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Discussion Starter #1 (Edited)
2002 Chevy S10 Blazer 2wd RWD Automatic.

Shell No ICE weight = ~2000lb
Rear Ratio 8.75
Wheel size = 28 inches

I hope to remove the transmission, flip the rear differential to face the back and install a cheap used (<$500) DC motor direct where the gas tank was. This car use to have a 22 gallon tank weight around 200lbs with fuel and tank. Several mechanics feel the flip will be possible and not present issue with rear drum breaks.

I'd like to go with Lithium and fit them and other components (minus the motor) all under the engine bay.

If my goal is a modest 40 mile range, 40 mph max....

What's a good used readily available DC motor? How many Lithium batteries/voltage will I need? What's a good reasonably priced controller for my requirements? Can it be this far from the engine and must it be cooled?

Any suggestions for direct connection and Adapters. Yes there will be efficiency losses. Any way to minimize them? Is there way to reduce or increase to a set gear for a sweet spot? I always hear that in many DIY EV builds rarely even switch gears.. and this begs the question of losses from transmissions, transmission weight, axle distances and direction changes cost. Is there logic in thinking that a direct connect might returns some power gains even if not efficient at low speed/high torque? Please help me understand this better... I'd like to keep things simple and get rid of bucket of transmission fluid and a component that often fails in my conversion.



Thanks in Advance.
 

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Discussion Starter #2
I've been talking the gear heads on a Chevy forums they feel flipping the rear axle would have some serious challenges. I still want to go without a transmission and have some support that my 8.5 to 1 ratio Rear end might not need to shift if the motor is a high RPM motor. I guess I am wondering if I go with an 11 inch diameter used DC forklift motor direct drive right in front of the rear differential on my S10 Blazer, Can I fit enough Lithium batteries in the engine bay to get my modest 40 mph/ 40 mile range requirement?

check this out:

YouTube search "Torquetrends 2:1 Direct Drive for EVs" (and skip to 17:41)

https://youtu.be/WX6Xhl-SP9Q?t=1044
 

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Discussion Starter #4

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That Blazer is a lightweight rig for its age.

10 kWh of Li-ion can weigh anywhere from as high as 115 kg and as light as 55 kg. By the time you add all the framework, enclosure, conductors and contactors it might be as much as 10 or 15% heavier.
 

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YouTube search "Torquetrends 2:1 Direct Drive for EVs" (and skip to 17:41)

https://youtu.be/WX6Xhl-SP9Q?t=1044
There might be some useful comment in there, but I can't imagne listening for an hour in hope that there might be, and I couldn't be bothered to dig out the headphones to listen to whatever is said that he couldn't be bothered to type. This is the product:
ev-TorqueBox
 

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Rear Ratio 8.75
I still want to go without a transmission and have some support that my 8.5 to 1 ratio Rear end might not need to shift if the motor is a high RPM motor.
Something is strange there, too - I can't believe that any Blazer has a 8.75:1 final drive ratio - that's insanely extreme. Do you mean that it has a GM rear axle with an 8.75" diameter ring gear (known by terms such as "8.75 rear axle")? Even that would be strange, as this is an obscure axle, which does not appear to have been used near the time of this Blazer. Perhaps the second post has it right, and this is the common 8.5" 10-bolt corporate GM axle; that would explain where "8.5" value came from, but the axle ratio is unknown.
 

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I hope to remove the transmission, flip the rear differential to face the back and install a cheap used (<$500) DC motor direct where the gas tank was.
...
Several mechanics feel the flip will be possible and not present issue with rear drum breaks.
I've been talking the gear heads on a Chevy forums they feel flipping the rear axle would have some serious challenges
It should be reasonably straightforward to turn the axle around and mount it that way, and the brakes can likely be flipped around to work properly. As you probably already know, the issue is not with the brakes, it is with running the ring and pinion gears in the opposite to the normal rotation. I suspect that you would need a new ring-and-pinion set, or perhaps a set from a front final drive unit, but I haven't done this, and others have.

This configuration, with the shaft coming into the rear axle from the rear, is normal for rear-engine buses and motorhomes... but they are built from the beginning that way, they don't take a used axle and turn it around.

This configuration was also used by Solectria for the E-10, which was an EV version of the S-10 pickup (which was related to the S-10 Blazer). In that case, two motors were mounted behind the axle and between the frame rails, one on each side of the shaft, with their outputs facing rearward and belt drives from the motors to the shaft.
 

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There might be some useful comment in there, but I can't imagne listening for an hour in hope that there might be, and I couldn't be bothered to dig out the headphones to listen to whatever is said that he couldn't be bothered to type. This is the product:
ev-TorqueBox
That thing is absurdly expensive. Just use a normal transmission and spend the 3k you saved on more batteries instead.

Additionally, why are you flipping the axle?

I didn't realize that you were ditching the transmission - there's no way you have an 8.75:1 rear end there. Keep the stock transmission if it's a manual. Your requirements are not that crazy.

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That thing is absurdly expensive. Just use a normal transmission and spend the 3k you saved on more batteries instead.
It is very expensive for what it is, mostly because it is a very low production product. It is much smaller than a whole transmission, and more efficient and much simpler than an automatic transmission, so it has its uses.
 

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Additionally, why are you flipping the axle?
I thought that part was relatively obvious: put the motor behind the axle, and leave a much more usable space ahead of the axle, without the shaft down the middle. Solectria obviously had the same idea.

... there's no way you have an 8.75:1 rear end there.
I agree :); we're just waiting for clarification.
 

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Discussion Starter #13
It's a 2002 2door 2wd curb weight 3500. My mechanic said it would lose 1200 with all the Gas parts out including the transmission. did a partial interior redesign removing the spair tire, passenger seat, entire dash (radio, airbags)… not sure maybe 2300lb - 2500lb clean?

Yes, sorry for confusion, seems rear end ratio can't be 8.75, that appears to be the size of the ring (not sure where I got that). Not sure exactly what it is but likely around 3.4 (my bad).

The video was to support the idea of direct drive on 8.75 rear end ratio... yeah product is way too expensive, but still wondering about direct drive options on a RWD and getting to around 9:1 which is what Tesla uses.
 

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I thought that part was relatively obvious: put the motor behind the axle, and leave a much more usable space ahead of the axle, without the shaft down the middle. Solectria obviously had the same idea.





I agree :); we're just waiting for clarification.
It's a needless complication for this build. His requirements are not very high.

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It's a 2002 2door 2wd curb weight 3500. My mechanic said it would lose 1200 with all the Gas parts out including the transmission. did a partial interior redesign removing the spair tire, passenger seat, entire dash (radio, airbags)… not sure maybe 2300lb - 2500lb clean?



Yes, sorry for confusion, seems rear end ratio can't be 8.75, that appears to be the size of the ring (not sure where I got that). Not sure exactly what it is but likely around 3.4 (my bad).



The video was to support the idea of direct drive on 8.75 rear end ratio... yeah product is way too expensive, but still wondering about direct drive options on a RWD and getting to around 9:1 which is what Tesla uses.
You are going to need some kind of gearbox to reach that ratio. Why not just use the transmission you already have, even if you never actually change gears?

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Discussion Starter #16 (Edited)
You are going to need some kind of gearbox to reach that ratio. Why not just use the transmission you already have, even if you never actually change gears?

Sent from my SM-N960U using Tapatalk
Well.. Can I mount a 250 lb motor in front of the transmission and store 20kwh of LiIon and all other components in the front engine bay? (nothing in the back)?

One other question, when they remove the engine, does the transmission have to come out to move/roll the truck?
 

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Well.. Can I mount a 250 lb motor in front of the transmission and store 20kwh of LiIon and all other components in the front engine bay? (nothing in the back)?

One other question, when they remove the engine, does the transmission have to come out to move/roll the truck?
I just read that you have an automatic. It can be made to work, but a manual will be easier and more efficient.

Theres more room than just the back cab area and engine bay for batteries. You could split up the pack and have some in the original gas tank location. There's probably more room available than you think.

The transmission doesn't technically have to come out to move the vehicle. It'll probably be wobbly if the engine isn't there, though, being supported by just the crossmember.

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Discussion Starter #18 (Edited)
I just read that you have an automatic. It can be made to work, but a manual will be easier and more efficient.

Theres more room than just the back cab area and engine bay for batteries. You could split up the pack and have some in the original gas tank location. There's probably more room available than you think.

The transmission doesn't technically have to come out to move the vehicle. It'll probably be wobbly if the engine isn't there, though, being supported by just the crossmember.

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These trucks have decent and deep engine bay. Seems it would be clean and elegant to have all the batteries in the front . Is it a space or weight issue? Is there a safe height for the pack in the engine bay or if we could , would it make sense to rack them on an encloser as low as chassis level?


So no known cheap (cost and space) way to do a 2:1 ratio reduction inline without a full transmission like that Torquetrends 2:1 adapter product is doing? Seems like such great product idea, baring the crazy cost. Not sure why but rotating the rear axle and direct drive sounds so elegant given the great space gained from the gas tank.
 

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Discussion Starter #19
I thought that part was relatively obvious: put the motor behind the axle, and leave a much more usable space ahead of the axle, without the shaft down the middle. Solectria obviously had the same idea.
Do you have more information on the Solectria project .. is that the Sunrise Solectria?
 
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