Compression ratio in the V-6 X's

I am wondering why Nissan uses a compression ratio of 8.9:1 in both the superchargered VG33E and the normally aspirated VG33E. Is it just an ease of manufacturing? Using a higher compression ratio in the non-supercharged V-6 would increase power and efficiency of the engine which would help the only weak link I have found on the X. If you know why they don't bump up the compression, let me in on the secret.

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That is if I'm not mistaken and they are both actually 8.9:1.

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Probably because the engine is 15 years old.

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Regards,
Ian

If the normally-aspirated VG33E had any higher compression it would almost certainly need premium fuel. People don't like hearing that these days unless they are buying something intended to be high performance. My '84 VF1100S has 10.5:1 compression and pings like mad on anything less than 92 octane.

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Does the Frontier require more than unleaded regular to prevent pre-detonation?

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Same engine. Nope. If it's supercharged, it will need premium though.

Brent

Here's a list of vehicle engines sold in the N. American market. That 8.9:1 seems to be about as low as it goes.

http://www.wardsauto.com/docs/Mahle2001.pdf