Estimated HP gains - bolt on mods and reflash?

[serialk11r]

Err run out of breath up top? But the torque peak is confirmed at 6600...that doesn't sound like midrange to me lol. The pictures released strongly suggest it is just a cam phasing system, no lift. FB20 has no lift, and the width of the engine is already pushing it.

@HomemadeWRX you say 2.4L? O_O Increasing bore? The engine already runs right up to the wheel wells as is.

[Calum]

Originally Posted by Homemade WRX

I'll see what it looks like. I really need to spend time with the head on flow bench to see if large valves are even necessary and to see what flow these heads can actually support. Lighter is better regardless but I've been fine sending EJ's to 9K+ with OTS springs.
Just because the bottom end can take 10k doesn't mean the head will support the power

I'll be working with a supplier on some ovate wire, beehive springs for the FA engine. The cam stock is going to be pricey part. Speaking of which, I've seen people comment on hear that the car was coming with AVLS, which I can't find anything supporting this. I'm fairly sure it is simply a dual AVCS head.

Regardless, I am VERY anxious to get my hands on the FA platform!! I'm thinking 2.4L without the crazy high rev's will be the ticket. You know, something mild like 8500...but really I'll put redlines where it's done making power.

Perfect, when you get the package done I'll be waiting.

[Dimman]

Originally Posted by serialk11r

Hey uh, typically for higher rpm people switch the valve springs right? But a lighter valve instead would reduce float with less friction...are titanium valves very cost prohibitive? Seems strange, since valves are relatively small. What is the lightest type of valve? Hollow stem titanium?

I think Titanium-aluminide is the lightest. Intermetallic compound, not technically an alloy. Even more cost-prohibitive than plain Ti.

(Metal side note, you can make 18k gold that is purple all the way through, not just a surface treatment, with aluminum as the alloy. Also an intermetallic compound.)

[old greg]

Originally Posted by serialk11r

O_O Increasing bore? The engine already runs right up to the wheel wells as is.

Huh? What does bore have to do with deck height?

[Levi]

Originally Posted by Homemade WRX

Regardless, I am VERY anxious to get my hands on the FA platform!! I'm thinking 2.4L without the crazy high rev's will be the ticket. You know, something mild like 8500...but really I'll put redlines where it's done making power.

That is more what I am interested in. Something about 2.5l, 300 PS and 9.000 RPM redline. I'd like to drive it directly to the track so I want it to be street legal and street drivable.

Underground Midnight Races?

[serialk11r]

Originally Posted by old greg

Huh? What does bore have to do with deck height?

I thought I was looking at an old post for a sec rofl.

If he simply extends the stroke 20% up to 103.2mm, that eats up 8.6mm rod length, which sounds like a problem to me. 1.205 rod stroke ratio, horrendous increase in friction and bearing force? Unless I'm severely mistaken about engine geometry...

[Homemade WRX]

Originally Posted by serialk11r

@HomemadeWRX you say 2.4L? O_O Increasing bore? The engine already runs right up to the wheel wells as is.

Bore doesn't change deck height...

Originally Posted by serialk11r

If he simply extends the stroke 20% up to 103.2mm, that eats up 8.6mm rod length, which sounds like a problem to me. 1.205 rod stroke ratio, horrendous increase in friction and bearing force? Unless I'm severely mistaken about engine geometry...

so now you've gone from bore to stroke...

There is more than one way to skin a cat.

[serialk11r]

So I'm a bit confused but what I mean by increasing bore was I don't see how stroke can be safely increased much.

[Homemade WRX]

I never said I was going to increase stroke

What spec do you have for the rod length on the FA20...curious.

[serialk11r]

So the FB20 has narrow angle ports, 129.3 mm rod length, 90mm stroke. FA20 is said to be same dimensions, valvetrain is similar, rollers on cams, no variable lift, I hear narrow angle is good for performance so I assume they keep that. FB20 has 10.5:1 compression ratio, FA is 12.5:1. Reduced stroke => 2mm off the crank, 2mm to the rods for a 131.3mm rod, with the same deck height. But then combustion chamber is different due to the higher compression ratio...if they only reduce the deck height to increase the compression, I calculated 1.7mm maximum to the rods. So if the engine is as similar to an FB20 as people seem to think, the maximum length the rods could be is 133mm, probably a little less?

[Dimman]

Originally Posted by serialk11r

So the FB20 has narrow angle ports, 129.3 mm rod length, 90mm stroke. FA20 is said to be same dimensions, valvetrain is similar, rollers on cams, no variable lift, I hear narrow angle is good for performance so I assume they keep that. FB20 has 10.5:1 compression ratio, FA is 12.5:1. Reduced stroke => 2mm off the crank, 2mm to the rods for a 131.3mm rod, with the same deck height. But then combustion chamber is different due to the higher compression ratio...if they only reduce the deck height to increase the compression, I calculated 1.7mm maximum to the rods. So if the engine is as similar to an FB20 as people seem to think, the maximum length the rods could be is 133mm, probably a little less?

Can get more compression from different pistons, too.

[OrbitalEllipses]

Originally Posted by Homemade WRX

I never said I was going to increase stroke

What spec do you have for the rod length on the FA20...curious.

Micah, you're already talking about rods in this boxer?!

[Dimman]

Originally Posted by Homemade WRX

I never said I was going to increase stroke

What spec do you have for the rod length on the FA20...curious.

Are you thinking along the lines that the blocks between the FA and FB are pretty much the same die-casting with different cores. Bore pitch would be the same, so the FA can be safely bored to the same 94mm as the FB25, which would give you your speculative 2.4L with an 86mm stroke? Something like that?

[MrVito]

Quoting the use "oldeskewltoy" from club4ag here...

"Is it just me... hmmmm, but wouldn't a compact S/C fit in between the alt and A/C and place it directly in front of the T/B???


Hmmmm, I also note a single belt. That means it won't be easy to remove much from the belts path without extensive tensioner placement adjustment"