When I installed my J's header I noticed the primaries are WAY bigger than the head ports, about 1/16"-1/8", with 50mm primaries I should have expected that, duh.

I was thinking I'd get a 70mm TB, port the intake manifold, and port match the head. But I've read some post's saying porting is a waste of time on the F20, is this true, what have others done?

ps - my goal is mostly mid-range (4.5k+) power, but I hit 9k all day too

 

Port matching the throttle body/intake manifold and header and exhaust ports would make sense. Never read about anybody actually doing it to the exhaust ports/header though.

If you are talking about porting/polishing the actual head, doing a valve job and combustion chambers, then that's another story. The F20C head is one of if not the best flowing production head out there. Improving it is not as simple as making everything as big as possible. It's easy to screw it up if the person doing the porting doesn't have F20C experience with flowbenched results. The only two shops that I've seen documented results from is Alainiz and Portflow. They both typically show about 5% flow increase at mid-range valve lift on intake and around 10% exhaust flow from mid to high range valve lift.

 

I'm thinking about doing everything, port/polish-head/intake, valve job, chambers...

 

The head doesn't really need to be ported until you hit about 270whp from what I have heard, but also I've heard that at that level the exhaust ports become a large restriction, I've heard a really reputable S2000 engine builder say that porting the exhaust ports would potentially unleash a lot of power on a really highly-modified engine.

From your mod list I can't tell what you've really done to anything, but assuming you have the Borla catback exhaust it would seem that if you're trying to make more power right now, switching to a 70mm catback would be your best bet. If your engine is already modified extensively, then porting would become an issue but on AP1s the head is already a ridiculously high-flowing head.

 

Power Mod's so far:
-J's Header
-Invidia Test Pipe
-Borla Cat Back
-VAFC-II
-K&N Drop in

I'll be switching to T1R 70mm header back and AEM EMS this year, havent decided on an intake, thinking 70mm BDL, Samco intake tube, and knockoff carbon intake.

Next year will prob bring cams & pistons.

I want to hit 270whp

 

You will get better dyno #s off of a CAI like an AEM V2 or the like, snorkel-type intakes give real world gains but don't show up on a dyno, so that doesn't matter. The exhaust and EMS combo should definately be done before you start tearing apart the engine, and as far as cams go I would be very wary -- it is very hard to find a good set of cams for an F20C engine, definately talk to some shops that have had good results before, even Brian Crower's cams did nothing when he released them a little while ago, the top end of the engine (head, cams, etc.) is pretty dialed in, maybe swap springs and retainers but after that it becomes very tricky and you really need a great shop that knows what they're doing. Good luck though, it sounds like a really nice build!

 

I think you might have to adjust your expectations. For 270whp (assuming typical Dynojet numbers) you're going to definitely have to go for the all out NA build. That means opening up the engine and getting some kind of build strategy (which includes matched cams, header, intake and engine configuration). Just putting a bunch of parts together will likely leave you short of your goal. That's means a good builder, unless you have the time and experience (or money) to do all the experimentation.

Just to throw out some numbers (although I should know better ):
200-220 whp : with I/H/E
220-240 whp : add engine management with fuel and timing control
240-260 whp : cams, valve train upgrades, perhaps cam gears if needed
260+ : increase displacement, modify compression ratio, port head, bigger injectors (read that stock max out around 270 whp)

 

theres a artical in the this months import tuner mag with a NA S2K with like 294hp and 200 trq with a 2.3 stroker and itbs. It may be something to look at.

 

good luck with your build........I would wait for inlinepro's cams to be released
N/A rocks