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Boring my 1.8l BP

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Old 06-20-2019, 05:29 PM
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Default Boring my 1.8l BP
Is it worth boring my 1.8l BP to 84mm? I think about getting 84mm supertech forged pistons and can you help me with what compression I should go with
I'm sorry about this question I'm a noob to the car world
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Old 06-20-2019, 05:39 PM
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8.6:1 Supertechs in 84mm with Weisco rings is probably the most common ones used on here.
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Old 06-20-2019, 08:39 PM
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First start by telling us why you want forged pistons?
What are your goals?
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Old 06-20-2019, 09:19 PM
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Originally Posted by borka
First start by telling us why you want forged pistons?
What are your goals?
well Im hoping to go the turbo route gonna get the Garrett gt2560r wanting to put out at least 300
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Old 06-20-2019, 09:23 PM
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To support that much hp I was gonna just re build a 94 1.8l BP bottom and do a 99 head swap
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Old 06-20-2019, 09:28 PM
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A gt2560r will not get to at least 300hp. It taps out around 280hp.
Under the most ideal setup, it will maybe hit 300hp, maybe.

You need a gt2871r or a efr6258 for 300+hp.

8.6:1 Supertechs in 84mm with Weisco rings, like Lars said above. Most popular.
you also must have forged connecting rods.

300hp ain't cheap. Around $6-8k once you figure supporting drivetrain upgrades.
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Old 06-21-2019, 12:06 AM
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Originally Posted by borka
A gt2560r will not get to at least 300hp. It taps out around 280hp.
Under the most ideal setup, it will maybe hit 300hp, maybe.

You need a gt2871r or a efr6258 for 300+hp.

8.6:1 Supertechs in 84mm with Weisco rings, like Lars said above. Most popular.
you also must have forged connecting rods.

300hp ain't cheap. Around $6-8k once you figure supporting drivetrain upgrades.
I made 296whp/302tq @17psi with a 84.5mm engine and FM manifold/2.5"dp/3" exhaust.
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Old 06-21-2019, 12:09 AM
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Originally Posted by Luis Batres
To support that much hp I was gonna just re build a 94 1.8l BP bottom and do a 99 head swap
That's what I have a 94 BP block bored to 84.5mm. wiseco 8.5:1, Manley rods, ACL bearings, ARP head/main studs. Bp4w head squaretop IM, bp5a intake cam.
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Old 06-21-2019, 01:05 AM
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Originally Posted by andyfloyd
That's what I have a 94 BP block bored to 84.5mm. wiseco 8.5:1, Manley rods, ACL bearings, ARP head/main studs. Bp4w head squaretop IM, bp5a intake cam.
What ACL bearing size set did you use?
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Old 06-21-2019, 07:38 AM
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Originally Posted by Luis Batres
What ACL bearing size set did you use?
Lol, the ones that fit your engine. You wont know what size you need until you take it apart.

If the journals are in good shape, then standard size is probably fine. again, wont know till you open it up.
Last edited by ryansmoneypit; 06-21-2019 at 10:30 AM.
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Old 06-21-2019, 08:39 AM
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Originally Posted by Luis Batres
What ACL bearing size set did you use?
You have the machine shop check for that stuff. Mine were standard though.
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Old 06-21-2019, 12:26 PM
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I think the EFR is better bang for the buck. borka has a efr and i have one but not installed.
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