Open Source Electric Supercharger

[al3k]

T04E 54 or 50 trim compressor seems like the way I would go combined with a motor thats able to reach 70k rpm, this should be able to feed the low end area 2000-3500rpm around 50-100% the lb/min flow I have today, starting at 8psi. Low end torque is the only priority here.

I dont know how much kw is need to do this, but there isnt much to pick from either with high rpm so will get something around 6kw and try to feed it with as much it can handle.
Any tips would be usefull, this is the flow numbers from my current setup with the latest log (Maf g/s converted to lb/min)
2000 - 5
2500 - 8
3000 - 12
3500 - 19
4000 - 26
4500 - 28
5000 - 31
5500 - 34
6000 - 39
6500 - 40
6800 - 41


Did some calcs for a compact battery solution for a 44.4v system using two 22.2v packs
ZIPPY Compact 4500mAh 6s 40c Lipo Pack w/XT90
6s 4.5Ah 40c = MAX discharge 180A
22.2V x 2 = 44.4v
180A x 44.4v = constant discharge 7.99kw, duration 1.5minutes (peak discharge 16kw)
This should be plenty, not thinking about recharging while driving for the moment.

[Matt@Cosworth]

the main trouble you have with applying an ESC on a powerful engine is you don't want any restriction at the top end
and with 41lbs / min thats 310 grams /sec thats a pretty big blower

so if you have a TD04 with a 54mm wheel that's a good size to give the low end response at 75K rpm ( about 160grams/sec max airflow I think) but you'll then need a bypass valve to open up at high engine speed so it won't choke over 160 grams /sec

all do-able of course

[Lantanafrs2]

Sounds like more trouble than it's worth. Boost is supposed to build with rpm not decrease.

[al3k]

Originally Posted by Matt@Cosworth

the main trouble you have with applying an ESC on a powerful engine is you don't want any restriction at the top end
and with 41lbs / min thats 310 grams /sec thats a pretty big blower

so if you have a TD04 with a 54mm wheel that's a good size to give the low end response at 75K rpm ( about 160grams/sec max airflow I think) but you'll then need a bypass valve to open up at high engine speed so it won't choke over 160 grams /sec

all do-able of course

You might misunderstood this, this is what I run today with the EFR6758 and the ESC wil be added additionally with a bypass valve to make the car very snappy from low rpms only. Its expensive and hard, but somebody has to do this or at least try, I have a strong belive in this, theres other ways to get the same results but this is the way I wanna see it get done.

Edit: Sorry I think I misunderstood you, and forgot to mention the log values I posted was from 2nd gear WOT with the EFR6758 on my 2.0l so airflow would have been higher if started from 2000rpm in 4th and did the pull in the low end of the powerband. So i need to be able to pull around 10 - 25lb/min from 2k-3krpm instead of 5-12 which it currently is in 2nd. I will check the TD04 with 54mm wheel, Im trying to find a Compressor map.
This is the T04 50trim:

[churchx]

Trying to ask from ESC too much, for it's boost to be on par with classic SC, imho will unreasonably rise kit complexity/weight/cost. More boost = bigger power from heavier battery dump pack consisting of double or quadruple batteries needed, that will cost more, will weight more, will be harder to find mounting space for, and probably more complicated controller for eg. charging & cooling will be needed, pack will charge longer to full charge. Imho Phantom ESC with mild boost was fine time proven compromise costs/implementation/gains wise.

[Matt@Cosworth]

thanks for posting up the compressor map
it looks like if you run the compressor to 75K rpm ( about the limit of the electric motors it seems) then you'll get 25 lbs /min with a pressure ratio of 1.4

so thats not bad certainly good enough for a FA20, I'm considering making one for my RX8 and that drinks 25lbs / min at full chat

[al3k]

Originally Posted by Matt@Cosworth

thanks for posting up the compressor map
it looks like if you run the compressor to 75K rpm ( about the limit of the electric motors it seems) then you'll get 25 lbs /min with a pressure ratio of 1.4

so thats not bad certainly good enough for a FA20, I'm considering making one for my RX8 and that drinks 25lbs / min at full chat

That second speed slope from below is actually 69704rpm so only around 70k rpm motor is needed, I will check how much hp is needed on a motor for 25lbs/min

[al3k]

Looking at logs with my stock (k03) turbo, it looks like 15lb/min is plenty to match that small turbo spool up.
Making a system with less voltage and turbo rpm to reach this will also make it less complicated, but having a bigger motor could really help sorting out potensial bugging/coughing issues i guess.
It probably doesnt sound exciting at all, I also realized there might be to small space for a proper bypass system afterall. But its doable with more customized piping.
Also pressure ratio will need to be low as possible at 2000rpm or less you dont want to full boost a stock eninge with a 10:1 compression ratio, the stock turbo was showing 4psi @ 2100rppm and 10psi @ 2440rpm without knock retard, so somewhere between there should be good if intake temps dont increase

[al3k]

TD06-20G looks to have a very nice area which can be used with different motors 55000-75000rpm++

[Matt@Cosworth]

Only trouble there is you will definitely need a bypass to avoid it being a restriction at high engine speeds
I'm assuming the x axis is in kg/sec? as even a stock FA20 is about 160g/sec flat out

I prefer the look of the previous TD04 map as I need 220 g/sec or 29 lbs/min air flow at full revs

and its looks like the OEM's have finally brought something to market too

looks like the 1st one out of the gate is Audi
as the latest TDi Q7 uses an electric charger to provide low end boost on top of the turbos

https://jalopnik.com/this-is-how-audis- ... 1823681637

just need to find a crashed SQ7 and strip it mercilessly of the interesting stuff - hopefully the breakers won't cotton on too quick to this one

[Teseo]

Originally Posted by Matt@Cosworth

Only trouble there is you will definitely need a bypass to avoid it being a restriction at high engine speeds
I'm assuming the x axis is in kg/sec? as even a stock FA20 is about 160g/sec flat out

I prefer the look of the previous TD04 map as I need 220 g/sec or 29 lbs/min air flow at full revs

and its looks like the OEM's have finally brought something to market too

looks like the 1st one out of the gate is Audi
as the latest TDi Q7 uses an electric charger to provide low end boost on top of the turbos

https://jalopnik.com/this-is-how-audis- ... 1823681637

just need to find a crashed SQ7 and strip it mercilessly of the interesting stuff - hopefully the breakers won't cotton on too quick to this one

We need to find some audi and rear end it as much as possible so the front can be intact for research purposes

[pcguru2000]

Maybe this is off topic, but wouldn't an electric motor directly driving the pulleys via a chain or belt be more efficient and also be smog legal, not require modification of fuel maps, intake, exhaust, etc.

[churchx]

pcguru: how adding parts that will need extra maintenance and will introduce extra mechanical losses can enhance efficiency/change emission legality/not require ecu tune? :/
I can imagine only one scenario and only for efficiency bit, if one uses electric motor with different rpm range then is optimum for spinning turbine/compressor. But then egain choosing right electric motors seems wiser to me then using wrong one + adding mechanical parts to change gearing ratio. And how that can change something with emissions or tune? :/

[Matt@Cosworth]

Originally Posted by pcguru2000

Maybe this is off topic, but wouldn't an electric motor directly driving the pulleys via a chain or belt be more efficient and also be smog legal, not require modification of fuel maps, intake, exhaust, etc.

trouble is you need to make a gearbox / belt / chain drive that's happy with 75K + shaft speeds
this is not easy

direct drive is right route