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Old 02-06-2010, 10:59 PM   #1
epicsys1
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Member#: 237157
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Default Finding a cheap starting point

Here's the deal, building a full tube chasis similar to the Areal Atom. Have the structure mostly complete with c4 corvette rear end, full one off fabricated front suspend and mazda rx7 trans. Im looking to use a subie engine because of it's light weight, low center of mass and frankly, the sound of it. My target finished weight without driver is 1200#. I would like 400 crank HP to get my power to weight ratio where I want it. I picked the rx7 trans because it has the starter mounted on the tranny side which is a must for using subie or Vw engine "which was my first thought". My question is; could I get one of these ej25's from a 98 - 99 legacy and successfully turbo it to this power level without killing the block. I plan to install forged internals but my concern is the block and heads. I can pick one of these engines up for around 900$ Any thoughts?
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Old 02-07-2010, 11:24 AM   #2
2milehi
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Location: Dillon, CO
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'98 RS-T
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If you are going to replace all the internals get yourself an engine that has a rod knock. I did a complete rebuild for $1300, this included parts and machine work (I rebuild the heads myself). With a tunable ECU, bigger injectors, & fuel pump I should get be able to get to 300 CHP. For 400 CHP, you should add aftermarket rods and at least replace the exhaust valves - IMO.

A link on my build-up
http://www.rs25.com/forums/f128/t874...ist-150-a.html
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Old 02-07-2010, 02:07 PM   #3
epicsys1
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Yea, the crank,rods, and pistons will be replaced w/forged units. I have a stand-alone ECU that I will be using. You say that the exhaust valves will give up between 300 and 400 hp hu? Which valves would you suggest? And just to recap...the non-turbo block from a 98 or so 2.5 legacy will take the extra stress? thanks
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Old 02-07-2010, 02:20 PM   #4
epicsys1
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What does a subie long block weigh? I allowed ~~400lbs in my calculations for engine, alt, ps pump, turbo, piping and and custom exhaust manafolds.
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Old 02-07-2010, 04:06 PM   #5
2milehi
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Quote:
Originally Posted by epicsys1 View Post
Yea, the crank,rods, and pistons will be replaced w/forged units. I have a stand-alone ECU that I will be using. You say that the exhaust valves will give up between 300 and 400 hp hu? Which valves would you suggest? And just to recap...the non-turbo block from a 98 or so 2.5 legacy will take the extra stress? thanks
I would suspect the factory exhaust valves at the 400 hp level, but I am not certain. Heck I might be burning up my exhaust valves when I hit 300 CHP.
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Old 02-07-2010, 09:31 PM   #6
epicsys1
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Default Cmon

Come on guys, I've seen 44 views since I posted this, no body knows what one of these things weighs? lol
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