F20a4 Rod journal size needed for turbo setup

Brozilla · Post by **Brozilla** » Tue Feb 21, 2017 7:38 am

I got bored with my stock boosted f20a4, still running, but I want to push it a bit more because why not.

Ofcourse, there are no forged internals for F20a4 so I spent the last few months choosing appropriate parts.This should work, but I have a concern regarding rod journal size.
H23a2 head
F20a4 block
F20a4 crank
H22 forged rods
FA20-GSE Toyota GT86 low-comp pistons.

Deck height is 219.5mm. Stroke is 88mm, GT86 pistons are 32.51mm and -11cc dish. That would make them flush with block.

Thing is, H22, H23 and F22 are 48mm rod journal size, but I cannot find dimensions for F20a4. Does anyone know for sure does F20a4 has 45mm or 48mm, or is willing to measure it? Thanks

Post by **NafemanNathan** » Tue Feb 21, 2017 8:41 am

Is a H23a2 head a direct bolt-on?

Going by the ACL catalogue the rod bearings are the same size...

http://www.acl.com.au/WEB_ACL16_V2_LTRXP.pdf (F20a4 Page 345, H22a1/2 Page 346).

How much power are you looking for?

Brozilla · Post by **Brozilla** » Tue Feb 21, 2017 9:53 am

One oil passage needs to be sealed, other than that it is direct.

Not much power, aiming 331HP because it is opposite of factory 133

Pressure will be between 1.2 and 1.5 bar.

But since I am already taking it apart, i want to make it fully forged. Cost difference is not big between rebuild with OEM parts and this strange combination I plan to do.

Thanks for the info Nathan, will check it out

Post by **NafemanNathan** » Tue Feb 21, 2017 9:57 am

Brozilla wrote:aiming 331HP because it is opposite of factory 133

I like it!

No probs. Good luck bud. And keep us up to date