Small bore engine

P

Pridanc

New member
Hey everyone. Relatively new here and some friends and I are on a project to build a very small bore hot-rod motorbike.

We have lots of turbo experience but really want to explore an e-blower of some sort. Our only concern (aka lack of knowledge) is driving a centrifugal compressor at enough rpm to make the boost we feel we need for the duration of a run. We will need boost for between 2.5-3 minutes.

And to carry that thought farther, is there any merit to running a very small screw type compressor via electric motor? IE, would that take potentially less power from the e motor and battery capacity to drive and achieve the boost needed or am I barking up a tree? Remember small engines like this have small CFM needs.

Can you tell I have zero knowledge or understanding of electricity? Once I gather the info we can decide to go standard turbo or e-blower. The turbo is easy which might outweigh all the other reasons to use something else, but until I know more about e-blowers I'm not choosing just yet!

Huge thanks in advance.
 
First, found your needs. What power you want to make on your specific engine and how much boost you will need. When you found this, try to find your compressor you want! Centrifugal or screw. When you found your compressor, check for how much RPM you will need for that! Now then, we can discuss on which set up you will need!
In the world of e-boost, we are verry limited by the RPM we can run a set-up. It was the main problem for years until Alex and I were about the same time able to make it happen.
Since you have a small engine it should be easier to find a combo for you. The complicated part I think is to find the right compressor to fit with the electric motor combo
I think I was able to achieved the highest RPM with 65k rpm. I am hoping for little bit more this summer but keep in mind that is about the highest you can go.

With proper cooling you should be able to have boost for couple time but minutes non-stop ? Maybe not. A capacity of couple minutes thats easy but running it for 3min straight maybe not. The cooling will be your worst enemy
 
WB, so you are saying that cooling of the motor is the enemy?

I know all the particulars of my needs (CFM etc) and am looking for information from the compressor manufacturers right now, but my real curiosity is if anyone here had run a screw type compressor to see if the screw compressor take more energy to turn than a centrifugal compressor. Probably does but a screw compressor also does not turn as fast as a centrifugal compressor for any specific amount of flow/boost pressure.
As you can see, I am a curious person.

TY for your thoughts and I look forward to hearing if anyone has attempted a twin screw compressor.
All the best.
 
When I said « your worst enemy » I mean, heat will be your biggest enemy and cooling will be a challenge!
I did pu a huge heat sink on mine where the car airflow intake shoot right on it!

I think the screw will require more energy due to more friction, I guess, and oiling will be something to look for too! I am not too much into the screw supercharger but everything is possible. Just check the pros and cons! We all have a different setup here trying different things but there’s no right way hahah
 
WB, your thoughts of more energy for a screw compressor makes sense. I think for now I will forget about the screw compressor and build a small centrifugal compressor with a motor to test as I see you guys do it. While I'm doing that I will test how long the batteries can make the boost we want!

OR, I might just say "forget it" and use a simple turbo! We shall see but I really appreciate your help and advice.
 
The nice part is we almost did it all and know what should work first time 😂 don’t need to work on it for years before find something that works hahah
 
IF we end up building a small e-turbo, I will share with you / this forum everything we learn. I said IF... 😇
Many thanks for all your help as I appreciate it.
 
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