Build up of F23.

[bagoon316]

the compression calc i use, shows the cr jumping 2.5 points from being in the hole 0.079" or so his 2mm measurement states.

11:1 cr piston is about -1 cc on the piston. my calc says he will have a 13.6:1 if he uses a shorter rod. dunno if thats correct or not, please someone correct me.

******* EDIT: nvm, i read it wrong. the -1 cc would be if the piston was supposed to go into a f23 block and head, but he is using a k20 piston. let me recheck my math

I'm at 16.8:1 CR using 11:1 K20 pistons in the f23. cuz the stroke of the f23. longer stroke raises CR. JE 10.8:1 has a cc of 7.1.

 

[x5carl3tMurd3rx]

Not entirely false. You really would be an idiot to do either of them.

Anything with 11:1 compression and using a VAFC to tune with will not last.

I wasn't sayin to combine the two. but I've seen 500+hp cars tuned with a VAFC with no problems. I've also seen race engines running high boost on 11:1 or higher CR. In an accord thats going to be a street car, no its not practical. Both can make very good power and be reliable enough to race with though. Thats all I was tryin to say.

the compression calc i use, shows the cr jumping 2.5 points from being in the hole 0.079" or so his 2mm measurement states.

11:1 cr piston is about -1 cc on the piston. my calc says he will have a 13.6:1 if he uses a shorter rod. dunno if thats correct or not, please someone correct me.

******* EDIT: nvm, i read it wrong. the -1 cc would be if the piston was supposed to go into a f23 block and head, but he is using a k20 piston. let me recheck my math

I'm at 16.8:1 CR using 11:1 K20 pistons in the f23. cuz the stroke of the f23. longer stroke raises CR. JE 10.8:1 has a cc of 7.1.

........ how would compression go up with a shorter rod? chu make no sense.

 

[bagoon316]

the compression went up cuz of the stroke, not cuz of the shorter rod. je pistons in a k20 is for 86x86, ur going to a 97mm stroke, stroke increases cr.

chu make no sense.

put it in a calculator, 11:1 on a k20 stock, and put the same pistons in a f23, bet money that compression will jump regardless of the shorter rod.

 

[bagoon316]

i dunno what it will do with the shorter rod, cuz the calc i use for some reason isnt compensating for a negative #, so its being stupid.

but if he was still even or that .5mm whatever it is stock, hes still at roughly 12.9. im not sure what the 2mm difference does when he's that far into the hole. it will go down, but that stroke difference from k20 to f23 is going to raise it.

 

[99CcordMTF23]

So 9.8:1 k20a3 pistons would be better? This is some **** man. So the compression will raise due to additional stroke? So with a k20a3 rod the stroke would be 95mm.

 

[bagoon316]

the stroke is still 97, cuz thats the crank.

these are the only pistons i see...

http://www.jepistons.com/Catalogs/Sport-Compact/Honda-Acura/k20a2_a3.aspx

the one is 9.0:1 for traditional round.

with a f23 crank, those pistons, k20 rods, and f23 head, i have you .079" in the hole and CR of 8.7:1

 

[99CcordMTF23]

Bah, you were right. The stroke stays the same. So if I got a set of those pistons, in say a 9.8:1 compression. It would be roughly, 9.5 in the end?

 

[Russianred]

If this is indeed the case, for a serious boost build, you want to be on the lower end of the spectrum anyways, considering roughly ~8.3-9.3 is safe. Why go through the trouble to to raise the compression even more from stock to 9.8?

 

[bagoon316]

^^ agreed.

 

[99CcordMTF23]

No, I meant if I ordered 9.8:1 pistons for kseries it would drop to 9.5:1 in the f23 block. I was looking for about 9.0:1 for my build.