oh and kannibul the throttle bodies are required to generate the vacuum needed for the power brake system and evaporative emissions systems as well as a back up in case there should be a problem with the vvel being stuck open causing a catastrophic accident(it isn't pretty when you put a driver who isn't experienced behind a car that is stuck at full throttle also the reason for the throttlebody heaters for cooler climates). The timing and demand for vacuum isn't constant so the electronic control of the throttles becomes necessary and complicates the engine control systems.
This is especially important for screw superchargers because in a typical installation the throttle body is mounted as a restriction in the intake path of the supercharger so that vacuum can be formed. due to the nature of positive displacement pumps(piston engines also fall here) you get vacuum on one side and pressure on the other and since a supercharger is timed to the engine to produce boost(additional intake capacity beyond what the engine normally sees)if you were to not have throttlebodies causing a restriction on a supercharged vehicle there wouldn't be enough vacuum to run said accessories not to mention that if the vehicle didn't have variable valving it would want to run at full throttle all the time.
So basically no throttlebodies = no power brakes
no TB's + supercharger = constant boost condition (still throttle-able with VVEL but you encounter boost problems)
The problem comes when you want to use the stock ETB's in front of a positive displacement supercharger because the ecu in the 370 will leave the trottlebodies open unless it senses a low vacuum condition in the power accessories which is essentially like not having them at all.
Possible ways around this:
1. if applicable trick the system by removing all vacuum reservoirs to force the throttlebodys to stay closed but you don't know if the ecu prioritizes safety and will then never open the throttles. Either way you effectively ignore the VVEL.
2. Hope everything goes well and the ecu throttles the engine with the valves and closes the throttlebodies to create the necessary vacuum and install a centrifugal instead of a twinscrew or roots to allow the manifold pressure at low demand to backflow through the supercharger and while suffering efficency loss your manifold won't blow open from continuously building pressure. This is the second easiest but most half azzed way. also this probably what stillen will do to the dismay of us twinscrew guys.
2a. What happens if you don't use a supercharger that allows back flow once its peak pressure(say 30) is reached is that you start the car and throttlebodies are closed everything is happy because all the twinscrew is pumping is vacuum created by the throttlebodies to less vacuum behind it. Then the vacuum reservoir is filled and the engine decides it doesn't need anymore vacuum so it opens the throttlebodies. the supercharger now has 14.7 psi of atmospheric pressure in front of it and begins compressing that air into the manifold against the restriction created by the valves. In the industrial world we use twin screws as 100psi+ air compressors and if you give it air it'll squeeze it to the other side until something blows up. A bypass valve could solve this but unfortunately they are controlled by the vacuum created behind the throttle bodies.(if the manifold doesn't blow up the supercharger will hit it's maximum psi and not wan't to spin anymore because it won't be able to shove the air anywhere and you will have belt problems to say the least)
3. slap a twinscrew on, leave the ecu alone, install a LARGE bypass valve to cure 2a, only since the throttlebodies are useless you would need to reference the cylinder vacuum behind the valves. Meaning finding a way to get air into the combustion chamber to read the level of vacuum present, with a check valve to prevent the actual combustion gasses from from flowing through, metered against the pressure immediately in front of the valves. You would most likely need to to install a needle valve on both sides of the bypass valve actuator to adjust the pressure differential required for valve activation and a plenum on the combustion chamber side to smooth the vacuum pulses created by the closing of the check valve during compression, power, and exhaust strokes. This is probably the hardest yet most mechanical way
4. Install the supercharger like normal and get someone to make a program that lets you crontrol the settings on the ETB's like super Uprev or something to allow you to limit the amount of air available to the supercharger, and make everything work flawlessly. Assuming availability of said program this would be the easiest and best way to install a twin screw.
5. TOP SECRET this is my way of installing a twin screw while not touching the throttlebodies and i'm keeping it on my bar napkin for now
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There are other ways and i'll admit that this is mostly half-bakery as no one has tried this before but i'm sick of typing. I'm not very good at explaining things usually but if you have a question about something i will explain or reword it. I know a lot of you don't car either so if you don't read it thats fine too.
Edit: Thought i would add that if you use a centrifugal pump like the GTM you don't have to care as they don't produce boost at low rpms and if they did the blow off valve would mitigate it, same thing for turbo's, the roots supercharger is the only non centrifugal one i see as even having a chance of an easy install so the Eaton TVS guys can rest easier. Really the twinscrew is going to be the hardest.