Bobs 2024 Build Off Build

[Evanguy]

right on, id keep looking into those options if i was you.

but i would worry about running an intercooler with a draw through setup the gas will want to settle on the cooler walls of the IC, at WOT i cant see it being much of an issue at all but lower rpms it may be.

im building a rig with an oem amr500, used off a little Subaru opposed to China rebuild.

 

[bob58o]

right on, id keep looking into those options if i was you.

but i would worry about running an intercooler with a draw through setup the gas will want to settle on the cooler walls of the IC, at WOT i cant see it being much of an issue at all but lower rpms it may be.

im building a rig with an oem amr500, used off a little Subaru opposed to China rebuild.

I’m pretty sure I have a thread dedicated to this and similar ideas from years ago. I’ll have to look back. Then it came up again in the engine build. Then again once I started putting pieces together. I kept explaining the purpose of the recirculating bypass for when the throttle was closed. I kept getting called dumb and told I don’t need a blowoff valve, even though I explained my intent to have it open under vacuum (not boost) to send the air/fuel back to the non pressured side.

I never fully investigated how the vac/boost signal lines would need to be attached. Non pressurized on top, pressured on bottom. I think there are two nipples. Then find the right spring?

Also had an idea to clutch the blower so it doesn’t spin at idle.

I had lots of ideas. I think I called the old thread a think tank.

 

[bob58o]

This project has been in the works since 2017.
Lol

Supercharged 212cc Think Tank / Idea Board

Maybe this will happen? Maybe it won't? That is what this thread is for. A place for me to gather some information and ideas. https://www.aliexpress.com/item/Car-Snowmobile-ATV-Roots-supercharger-Mechanical-Turbocharger-gear-Supercharger-for-Displacement-0-8-1-8L-model/32273549916.html AISIN...

www.diygokarts.com

 

[Evanguy]

i think you are understanding this better then most, the bypass has nothing to due or even work similarly to a blow off valve,

a blow off valve just relives the pressure spike when the throttle plate closes because the compressor is still at 100k rpm and if you don't bleed that off you will get compressor surge

a super charger doesn't really have that spike as its driven off the crank, the bypass valve doesn't bleed off pressure or even let or release. its so the Sc isn't under vacuum and doesn't produce heat from pumping while your off the throttle, it naturalizes the pressure on both sides so the Sc is just free spinning not compressing building heat for no reason

 

[bob58o]

6 years later… same questions. Lol

 

[bob58o]

That was a good thread. Comical.
Good stuff learned at that time.
Firstly, only trust your gut.

itsid was one of the smartest guys on here.
He said I need a bypass. I felt I needed a bypass. My gut needs a bypass. My blood pressure is perfect though.

The idea of running the blower without a bypass but having it driven by a centrifugal clutched shaft was shot down because the blower would just be a huge restriction at idle. Not sure if that would make it inoperable at low rpm?

 

[ezcome-ezgo]

Notebook paper makes a less compelling argument.

 

[Rat]

Fastest way to explode a TC... have the blow off jam shut, and suddenly make maximum boost.
If the Turbo doesn't blow first, the engine will.

SC doesn't have that fatal flaw

 

[Evanguy]

Waste gate controls boost, blow off valve controls compressor surge. Waste gate stuck makes max bost

Compressor surge isn't that big of deal. And newer turbos are made.to handle it with anti surge features

 

[Denny]

You’re all confusing turbochargers with superchargers! His set up as he has it now is perfectly fine and almost correct. (Supercharger should be closer to intake valve.) No bypass or blowoff valves are necessary or needed. I have spoken!

 

[Evanguy]

some people here are confusing the parts of each setup for sure.

a roots blower doesnt need any form of blowoff valve at all i have no idea why it was brough up so many times by people when he was asking about a by pass valve (totally different thing)

yes SC should be as close to the intake port/valve for a draw through setup, of course it doesn't need a BOV its not a turbo setup, and i guess it doesnt need a by pass valve to run but that will really shorten its life, also require you to add oil to the SC really often, build way more heat when off the throttle, put a bigger load on the motor at idle and when in vacuum for zero gains,

the only advantage to not running one is, you don't have to make it.

it just neutralized the pressure on both sides of the SC at idle and under vac so it free spins the rotors with next to no load on the engine or heat being made.

 

[bob58o]

Perhaps the confusion stems from me wanting to use the wrong type of valve.

Without fully thinking it out, this is the type of valve I was thinking to use. Still need to think about it. These pics might help me. I will stare at them until I understand.

 

[Evanguy]

Lots of bypass valves are like a throttle body with an actuator. The need to flow more are then a blow off valve does. Although these are very small engines so it may flow enough for this setup.

https://www.ecstuning.com/b-genuine-mini-parts/bypass-shut-off-valve-for-supercharged/11617568423/?gad_source=1&gclid=Cj0KCQiAw6yuBhDrARIsACf94RWHV2fj1pLDDfoYJ2NS26HkrJ1sXO_ZYNMBW3WyG5PXX3sGx7jygcEaAm25EALw_wcB

 

[ezcome-ezgo]

Don't let the pressure out. Manage the pressure. Love the pressure. Be the pressure.

 

[bob58o]

Don't let the pressure out. Manage the pressure. Love the pressure. Be the pressure.

“Oh yeah. Lotta pressure. You gotta rise above it. You gotta harness in the good energy, block out the bad. Harness. Energy. Block. Bad. Feel the flow Happy. Feel it. It's circular. It's like a carousel. You pay the quarter, you get on the horse, it goes up and down, and AROUND. It's circular. Circle, with the music, the flow. All good things.”

 

[Evanguy]

Don't let the pressure out. Manage the pressure. Love the pressure. Be the pressure.

That's the beauty of the by pass valve. It doesn't let the pressure out (it stays behind the throttle.plate the whole time)and it does manage the pressure as well. Then you can love the pressure without damaging your SC and you won't be under pressure worrying about ruining your SC.

Sorry for so many comments I make my point he can do as he pleases.

 

[bob58o]

Comments are appreciated.
They help me understand. Understanding leads to wisdom. Wisdom helps me shine like polished aluminum.

 

[Denny]

Shine like a polished turd Bob, a highly polished turd.

 

[Denny]

I have never in my 58 years of playing with cars heard of blowers being sucked dry of oil. I can’t even fathom how that could happen unless it was sized far too small and had to be severely over driven. Now maybe with a Paxton type supercharger that could happen. But not a Roots!!

 

[bob58o]

How the turn tables have turned counterly.
Physics lesson of the day.