F23 pistons vs f22 pistons VS BOOST

[thepowderblue]

Thought: BOOST is a cool word
I was wondering because the f23 has a 9.3-1 compression ratio vs the f22's 8.8-1 if they have stronger ringlands because the higher compression and if so Will they withstand boost more then our f22a pistons?
Because I have a low mileage f23 block I want to put a f22a6 head on and run 8psi boost.

[hondakid1996]

Well im new to the whole boost scene. But im pretty sure all Honda ringlands are a week point. Im not positive but I doubt the f23 will be any different strength wise compared to the f22. Also, you're going to have mismatched combustion chamber and head diameters which I believe could cause problems especially under boost. Just my .02

[thepowderblue]

Also, you're going to have mismatched combustion chamber and head diameters which I believe could cause problems especially under boost. Just my .02

No the f23 has a 86mm bore and the f22 has a 85mm bore. They take the same head gasket.

[hondakid1996]

Exactly. The bores are different which will cause heat issues on that little bit of a lip on the cylinder head. Add heat with boost and it will blow.

[thepowderblue]

Exactly. The bores are different which will cause heat issues on that little bit of a lip on the cylinder head. Add heat with boost and it will blow.

1mm No it wont.
Like I said they take the same headgasket.

[hondakid1996]

You might want to check your gaskets again. The f22 takes an 85mm gasket. The f23 takes an 86mm. The gaskets aren't even the same. They have different oil passages. They line up with eachother but the bores are different and the oil passages aren't the same.

[Jarrett]

Honda kid is giving you sound information. While the real world effects of the 1mm difference may not be as bad, your argument against it is short and ignorant. With larger combustion chambers and smaller bores you have major hot spot issues. I covered that in this thread:http://www.cb7tuner.com/vbb/showthre...t=frankenstein

When you have a smaller combustion chamber the hot spot issue isn't nearly as prevalent because the angle is not so acute, but it's still a consideration that should be made. Many machine shops will insist on radiusing the combustion chambers for this very reason. Unless you're going for a pronounced quench area. A quench area is the the area around the circumference of a piston face in which the real estate is very limited. On many OHV engines this area is actually pretty large. It is designed so that you create "safely" hotter regions in the combustion chamber so that the gasses in that area will escape towards the cooler spots and create turbulence. The turbulence mixes air and fuel much better and creates a better and more efficient burn. It's up to you and someone who has experience boosting this combination to tell you whether or not the heat generated is to much for this type of design.


If it were N/A, I'd say go for it. Under boost there are just a few other things you need to consider. Also, the F22A and F23A headgaskets are different part numbers. I don't know where you go that information from.

That's just the issue of hot-spots and detonation. That's not even beginning to consider clearance issues for certain builds

[thepowderblue]

It would be the opposite of this
The head will be for a smaller bore not bigger. The f22a6 head I will use has a 85mm bore and the f23 block is a 86mm bore.

[Jarrett]

Reread please. I even big-boy-colored it for you.

[thepowderblue]

Reread you get hotspots if the bore on the head is BIGGER then the block you are using like shown. The bore of the f22 block is SMALLER then the f23 block

[hondakid1996]

Regardless there's a lip in the combustion chamber that can cause issues. But I wont stop your ignorance. Go for it. Good luck!

[GhostAccord]

To be safe I would suggest that you chamfer the 85mm combustion chamber edges. That way you will elevate any hard/sharp edges. Hard/sharp edges can become hot spots. Read some articles on knock and diesling (engine run-on) and you will understand how hotspots can occur. It really doesn't take much.

[thepowderblue]

To be safe I would suggest that you chamfer the 85mm combustion chamber edges. That way you will elevate any hard/sharp edges. Hard/sharp edges can become hot spots. Read some articles on knock and diesling (engine run-on) and you will understand how hotspots can occur. It really doesn't take much.

Just what I was thinking

[deevergote]

It would be the opposite of this
The head will be for a smaller bore not bigger. The f22a6 head I will use has a 85mm bore and the f23 block is a 86mm bore.

The hotspots shown will just be on the head, not the block. The same concept applies.

The F22 and F23 have different bores, so the gaskets simply cannot be the same. The f22's gasket would be poking into the combustion chamber of the f23, and the f23's gasket would leave a small gap all around on an f22... and that gap would allow for the gasket to get blown out very quickly.


Anyway, to address the initial question:
Most Honda pistons are fragile cast aluminum. Lightweight, cheap, and perfectly reliable for their intended N/A applications. Regardless of the higher compression ratio, the pistons won't hold up to boost any better. An H22 has a high compression ratio, but an H22's pistons will fail under boost just as quickly as an F22's pistons (assuming the tune was perfect on both engines, and detonation was not a factor.)

The only stock Honda pistons I know of that are forged are found in the F20C/F22C. I can't find any info on the K23A1's pistons, which may also be forged (as the K23A1 is a turbo motor... a rarity for Honda... also an 86mm bore.)



Honestly, the SLIGHTLY higher expense of simply buying proper forged pistons and rods for an intended turbo application will most likely end up being far more reliable (and in the end, cheaper) than any creative custom mismatched setup. It's always interesting to speculate, but for under $1000 you can get quality internals. You can grab this stuff for even less from people that have abandoned their projects... and there are ALWAYS people doing that!

[Jarrett]

I realize that you think I don't understand what you are trying to suggest. So I've taken some time away to draw a picture for you. How do you not see the potential for hot spots here?