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98RS (Unicorn), 05 GSXR 1000
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733 Posts
Discussion Starter #1
Buddy came up to work today to pick up some powder stuff and i knew he wanted to drop a 257 into his forester but obviously his plans changed.

Picked up the STi block halves, 40K miles, hot tanked, and good to go for $... I won't even mention it. :cool:

Now begins the fun. Time Attack (the class I'd run in is open at this point meaning i have no set way to decide but it'll go via this build) i was only looking for right around 300-350whp, also wanted quicker revs, minimal lag but something to hold up to the abuse.

What would you do in this case. You are starting from scratch. Destroke? Domed Pistons? Ratio? DOM 1.5? Nitril Crank?

So many limitless options just trying to get ideas. I'll have a list tonight of what I'm thinking and edit as I go. I'll have someone sticky this in my build thread as well to go off of.

I'm open to any ideas suggestions.
 

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2003 BRP 2.5 RS, 2005 Camo 20K
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82 Posts
Nice! I too was on the road to RSTI, but plans changed. Not much suggestion as much as "dude, awesome! this is what i was going to do. how would u do it" I was going to build 257 with LIC pinned halves, sleeved, forged rods and pistons. 08 Nitrate crank. ACL, ARP, Stage 2 cams (ti springs, 1mm OD valves) all this mated to WRX 5 speed casing with PAR STI 5spd helical syncro mesh. In the long run, i want to build a straight dog box! Good luck with your build im ill deff be keeping a good eye on this thread! :)
 

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95/99 Brighton STi
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2,945 Posts
Personally I wouldn't destroke. I'd go with forged, lightweight, high compression pistons. The lightweight will help with quicker and higher revs. The high compression will help with lowend torque and quick spooling. Forged rods are a must but again, personally is find the lightest ones possible without sacrificing strength. ARP rod and case bolts. I don't think a nitrided crankshaft is absolutely necessary. For bearings, I've become a fan of Kings new Subaru bearings. I'd run them on the looser side with a healthy oil pump. I'd probably ditch the OEM pickup tube for a KB unit. Throw some spicy cams in there and dyno tune with some anti-lag and flat foot shifting and go
 

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Premium Member
overdeveloped beater
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8,335 Posts
This is the path I am currently planning. Like you, I am researching the feasability of a hi CR- low boost setup for the off boost torque and quick spool. I am shooting for higher numbers at the wheel than what you posted, and am saddled with a mandated 46mm restrictor, but the car is not a street car anymore. Fuel is not an issue, nor is idle quality.

If I had a winning lottery ticket, I'd consider a turnkey GRC drivetrain or WRC motor clone. Until then, I'll have to build what will give me the most bang for the buck.
 

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98RS (Unicorn), 05 GSXR 1000
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733 Posts
Discussion Starter #6
Well my numbers for the block have changed after talking a little bit with PSI Proformance.

And honestly this is my FIRST engine build from bare minimum and i may be working myself up and i think i'm going crazy cause i always feel like i'm forgetting something.

Taking the block halves to get hot tanked tomorrow morning and to see if ANY machine work actually needs to get done on them. The walls are very clean and have no signs of any wear, where the rings sat there is a little carbon build up or burning like the block was ran lean. So if they don't require any machining this is what will happen. Maybe go 20mil over just for the new pistons.

Manley Rods
Manley Pistons 9:5:1
ACL Bearings
Heat treated crank (OEM)

From there I have my short block... Unless I'm missing something.........?!

But with that i'll easily be at 300-600hp depending on my heads and turbo set up. I know i'll be running a cosworth intake, more than likely a rotated set up, killer b header. But the turbo is in the air. But at least with a 9:5:1 i can safely run E85.

The real question is, is sleeving the block actually worth my time, hence i've seen open deck blocks safely run 400-500 all day.
 

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Premium Member
overdeveloped beater
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8,335 Posts
I'm going the sleeved route, mainly because:
-The block I have is already 100mm and I want to go back to 99.5mm
-I want to build the bottom end to be bulletproof once.

Still need to discuss things with a couple notable builders, bounce crazy ideas off them to see if there are any common denominators I can count on, then plug some data into a simulator to try and get an idea on cam sizing and such.

I'd put a fresh hone on the cylinders at the very least, for ring sealing. I won't be going with a cossie manifold since my 2.5i manifold has proven to flow within a very close margin to it and I already own it. I still have those ITBs too......but who knows if I'll go down that route again...... I donated a perfect condition nitrated crank and EJ255 block to a PPIHC/RallyAmerica build, but have a good condition block and crank in return. EJ205 heads need some love....but that's not a huge deal.

I'm thinking of going up to and possibly past 10:1 for compression. Another reason for the sleeving. Not worried about top end as much as bottom end for my needs.
 

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2000 RS Coupe Silverthorn 5spd
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565 Posts
Im gonna pick at you a little....Why ACL bearings? Why not go King? King's only like $2 more here....BuiltEJ :: 04-07 STI :: Engine :: Bearings

Which Manley rods?

For the shortblock to be bolted together, your gonna need Subaru OEM Ring Cylinder Block / Oil Pump Seal Subaru Models (inc. 2002-2014 WRX / STI) 10991AA001 at RallySportDirect.com x3 and only 1 of these Subaru OEM Crankcase O-Ring Subaru Models (inc. 2002-2014 WRX / STI) 806932030 at RallySportDirect.com I used rallysport as a reference. A complete engine gasket kit included these and can be had for $250 complete or less.

For your HP goal, sleeving it is not required. My .02cents.
 
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