F23 NA BUILD 200whp or bust.......

michaelp4283

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h22 just doesn't make enough torque for a 3000lb car IMO. AFACCORD stomps H22's with his F23. G23 would be nice, but I wanted to try this because its gonna be very unique and mind opening when its done.
 

michaelp4283

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I don't believe it will. I tried to fit my Euro-R IM onto my spare F23 head, and finally concluded it wasn't worth half the hassle. I forget exactly what issues there were, but I'll go mock it up tomorrow and let you know.

THANK YOU SIR. Guess I'll use the H23 mani that you're using, I've already got one here. I'll just run about a 70mm TB and port it a bit.
 

AFAccord

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THANK YOU SIR. Guess I'll use the H23 mani that you're using, I've already got one here. I'll just run about a 70mm TB and port it a bit.

Yep, my tuner is telling me to port the living **** out of mine. I'll be purchasing a 70mm TB from Polar Bear Tuning and getting it port matched. I really hope this fixes my vacuum issue...
 

michaelp4283

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i really hope to see an issue-free quality dyno tune from you soon. hit my goal for me. what compression are you running again?
 

AFAccord

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I hope to get a good dyno soon too. I street tuned Wednesday, but didn't make any cam adjustments. Once I get the vacuum issue resolved, I'll try to save some cash to get it dyno tuned. Until then, there's no point.

From my measurments of the head, it should be around 10.0:1. I'm paranoid about P2V clearance, but I was talking to Ken (NASOHC) who said Bisi is having him mill his F23 head .050", for about 10.4:1!! :gride:

On a good note, despite the power issue I broke 14's in the 1/4 mile. :147703263745b138a51 :boink: :rock: :lolrun:
 
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michaelp4283

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why so worried about the clearance? i know these are interference motors, but shouldn't we be able to run 11-12:1 compression without any problems? Does it make a difference how you achieve the compression, milling vs. custom pistons vs. valve type?
 

BlkCurrantKord

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I'll be between 11.5-12:1 w/ Bisi's stage2 cam.

Milling the head (or block in some cases), swapping in pistons with a higher/lower dome, or rod length are the main ways to change compression. Changing the valves isnt going to change your compression.
 

AFAccord

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why so worried about the clearance? i know these are interference motors, but shouldn't we be able to run 11-12:1 compression without any problems? Does it make a difference how you achieve the compression, milling vs. custom pistons vs. valve type?

With domed pistons you can run that high because the dome is filling the void space while still providing clearance in the valve reliefs, but lowering the deck height and/or shaving the head literally brings the pistons and valves that much closer together. One miss shift to 8krpm, float the valves, and you're done.

For our engines that don't make power up high, there's really no reason for upgraded valvesprings unless you're autoX'ing with a huge cam. The engine will still perform to the fullest of its potential in the 'stock' power band, but the springs do make for great insurance for miss shifts.




...Changing the valves isnt going to change your compression.

Unless you use flat-faced valves, but then you're just adding mass and increasing pumping losses.


EDIT: Just another tid-bit that I've probably stated before...

Milling the head is generally more efficient than using domed pistons. It's obviously not as effective since you can only remove so much material, but milling broadens the quench area of the combustion chamber and allows for a more efficient and complete burn, especially with our OE flat/dished pistons. Domed pistons do just the opposite by creating obstacles to slow the flame from traveling outwards, leading to a less efficient burn with more unburnt emissions leaving the cylinders.
 
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michaelp4283

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according to the zeal calc I'll probably want a custom F23 piston with between -5 and -7 CC dish for my ideal compression. Milling on my head is not excessive, and gasket thickness can be used to offset in either direction if needed. I would like some confirmation that this is correct before pulling the trigger.
 
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