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Old 02-24-2021, 12:22 PM   #1
Mindriddle
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Default Short Block Replacement..CR question

In a nutshell, I acquired a refreshed block with new CP std size pistons, 8.2:1 CR, new Manley rods and new crank. This is going in my 08 WRX running E85 (car is already set for it) with the stock VF52 turbo. This will be mated with my stock D25 heads and everything else just transferred from the old engine with new seals, timing belt and pumps of course. With this setup, I was recommended a 1.1mm headgasket to bring the CR back to WRX, from what I read is 8.55:1. Is this correct?

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Old 02-24-2021, 06:29 PM   #2
cboggess
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Yes. That is correct. Tomei makes a 1.1.
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Old 02-24-2021, 07:23 PM   #3
benflynn
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Thinnest you could find if ur E85 all the time, I just built an 8:5 engine but would of gone 9.5:1 if I had planned it better. If I was running 93 Id leave it 8.2 and see how o liked it.
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Old 02-24-2021, 09:13 PM   #4
Haevn
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let me know if you run a thicker head gasket and can't get your header to bolt up right if you run aftermarket. i have an iag closed deck block with .039 JE head gaskets and my aftermarket header wouldn't fit was like 1/8 to wide so i had to go back to stock header
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Old 02-25-2021, 05:37 AM   #5
Mindriddle
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Quote:
Originally Posted by benflynn View Post
Thinnest you could find if ur E85 all the time, I just built an 8:5 engine but would of gone 9.5:1 if I had planned it better. If I was running 93 Id leave it 8.2 and see how o liked it.
The car has the flex kit so I will be using E85 for the most part and 93 occasionally. Would you still recommend having a bit higher CR? Possible goal after the engine is done is to upgrade the turbo, just depending on how happy I am with its performance with the stock VF52.
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Old 02-25-2021, 05:39 AM   #6
Mindriddle
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Quote:
Originally Posted by Haevn View Post
let me know if you run a thicker head gasket and can't get your header to bolt up right if you run aftermarket. i have an iag closed deck block with .039 JE head gaskets and my aftermarket header wouldn't fit was like 1/8 to wide so i had to go back to stock header
Still a debate whether ill be changing the stock header. Thanks for the heads up though.
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Old 02-25-2021, 11:29 AM   #7
Jedi03
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I personally prefer higher compression...much better response and economy, many tuners have issues due to size of injectors needed to make this safe...the few I have done SR20 @ 9:1 and Honda at 10:1 were great...had to really throttle the boost to near nothing on the honda for multiple reasons the SR still running strong an getting 30 mpg on the highway
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Old 02-25-2021, 02:27 PM   #8
Mindriddle
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Quote:
Originally Posted by Jedi03 View Post
I personally prefer higher compression...much better response and economy, many tuners have issues due to size of injectors needed to make this safe...the few I have done SR20 @ 9:1 and Honda at 10:1 were great...had to really throttle the boost to near nothing on the honda for multiple reasons the SR still running strong an getting 30 mpg on the highway
Hmm..ill keep this in mind when i start to buy all the supporting parts, aka headgasket. The car currently has 1050cc injectors and AEM high flow fuel pump.
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