Q & A. Motor Build Options: Pro's vs. Con's

[Batmobile_Engage]

Besides the cost, what are the pro's and con's of the differences in each motor.

What about a 2.6 or 2.7 stroker would be a big plus, besides the ability to make more
power of course? I am eventually shooting for 450awhp but I still want my Subie to be
completely streetable as it's my DD. Am I assuming correctly, that the stroker would
probably make more torque down low in the RPMs but also eat even more fuel than
my motor already does?

How much are the differences in boost, fuel, etc. between an 8.0:1 and 8.5:1 compression ratio?
I'm 99% sure the factory STi comp. ratio is 8.2:1. Listed below on the page at the link, they
advertise custom compression ratios as well.

I'm sure other questions will come up as we begin to discuss what makes these motors
different and why that's good or bad for certain driving environments.

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http://erlperformance.com/subaru-ej25

PACKAGE	DESCRIPTION	BLOCK TYPE	BORE	STROKE	LITERS	CR	PISTONS	RODS	CRANK	PRICE
EE1	Turbo Street/Strip	Sleeved	100	79	2.5	8.0:1	Wiseco	Manley	Subaru	$3,500.00
EE2	Turbo Race	Sleeved	100	79	2.5	8.0:1	CP	Manley Pro	Subaru	$3,850.00
EE3	Street Stroker	Sleeved	102	82	2.7	8.0:1	Wiseco	Manley	ERL	$4,400.00
EE1N	Turbo Street	Stock Sleeve	99.5	79	2.5	8.5:1	Wiseco	Manley	Subaru	$2,500.00
EE2N	Turbo Street	Stock Sleeve	99.5	79	2.5	8.5:1	CP	Manley Pro	Subaru	$2,850.00
EE3N	Street Stroker	Stock Sleeve	99.5	82	2.6	8.0:1	Wiseco	K1	ERL	$3,400.00

 

[Grinder34]

A suggestion:

Split this into a few threads.
IE
1) Stroker vs Stock
2) Compression ratios
3) Sleeved vs Stock

as for #2, it looks like Fuji started one here: http://www.igotasti.com/vBforum/showthread.php?4767-Compression-Ratios-and-You

 

[Batmobile_Engage]

I read Fuji's thread. A lot of good information there! Sleeved vs. Stock seems pretty straightforward to me. I've
always been told that you can bore the EJ257 up to +0.5mm over before you NEED sleeves, but if you plan to make
lots of power, you should have them anyway. Anything beyond +0.5mm bore absolutely REQUIRES sleeves because
the cylinder walls will be a bit too thin and can tend to warp.

I guess what I should be asking is, I understand a 2.6 or 2.7 could make more power than a 2.5, but how is it going
to drive differently? Am I going to have much more torque down low (that would not only be beneficial to racing but also)
that will make daily driving and commutes that much better or maybe, the increase in displacement would give my GT30
more room to breath, more exhaust flow and maybe a faster spool?

Let's just go with it for a little bit. I'll work on splitting the info into a different set of threads a little bit later depending on where we take this thread.