So let continue, now Im going to show you, just you. You have to promise that you don't show this or talk about this to anyone outsider..
This is top secret stuff!!
Well have to confess that don't know if this actually works or not.. one those one off things.. Havent figured it out 100% yet..
AND I didnt come up this. Entirely, saw a post in IG of one drag race Mustang in somewhere NW of US. It had some odd squar tubing thingy bolted between throttle body and the supercharger and it had like legs sticking out on both sides of the supercharger and had blow off valves bolted on the ends..
So I had to contact the owner and ask more info about that. He told me that had come up as how to control the boost of the Kenne Bell-twin screw and best part that it works great.
I told him that I may copy his idea but would build it differently and take the idea even longer.
We have talked a lot since, tossed ideas back and forward..
Went and bought two cheap oriental copies of known blow off valves from evil-bay, just to get started. May buy real ones later.
So I designed and machined a kind of plenium for two blow off valves. But the air they bleed, is collected and circulated back to intake side of the supercharger. Between case and the throttlebodies.. Had to make those flances and tube between blow offs and intake. Also had to machine the body of the by pass to make a sealing flance to it.
Idea is to used as light springs in them, just so that valves are closed at natural state. When engine is running on vacuum (0.1 or more), valves would work as by-pass valves. Vacuum would be connected to " normal port", on top of the membrane.
Fun fact: Did you know that the twin screw is the only real compressor in automotive use that dosent leak (actually compresses air inside of it = compressor)so with out by-pass valve of some kind it tryes to suck it self to "bottle", heats up really bad and may even get damaged by doing so. So it needs some by- passing to survive.
And when engine goes on boost, the boost itself starts to push those 2" valves open and bleed off, back to intake. Loosing boost pressure.
Why back you may ask. Cos air is taken from the "cold" side of then intake after the massive special made intercooler, or intercoolers in this case.
Now the clever part, by controlling with ECU the PWM given dome pressure, I can adjust boost any given time, by traction, by gear, by power level tune or just like overtake button.
The part I havent figured out yet is the pneumatic valve. How to get it to work properly. First it deliveries vacuum on top of the membrane and when the boost comes on it turns and lets the PWM pulse through it but not to the intake where it takes the vacuum. We dont want pressurized air leak that way. Also it has to breaths so the PWM pulse would works fast and accurate.
The plan is to use compressed air as pressure source, car will have air compressor for the suspension coil over air cups. Engine ECU, swedish made Maxxecu PRO can handel the task.
By the way, Lysholm-factory calculated that 4.9L supercharger in my 8.3L engine with 3" upper pulley and my custom ordered 9"ish ATI Superdamber the boost pressure is just 54psi~3.78bars !! thats over x2 too much. Aim is for 1.5 bars max~ 21psi. The 4.9L supercharger is nuts. It puts out wopping just shy of 1m3 (one cubic meter = 100.000L) ~ (26417 gal) of air per minute. (to be exact: 0.98 m3 =98000L=25888gal per minute)
Nowdays there may be smarter option to this, again Im nnot 100% sure but Turbosmart has those electro-macnetic bypass valves of modern torquemanagement vehicles.. they may work in this application as well..
Next I'll do something cool and precise..
__________________
, Juhani
|