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05 sti head upgrade questions


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im currently in the process of rebuilding my motor. my question is i wanna go one step bigger cams so what else do i need to upgrade or should i just go with getting the heads ported to breath better and keeping the stock head internals,or will i gain more and cost less with just getting bigger cams?

 

this is my daily driver.

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I gather these are the single AVCS heads ?

 

If the shop knows what they are doing you can have them do porting down in the valve pocket and thin out the divider, do not touch the outer port areas where it meets the manifolds. You need to have to velocity.

 

You can go with bigger cams, or just run another psi of boost. How much do you need for a DD ?

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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well its just that they will be off already. i dont know if they will be damaged or not i will see buy this weekend, but i just want to have non stock heads. so what will i gain more in vs cost a port job or bigger cams or a port and bigger valves or honestly should i just leave them alone? i really dont have any money everything i have will have to be saved since i just put all my tax money and pocket over 5k in the motor and that was a waist.

 

i just want a solid motor that wont blow on me again. i plan on forged pistons and rods and bigger injectors anything past that will be just wants ya know.

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I gather you have a 5mt for a tranny.

 

You may want to go back to your other thread and keep this all in one place.

 

Or start a new thread stating your hp goals and tranny type and turbo.

 

The 5mt seem to hand up to 350ftlbs before they complain. Moore Performance makes Blast Plates that will will the 5mt survive.

 

I have them on my wagon and they make the tranny shift so much better.

 

I think you understand my set up and how reliable it is.

 

A few more hp may be nice but to spend that amount of money (injectors and fuel pump) I'd only gain may be 20hp with the vf52.

 

My heads have some porting, I do enjoy the mid-range pull in 2nd and 3rd gears. I told my machine shop buddy to do $300 worth of porting. Most of the work is done down in the valve pocket, where is can't be seen.

 

http://i185.photobucket.com/albums/x40/92Si/DSCN4773.jpg

 

http://i185.photobucket.com/albums/x40/92Si/DSCN4772.jpg

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

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ok i thought the other thread was more for posting engine problems sorry bout that.

 

ive got a 5eat with the hexmods valve body mod in right now. going to install the bulletproof center differential bushings while building the motor.

 

i am able to see the casting numbers on my block and heads now that i have everything off except the intake and turbo.

 

short block casting numbers say b25c 704.

 

heads say b25 001

 

ive read this is not a good casting.

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B25 heads are fine. Just don't overdo the porting like Max Capacity says.

If you upgrade cams, you generally need to upgrade the springs and retainers also. It's not a cheap upgrade and $/hp is not the best. If you are 272 duration or less, the entire power band has gains above 2500 RPM.

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