# Compression



## staytuned33 (May 25, 2004)

I was reading some guys testing on turboing a sr20ve and he said that they had 11:1 compression stock. He also said to turbo the sr20ve, you will have to get the compression around 8:1 or 9:1. Why? I thought the better the compression the better the power. Maybe it would be too much if your going for efficiancy? Just curious. Thanks


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## lshadoff (Nov 26, 2002)

You can't run as high boost in a high compression engine due to detonation (inother words, you can run higher boost in an 8.5:1 comression engine than in a 10:1 compression engine). Most forced induction engines have 8.5:1 compression or lower.

Lew


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## 180SX-X (Sep 21, 2003)

yeah, imagine building a high compression,lets say 12:1, N/A motor..makes 240hp, but you want more..so slap on a turbo with the compression still 12:1, you run the turbo at 7psi..at the moment our engine makes boost, your engine goes BOOM!..thas whatll happen..this is a dramatized effect because the high compression Matrix(11.1:1) can be turbo'd at 7psi, but you need high octane gas..8.5:1 is the norm..


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## Joel (Jun 11, 2003)

just run avgas


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## 180SX-X (Sep 21, 2003)

go methonal injection and c16 with alchohol mix and your good...


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## Murph (Aug 8, 2002)

PS. air heats up when compressed, and when compressed too much, it tends to ignite.


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## lshadoff (Nov 26, 2002)

Murph said:


> PS. air heats up when compressed, and when compressed too much, it tends to ignite.


Only if it has something flammable mixed in with it, like gasoline.

Lew


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## Murph (Aug 8, 2002)

In Soviet Russia, car burns YOU!


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## muleman (Apr 22, 2004)

right now i am running 10.4.1 comp, and a fully build motor with gt35r turbo and running 10psi on pump gas and it runs very very strong.I just poped 3 gear @ 10psi runing up and down the road and yes the tranny was cryoed.also i get boost @ 2800rpms


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## Chillboy (Oct 8, 2003)

^^^SR20 in a 240?


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## javierb14 (Jul 9, 2002)

some good info on high vs low compression from an experienced honda tuner
http://www.boosted-hybrid.com/viewtopic.php?t=19&highlight=compression


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