I think you are going to end up with a lot of turbulence with the maf location in both drawings. I would suggest true blow through design. I would want the maf to be in a straight shot to where it enters the engine.
My drawing is intended only to show relation of the components and is no way intended to indicate scale. proper location of the blow off valve in relation to the MAF will be critical and may require some trial and error.
here, I am a terrible artist but maybe this helps.
For maf you need blow through maf. Any air that passes the MAF MUST NOT EVER leave the engine other than through the cylinder.
You only need one blow of valve and that is in front of the throttle plates and MAF.
Your waste gate pressure reference must be plumbed to the intake manifold, not the compressor side of the turbo.
Twincharging with a positive displacement blower is relatively easy. You don't need all those blow off valves, only one in front of the throttle plates for when the snap closed. (and by rule in a MAF system the blow off valve must also be in front of the MAF.
the really only complexity is sizing the turbo. As the blower being in the mix changes things enough that you can't simply rely on the standard I want to add a turbo charts. Ideally find your net boost you want in the system. Then you can essentially cut that in half and you now now how much boost you need from the turbo. Size to that pressure ratio on the compressor side. The turbine side you will want slightly larger than might normally be recommended as the exhaust air flow rises much faster in a twin charged system allowing you to leverage a larger turbine AR.
What happens when you run a turbocharger at low boost with high volume of piping you get compressor surge. This will create a lot of turbulence at part throttle and make it very difficult to tune some maf counts correctly. Also it's recommended to reference boost at the compressor outlet. I don't even use a bov on my setup for what I do and because my car is an auto. If it were me I'd run a slot maf right before it enters the engine, back as far as I can get it and after any bov or recirculation valve.
One thing im confused about in the picture design, is the waste gate plumbing. could someone explain the waste gate piping from the intake? would it being there keep the ambient pressure in the engine 20lbs of boost (in this set up I plan on boosting a max of 20)? what happens if it opens cause boost on the intake side is above 20 but pressure on the exhaust size isn't 20? would it only open for the intake side? how would you control the trubo? then?
In that diagram the line going from the waste gate to the intake manifold would just be a vacuum line which connects to the waste gate to set sense pressure. The purpose is to set the system total pressure. The waste gate works off a sense pressure. In turbo applications that sense pressure comes from the outlet of the compressor to set the net total boost out of the turbo. In a compound setup you want to drive that sense pressure off the intake manifold since total system pressure will be a function of the combined boost from the turbo and the blower.
The waste gate maintains overall pressure by bleeding off exhaust energy around the blower turbine which corresponds to a decrease in pressure from the compressor side. Ideally you will have sized your blower overdrive and your turbo size so that at your various RPM's they will allow it to work well together.
I think it would be easier to maintain a set amount of boost/pressure at the inlet of the supercharger, by referencing the waste gate to the compressor housing as opposed to the intake manifold. I understand that total manifold pressure can only be referenced after the supercharger, and this would be necessary for controlling the fuel pressure regulator or measuring the air pressure at the intake valves. If using the total pressure to control the waste gate you will need to use a much heavier spring to counteract the total manifold pressure of around 20 psi, instead of controlling only around 5 psi at the supercharger inlet.
Either way would work and our drawings are essentially the same.
While I can see the point about the spring size, the pressure at the intake manifold will be much more accurate vs the pressure at the inlet of the blower. Consider both the heating of the air from the blower and the cooling of the air at the intercooler.
Since no one that I know of has done this in a daily driven street car, I think the actual design will be many trade offs from the theory. Personally I would rather drive off the intake manifold pressure, but it certainly isn't necessary. Just be aware that if you put it somewhere else then your total pressure value could vary materially.
thanks you guys for all your help and insight. I didn't realize how much goes into each system, turbocharged and supercharged by themselves. when I thought of this Idea a couple of months ago I felt it was was a pretty cool set up. I found having sufficient boost through the entire rpm range fascinating. also my cousin told me that a twincharged set up was impossible, I have now proven him wrong. I understand that with twincharging a vehicle you cant get the result you could from just a good set up turbo or blower, but I do find the set up to be truly unique and surprising. I am a big fan of turbos and I know if done right there is little to no trubo lag, but I like this Idea for the instantaneous power offered by twincharging. versus just a big supercharger or turbo. this isn't a project that I plan on doing tomorrow, but this is something I want to own. I want a twincharged vehicle it may not fly down the track cutting into the 10s but it is something that you wouldn't see everyday. imagine the looks you would get when people hear a whining form the supercharger followed by an intense whistle of a turbo. since this is such an unexplored design It would be awesome to have the prestige to say yeah I did that.
Hey, My name is Daniel. I've been a proud owner of my 92 for years now and btw im 17
I have some big plans for my sc and I was wondering what you guys think. I'm planning on twin charging my sc in the future but I was wondering what you guys think, and some things I should think about.
10% overdrive pulley
stage 2 cam
matched port and polished heads
cold air intake
no cats/2.5 in. exhaust pipe/ flow master
stage 2 clutch
3200lb pressure plate
t56 tranny (97 Selene mustang 6 speed)
limited slip 2:1 differential
100hp shot of nos (wet kit)
what I was planning was mounting the turbo in the back like mid way theres room to mount next to the tranny and run a pipe off the air intake after the MAF sensor to the turbo , use the exhaust on the way back to the engine as the intercooler for the turbo. reroute the supercharger boost pipe to follow down over the air intake pipe. get an aftermarket intercooler, then a Y pipe to hook the turbo and the supercharger into the ic. put a butterfly valve or what ever its called before each pipe hooks into the Y pipe. then a blow off on the supercharger pipe for when the turbo out boost the supercharger and the door closes it can just blow off. I know I will probably have to rebuild the bottom end.
My questions are:
how much boost should I push (turbo)
what kind of turbo?
bottom end rebuild tips and upgrades?
fuel system upgrades?
anything else im not thinking of?
thank you so much for your help and input, I wanna try to cover anything possible so I can start compiling a list of parts to buy. I can do the pipe work myself, and finally Ive researched other set-ups with the supercharger feeding into the intake side of the turbo but I can see that causing problems as it will pull more air than the sc can push. right?