While I haven't seen it the only thing I can think of would be to bleed air out from an earlier stage and send the rest into a closed loop mode so you could vary pressure based on number of stages currently in use. I'm not even sure it could work but is it something along those lines?

 

nope
good idea, did think of that; However I think that would that not require a major redesign of the compressor housing to allow those flow paths/controls.


My idea allows a single high pressure AFSC to be applied to a multiple number of vehicles regardless of max RPM and displacement (assuming the displacement of the engine is not so large the CFM @ specific pressure is larger then the AFSC can supply).

It also allows the compressor to be more efficient(mechanically; less power form the crank at a given pressure) when running pressures below its maximum out put as compared to a lower max boost compressor running at the same output pressure.

I am designing this device to keep along the lines of what RP has already created to keep prototyping times and cost down.

Main thing I am going to need is a compressor that is capable of producing 13psi at a max RPM 8K on my test mule (S2000). While I could prove the design on a lower max psi AFSC I want to make sure the device has enough fidelity and response time to maintain 8psi during VTEC Switch over. Desired boost profile based in a 13psi uncontrolled ASFC at 8K engine rpm would be at 100% throttle 7.5psi at 2.5k rpm and 8 at 3krpm with the device keeping boost at 8 psi there and above. This in an attempt to directly compete with the Turbo applications for the S2000 with most of those systems reaching full boost (8psi) around 3 to 3200RPM with this system having no boost lag and the reliability of a supercharger.

 

The device would also be double fault tolerant to prevent any sort of over pressure during prototyping and this double failure protection would most likely carry over the final product if it does get into production.

 

No problems mate - it's just that we dont always short shift at 9000

LOL!

Cheers,
Hymee.

 

Hurry up Seven Stock--I am going to die before this dang thing is available.
Might say to hell with it and just break out my old Cushman Motor Scooter.
olddragger

 

Why does it have to be like a Christmas day surprise???

Come on RP, Just "spill the beans" and tell us everything.

 

Thats basically how its usually done on larger units. When certain conditions are met blowoff lines open up somewhere around the middle stages and feed the air back into the early stages of the compressor - its used to greatly reduce compressor surges

 

Cant wait to see how SS9 turns out... I expect someone going to SS9 to have a laptop with a wireless connection with continuously updated pictures or a live feed

 

^^^

SS is gonna

 

Many have waited long enough for this year, SCs, TCs, TUNING!... man... The 8s are gonna fly.
________
WEB SHOWS

 

and just like the rx7, we are gonna see lots of whining over blown engines from people who need thier hood welded shut and can't resist the urge to tinker with what they don't understand..

 

Can anyone explain what is it about the AFSC that has you all so excited vs other types of SC or turbos ?

 

lightweight and compact

linear boost profile, which maintins ther characteristics of the stock power curve

it's different, and pretty damn cool.

it's efficient, much more so than existing solutions

I'm sure there are more.

 

I've been looking at the centrifugal supercharger & it provides linear boost also but I think it will heat the air more (perhaps) . So in that comparison the advantage would be that the need for an intercooler is gone - yes ?

 

it is to be released with out an intercooler as we are told.... should have lots of info after this weekend...

this is going to be a big weekend for fi rx8s.

beers

 

It is a more efficient compressor that is lighter weight and takes up less space. A centrifugal conpressor has to turn the airflow 90* when compressing it but an axial flow does not turn the flow at all. It compresses it as it moves through each stage from the intake back to the manifold so there is less power required from the engine to make the same boost and you can flow more air in a smaller unit. It is the same concept as most modern gas turbines use today. You can read up on jet engines to learn more about the concept.

 

The air still has to take a 90° turn when it leaves the compressor - not to mention all the other turns it makes to get into the motor. Any change in direction impinges on flow. However, all FI solutions have to deal with this to some degree.
Add to that the angle of the inlet - a jet engine takes air directly into the first compressor row, but the AX has a drive mechanism there, so It has to enter at an angle.

 

the efficiency is in the compressor blades and their orientation... not which way the air flows

 

True - in rating the eff of the compressor itself.
However, everything counts in the real world.

 

That's what I was referring to. Agreed you still have an angle the airflow goes around on entry and when you go through the intake manifold there is some loss but the compression process does not take as much power from the engine and can flow more so you have less power drain and more flow than a comparable centrifugal compressor.

 

by orientation i meant successive stages where the pressure is raised in smaller steps by blades that are designed to raise that small step with the least amount of drag possible - thats where the design really differs from other compressors

in the gas turbine industry there are generally 2 setups for the burner arrangement on the discharge of the compressor section. One is a "can-annular" setup where the burners are located aound the discharge of the compressor and airflow is remained straight though to a turbine section... this is the air craft design. The other design is a "silo" design where the compressor discharge is directed 90 degrees up around the outside of a silo shell and then redirected 180 degrees back down the center of the silo and sent through the burners and then makes another 90 degree bend to the turbine section. It would seem the silo method would be very ineffecient, but when done correctly real world data says you lose practically nothing.

 

I beg to differ. Centrifugal Superchargers have exponential boost curves which result in exponential power curves. Turbo-charges, BTW, are exhaust driven Centrifugal SC's.

 

show me an exponential power curve and i'll show you a 4 legged chicken .

 

A belt-driven centrifugal is exponential to the extreme.
A turbo, while centrifugal, is not limited by input RPM, so its delivery can be tailored to fit the desired boost profile.

 

OK - i'm not sure on the boost chart but dynos i've seen are almost an exact copy of the N/A chart (linear) but with double the power .
BTW - I can show you a 4 legged chicken