When and If E-Charger is not Running? Tradeoffs vs Conventional FI units

S

SQCTS

Member
If I missed this in another thread please forgive me and remove this thread. I admit i haven't read every post in every thread.

Now being that this is a E-Changer and if your vehicle is a daily driver, is your the E-Charger going to be in continuous use? If so what is the life expectancy of the motors. More so the batteries. So I guess this is where the smart control system comes into play where the system say all boost at higher % of the throttle position or at this rpm range. If no smart system doing a simple WOT switch or the sort.

Ok,

Now when the E-charger is not in use, impeller not spinning how much lose or any lose is happening do to the resistance of the motor not allowing the impeller to turn or turn freely from Air follow coming in on the intake side? Is the E-charger a restrictions at that point? In conventional turbo set the impeller is also in use and in conventional supercharger setups the engine is always driving the supercharger so there is no restrictions or much less restrictions at lower rpm.

If the E-Charger is a restrictions or somewhat of a restrictions, is there enough hp lost to be noticed. Is this something we need to account for in our tune. Now if the motor life expectancy is long from continuous use at low and high rpm use this shouldn't be of much concern.

Now is this the trade off of our E-Charger? Like the conventional units there is tradeoffs, supercharger there is lose do to the engine having to drive another component via the belt system. Turbo using heat exhaust air to make power and lag.

Thoughts please.

Thinking ahead or overthinking it. I was looking at doing an open and close valve when the system is not in use. Basically an open/closed exhaust valve. They comes as large as 3.5", well maybe larger, i just did a search for 3.5" as that is the size of my current intake. Issue would be space to do a such a setup for many.

3.5" Motorized exhaust bypass valve

3.5" Motorized exhaust bypass valve and more!
www.allpurposepipes.com

And honestly I guess it doesn't have to be a valve setup, it could just be a Y-pipe type setup. I wasn't sure how the air from a simple Y-pipe would effect the blower side of the system so the valve system seem like a better solution to the problem (that may not be a problem) than the standard air intake side when the blower is in use. Now like above will this have to be take into consideration in the tune.

Yep maybe i am overthinking this!!
 
Battery life.
There are many factors affecting battery life and i can't be bothered going into them all because the rough answer is the battery's should last forever... A123 26650 .. have an apparent 4000 cycles to 80% capacity.. If i cycle them once a day 6 days a week. that is 52x6 =312 4000/312 = 12.8 years. but it's not like they will stop working at 80%... the next question is how many times will i cycle the battery's. This depends on the capacity you have and your expected run time..
I will quote myself for the next part

My example of 18ah .. with 100amps pulled gives me 10.9 minutes of run time .. lets call it 10minutes... but remember that's 10 minutes of constant draw... this sounds like nothing but it's actually alot that is 60 10 seconds runs without charging !, I would be in jail for long time if it did that ! lol
Obviously as long as there is some charging going on too then the numbers will increase..

If i charge at 5amps then it will take 20 times longer to charge than discharge.. so a 10 second run would take 200 seconds to charge... this also sounds bad but thats less than 2 minutes,, and this is for an impractical 10 seconds run that maybe you'll do every now and again.. and also as their is a 200 second gap you can do this endlessly.
Click to expand...

SO in reality's i dont believe i will cycle the batteries even once a week with normal driving.. Id have to go out of my way to run the pack flat... SO battery life expectancy is incredibly huge intheory. many many many decades.

E-Trubo Restriction.
People asking "but what restriction does the e-turbo put on the engine at WOT when it's off" has always annoyed me because it shows a lack of understanding.. the answer is obviously nothing because their scenario never happens.. At WOT the E-turbo is always running.

At part throttle when the e-turbo is not running is a scenario that would actually happen. e-turbos dont need to be spinning to pass air so you can work out the sectional area of a E-turbo then compare that to the sectional area of your part open throttle. A not fully open throttle is intentionally trying to restrict air into the engine so what does it even matter is the e-turbo is causing a slight restriction anyway because you are intentionally trying to restrict air into the engine .

Assuming that you have a powerful enough alternator and pack charging system .. you could in theory run the e-turbo at a super low enough RPM so it's never a restriction. However then you a pulling more power from the alternator and thus loading up the engine more in that way so would you really be winning ?

Exhaust valves
My experience with them is that they dont seal perfectly and they open and close slowly so get one and test it first.
 
The concept of a E-turbo being completely OFF at say 79% throttle and at 80% throttle being completely ON will be undrivable on a road car in my opinion and be down right dangerous.. A more realistic system would say start spinning the turbo at say 50% and building up to max boost at 80%.. this will allow you to drive around at least in theory at say 1PSI (or less) ... and since the turbo is now starting at a lower throttle position then the argument for the restriction at lower throttle position becomes even more moot.
 
Agree with MSA!

Especially with MAP or load request monitoring you can find a smart way to eliminate any possible restriction at mid throttle ... but the thing is: at part throttle a possible restriction might not get noticeable anyway for the driver.

What might happen in those typically closed loop areas that for your engine to run stoich (AFR 14.7 or Lambda 1) your ecu might reduce fuelling due to less air ... but again: might not be noticeable at all for the driver!

I must admit: at some point I was thinking about bypass tubing myself ... but on further thoughts it would only be justified if you want to maintain stock behaviour on completely switched off (or drained?) eBooster (for beyond part throttle). (And for that I would not use a exhaust bypass valve but more likely a DBW throttle body in the right size)
Lets get a working setup and do some real life measurements ... and then take it from there. Results will be highly "individual" depending on engine size, activation point(s) of the eBooster and size of the booster/restriction ...
 
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MSA Let me start with this, So you being annoyed has no place here when we all have questions and are all trying to figure out the best set-up or a few different was to make the system work, wait a second unless your the E-Charger GOD and know all there is to know.

I have also find it annoying for people to
get annoyed and make assumptions when you don't know someone. Even if a person ask a question usually it is because of a few reason, they want to learn or want to verify what they have learned to be consistent with what others have learned or to verify thier thought process. So if someone don't want to give an answer without a smart attic comment keep it to yourself.

Now

The restriction matters because of what you just said. At part throttle we are restricting air flow anyways the E-Charger will cause a greater restrictions even if it is only slightly when it is not in motion. We can't have our cake and eat it too. The system has its limitations just like any other FI system. What we are doing here is trying to minimize them as much as we can.

Now with that said there are couple test with the Troqamp inline and when it was not in use, but in the AIR intake system, the engine last power compared to the stock run on the dyno. Was it much, nope but never the less there was a loss in power. So you taking the restriction topic to heart and seem to think I meant it was going make the engine loss 100 hp, really come on now please don't assume. A restriction is a restriction no matter how large or small it may be. If it is less than what the stock engine does it is a restriction by ever definition of the word. Noticeable or cause for concern maybe not, but we can't act like the system are with limitations.

Now I 100% agree with you on at what % of throttle position the unit should kick in and at what throttle position it should be at full boost.

But anyways the battery question was addressed and they that wasn't the mine question. However to think the batteries would last forever, not in the real world, and damn sure not in system such as we are using them. More so bad cells happen every day. So as you gracefully put it in another thread, them lasting forever with no issues is only in a prefect world which we damn sure are not in.

YET where is the MOTOR LIFE EXPECTANCY topic and/or answer? No one has addressed this, which was the top question. Why because either we don't know the answer and need time to research around the net or phone a friend to for the answer. Nope it because we have no idea. Because there is 1 or 2 people here that have working systems. However we can get an idea from talking to people like the RC ladies and gentlemen that have used these Brushless motors for decades now. In daily driver the motor will see a ton of use even if the start of operation is at 50% of full throttle. These motors will be exposed to a crap load more heat than any RC vehicle could subject them to.

So how do we prolong the life of the motor. Things like water cooling, trying to mount them in matter so they are somewhat shielded from the heat of the engine? These motor that we are using where designed for RC use which is not an everyday occurrence and they are not subjected to the harsh environment of an engine bay.
 
I will just ignore the first part.

Motor life.. There is theory and realty just like the batteries so it depends on how pedantic people want to be especially if you want to include manufacturing defects..

You could say that the only moving part of a brushless motor are the bearings so that is the only thing that will wear out. So you could do the math on expected run time and work that out form the expect run time of the bearings (Life). It should be a long long time with out even running the numbers.
Motors magnets will demagnetize due to heat so keeping them cool will improve their life.
In the real world keeping dirt out will be one of the most important factors to motor life and of course keeping the motors within spec.

As for real world scenarios probably the best examples we have of battery life and motor life are hybrid cars.. where they can last for incredibly high millage.. Probably more miles than we will add to our cars on top of what they have before adding a turbo.
Electric cars are less of a direct comparison but go look how long they can last.

Both the motors and batteries should last incredibly long as long as both are treated how they should be. Will they be treat well .... Well that is probably the real question.. So far i dont see people running propper full proof BMS's Alex is not ( i wouldn't too it's just a drag car) WB Projects is also not.. So we shouldn't expect their batteries to last as long...
 
Agreed!

I do agree with you on the BMS and do plan to run a BMS on my system. Biggest reason Because at the moment I will be using Lipo batteries and and being that they are very volatile. I need to keep a close watch on the battery system or should i need something to keep close watch for me of the battery system.

You hit the nail on the head treatment of the system and care taken to keep the motor safe from the elements. And heat is the enemy of any motor so percussion take to limited and lower the operating temperature of the motor and ESC also being that it will also be mounted in the engine compartment.
 
It is always good to do a lot of brain storming in advance!

Sometimes we do overthink certain aspects and some other times further down the road we find "surprises" (daumn, not really, why di I not think about it earlier).

Engine bay heat and dust, as well as engine tuning (or "component protect" aspects) are things to solve, still!

We just started scratching the surface with blower/charger map and sizing/motor rpms/amps/battery voltage and capacities/recharging/cabling/ESC powerstages (and commutation) . Topics like engine tuning, boost control (blow off valve), charge temps (intercooling) and a eMotor throttle control are more topics which we need to tackle.

We are looking at 12-20 kW being produced by tiny itsy bitsy but HOT rc motors whirring at 30000 rpms at least ... and burning something like 200-350 amps ...
A LOT of stuff to tackle ... and the "going wrong" is lurking everywhere!

And it is EXACTLY the reason why I like this project! Easy is boring!

And it will NOT be cheap ... burning a ESC here and there, changing battery build and chemistry ... and trying out "another motor" has ALREADY tested the patience and wallet of pioneering adventurers here ... and don't think they went through "worst cases"!

A blown combustion engine is even more money ... a torched car (due to electric screw up) even MUCH more expensive.

I am grateful for all the information exchange ... be it inspiring questions, subjective or objective responses or just simple "failure reports" ... it will pave the road for all of us!

I love this project 🤪👹!
 
Hey guys - I can tell you this: On my setup, with the e-turbo not running, there was pretty much exactly the equivalent of 1 psi boost loss - in the case of my engine about 30-40 hp. I give you a range because I swapped to a larger TB (100mm) from a 75mm unit; there was a small amount of vacuum present at WOT with the 75mm tb - on the order of .2-.3 psi boost loss. Not much, but something. Keep in mind, this is on a 365 cubic inch V8 with good heads, intake and exhaust. On anything below say 400hp N/A, sucking through a non-spinning a Vortech Si trim wouldn't be noticeable. Even at my N/A power level (~500 hp), you'd be hard pressed to notice, simply because the loss only occurs at high rpm - peak loss occurs at 6,000 rpm; which happens to be my HP peak as well.

By the way, the impeller blades don't spin when just sucking through the e turbo.

To be honest, I wouldn't run the e turbo unless you're over at least 3,000 rpm and more than 80% throttle. I'd do it as an "and" condition - i.e. both conditions need to be met in order for the e turbo to run.

Though looking for gobs of low-end torque sounds good on paper, I can tell you with certainty (after screwing around with positive displacement blowers for well over 25 years), too much low end torque leads to excessive cylinder pressure. Excessive cylinder pressure can lead to all sorts of nasty things - melted pistons, blown head gaskets, cracked main webbing, etc. I've done them all. I actually cracked all the mains in a stock 5.0 Ford block one time:

Main2.jpg

Check out all that fretting on the fractured side - and the cracks go all the way to the cam tunnel. I was able to drive it home from the track (about 70 miles) only because the intake manifold and the main girdle I put in held it together. But when you'd give it gas on the highway going home, the oil pressure would drop as the cracks all opened up. That was fun.

Anyway, in my view, no matter what the application, the e turbo (or any power adder for that matter) not only doesn't need to be running all the time, but shouldn't run all the time. What happens in actuality is your tuning window at low rpm dramatically shrinks; and things like detonation become very difficult to keep in check. You actually hit a point where no amount of timing retard will keep detonation at bay.

On a smaller engine driven aggressively, you'll be running the e turbo much more often; but I'd still hazard a guess even on a road course you'll probably still be under 50% duty cycle.

The absolute best way to deal with heat like this is water cooling. I'm re-using my old A/W intercooler tank (which had a 2,000 gph bilge pump circulating ice water through the intercooler core I built and rejected enough heat to melt 10-15lbs of ice in 10 seconds (!). That's a 3 gallon tank, btw. I fully anticipate only needing to fill it up with ice once on a typical track day for me, since these setups are so much more efficient.

In fact, that block damage above happened at about 8-10 psi on a 306 cubic engine with an Eaton M112 blower cribbed from a Jaguar. The really interesting thing is here are the time slips:

CecilSlips.jpg

Compared to my first drag test video with the e turbo where we went 10.58 at 127 mph, the ETs are similar, though the MPH is a little higher. BUT - the e turbo is so much more efficient that it did the same deed with less than half the boost (though the new engine has about 80 hp more N/A than the old one). That's important, but the real magic lies in the fact that the above timeslips were obtained with optimized gearing. In other words, I was going through the traps at about 6,200 rpm. Where as with the e turbo, we were only going through the traps at about 5,700 rpm. 500 rpm doesn't sound like much, but the above timeslips were gotten using 3 gears in a 4 speed automatic tranny; we're now only using two gears. Had the car been optimized for the e turbo run, we would've seen 10.4x at about 128-129 at least. And then add in the fact that we were on a no prep surface, and tire spin at mid track was pretty bad vs absolutely zero tire spin in the above time slips, and you could make a strong arguement that even 10.3s are possible at only 4 psi at HP peak rpm.

I'm going a bit off-script here, but the primary take away is I wouldn't worry about running the e turbo all the time; or even half the time (unless you plan on open tracking the thing). The restriction on most engines with the e turbo off is negligible, and running it too much at too low of an rpm will cause you all kinds of very expensive damage:


That's my two cents anyway.
 
Besides which, you'll likely run into compressor surge anyway. From my perspective (an automatic transmission), it's almost a moot point in reality anyway. The second I floor it off idle, the engine will flare (rpm-wise) against the torque converter. Anything over 50% throttle results in a near-instant 3,000-4,000 rpm jump. The e turbo would just be spooling up at that point. In a stick shift car, most decent drivers know no to lug the car at too low of an rpm - lugging can result in more engine damage and wear than simply choosing the right gear at the right time - even with the "right" gear resulting in a little higher rpm.
 
I was just reading through this. somewhat skimming through so forgive me if this has been covered but, it occurred to me there could be a potential fuel economy advantage with the correct control strategy. This will likely be tackled after an "end-user" e-turbo has been finalized but, positive pressure at part throttle/cruise could allow for a more efficient combustion event & even a lean/super lean cruise strategy. With an e-turbo the boost available can be chosen & maintained based on load, rpm, throttle position, etc.
Maybe not practical with the energy density available with modern batteries. Fortunately, we have an industry already driving battery improvements; e-cars!
Variable boost available on demand. I SO love this!
 
I think honestly that you won't gain much economy, if anything, over simply leaning things out/adding timing while cruising. I also think it'll be tough to beat OEM tunes, since they have to meet CAFE standards. But I could be wrong.
 
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