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1999 Forester
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78 Posts
Discussion Starter #1
This had been in my head for almost a year now. If I had not built my kids a 2 stoke mini snowmobile clutch drive setup powerwheels I would have been much further along.
Even though it being designed from a forester I hope it will have the clearance to fit under other subaru models. I now have 4 superchargers with access to 2 more still.
To prevent alot to double postings please check out my primary posting on rs25 and comment on here then.
In my opinion the best way to boost with a M90 - RS25.com: Subaru Impreza GC8 & RS Forum & Community
 

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1999 Forester
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78 Posts
Discussion Starter #3
yeah, some people cant think outside the box and or even double check their math. The funny part was when I used a real example of that same supercharger making 30psi on a larger v6 when overdriven into untested rpms. I'm pretty sure if the engine displacement was 1.3 liters smaller it would be beyond 30 psi!!
 

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2009 Outback XT-B 5MT
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10,409 Posts
This is a really cool project! I had always wanted to do an M90 EG33 in my old SF. That would have been awesome.
 

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1999 Forester
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78 Posts
Discussion Starter #5
can anyone tell me if the 2.2 and the 2.5 share the same alternator/powersteering and ac units and mounting plates?
 

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2009 Outback XT-B 5MT
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10,409 Posts
Mostly. The powersteering pumps were different between turbo and n/a models, but the alternator was interchangeable. The AC units depend on the year, but I think the brackets ARE interchangeable.

I seem to recall a friend swapping a newer Calsonic R134a compressor into his R112 Legacy using the stock bracket, and I know I used a WRX alternator for a short period of time.

The power steering pump is different, but I think it is the same between the N/A cars, and the same between the old Turbo cars.
 

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1999 Forester
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78 Posts
Discussion Starter #7 (Edited)
I need to know this so I have an extra setup to start finding 6 rib pulleys in the junkyard to swap or have machined if none can be found. A supercharger can be driven off of a static tensioned belt but not at high boost of for very long. The SC can demand a lot of HP underload; this will stretch the belt momentarly causing belt slip. Problem just gets worse and will leave you stranded. I have to come up with a single serpintine belt setup that uses a srping tensioner
 

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2009 Outback XT-B 5MT
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Why not just do the math for belt calculations? Seems like a lot of guess-and-check.

If you are asking if the pulleys are the same, they aren't. The PS belt uses a 4-rib, the AC/Alternator uses a 5-rib. Or it might be the other way around. If you are asking if the pulleys are the same between the 2.2 and 2.5, they are.

If it were me, I'd make a custom crank pulley and use a cog-belt for the S/C.
 

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1999 Forester
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78 Posts
Discussion Starter #10
new number for pulley sizes

All specs at max 6K rpm and using a stock crank pulley size, pretty sure the calc doesnt account for 70-75% blower efficency, so maybe take 25% off. At zero boost the calc says 149hp, so its close.

3.4=10psi 250hp 2.6=17.8 328hp
3.3=10.7 257 2.5=19.3 343
3.2=11.6 265 2.4=21.0 360
3.1=12.8 277 2.3=22.8 378
3.0=13.7 286 2.2=25.0 400!
2.8=15.1 301! 2.0=27.2 423
2.7=16.2 311 1.9=30.0 451!!
Well there the numbers, probably assuming a good water to air intercooler is being used and the heads/exhaust can take the extra flow

Not thrilled about the thread being moved as it more pointed toward 2.5's but can be used on 2.2's with higher boost #'s. Not really a motor swap either, conversion maybe; from NA to FI:confused:
 

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2009 Outback XT-B 5MT
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10,409 Posts
Not sure why it was moved either.

Calculate the horsepower required to turn the blower with a driving RPM of 6,000 and we can design a belt drive system that will likely be far more efficient than a random 6-rib setup.
 

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1999 Forester
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78 Posts
Discussion Starter #12 (Edited)
On the highest pulley setup it would be 60+ hp, not so much from the 14K rpm but more the force of the boost trying to spin the SC's rotors backwards. I'd prefer to stay away from noisy cog belt setups and stay with the 6rib gm aftermarket pulleys. Can a 6 rib hold up at 60 hp? not sure yet but with 80% belt wrap and some extra spring/belt tension it might be possible. My black 94 Thunderbird SC was last running 19+psi boost. It used a 8 rib jackshaft to crank belt, from the jackshaft pulley to the SC was a monster 10 rib belt. Was running it at 15% over-driven.
On my 99/00 blocks my timing gear has two holes on its face along with its keyway. The key on the crank only extends 3/16's into the crank pulley, which is fine for stock accessory loads. Now demand up to 60+hp and whatever else the accessories draw and that 3/16's of key is going to shear. I propose drilling 3/8 deep holes equal to the ones on the timing gear. Get some slightly oversized steel drill stock rod. A few taps, cut to 3/8 sticking out. Line up the crank pulley and install into timing gear. NO worries.
 

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1999 Forester
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78 Posts
Discussion Starter #13 (Edited)
Expected whine

It might sound like this depending on if I seal the sound ports off or not and if I use all metal tube intake.. Some like it some hate it.
[YOUTUBE="hi"]http://www.youtube.com/watch?v=HRMhamGFa5c/YOUTUBE]
 

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2009 Outback XT-B 5MT
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10,409 Posts
Neat! I want to learn how to MIG weld. I've got a TIG welder that I use at school, but I hear they are quite different.
 

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1999 Forester
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78 Posts
Discussion Starter #17
I'd love to tig weld instead of mig. Mig is 6x faster but pretty limited to what metals i can weld; steel and aluminum, sometimes stainless but its gotta be really hot.
 

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hey mom, can i
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Subscrided. I want to do a procharger on a stock 2.5 until it goes kaboom and then do a sti block internals and heads (maybe wrx heads) but something that can handle say 20psi and have a supercharger pushing that. But I Haven't really done any research on this. So maybe I'm just dreaming.
 
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