less weight I can do this with, the better (with the caveat that I want it to go 50 miles). So the battery requirements are to get me 50 miles, and 50 miles alone, with 1400 amps being able to be put through the motor by the controller.
It seems to me that the CALB batteries do not have enough of a C rating to do this, as to get the amount of power required to make 1400 amps for 10 seconds I would need more batteries than I need to go 50 miles, which would add extra weight, as they have a C rating of 10.
But the ampahaulic batteries have a c rating of 50, so the number of cycles drops, despite the fact that the power/weight ratio goes up. The ampahaulic batteries have too much C for my application, and for the number of batteries that I would need to go 50 miles would do much more than 1400 amps at a time.
So I guess (if I am understanding this correctly) is that I need something that will have a the perfect C rating to take me 50 miles, and also to run at 1400 amps. Dougingraham mentioned 20-30 C batteries from hobby kits, but they are mostly Lithium polymer batteries, and aren't those batteries dangerous?
If you guys could let me know what C I should be shooting for, and I'd appreciate it. 2800 lb car, 50 mile range, 1400 amp max.
Additionally, the car does not have a transmission. I bought just a shell. So I will be buying a transmission if i need one. I have my eye on a two speed transmission, a Powerglide. It is a simple, automatic transmission that others have used before. I don't want 5 gears unless I am going to use five gears. I can probably more or less change the final drive ratio in each gear to pretty much anything with a combination of after market gears in the powerglide and an aftermarket rear end. So the idea is that I can shift right at the point when the motor starts to lose torque, and for the final gear to allow a top speed of about 85 at peak torque. I can build the power glide. The problem is the 11 HV says continuous RPM of 3000, but max RPM of 5000. Does this mean that I can gear first to 5000 rpm to 40 mph, and second to 75 (max sustained highway speed) at 3000 RPM? How should I determine my two gears?



dougingraham said:


> What seems like a simple question encompasses a lot of topics.
> 
> There are four figures of merit that are normally given to batteries.
> 
> ...


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## Yabert (Feb 7, 2010)

Hi.
A lot of questions about batteries... Well, you can buy a Chevy Volt battery for 2K$ and have a lot of fun with your kind of car.
A water cooled Volt battery can give a peak power over 250 Kw.

300-500 lbs-ft of torque (motor dependent) and over 250 hp... That could be a good start!


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## rp0029 (Jun 8, 2015)

You are right. GM Parts Direct lists them for $2400.... I wonder what kind of range I will get?

I was thinking using LiPo batteries, but that is out due to safety, but maybe the volt battery is the way to go. I was thinking either lifepo4 batteries with 30C burst... but now I am not sure.


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## BWA (Mar 14, 2015)

The Volt battery is listed, but, you can't actually buy one from the dealer.


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## rp0029 (Jun 8, 2015)

Where do I get one, and will the zilla 2k and warp motors work with one?


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## dougingraham (Jul 26, 2011)

rp0029 said:


> A few more questions. Why an 11 hv instead of two warp 9s? And does a transmission/gearing effect range in an ev, and how so?


Two Warp9's are something like three feet long and cost more than a WarP 11 HV. They weigh more than a WarP 11HV. And no way do you need two WarP 9's in a daily driver. You can do something like 340kw (455 HP) with a pair of WarP9's. Wheel HP would be around 390 HP. It would be the step up if you need more than the 11HV would give you (280kw, 375 HP or 319 wheel HP).

It just adds extra complexity and weight when you don't need it. A single Warp 9 is great plenty for a daily driver in a light car like an RX-7.


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## rp0029 (Jun 8, 2015)

I want the FD to have similar states to my vette - like a 12 second 1/4 and 0-60 in 4 seconds. Is that possible with a 9" motor?

I thought with 1000 amps and a 9" motor I will get about a 14 or 15 second quarter mile? Don't I need to have the 1400 amps and the 11 HV to get it up there? Wouldn't that prevent the volt battery, etc?


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## John Metric (Feb 26, 2009)

I have got to say, Doug Ingraham is pretty darn smart with this stuff. I can't find a thing wrong with the advice he is giving.

Couple points though mentioned up there....we sell the 75C&100C cells now not the 50C anymore.

We can supply any size lithium cobalts from 25C to 200C if you meet the MOQ, which varies.

We sell complete battery packs as well. Complete with Orion BMS if needed. Frank John's pack has everything in there, contactors, amperage shunts, fuses, BBS taps, everything...


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## dougingraham (Jul 26, 2011)

rp0029 said:


> Where do I get one, and will the zilla 2k and warp motors work with one?


The Volt or Leaf packs I assume you mean. From salvage yards. There are threads in the battery section where you should ask this question. 

A volt or leaf battery can probably put out 300 to 400 amps peak without being damaged. If you need 1400 amps that means you would need to parallel at least three of them. This would give you great range and still cost less than my little pack for daily driving. The older volt packs are 16kwh which would give you approx 57 miles. Three of them would not give you three times the range because of the additional weight. And the additional weight would somewhat hurt your performance.


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## rp0029 (Jun 8, 2015)

Doug I am thinking about this a bit more, and you mention that 1000amps through a warp 11 hv will get me 300 ft/lbs of torque.

Assuming hp= Torque * RPM/5252 this is 257 hp @4500 rpm. Drag racing calculators tell me that even assuming 2900 lbs (with me in the car) I'd do a 13.24/102 mph, a bit quicker than the 14+ seconds you suggested? 

Can you tell me more about the calculator you are using, because I want to get it. Does it factor in transmission, gear ratios, etc?




dougingraham said:


> The least expensive way to get to under 6 sec 0-60 would be with a warp 11-HV and a Zilla Z2K EHV. You get about 300 ft-lb at 1000 amps and you can probably run it that way with the street brushes for a long time.
> 
> You need a battery that can do 1000 amps without sagging below 280volts. That will be the trick. At 1000 amps and 280 volts this is an input power to the motor of 280000 watts which is 375 hp. You get that 300 ft-lbs from zero rpm up to around 4500 rpm.
> 
> ...


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## rp0029 (Jun 8, 2015)

Also what sort of power could I get from a k9 HV? They are about $1500 cheaper than a warp 11. Would that and a soluton1 make a good setup? What sort of performance could I expect?


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## dougingraham (Jul 26, 2011)

rp0029 said:


> Doug I am thinking about this a bit more, and you mention that 1000amps through a warp 11 hv will get me 300 ft/lbs of torque.


I don't have really good data for any of the WarP motors. The 300 ft/lb number is my best estimate from the published numbers. I would give it a plus or minus 10%. I know my wheel numbers for the warp 9 was a peak of 266 ft/lb at 1000 amps. This was higher than I expected so I am thinking the DYNO operators did not have good RPM data. It was not too far off because it seemed to match the tach in my instrument cluster. But I don't know how good that is.




rp0029 said:


> Assuming hp= Torque * RPM/5252 this is 257 hp @4500 rpm. Drag racing calculators tell me that even assuming 2900 lbs (with me in the car) I'd do a 13.24/102 mph, a bit quicker than the 14+ seconds you suggested?


And this might be a good estimate or it might not be. There are so many variables. The 300 ft/lb number is the motor number. Not the number at the wheels. Typically you lose around 5% through the differential and another 10% in the transmission (if you have one). I don't have a dyno plot for the WarP 11HV. I was estimating that the torque curve was fairly flat up to 4500 RPM. It could taper off early or later than that number.




rp0029 said:


> Can you tell me more about the calculator you are using, because I want to get it. Does it factor in transmission, gear ratios, etc?


It is one I wrote in a couple of hours. It does not take into account losses due to air drag and rolling resistance. It does roughly calculate the losses in the transmission and differential. I have a version that shifts through the gears at the optimum point in zero time. It needs a lot of work!

The numbers I generated for you used no transmission and I guessed at the tire size. I think your real tires are larger which would slow you down. If you get any wheel spin that would slow you down too.

The program is not something anyone else could really use. The parameters are entered into the program and then I compile it. I suspect some of the ones found on the internet take into account more things and probably are compared to real track numbers to tune them.

I think any prediction program is going to be no better than 10%. There are just too many variables and unknowns to consider.


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## dougingraham (Jul 26, 2011)

rp0029 said:


> Also what sort of power could I get from a k9 HV? They are about $1500 cheaper than a warp 11. Would that and a soluton1 make a good setup? What sort of performance could I expect?


You will need to look at dyno numbers if you can find them.

I have been told that unless you order 10 motors you might have to wait a while to get one. Or look for a used one. There was one in the classifieds here for $1500 a few weeks ago. And I think the Soliton 1 is currently out of production. I believe this is a temporary situation though. I hope it is. It would be a used one or go with a Zilla. The NGC (NetGain Controls) is also a possibility but I have heard horror stories about getting them repaired if there is a problem. (I have heard even getting someone to answer email has been a problem.)


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## Batterypoweredtoad (Feb 5, 2008)

The K9HV is smaller than the WarP9 in every way.I think Kostov' s 10" motors are a closer competitor.


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