need help on CR?

D15, D16, D17 and Mini-Me swaps
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need help on CR?

By eghatch21
- Tue Apr 20, 2010 11:16 pm #188870 i keep doin the comprssion ratio calculator and idk if its right so if someone else could find out wat my CR would be on my mini me swap. i got a d15b2 block wit a d16y8 vtec head


thanks
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By eg84dr
- Wed Apr 21, 2010 12:32 am #188874 what head gasket you running ?
with a b7 headgasket your cr is 9.95 to 1
with a z6 headgasket your cr is 10.22 to 1
with a y8 headgasket your cr is 10.54 to 1
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By eghatch21
- Wed Apr 21, 2010 4:38 am #188923 ok kool thanks which means i can still run unleaded unless i bump my compression up to higher than 11.5:1
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By forcefedEG
- Wed Apr 21, 2010 12:41 pm #188953
eghatch21 wrote:ok kool thanks which means i can still run unleaded unless i bump my compression up to higher than 11.5:1


ive heard of up to 12:1 or 12.5:1 on a b series with a killer tune???
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By suspendedHatch
- Wed Apr 21, 2010 3:30 pm #188970 Not sure I would trust those numbers since the Z6 and Y8 headgaskets have been consolidated many years ago now.
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By eghatch21
- Wed Apr 21, 2010 7:33 pm #189025 wit the y8 gasket its 10.5:1 like it says above but if i but p29 pistons(88-89 integra) in it the comression will be 12.6:1 done read alot bout that

By AutoXCivic
- Thu Apr 22, 2010 12:49 am #189086
forcefedEG wrote:
eghatch21 wrote:ok kool thanks which means i can still run unleaded unless i bump my compression up to higher than 11.5:1


ive heard of up to 12:1 or 12.5:1 on a b series with a killer tune???


It's actually easier to run higher compression on the D-series motors because of the smaller bore, it prevents detonation. Think about it some motorcycles run upwards of 13:1 compression stock, and use pump gas.

I've seen someone run 86 octane fuel at 12.5:1 but he was a really good tuner, and incredibly smart.

You'll be fine with 91 octane fuel for a mini me swap.
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By forcefedEG
- Thu Apr 22, 2010 12:50 pm #189224 ^ very true about the bore thing... never thought of that before but it makes good sense :thumb:

By AutoXCivic
- Thu Apr 22, 2010 1:18 pm #189227
forcefedEG wrote:^ very true about the bore thing... never thought of that before but it makes good sense :thumb:


If you want I can see if I can find the thread where the guy was getting 12.5:1 to run on 86 octane without pinging. It was a really good read, and very informative.


EDIT: Found it ... 87 octane not 86, but still.

Anyway here's the link http://www.d-series.org/forums/naturally-aspirated/95775-any-high-cr-87-octane-experience.html

There's some BS to sift through (frickin' haters), but also some very good information in there.
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By forcefedEG
- Thu Apr 22, 2010 1:57 pm #189235 ^ hell yea man ill take a look :thumb:
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By eghatch21
- Sat Apr 24, 2010 5:47 pm #189799 i knew 91 octane would work n that very true higher compression is easier on d-series motors that one of the reasons y i chose the mini me swap they put out a good amount of power

By j0keefe21
- Sat Apr 24, 2010 8:42 pm #189838 i run 12.5 to 1 in my z6 and i didnt have to pull timing
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By eghatch21
- Sun Apr 25, 2010 2:23 am #189884 hell yea wat pistons u runnin in ur z6?
i was thinkin bout gettin p29 pistons for mine
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By forcefedEG
- Mon Apr 26, 2010 3:32 pm #190159
eghatch21 wrote:i was thinkin bout gettin p29 pistons for mine


heard the p29 pistons arent notched rite for the valve reliefs on a vtec head...
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By eghatch21
- Mon Apr 26, 2010 8:54 pm #190221 thats wat i was thinkin but ive seen ppl use them for high compression builds i need to read more on it cuz those pistons r cheap
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