Hey all
I am currently building a new ej207 and was just wonder as I haven't had much to do with the flat 4s what are the best mods to do to a bottom end of a ej207 to get decent hp out of them I'm thinking better mains and big end bearing, forged pistons and conrods can any one help here
Thanks

Or can someone point me to a site or contact that has the info
Thank you

What are your goals first? How much power are you chasing and what will the car be used for?

You can spend $15k on a bottom end if you want, but a standard 207 may do the job adequately.

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500+hp and helis on tap, eta - June 2025.

Best bet is to hit the search button and see what builds people have done

You can build a decent 2.2 now days using a nitride treated crankshaft out of the 2010 Subaru WRX STi EJ257, decent bottom end parts to suit from Real street performance in the USA. There are many options out there from low budget builds to sleeved high hp builds.

Here is a link with a good read and there are plenty more on nasioc and other forums

Discussion EJ207 built 2.0 vs 2.2 stroker - NASIOC

Cheers DZENCI that's a very helpful write up will give it a good read over n keep researching n make a dission
Thanks for your help

cosworth or number or #12 oil pump that has been correctly ported & the PRV set correctly is a must have. If you dont do this your wasting you will do a bearing.



If you use a 2.5 crank I would recommend you send the crank to Knight racing motors in SA to be oil phased. I post a photo of this tonight as Tuna asked me

Killa B sump baffle/ windage tray & oil pick up

read Roscos post on oil lines to catch can.

Tony knight in sa for sure if you want a killer combo.

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I am only an asshole on the internet :)

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The new #78 genuine pump has all the same changes that cosworth were making to the old #12 pump apart from shimming the prv.

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[CENTER][SIGPIC][/SIGPIC][/CENTER]
[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]

I would say - forged piston & rod combo for ~ 1000 - 1400, set of ARP head studs - 300, get the block decked and honed if needed ~ 400, new bearings ~ 150, OEM gasket set, and your bottom end is ready for 250KW atw? maybe 300? cosworht don't even sleeve there High HP blocks, which are a LOT higher HPO than 250KWATW btw. If you run the stock oil pump or just replace it with new and forged pistons - make sure you change to a thicker oil like 15W40 - will save your bearings for longer.

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STI RA V6.... 12.55 Stock

^^ crack pipe prices?

15w40 is too thick for a new motor.

Pricing from my build 12 months ago (all parrts sourced from Realstreetperformance.com):

Engine Rebuild Costing
Ej207 My00 Subaru STi

Manley H-beam rods 329.00
Wiseco Pistons 93mm 450.00
ACL Race Bearings EJ20 120.00
ARP Case Bolts EJ20 315.00
Subaru Genuine Oil Pump #78 115.00
Subaru OEM Water Pump WRX 115.00
BC0601 BC 272 Cams 575.00
BC Valvesprings & Retainers 215.00
ARP Headstuds Subaru 2.0L 189.99


Subtotal: $2,425.99 Usd ($2,527.86 aud)


Locally sourced:
Oem gasket set $455.00 aud

Parts total $2,982.86 aud

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[CENTER][SIGPIC][/SIGPIC][/CENTER]
[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]