[GThound]

I like the idea of have having some of the benefits of a turbo charger with legitimate boost, without the complexity of the build. Now that I have my '75 EFI intake manifold with modern engine management (Holley Terminator X), I love the idea of piping in some boost.

There is a youtube video I watched where a guy took the compressor side of a vortec supercharger (centrifugal compressor like a turbo has) and powered it with a very high output motor (50,000 RPM 40 KW motor) using a dedicated high voltage battery and motor controller system on a big V8 (~800 HP 10 second car). The advantages of the e-turbo are clear. Nearly instant spool up time, lower end torque boost, high end power boost with super flat curve. Similar technology exists on F1 cars, but is super expensive, proprietary, difficult to procure, and actually is used in conjunction with a conventional turbo for faster spool up and power harvesting. There are quite a few gimmicky low cost e-turbos out there, that I am sure to be disappointed in. If this youtube guy could DIY a high performance electric motor driven boost, why couldn't I?

I am just starting the research, thinking, and pondering. Here is my starting point for a DIY build.

• ~ 5-7 psi boost target (keeping boost low for more affordable motor, batteries, and controllers)
• Compressor side from something like a Subaru TD04 turbo. Any other ideas?
• Direct drive shaft coupler to high output DC brushless motor used in large scale RC models ~ 10 KW motor (could have peak ~ 10HP)
• High output motor Electronic Speed Controller as used in high end Radio Controlled models
• Dedicated battery system (probably something like 48 volts) that would charge when car is idling / cruising
• 48 volt battery packs, controller, motor and compressor in Opel GT belly plan space
• Boost engagment and level actuated by my ECU as a PWM output as a function of Throttle Position Sensor

 

[LynnB]

Not saying it can't be done, but seems like it would be simpler to just use a small turbo. Lots of existing technology and support.
48 volts of battery will be expensive. Putting it in the nose will upset the front rear weight bias.
I don't see the need to reinvent the (compressor) wheel.

Just shooting from the hip here.

 

[GThound]

Not saying it can't be done, but seems like it would be simpler to just use a small turbo. Lots of existing technology and support.
48 volts of battery will be expensive. Putting it in the nose will upset the front rear weight bias.
I don't see the need to reinvent the (compressor) wheel.

Just shooting from the hip here.

Thank you for sharing, those are some great thoughts grounded in reality.

Not only would the batteries be expensive, but the motor is expensive and the motor Electronic Speed Controller would is even more expensive yet. Perhaps this is an idea before its time. Maybe I need to do a cost estimate. The energy density should continue to go up as the cost of these components go down. If i go low boost does that mean that the need for an intercooler is negated? The turbo fabrication might have to wait until the distant future after my 2.4 build.

 

[Autoholic]

I think it could be a good idea and stop to evaluate how much power you think you’ll gain from such a system and how much would it cost and how much time it would take to get it right. It will be easier and cheaper to figure out how to add a turbo or a supercharger to a CIH for your GT. A supercharger like the Procharger, where you could run it like an AC compressor, would be pretty easy to figure out compared to an electric system. And if your target is only like 7 psi, that should be easy to reach.

 

[Autoholic]

Put something like this on the driver side of the engine in a GT.

PanDair General Supercharger, Car SUV Aluminum Cherokee Roots Supercharger Compressor Blower Turbocharger Turbo Remanufacturing Kit Compatible with 2.0-3.5L

Buy PanDair General Supercharger, Car SUV Aluminum Cherokee Roots Supercharger Compressor Blower Turbocharger Turbo Remanufacturing Kit Compatible with 2.0-3.5L at Amazon. Customer reviews and photos may be available to help you make the right purchase decision!

www.amazon.com

 

[DavidF1972]

Science the 💩 out of it and build it!!

 

[GThound]

BTW the guy who did the inspiring experiments started a forum.

Electrified Boost

Community platform by XenForo®

www.electrifiedboost.com

They are very DIY and pretty grounded in the science. They do not have a lot of cars on the road, most are still on development. It is a new site, but I will keep an eye on it for nuggets of wisdom.

 

[72Vince72]

Home - TORQAMP

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This company has built a legitimate electric turbo.

 

[LynnB]

"If i go low boost does that mean that the need for an intercooler is negated?"
If BMW engineers have a clue about turbos, then no, the need for an intercooler is NOT negated.
On the first gen 745i there is no intercooler. Boost was 6 psi. They found significant gains (although "factory" HP ratings did not change) by adding an intercooler, but keeping the boost at a very conservative 6 psi. On my second gen, I have increased the boost. I run 11 psi. I have run as much as 15, but I twisted a drive shaft and kept grenading CV joints in the rear. The stock chassis just can't handle that kind of torque. 11 seems to be the sweet spot. Have not lost a CV joint or burned up a clutch in over 10 years now.

 

[GThound]

Home - TORQAMP

IMPROVE ANYCOMBUSTIONENGINE. I want it! Dyno Results MEET TORQAMP The one and only electric turbo to improve your performance Order! Find out more BOOST ANY ENGINE Even for power generators, tractors, trucks, boats, powersport vehicles, planes, the TORQAMP can change a heavy load into a small...

torqamp.com

This company has built a legitimate electric turbo.

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.

 

[GThound]

If i go low boost does that mean that the need for an intercooler is negated?
If BMW engineers have a clue about turbos, then no, the need for an intercooler is NOT negated.
On the first gen 745i there is no intercooler. Boost was 6 psi. They found significant gains (although "factory" HP ratings did not change) by adding an intercooler, but keeping the boost at a very conservative 6 psi. On my second gen, I have increased the boost. I run 11 psi. I have run as much as 15, but I twisted a drive shaft and kept grenading CV joints in the rear. The stock chassis just can't handle that kind of torque. 11 seems to be the sweet spot. Have not lost a CV joint or burned up a clutch in over 10 years now.

Cool examples. Sounds like you are making some serious torque!

Makes sense to me. I have even seen substantial gains on my GT going when adding the cold air intake and dropping manifold air temp by 20-30F.

That said, an e turbo is different in a few ways which may reduce the heat, but not sure by how much.

1. It is not in physical contact with the exhaust
2. It only runs when under high load where throttle plate is nearly wide open (this will depend on how I program it).

 

[GThound]

In terms of my budget eboost approach, one way I can envision to keep the cost down is to use a power system that I already have. I have an EGO leaf blower. I am not thinking about using the blower, but it has a monster 56 volt battery and battery charger.

When used as a leaf blower in low mode it lasts 90 mins. As a leaf blower in turbo boost mode (650 CFM leaf blower) it claims to last about 15 mins.

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. Hopefully it is even better than that as the peak may only happen instantaneously when resisting the momentum of the turbine for its insanely fast spool up.

I think that the above calculations if correct, put me in the realm of reasonableness for my application scenario. It seems to fit my driving habits, as I go out on frequent, but short drives. I could use some boost at lower RPMs and usually only hit it hard once per drive and only for a limited number of seconds. Then I could pop out the battery and put it back in the charger so it is ready for next use. If the battery died, the engine should just be able to suck the air through the compressor blade and housing with livable looses, since it is not positive displacement.

Also, let’s check the size of the ESC (motor controller using the above). 7,400 watts / 56 volts = 132 amps. So I’ll check options and pricing on 56volt motor controllers in the 150-200AMP range.

As next steps, I am going to:

1. Export and analyze the data log of my typical drives to see how many seconds I spend at various throttle positions which would correlate with seconds of boost at various levels.
2. Study compressor charts and understand how much work is done at various regions to understand energy requirements.
3. See if I can find a low cost turbo (junk yard?) that I can ply with in the basement.
4. Identify options and get cost estimates on motors and controllers.

 

[Young Gt Lover]

I am definitely following this! This is really interesting. What if your could somehow hook up the battery to the alternator? Just curious do you have a pic of your cold air intake set up?

 

[fjm568]

Article...

Leaf-Blower Supercharging! - Roadkill - Hot Rod Magazine

They said it would never work. “They” being Internet keyboard commandos, “it” being using a garden-store leaf blower for supercharging an engine for more power. Was this all worth $1,600 in blowers?

www.motortrend.com

Video...

Enjoy!

 

[GThound]

At the time I bought it, my EGO 56volt leaf blower was the strongest one out there at 650 CFM. It can blow wet leaves and rocks, etc off the driveway. Trying to hold onto it in turbo mode gives me tennis elbow.

It moves a lot of air, but it doesn’t create a lot of pressure. The best I could do is about 1/3 of a PSI with a quick garage test even using a restricted outlet (read duct tape). The reading on the digital nanometer is in PSI.

Maybe I could try that first with a quick test and see if my EFI system could tell a difference in manifold pressure. Currently at wide open throttle I am very close to atmospheric pressure, as there is quite low resistance of that particular 75 injected intake manifold.

 

[GThound]

What if your could somehow hook up the battery to the alternator?

Yes, the alternator can be used as charging system. As a rule of thumb it takes 10 seconds of charging for every 1 second of max boost. A step up transformer would be required to charge the batteries in the car as they will be in the 36-56 volt range vs the alternators 14 volt output for the cars 12v electrical system.

Some Formula 1 cars are using the boost motor as a generator spun by the exhaust gases to charge the battery system. That said, they are in another league with massive budgets and proprietary 400-800 volt systems.

 

[Young Gt Lover]

I just thought of an interesting idea. What if you put like a supercharger on an engine. And a supercharger is like a air compressor. So what if you make like a small storage tank for the pressurized air from the super charger. Then you can turn on the air tank so you can have a big amount of psi at once to use. Or is that a dumb idea. But this would take a lot of space in the car. Just an interesting thought.

 

[opelbits]

First off....a little history! Superchargers came from air compressors. The familiar Roots type blower is an evolution of the air compressors used to pump fresh air into mines and such.

Using an 'on/off' auxiliary air supply might mean a complicated fuel system to supply additional fuel to mix with the additional air. It's the difference between turbo/supercharging versus nitrous oxide.

 

[Young Gt Lover]

First off....a little history! Superchargers came from air compressors. The familiar Roots type blower is an evolution of the air compressors used to pump fresh air into mines and such.

Using an 'on/off' auxiliary air supply might mean a complicated fuel system to supply additional fuel to mix with the additional air. It's the difference between turbo/supercharging versus nitrous oxide.

Yeah I was thinking something like that would be needed. Maybe the air tank is just a bad idea. LOL

 

[Autoholic]

There is a good reason why superchargers are used to provide enough boost and not just an electric air compressor. I’m sure automakers would have used an electric air pump if it made sense. A supercharger is going to take less space and it can flow enough air. NOS is more or less just an air tank under lots of pressure. NO2 isn’t the same as air however, it’s a mono propellant. So it has what it needs to ignite by itself. Running NOS would be easier and cheaper however than trying to create an electric supercharger.

For anything electric, it would likely boil down to the CFM that is possible and at what pressure. This is why electric turbos make sense. The turbo impeller can handle the flow requirements, it just needs something with enough torque to drive it.