[bolbers]

Years ago I saw an old experimental dragster at the Don Garlits museum. It tried to avoid the (surprisingly large!) HP losses associated with driving a supercharger by means of a gigantic compressed air tank to feed the engine for short (i.e. 1/4-mi) runs. It wasn’t successful, I think due to the weight of the tank itself. I mentioned a while back in another thread that the Kalitta drag race team has a dyno for their super chargers which uses a big-block Chevy just to spin the damn things under full load!

 

[MattsAwesomeStuff]

I like the look of the torqamp, and would probably go that route and give it a try if it were not at the $3K price point. It is essentially in concept what I am trying to DIY.

Cleetus and his fellow goofballs tried out the Torqueamp a few years ago, after trying out some $400 and $26 electric turbos that reduced horsepower.

...

So, a little quick math to check viability. 56v x 5AH = 280 Watt hours x 60 min / hr = 16.8 KW minutes.
If I get a brushless DC motor that maxes out at about 10 HP. That would take 10 HP / 1.36 KW per HP = 7.4 KW to power it at peak load. So at max boost, I should be able to get 16.8 KW minutes / 7.4 KW = 2.3 min at max boost.

Ugh, your math went around in circles far more than needed. Also you made two errors in opposite directions that coincidentally cancelled out.

280 watthours in the battery.
7500 watts power draw.
280wh/7500w = 0.037 hours = ~2.2 minutes.

So, yes, you ended up at the right answer.

I think that the above calculations if correct, put me in the realm of reasonableness for my application scenario.

Hmm, no, sadly.

That's only considering energy. The next question is, can your battery spend that energy fast enough (power)?

And the answer is no.

There's a tradeoff for lithium cells the same as there is for lead acids, in terms of starter batteries vs. deep cycle batteries. You optimize towards storing more energy vs. getting to the energy faster. Power tools tend to use power cells, but, they'll use the least powery-cells that would work for the application, and optimize more for energy if they can. On those outdoor tools, they're generally all lower-power, longer-longevity, versus something like an impact gun or nail gun where you need every drop of power so it doesn't get bogged down. Outdoor/constant draw tools people complain about running out of battery, not power.

Those cells might be, at best, 30C cells. Maybe more like 5-15C. Meaning, absolute best, highest power draw cells in the world, they'll be rated to discharge at 30x the rate that would deplete them in an hour (2 minutes). So your best case scenario is "maybe". But, the rest of the battery and it's control circuitry, its built-in fuses, etc, are almost certainly going to fry well before that because at that point you're basically dead shorting the battery. Since no tool is going to have that kind of power draw, the wiring won't be built for it, and the fuses will be set for lower draw because anything that high indicates a flaw.

Looking at the tool in typical use, you say it lasts 15 minutes. So, 4C cells would be sufficient. But, the cells would have to sustain whatever the highest-draw tool they would be compatible with. It's possible they're as high as 20C, maybe 25C, I doubt they're 30C.

wasn't going to, but, digs around a bit

The mower is 1000W, or 20A. The snowblower and pole saws claim 2000w (always exaggerated), so, 40A if they're true. Looking like 8C cells would suffice.

digs more

The cells used are unlabelled mystery meat cells, with no identifying information on any of their 3 layers of wrapping. Former EGO engineers apparently purport that they're Samsung INR18650-25R cells which are great cells, though the older ones might be Sanyo UR18650RX cells with famously poor C ratings and voltage sag under load (looks like Sanyos to me). Either way, the cells are rated for max of 20A discharge or ~8C. The 5AH unit is going to have 2 of those in parallel, so, 40A (still 8C).

Someone doing a little math on the physical measurements of the SMT fuse, looks like it should be rated for a ballpark of 40A, maybe a smidge more (50A?) due to some heatsinking on the board itself that'll buy it some time.

I'd say all 3 indications lining up to the pack having a max draw of 40 amps is pretty solid evidence it'll only do 40A.

56v @ 40A = 2240 watts = 3hp. .... and that's when max charged, and, will plummet 10% almost immediately, 30% under high load shortly thereafter.

So, in conclusion, you pull more than 3hp from that battery and it'll hopefully blow the fuse before the wiring, before the circuitry, before the cells shortly thereafter if they don't. So even beefing up the wiring, bypassing the fuse and the electronics, and pulling power from the cells directly, you're going to get 3 horsepower before they grenade on you.

Anything faster than 12 minutes discharge will cook it.

...

I know almost nothing about superchargers (or cars), is 50,000 RPM necessary? That's... fast. I dunno of any easily accessible motors that would spin that fast other than RC motors, and that's pushing the upper ends for them. Something like a little dremel or die grinder might get that high, and you could skip the controller and just wire it straight to the battery without resorting to brushless AC motors, but, you're looking at only 100-500 watts in that case.

 

[LynnB]

I was just getting ready to post a link to that Cleetus video of the Torqamp test. Matt beat me to it.

I have to say, the power increase on that 2.2 Cobalt was impressive. Of course, he has a pro tuner on site making changes to the ecu.

Assuming you ALREADY have efi (boost using a carb is a loser imho.... and I have a boosted car with a carb) at 2500 bucks, I don't know that you can DIY engineer a better set up for a 2.0 liter engine (or a 1.9) for less money, assuming you figure SOMETHING for you labor.

 

[Autoholic]

Supercharger and turbocharger RPMs can get pretty high. It’s necessary to move enough air to build pressure in a system that is constantly consuming air. I don’t believe you can tackle this from a cheap standpoint and have a reliable product. Anything that would be properly engineered for this would likely cost a few thousand at least. I also highly doubt an electric supercharger or turbocharger being cheaper and more reliable than a belt driven supercharger or a conventional turbocharger.

What is more important in this idea/project? Having (reliable) forced induction or playing around with electronics? I think that is an important thing to consider. Is this a science project that if it fails, oh well? Or are you focused on coming up with forced induction that fits in a GT? If it was easy, not even considering cheap, to build an electric-driven turbocharger or supercharger, I think we'd see it already in the aftermarket by a company like Garrett or Procharger. The reality is it takes a lot of work to compress air and provide it constantly in large quantities, for ordinary engines. With EV's becoming the mandated future as well, who knows if these companies will even bother trying.

TorqAmp costs $3k and has already done all the engineering behind this. I doubt a DIY version could beat their product and cost less at the same time. You need the compressor side of a turbo to work on this and that includes a custom body to connect an electric motor to the compressor impeller. You need a considerable battery pack. You need an electric controller that can manage the motor and the batteries. And you need an electric motor that can handle the job. $3k for their system and it only gets you roughly 5 psi of boost.

 

[GThound]

I was hoping that a DIY e-supercharger could be cheaper than the Torqamp (€2749 ~ $,2918 USD at current exchange rates) and better. Well, I don't think I can have both (better and cheaper), I would have to choose one or the other or the Torqamp. Sounds like through my research below, I came to the conclusion LynnB and Autoholic came to.

I don't know that you can DIY engineer a better set up for a 2.0 liter engine (or a 1.9) for less money

TorqAmp costs $3k and has already done all the engineering behind this. I doubt a DIY version could beat their product and cost less at the same time.

Here is how I have bucketed out the components and a low end cost estimate for a high end system.

Component	Learning / Commentary / Options ​	Cost
Battery system	I was hoping to use my 56V EGO blower battery. And I could use it as a starting point. But, those who are building streetable systems are building their own battery packs out of an array of 3.7v high amp hour batteries like the A123 LiFePO4 pouch battery. Realistically, it will probably be in the $500 ball park or more for 20-50 AH high voltage battery system, battery management system, and more if you include large capacitors to avoid voltage spikes	$500
Motor Controller	This is a part to not source from China. Folks seem to be leaning towards MGM motor controllers used in high end RC models for direct drive units. They can handle high voltage and high amperage (in realm of 360-500 amps) current. Another option is to go lower voltage and non-direct drive, but there is a host of other problems that introduces.	$600
Motor	The motors of choice here are all brushless DC motors used in high end RC models. Entry level motors could be in the $200 realm. As the voltage goes up the cost of the motor goes up. Also, sensored motors (they keep track of the rotor position) are more expensive, but help prevent weird back EMF that has a tendency to fry motor controllers.	$200- $600
Compressor	It seems that there is a supercharger that is about the right size that would make the job easy. The Rotrex C15 is about the right size for the CIH engine but they are a bit spendy ~$2000. So, that leads me back to using the compressor side of a turbo charger. So, that leads me to something like GT35 turbo. $1,700 from Garrett or new low cost clones for $150. The challenge is that it would have to be modified with custom fabricated back plate, bearing etc. Lots of custom work. Plus, If i wanted a lighter billet impeller, it is even more.	$500
Fabrication Components	4 gauge solid copper wire, relays, breakers, fittings, fixtures, turbo piping, casing, hardware	$500

So, the price of the major components is in the realm of $2000+ $500 for all of the miscellaneous fabriation componts would be about ~ $2500. Plus, when charting new waters like this, there are often blown components, so the price goes up even more with R&D. This would be a difficult project, but doable. It is no surprise that a system that performs well is going to be pricey.

That said, I am hoping / predicting that high power motor controllers and batteries will continue to come down in price over the years as the technology advances driven by the market demand for electric vehicles.

Thus, I may still consider beginning the R&D (get a cheap turbo, motor, and controller) and begin the learning journey with out embarking on the project at this time. I don’t have a lot of spare time or money, but I do love to learn!

To that end, let me know if you have a spare suitable turbo or super charger lying around. I may be able to put it to good use.

 

[Autoholic]

You are already at $2k from your research. It will likely wind up costing more than that by the time you are done. So why do all this when there is an option that meets your requirements for $3k? If it’s to save money as to why you want to try all this, I really doubt that will end up happening. If it’s to design your own system and you know you’ll end up spending more, then that’s ok. Remember, project budgets rarely stay the same as the initial plans. You have to account for the unknown.

For example, designing your own turbo housing to include the electric motor will require a decent amount of 3D printing before you get the final design made. You aren’t accounting for that. Do you have a 3D printer already? Or is your plan to outsource the 3D printing on Fiverr or pay a professional company? R&D is an iterative process and you need to budget for that. I could easily see $1k being spent on just the 3D printing, no matter how you go about doing it. Just read the posts from Charles Goin about designing his own intake and modified dizzy. The intake is on version 17 or something like that. Then he had to reproduce and redesign a piece for his dizzy because the gear wouldn’t pass through it and he didn’t think of that earlier. R&D has to have a budget that is separate from the cost of parts. And then when you are ready to have a one-off turbo housing piece machined out of billet aluminum or cast in it, you’ll spend somewhere around $1k on that is my quick estimate. It won’t be cheap to get that made. You could literally spend $3k just to get the electric turbo designed and produced, not including any of the other parts needed.

I know it might look like I’m just ripping into your plans to be mean. That’s not my intention. A good plan for a project requires a lot of discussion and getting important feedback on how your plans need to improve to get the results you are after. My own thread about solid lifters is a good example. I’ll need to spend about twice as much as I had planned on the lathe, not including some expensive tools for it.

 

[RallyBob]

I’m currently at around $1400 invested in this project.

eBay turbo, lots of simple fabrication, freshened up shortblock, revised cylinder head. My single most expensive component so far has been the camshaft….even the turbo cost less!

Yea, I didn’t need to make it look pretty but I couldn’t help myself. Probably would’ve saved myself $500 if I eliminated powdercoating and zinc plating.

If my estimates are correct, I’ll be between 180-200 hp on pump gas. Should still have less than 2k into it by the time I’m done. So I’m doing pretty good on the HP-per dollar scale, with a freshened up engine to boot.

 

[MattsAwesomeStuff]

I was hoping to use my 56V EGO blower battery. And I could use it as a starting point. But, those who are building streetable systems are building their own battery packs out of an array of 3.7v high amp hour batteries like the A123 LiFePO4 pouch battery. Realistically, it will probably be in the $500 ball park or more for 20-50 AH high voltage battery system, battery management system, and more if you include large capacitors to avoid voltage spikes

Scratch all that.

No one's used A123 LiFes in like, 10 years. Those were the old 1st gen Dewalt lithium cells. A123's goal was to build EV batteries, but back then there were no EVs, so their way to establish an income source and business beachhead was to build tool batteries. They went out of business... I dunno, 8 years ago? Shopped around, was a ghost company for a while, and eventually someone picked up the pieces and tried to salvage the brands. They make new stuff now, but, no one uses LiFes anymore except in automotive starter battery replacements (and other RV and marine use that has always been based on the "12v" battery building block). And the only reason they're used there, is because they're so much worse than ordinary lithiums, and have lower voltage and energy capacity, that they coincidentally are a closer voltage match to lead acids if you chain 4 of them in series. With your other lithium chemistries, it's a awkward place between using 3 or 4. 3 is too low (12-12.6v is their ceiling, can't handle 13.8 or 14.4v that an alternator will put out), and will get overcharged. 4 is too high (16-16.8v full, 12v dead empty), and you're wasting half your capacity by never charging up fully.

LiFes are marginally safer (ltihiums went through a moderately bad phase 6 or 7 years ago as they'd found ways to get more energy into them but with less stability),

LiFes were originally used in power applications because the competing lithium technologies back then were unsuited for high power draw. As in, an 18650 would max out around maybe 2 amps. Today they'll do 50 amps. 1-2 amps was fine for laptops, right back to the 1990s, because you'd never drain a battery faster than in about an hour anyway. But it couldn't run so much as a dremel. Dewalt used them for 2-3 years before pulling the plug and switching to modern lithium chemistries. Woe on you if you bought Dewalt back then, they're not compatible with batteries before or after, basically just threw your money away.

LiFes are also really temperature and charge sensitive. The first time you try to charge it when the temp is below the freezing point, instantly ruins them, done, throw it away.

...

What I would use in your place is part of a used hybrid battery. Hybrid batteries are garbage for energy storage, but, nothing has higher power capacity than them, because they're designed to be fully charged or discharged in under a minute. The whole point is to recover energy while stopping, and boost your power while accelerating, without taking up much space.

A crappy old Prius pack will be ~200v, but, the cells are just stacked together like Lego bricks, you use as many as you want. You want a 50v pack? Use 1/4 of the stack. It'll be 20lbs. You won't pay anything close to $500 for one. Even 2nd gen Prius packs are rated for 36hp for the whole pack, so, using 1/4 pack, you'll be at 9hp, pretty close to your target.

Newer hybrids will have lithium packs that will be a fraction of the size and weight, and, usually aren't overly desireable. You can probably buy portions of a pack on ebay.

Or, if you can handle a minimal amount of DIY (a little soldering and making an enclosure), something like this: 48v 6.4ah 307.84wh Battery with Panasonic Cells - $81/kWh

$25. 48v. Pack will easily push 100A, has a 150A fuse if you push it. That's 5hp. Put two in parallel if you want, you're at 10hp. For $50. They're "used" but were premium grade medical backup packs and most of the time, literally never discharged even once.

I don't know what methodology led to you picking a specific voltage, but you could find or make or modify packs to be any voltage you want. Generally, if you want a motor to spin faster, you need a higher voltage (or, to choose a motor that was physically designed to spin faster at a lower voltage).

Folks seem to be leaning towards MGM motor controllers used in high end RC models for direct drive units. They can handle high voltage and high amperage (in realm of 360-500 amps) current. Another option is to go lower voltage and non-direct drive, but there is a host of other problems that introduces.

You could skip that, use a DC motor (nearly free) and handle the speed by belts or whatnot. Same way you would have to if it was engine-driven. If your goal was to get away with as low of cost as possible, a 10HP DC motor, or, one capable of 10hp in a surge is probably $20-40 in scrap, and they're thrown away all night and day.

Generally controllers can handle higher voltages and just choose to chop it down to whatever voltage the motor wants. So you don't necessarily have to match your battery voltage to your motor voltage. Higher voltage being better if possible, because you have the option of higher speed (lots of amps at low voltage will end up sitting idle because it can't push the motor faster than "max" for that voltage).

The motors of choice here are all brushless DC motors used in high end RC models. Entry level motors could be in the $200 realm. As the voltage goes up the cost of the motor goes up. Also, sensored motors (they keep track of the rotor position) are more expensive, but help prevent weird back EMF that has a tendency to fry motor controllers.

I didn't even know they made motors for BLDCs that didn't have hall-effect sensors. Yeah, you can spin them up blindly because they're low mass and can get yoinked into the position that matches the coil pulsing, but, I didn't know anyone did that.

Also, they're going to be... fragile. The little motors are skimpy and lack thermal mass. So, their "max" power is not really a suggestion like it is with the heavier iron. They're built like a balloon, not like a bridge.

7500 watts out of an RC motor is... a lot. Like, a lot a lot. It should be the size of a volleyball, but, it'll end up being not much bigger than your fist. Part of that corner cutting is that it'll be designed to be kept in massive amounts of airflow for cooling (i.e. at the axle of a propeller, free cooling), which, you won't have.

It seems that there is a supercharger that is about the right size that would make the job easy. The Rotrex C15 is about the right size for the CIH engine but they are a bit spendy ~$2000. So, that leads me back to using the compressor side of a turbo charger. So, that leads me to something like GT35 turbo. $1,700 from Garrett or new low cost clones for $150. The challenge is that it would have to be modified with custom fabricated back plate, bearing etc. Lots of custom work. Plus, If i wanted a lighted billet impeller, it is even more.

Stupid question, but why go electric at all?

Why not just power it off of the engine?

At the end of the day, the compressor is something you have to buy, and all you're saving going electric is having a way to spin it.

That said, I am hoping / predicting that high power motor controllers and batteries will continue to come down in price over the years as the technology advances quickly driven by the market demand for electric vehicles.

Did you want to be waiting years for this?

High power controllers have more or less bottomed out. Batteries don't have much more room to fall. And, there aren't any 10hp EVs floating around, you're off by an order of magnitude minimum, so, the costs of motor controllers dropping from the EV industry aren't going to exist from your perspective.

...

If you enjoy the process and want to spend time instead of money, you could get this done for really cheap. Junkyard and used parts, and then you spend your time and effort mashing it together. Any budget-conscious DIY project is just a series of bodges until it kinda works.

 

[Autoholic]

Stupid question, but why go electric at all?

Why not just power it off of the engine?

That's not a stupid question. I tried to point out the same thing. If adding cheap forced induction is the more important priority here, going with a conventional supercharger or turbocharger is going to be cheaper. While RallyBob's fab skills shouldn't be overlooked, he did an awesome job for $1400. But, that includes his fab skills to build a turbo manifold. You could add a belt driven turbo compressor for relatively cheap.

World's Smallest Procharger Supercharger - BangShift.com

Earlier today we wrote about the new ShockWave air suspension for UTVs, and we started wondering if there was anything actually cool that can be done with one of those glorified riding lawn mowers. There is! Check it out, Procharger makes a little blower for them! This gives us thoughts, most...

bangshift.com

POWERSPORTS SUPERCHARGERS SPECS

www.procharger.com

For his $2k budget, I really think something like this could be done. Design a bracket to hold a Procharger above the alternator for example. Then you just have to add plumbing and possibly an intercooler. It will weigh less and take up less room.

Or get a small turbo and have a turbo manifold made from stainless steel pipe. Would have to figure out where the turbo will fit in a GT but it's not impossible.

 

[GThound]

Scratch all that.

No one's used A123 LiFes in like, 10 years. Those were the old 1st gen Dewalt lithium cells. A123's goal was to build EV batteries, but back then there were no EVs, so their way to establish an income source and business beachhead was to build tool batteries. They went out of business... I dunno, 8 years ago? Shopped around, was a ghost company for a while, and eventually someone picked up the pieces and tried to salvage the brands. They make new stuff now, but, no one uses LiFes anymore except in automotive starter battery replacements (and other RV and marine use that has always been based on the "12v" battery building block). And the only reason they're used there, is because they're so much worse than ordinary lithiums, and have lower voltage and energy capacity, that they coincidentally are a closer voltage match to lead acids if you chain 4 of them in series. With your other lithium chemistries, it's a awkward place between using 3 or 4. 3 is too low (12-12.6v is their ceiling, can't handle 13.8 or 14.4v that an alternator will put out), and will get overcharged. 4 is too high (16-16.8v full, 12v dead empty), and you're wasting half your capacity by never charging up fully.

LiFes are marginally safer (ltihiums went through a moderately bad phase 6 or 7 years ago as they'd found ways to get more energy into them but with less stability),

LiFes were originally used in power applications because the competing lithium technologies back then were unsuited for high power draw. As in, an 18650 would max out around maybe 2 amps. Today they'll do 50 amps. 1-2 amps was fine for laptops, right back to the 1990s, because you'd never drain a battery faster than in about an hour anyway. But it couldn't run so much as a dremel. Dewalt used them for 2-3 years before pulling the plug and switching to modern lithium chemistries. Woe on you if you bought Dewalt back then, they're not compatible with batteries before or after, basically just threw your money away.

LiFes are also really temperature and charge sensitive. The first time you try to charge it when the temp is below the freezing point, instantly ruins them, done, throw it away.

...

What I would use in your place is part of a used hybrid battery. Hybrid batteries are garbage for energy storage, but, nothing has higher power capacity than them, because they're designed to be fully charged or discharged in under a minute. The whole point is to recover energy while stopping, and boost your power while accelerating, without taking up much space.

A crappy old Prius pack will be ~200v, but, the cells are just stacked together like Lego bricks, you use as many as you want. You want a 50v pack? Use 1/4 of the stack. It'll be 20lbs. You won't pay anything close to $500 for one. Even 2nd gen Prius packs are rated for 36hp for the whole pack, so, using 1/4 pack, you'll be at 9hp, pretty close to your target.

Newer hybrids will have lithium packs that will be a fraction of the size and weight, and, usually aren't overly desireable. You can probably buy portions of a pack on ebay.

Or, if you can handle a minimal amount of DIY (a little soldering and making an enclosure), something like this: 48v 6.4ah 307.84wh Battery with Panasonic Cells - $81/kWh

$25. 48v. Pack will easily push 100A, has a 150A fuse if you push it. That's 5hp. Put two in parallel if you want, you're at 10hp. For $50. They're "used" but were premium grade medical backup packs and most of the time, literally never discharged even once.

I don't know what methodology led to you picking a specific voltage, but you could find or make or modify packs to be any voltage you want. Generally, if you want a motor to spin faster, you need a higher voltage (or, to choose a motor that was physically designed to spin faster at a lower voltage).



You could skip that, use a DC motor (nearly free) and handle the speed by belts or whatnot. Same way you would have to if it was engine-driven. If your goal was to get away with as low of cost as possible, a 10HP DC motor, or, one capable of 10hp in a surge is probably $20-40 in scrap, and they're thrown away all night and day.

Generally controllers can handle higher voltages and just choose to chop it down to whatever voltage the motor wants. So you don't necessarily have to match your battery voltage to your motor voltage. Higher voltage being better if possible, because you have the option of higher speed (lots of amps at low voltage will end up sitting idle because it can't push the motor faster than "max" for that voltage).



I didn't even know they made motors for BLDCs that didn't have hall-effect sensors. Yeah, you can spin them up blindly because they're low mass and can get yoinked into the position that matches the coil pulsing, but, I didn't know anyone did that.

Also, they're going to be... fragile. The little motors are skimpy and lack thermal mass. So, their "max" power is not really a suggestion like it is with the heavier iron. They're built like a balloon, not like a bridge.

7500 watts out of an RC motor is... a lot. Like, a lot a lot. It should be the size of a volleyball, but, it'll end up being not much bigger than your fist. Part of that corner cutting is that it'll be designed to be kept in massive amounts of airflow for cooling (i.e. at the axle of a propeller, free cooling), which, you won't have.



Stupid question, but why go electric at all?

Why not just power it off of the engine?

At the end of the day, the compressor is something you have to buy, and all you're saving going electric is having a way to spin it.



Did you want to be waiting years for this?

High power controllers have more or less bottomed out. Batteries don't have much more room to fall. And, there aren't any 10hp EVs floating around, you're off by an order of magnitude minimum, so, the costs of motor controllers dropping from the EV industry aren't going to exist from your perspective.

...

If you enjoy the process and want to spend time instead of money, you could get this done for really cheap. Junkyard and used parts, and then you spend your time and effort mashing it together. Any budget-conscious DIY project is just a series of bodges until it kinda works.

Thanks for all of the data and examples used to challenge / clarify / vet my ponderings. I love the data!

Also, I love the challenging of conventions (having to buy new battery tech). And your adaption and repurposing of what already exists (Prius battery), by reconfiguring it (using 1/4 of the stack). That kind of thinking could remove constraints that could unlock a DIY project like this.

 

[LynnB]

I’m currently at around $1400 invested in this project.

Bob; if you figured a ridiculous $30 an hour for your time, any idea where you land on this deal?

 

[RallyBob]

Bob; if you figured a ridiculous $30 an hour for your time, any idea where you land on this deal?

I haven’t logged hours, so no, I really have no idea. I work on it when I have free time.

 

[RallyBob]

I won’t post pics without permission, but another forum member recently sent me pics of their GT’s engine with an AMR500 supercharger and the Holley Sniper fuel injection.

The AMR500 is on the small side so you’re not going to see 300 hp or anything, but if you want 5-6 psi and instant response, it’s ideal for a street car. I imagine it will run like a 2.5 liter engine, but from a stock 1.9.

 

[GThound]

I hear you guys regarding the motor powered supercharger. I appreciate your perspecitve and I agree it is a good option to include in my 5-7 PSI boost ponderings.

why go electric at all? Why not just power it off of the engine?
At the end of the day, the compressor is something you have to buy, and all you're saving going electric is having a way to spin it.

I doubt an electric supercharger or turbocharger being cheaper and more reliable than a belt driven supercharger or a conventional turbocharger.

another forum member recently sent me pics of their GT’s engine with an AMR500 supercharger and the Holley Sniper fuel injection.

Bob, were you considering a supercharger from a Toyota pick-up for one of your projects?

That said, I may expand my ponderings to include a low boost affordable supercharger that could work on a 1.9-2.4 liter CIH engine for an Opel GT.

 

[Autoholic]

Please don't take my posts as being negative towards the idea of an electric turbo, as if it doesn't have merit. It does, you don't have to worry about turbo lag and it could provide constant levels of boost. That actually can make it easier to tune EFI since you don't have a variable intake pressure to deal with. An electric turbo kit however would likely cost at least what the TorqAmp costs. Focusing on bang for the buck though, a conventional supercharger or turbocharger will cost less. You'll still have one of the only forced induction CIH powered GTs in America.

Maybe something like this could be mounted to a bracket and a pulley could be fitted to it. Then you'd just need a longer belt to drive it. SendCutSend can help you out with making brackets from thick plate steel or aluminum. Cardboard can be used to figure out the design for the bracket to help with the CAD work behind it.

https://www.jegs.com/i/Speedmaster/746/PCE157.1002/10002/-1

 

[GThound]

Maybe something like this could be mounted to a bracket and a pulley could be fitted to it. Then you'd just need a longer belt to drive it. SendCutSend can help you out with making brackets from thick plate steel or aluminum.

https://www.jegs.com/i/Speedmaster/746/PCE157.1002/10002/-1

I like that path. I really like the P2 price and how it has the backplate and gear drive system for the centrifugal compressor. It is what the guys with big V8s are using on the electrifiedboost.com forum. Alex uses that on his LTD that makes in the realm of 800 HP and near 10 second car with his electrified boost.
I really like that conceptual approach, but believe that the P2 is just too big for our 1.9 - 2.4 CIH engines. A smaller version of that would be a great starting point and reduce the energy to get it spooled up to 50,000 RPMs, which is just barely on the compressor map. My hunch is that if an e-turbo gets sized properly for an engine, it may negate the need for a blow off valve. And using it as a super charger, I still believe that sizing it properly is a key design element. Just need a smaller smaller one.

 

[Autoholic]

Procharger has smaller sizes, built more for ATVs and the like. But if you look into the prices for them, it breaks your budget. So, more research would be needed for the right size. Maybe looking for motorcycle related superchargers could help with getting the right size.

 

[RallyBob]

Bob, were you considering a supercharger from a Toyota pick-up for one of your projects?

That said, I may expand my ponderings to include a low boost affordable supercharger that could work on a 1.9-2.4 liter CIH engine for an Opel GT.

I have a Camden supercharger that I once had on my Toyota pickup in the late 1980’s. At 6 psi it added about 40% more hp and torque. It’s an 80 cubic inch blower.

I’m going to build an intake manifold to fit the CIH engine. I’ll most likely put this into my 1972 wagon, with a modified 2.6 liter engine. But I’ll have a modified head, increased boost, and appropriate camshaft for forced induction. I should see 270 hp or so with over 300 ft lbs of torque.

 

[Young Gt Lover]

I have a Camden supercharger that I once had on my Toyota pickup in the late 1980’s. At 6 psi it added about 40% more hp and torque. It’s an 80 cubic inch blower. View attachment 454830




I’m going to build an intake manifold to fit the CIH engine. I’ll most likely put this into my 1972 wagon, with a modified 2.6 liter engine. But I’ll have a modified head, increased boost, and appropriate camshaft for forced induction. I should see 270 hp or so with over 300 ft lbs of torque.

View attachment 454831 View attachment 454832 View attachment 454833 View attachment 454834

Wow! I can’t wait for that build!

 

[GThound]

Scratch all that.

No one's used A123 LiFes in like, 10 years. Those were the old 1st gen Dewalt lithium cells. A123's goal was to build EV batteries, but back then there were no EVs, so their way to establish an income source and business beachhead was to build tool batteries. They went out of business... I dunno, 8 years ago? Shopped around, was a ghost company for a while, and eventually someone picked up the pieces and tried to salvage the brands. They make new stuff now, but, no one uses LiFes anymore except in automotive starter battery replacements (and other RV and marine use that has always been based on the "12v" battery building block). And the only reason they're used there, is because they're so much worse than ordinary lithiums, and have lower voltage and energy capacity, that they coincidentally are a closer voltage match to lead acids if you chain 4 of them in series. With your other lithium chemistries, it's a awkward place between using 3 or 4. 3 is too low (12-12.6v is their ceiling, can't handle 13.8 or 14.4v that an alternator will put out), and will get overcharged. 4 is too high (16-16.8v full, 12v dead empty), and you're wasting half your capacity by never charging up fully.

LiFes are marginally safer (ltihiums went through a moderately bad phase 6 or 7 years ago as they'd found ways to get more energy into them but with less stability),

LiFes were originally used in power applications because the competing lithium technologies back then were unsuited for high power draw. As in, an 18650 would max out around maybe 2 amps. Today they'll do 50 amps. 1-2 amps was fine for laptops, right back to the 1990s, because you'd never drain a battery faster than in about an hour anyway. But it couldn't run so much as a dremel. Dewalt used them for 2-3 years before pulling the plug and switching to modern lithium chemistries. Woe on you if you bought Dewalt back then, they're not compatible with batteries before or after, basically just threw your money away.

LiFes are also really temperature and charge sensitive. The first time you try to charge it when the temp is below the freezing point, instantly ruins them, done, throw it away.

...

What I would use in your place is part of a used hybrid battery. Hybrid batteries are garbage for energy storage, but, nothing has higher power capacity than them, because they're designed to be fully charged or discharged in under a minute. The whole point is to recover energy while stopping, and boost your power while accelerating, without taking up much space.

A crappy old Prius pack will be ~200v, but, the cells are just stacked together like Lego bricks, you use as many as you want. You want a 50v pack? Use 1/4 of the stack. It'll be 20lbs. You won't pay anything close to $500 for one. Even 2nd gen Prius packs are rated for 36hp for the whole pack, so, using 1/4 pack, you'll be at 9hp, pretty close to your target.

Newer hybrids will have lithium packs that will be a fraction of the size and weight, and, usually aren't overly desireable. You can probably buy portions of a pack on ebay.

Or, if you can handle a minimal amount of DIY (a little soldering and making an enclosure), something like this: 48v 6.4ah 307.84wh Battery with Panasonic Cells - $81/kWh

$25. 48v. Pack will easily push 100A, has a 150A fuse if you push it. That's 5hp. Put two in parallel if you want, you're at 10hp. For $50. They're "used" but were premium grade medical backup packs and most of the time, literally never discharged even once.

I don't know what methodology led to you picking a specific voltage, but you could find or make or modify packs to be any voltage you want. Generally, if you want a motor to spin faster, you need a higher voltage (or, to choose a motor that was physically designed to spin faster at a lower voltage).



You could skip that, use a DC motor (nearly free) and handle the speed by belts or whatnot. Same way you would have to if it was engine-driven. If your goal was to get away with as low of cost as possible, a 10HP DC motor, or, one capable of 10hp in a surge is probably $20-40 in scrap, and they're thrown away all night and day.

Generally controllers can handle higher voltages and just choose to chop it down to whatever voltage the motor wants. So you don't necessarily have to match your battery voltage to your motor voltage. Higher voltage being better if possible, because you have the option of higher speed (lots of amps at low voltage will end up sitting idle because it can't push the motor faster than "max" for that voltage).



I didn't even know they made motors for BLDCs that didn't have hall-effect sensors. Yeah, you can spin them up blindly because they're low mass and can get yoinked into the position that matches the coil pulsing, but, I didn't know anyone did that.

Also, they're going to be... fragile. The little motors are skimpy and lack thermal mass. So, their "max" power is not really a suggestion like it is with the heavier iron. They're built like a balloon, not like a bridge.

7500 watts out of an RC motor is... a lot. Like, a lot a lot. It should be the size of a volleyball, but, it'll end up being not much bigger than your fist. Part of that corner cutting is that it'll be designed to be kept in massive amounts of airflow for cooling (i.e. at the axle of a propeller, free cooling), which, you won't have.



Stupid question, but why go electric at all?

Why not just power it off of the engine?

At the end of the day, the compressor is something you have to buy, and all you're saving going electric is having a way to spin it.



Did you want to be waiting years for this?

High power controllers have more or less bottomed out. Batteries don't have much more room to fall. And, there aren't any 10hp EVs floating around, you're off by an order of magnitude minimum, so, the costs of motor controllers dropping from the EV industry aren't going to exist from your perspective.

...

If you enjoy the process and want to spend time instead of money, you could get this done for really cheap. Junkyard and used parts, and then you spend your time and effort mashing it together. Any budget-conscious DIY project is just a series of bodges until it kinda works.

Who are you and what kind of an engineer are you? I am a chemical engineer by training, but mostly dabble in the design and mechanical engineering spaces. I love your thinking, the data, the practicality, the recommendations. I am learning driven, so thanks for sharing.