Imho extra compressed air tank also will add complexity, mounting difficulty and mass.
For it to be effective for longer boost time it needs to be big/heavy to hold more air volume at higher pressures (=probably in boot, like air suspension tanks, not under hood with no place for it and possible heat soak issues from nearby hot engine) + extra air tube routing. Compressor for it will need to be optimised for high pressure, i guess speed/volume of air compressed may suffer, thus longer times w/o boost, while it's getting pumped up. And costs.
Nah .. keep things simple, and most probably feasible is something like phantom ESC, tried and true solution/kit of compressor/controller/battery pack. Yes, only mild boost, but small size/simple retrofit/simpler design & make/reasonable price. Power & torque will still be more then with NA. Though that is also pro, as it won't require strengthening of engine internals/clutch/transmission. For those, to whom it's not enough, there are already tried & true classic SC/turbo setups.
ESC has it niche. Trying with it to outperform or perform on par with classic forced induction ways may eliminate it's strengths of simplicity/ease of retrofitting/lower costs. One can make pickup truck to perform well on track by extensive modding, but should one? Own niche product with own set of pros & cons, that will do best if used within that niche.

I agree that this sort of anti lag system is a different niche then the ESC concept. Obviously it’s for cars that already have a conventional turbo which makes adding an ESC all but pointless. However in terms of reducing turbo lag I think it’s an interesting idea possibly with its own thread somewhere, but I see no harm discussing it a little here in general terms.

I disagree about complexity and weight being greater. This sort of compressed air anti lag system would be far simpler than the ESC in terms of hardware since it would use mostly off the shelf parts. It’s just a comventiomal air compressor, tank, and solenoid operated valve. There would be no need for the batteries (lots of weight) or higher voltage charging system. It also wouldn't require modifying the intake which isn’t that complex on the BRZ/GT86 platform but not the case with every car. It would only need to add a compressed air line to the exhaust manifold (or anywhere before the turbine). I was thinking about it an it might even be possible to T into where the exhaust manifold pressure sensor connects on my C30 and other cars.

For practicality I think your over estimating the sizing of the compressed air system needed. It would only need to run for a very brief period of time to rapidly spool up the turbo (probably less than a second). Once the turbine is up to speed it it would cut the supply of compressed air. Also I’m not sure what you’re thinking of as high pressure but in most turbos I think exhaust manifold pressure to boost pressure is about 2:1 so I doubt you’d need anything over about 30 psi and probably much less just too spool it. Also I don’t think the volume of air is that great because it would be running for such a short period of time.

I was even thinking if you’re not using during normal driving and only when you are planning on more agressive acceleration you could possibly ditch the electric compressor and simply use a high pressure air tank, or better yet a nitrogen tank which would keep it from confusing the emissions controls.

It’s an interesting idea and I might look into it more. I’d love to reduce the lag on my C30 some.

Interestingly, I found Volvo has already developed and patented an electric compressed air anti lag system called Power Pulse that does pretty much exactly what I was describing...

https://www.carmagazine.co.uk/car-ne...-car-may-2016/

The power pulse system stores compressed air at 12 Bar (174 psi) and it only needs to release it into the exhaust manifold for about 1/10 of a second to spool up the turbo.

Very cool concept, but already patented so not legal to develop commercially. However not infringement for an individual like myself to tinker around with for personal interest under the experimentation exception. I might look into this more.

Supra Mk4 uses sequential twins, turbos are the same but the 2nd one is isolated while the 1 one spools and after a set rpm/pressure the 2nd one is released, this sytems is VERY complicated since you need bypass valves in the exhaust and intake.
Theres also a compund turbo system were you have a small and a big one in series which allows for incredible boost numbers but this is also complicated to make and takes a lot of room.

This is why I think the electric turbo is the way to go since you can have it placed on the intake side of the engine and doesnt need exhaust plumbing/modifications. I also realised you would only need 1 bypassvalve to bypass the ESC.
The tuning aspect shouldnt be to hard either, I do have programmable ECU and also a Torqbyte Fuel controller (Cm-5LT) which can be programmed with additional inputs and outputs I allready have configured with MAP sensor and RPM signal, and also have experience with arduino to make other controllers

I will try to make a compressor like you did using the Turnigy AquaStar 1280kv with around 48v, did you ever test this? I will do more research and 3d print prototypes but thats my first thoughts, there is quite a lot of room of the intake side of the engine so I think I will be able to make the bypass system also, but one step at a time.
edit: I guess the rpm is too low on that motor, I wil read through this whole thread to get more details

The compressed air system, I dont think that will work as easy due to as you point out the lambda/O2 sensor will get fouled, and also you dont want to cool the exhaust this is why they make turbine housings integrated to the exhaust manifold my car have this stock to keep the heat til it reach the turbine, cause heat drives the turbine and makes preassure in the exhaust side, more heat makes more velocity on the turbine (this at least how it works in my head).
I guess you could somewhow make a system work like that but for me it sounds way easier making a "ESC precharge sequential system". Imagine all that air from the ESC from lets say a 2000rpm wot pull will produce a lot of exhaust gass really fast and spool that big turbo way faster, Im so psyched up about this thought that I can barley sleep at night :D

Good luck, and keep us updated. I suspect you’re going to find this more difficult than you anticipate, but not impossible. It’s tricky enough getting the ESC alone to work well, in conjunction with a conventional turbo will be a challenge to say the least.

As for the compressed air system, I’m not to worried about the cooling effect of the compressed air. While you don’t want to cool the exhaust gasses driving the turbine as this would cause them to contract, it’s not actually the heat in the turbine that’s driving it, it’s the force exhaust gasses being expelled from the engine. In addition the cool compressed air would be absorbing that heat and itself expanding which should offset any volume difference from exhaust gasses being cooled. Keep in mind this only occurred for a fraction of a second not nearly enough to cool the thermal mass of the turbine itself by any noticeable amount.

We know Volvo has made this system work and claims it’s much simplier and cheaper to implement than using an electric motor directly connected to the turbo to spool it up, or an electric supercharge like the Audi SQ7. Volvo says this is because it doesn’t require a separate higher voltage electrical system. Aside from some sort of controller (needed for either system) really all that is needed for the compressed air system is a 12V compressor, storage tank and to connect it to the exhaust manifold. Compressors/tanks for air suspension systems or air horns seem ideal for this and aren’t very expensive.

Yeh I might have been alittle bit too amped about this, if there only was descent comericial ESC (Compressor/motor combo) availible to buy it would speed up the process a hell of a lot.
The compressed air system doesnt sound too bad actually, probably the way to go. BUT there is something about turboes that just looks and sounds soo much better. And since I have a top mounted turbo allready imagine poping the hood and see TWO top mount turboes, one on each side of the block even tho its a inline 4, you would normally only see something like this on a V-engine it would be very interesting if it works good as planned.

But I will digg around some more and see how to approch this, sooner or later there will probably be aftermarket options availbile, and the cost will probably not be very attractive for what you get.
I do wonder if this Audi SQ7 is released if its possible to go to a audi dealer to order a replacement part of this unit and experiment with it, but I kind of doubt thats the case if you dont have the car on such a special component.

I don’t blame you the ESC is a very cool concept, and I’m sure it could be made to work the way you want but I’m not sure how much time/money/expertise it would take to get there. I’m pretty good with that kind of stuff but I was still consulting with various experts I know and getting input from people here and other places. Even with that I had a ways to go before I would have had a truely viable system. The protype comprrssors I built worked and I had the start of a control system when life just got too busy.

Usually car companies are pretty restrictive about speciality hardware like that so I doubt you’d be able to get one anytime soon unless you actually owned and SQ7. Maybe someday, and as more and more manufactures turn to solutions like this I bet they will be easier for the aftermarket to get.

Even though I’m not currently working on building one myself I’m still happy to give advice to those adeveterous enough to try.

Too funny, just found this website, it is so close to my design (with improvements) I’m guessing they at least used some of my work as a starting point and no doubt the Phantom as well.

https://arcsuperchargers.com

Wonder how much will cost

"At the time of release, we estimate the cost of a complete kit to be $2300. This cost is subject to change as development matures"

but there Want more information about future availability? Click link is dead so i would not be holding my breath

I pass... with a little more you could fit the traditional sc

Looking the website over I doubt it will ever make it to production. The website hasn’t been updated in over a rear as far as I can tell and many of the links are broken. Not faulting them for trying I’d love to see a product like this available but as many people find out making a prototype is a far cry from getting a viable product into production and running a business. That’s why I started this thread to just share my interest and experiences rather than trying to start a business.

Hopefully some company with the resources and experience to develop this concept fully will see the interest from the aftermarket crowd.

Yeah it seems dead, I also wonder what happend to eCycle which was mentioned in page 33.

Ive been looking at motors and came across this one https://hobbyking.com/en_us/hobbykin...ess-motor.html

6kw and capable of 76000rpm seems to be a better choice than the turnigy aquastar T20. I will only be operating the ESC between 2000-3000 engine rpm or maybe just <1500-2500 is enough to make the main turbo really take of.
I need to learn more about compressor maps, ive been playing around with the borg warner matchbot calc and the cool thing is you can actually se of much hp it takes to drive the turbo shaft on different engine rpm,turbos,engine displacement, psi targets. and lots of other data. but these turbos is probably the most expensive ones that exists, im mostly looking at the ebay style compressor housings for now