Subaru 2.5L valve seat angles for performance

[accurate engine]

OK, I hate Subaru's. Now that its clear, my brother has an 2004 STI 2.5L he scattered a piston on. Wants to go faster. What valve seat angles are pulling better air flow. I do not own a flow bench at this point and I want this engine gone soon. I was thinking the VSC8-04045 would do the trick, but wanted some higher education from people in the know on these things. I have seen a little success by another shop at clover leafing the chamber. They are keeping the size and angle a secret. I don't blame them, but I will not do this for anybody other than my brother. Any info would be greatly appreciated. Thanks in advance

[Ron E]

PM Bill Jones. He's very well versed on Subaru heads.

[KnightEngines]

I've probably ported more of these by hand than anyone else anywhere! - over 200 sets to date.
Valve angles I use:

Intake - 25 deg chamber cut, 35 deg top cut .040" wide, 45 deg seat .040" wide, 65 deg bottom cut .120" wide, 75 deg throat cut.
Exhaust - 25 deg chamber cut, 30 deg top cut .040" wide, 45 deg seat .040" wide, bottom cut 5/16" radius, touch the throat with an 80 deg cutter.

[accurate engine]

Thank you so very much! You don't know how much I appreciate it!

[ptuomov]

I've probably ported more of these by hand than anyone else anywhere! - over 200 sets to date.
Valve angles I use:

Intake - 25 deg chamber cut, 35 deg top cut .040" wide, 45 deg seat .040" wide, 65 deg bottom cut .120" wide, 75 deg throat cut.
Exhaust - 25 deg chamber cut, 30 deg top cut .040" wide, 45 deg seat .040" wide, bottom cut 5/16" radius, touch the throat with an 80 deg cutter.

If it's not a business secret, how is the intake valve shaped? How wide 45 degree valve face on the intake? Is there a back cut, if yes then what angle? How much margin?

[wyrmrider]

Knight
from your numbers can you determine how far out on the valves the seats are then transfer to the heads? or vice versa
are you running them as big as possible?
did you mention any backcut on the valves and rounded margin on the exhaust if appropriate?
I'll have to read your post again but it has to be very helpful to Subaru folks
My relatives here in the states have had to have 3 engines replaced under warranty recently , IDK which ones ( three different new vehicles I know one was sucking oil)
WRF Suburu?

[MotionMachine]

The 2.5's have a big problem with breaking ring lands on the turbo models and also cracking the cylinders where the block is relieved for case bolt clearance. I've sleeved a couple hundred of Subaru's, real learning curve on those things, many quirks to doing them correctly.

[accurate engine]

Just a final update on this engine. He has ran the dog snot out of it since the rebuild. The dyno in Albuquerque says 481 HP as the final number. I guess we hit the sweet spot on this one. Thanks for all of your input guys.

[KnightEngines]

Timely update.

I'm just doing a set of heads right now to go on a one of the new willall racing billet blocks.

Aim is 1000+hp on E85.

Motor is 2.7L with billet cases, manley crank, carillo rods, CP slugs etc.

[KnightEngines]

[accurate engine]

That looks fantastic! The radius on the exhaust is beautiful. Are those setup for oversized valves? If so how much?

[KnightEngines]

Yeah, 1mm oversize valves.

Supertech do valves that are .5mm shorter than stock so you can sink the seats without running out of room for retainers.

The trick with the exhausts is to get into the short turns, gotta lay them back quite hard.

This is my 3rd set of ported EJ25 heads in 3 weeks, last count was around 200 sets in total ported by hand. I'm a little bit over these things. But it pays well & I can do it with my eyes closed.

[gunt]

just for anyones archives , so they can compare

http://www.sulegacy.com/inspection-3825.html