I apologize in advance for the confusing layout and strange terminology. I pieced this together as I went along and am having trouble editing it.
I was reading some threads about unusual setups and thought this up. What if you took a largeish turbo (sp67 area?) and ran it with a centrifugal supercharger. Obviously you would want a fully built engine to handle the VERY high boost level.
Btw, I am seriously looking into such a setup, though I would not be able to afford it right now, mostly because it is a HIGH OUTPUT setup requiring a built motor. The rest is fairly straightforward.
What you need:
-Big turbo (strongly recommend aftermarket tubular exh manifold! even if cheapo ebay)
-Supercharger (reasonable compressor size for fitment reasons and this guy will give you more low end. Yes, a centrifugal supercharger still makes better low end than a turbocharger)
-Front facing intake manifold (could do it on the stocker, but that'd be stupid for your power goals)
-Alternator bracket (to accomodate FFIM... there may be some FFIMs that don't require relocation, but I havn't seen them)
-Modified PS bracket (to put it where AC was... or you can just eliminate it)
-Supercharger mounting bracket custom made. Shouldn't cost much and you can do it yourself or contract someone like BIC (though I believe he is heavily backlogged with his own products).
-The rest is a no brainer and you would need with any setup. Big FMIC, fuel, some way to tune (probably standalone because of high output potential)
-Electric exhaust cutout (if going for the bigger turbo than supercharger route from SCENARIO 1) and means to control it.
WTF is SCENARIO 1? SCENARIO 2?:
-Crappily drawn schematics. First one is SCENARIO 1 and guess what the second one is?
1) The Supercharger would run off the belt, so you would make boost (from it) on a linear and predictable scale.
2) The Supercharger would help spool the turbo from the exhaust gas output (FROM SCENARIO 1 & 2) and possibly from the forced ingestion of SCENARIO 1.
3) Less space issues than a twin turbo setup (could mount centif supercharger in place of PS pump and move PS pump over to AC position or delete it altogether). Location of the air/water IC could be an issue if you want to run one.
4) Save money/space/complexity!
6) Better spool than just a big single and same/more power!
7) Would flow AMAZINGLY (especially if you use a water/air IC like in SCENARIO 1)
8) Could run less boost in the individual compressors, keeping them in their efficiency range, lowering lag, and saving you money on the type of gas you will have to run.
!!!!!!!!!Could completely eliminate supercharger circuit if you wanted to compare spool/power characteristics (SCENARIO 2)
1) Would cost more than a similar big single/SOME twin turbo setups (custom). The supercharger would be your greatest expense, though I THINK you can get a used one rebuilt (not sure!). Scenario 2 is easily cheaper than a twin turbo setup!
2) Would steal some power to run the supercharger (easily made up.. but this is the big "argument" against superchargers)
3) Would most likely need a front facing intake manifold due to pipe length/complexity issues (can get one custom made for ~$600 if you look around). Not really a disadvantage since at this power level, the stock manifold will be a bottleneck.
1) This one is very unknown to me. If the turbo were sized to flow a lot more than the supercharger, would it be choked by the impeller wheel of the supercharger and/or damage it? What if similar flowing compressors were used? Idea: You could rig up an electric cutout to switch the turbo over to its own separate filter! (not 100% or you'd damage the supercharger. Maybe 50% to take the load off the supercharger and let the turbocharger breathe) This would require converting to a standalone or system like the MAFT (because of the variable intake). In addition, if you used a cutout, you would need some kind of enormous 1way check valve (a BOV might work!) so you couldn't blow your compressed air out of the secondary intake). Also, you could just run them in parallel, meaning they would be separate circuits. That would eliminate the need for the water/air IC. A dual inlet intercooler (like the one used for other TT cars) would make it work perfectly.
2) MAY need standalone system (you'd outgrow the AFM system anyway, so whether that's a disadvantage or a nonissue is up to you). SCENARIO 1 would NOT require a standalone by design (one "intake"), but you'd most likely want one anyway due to HP goals. Not really a disadvantage because if you went twin turbo, you'd need a standalone anyway.
!You would have to have a PS pump bracket fabbed or modded to fit on the other side and get a proper sized belt (or just eliminate the PS and go manual rack from a mustang).
!You would have to have a FFIM made, which is taken care of by several members on the board. Or if you can weld or have a friend who can, make one yourself. It doesn't have to flow amazing, just gives us more room to route stuff.
!You would have to have a bracket fabbed for the supercharger. Wouldn't be that hard to do it yourself if you have access to the tools. Just bolt it up where the PS pump was with possibly one extra bracing bar to prevent it from becoming a vibration problem at high (compressor) rpm.
Why this and not twin turbos?:
-Space, fabrication, cost, and complexity will all be problematic with a twin turbo setup on the 7m. So just go jz? If you want to do that, you've missed the point of this endeavor.
On a side note, why do centrifugal superchargers cost so much money? It's just a compressor that runs off a pulley and has gear reduction (not sure on the exact specs, but think 1:5 or so? At 3000 RPM, the compressor is spinning at 15000 RPM). It seems like (at worst) it would only cost marginally more than a turbocharger setup of similar proportions.