11000ft driver Posted January 20, 2006 Share Posted January 20, 2006 I put a 2.5 sti short block in a legacy GT2.5, used sti gaskets, but stock heads. I'm getting ok power (comparable to what you'd expect from a healthy ej22), low compression, & HORRIBLE mileage) the engine runs PERFECT, so I'm leery about major changes, but need to figure this out. I drive over 11,000 ft twice a day, so the gas is killing me. any suggestions? I've got a weaponR intake & lightened flywheel, other than that no extras. Quote Link to comment Share on other sites More sharing options...
GLCraig Posted January 20, 2006 Share Posted January 20, 2006 Did you make sure that using this shortblock would not cause a change in the compression ratio? Quote Link to comment Share on other sites More sharing options...
cookie Posted January 20, 2006 Share Posted January 20, 2006 Well the good news is it might run forever. I believe the 2.5 STI is turbo isn't it? In this case you have about the same compression ratio as a Briggs and Stratton. I thought of doing this myself to make the ultimate tough 2.5. The bad news is that you would lose power and gas mileage most likely. It really should be just a bit better that a good 2.2 but will be running when you are dead. Quote Link to comment Share on other sites More sharing options...
11000ft driver Posted January 20, 2006 Author Share Posted January 20, 2006 it went down to 8.5 because of the increase in thickness to sti gaskets (I think) obviously at my altitude, a loss of compression was the last thing that I wanted, but the shop that did the work didn't mention that I would lose t with this setup (I guess it should have been obvious, but it didn't cross either of our minds) would 1/2 lb loss cause this huge change in efficiency? Quote Link to comment Share on other sites More sharing options...
11000ft driver Posted January 20, 2006 Author Share Posted January 20, 2006 it is NOT turbo btw Quote Link to comment Share on other sites More sharing options...
GLCraig Posted January 20, 2006 Share Posted January 20, 2006 There's the problem, asuming they left the STI pistons in that shortblock. Quote Link to comment Share on other sites More sharing options...
cookie Posted January 20, 2006 Share Posted January 20, 2006 I meant was the STI shortblock meant to be turbo? It sounds to me that you have exactly what you ordered. If you want to drive to CA I will be happy to trade engines with you. According to the STI I just looked up it should be a shortblock for a 300 hp intercooled turbo. If you put that together with no turbo and a stock set of 2.5 heads waht you have is exactly the result. Congratulations! You have just built an excellent non-performance motor. If you found the right set of 2.2 heads you might be able to get usable horsepower for your altitude. I suggest you check with NASIOC to see if anyone knows which heads have less ccs in the chamber. Quote Link to comment Share on other sites More sharing options...
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