LS1TECH - Camaro and Firebird Forum Discussion

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- Generation III Internal Engine (https://ls1tech.com/forums/generation-iii-internal-engine-5/)

- - DCR and Altitude (https://ls1tech.com/forums/generation-iii-internal-engine/547794-dcr-altitude.html)

MISERICORDIA

07-25-2006 03:55 PM

DCR and Altitude

Here in Utah we can only get 91 octane. It seems that I would need to keep my DCR at or below 8.5. Can this be higher since the car is usually at 4000 feet and never goes below 2000 feet?

CamKing

07-25-2006 04:17 PM

Yes.
If the air is 10% less dense it can be compressed 10% more.

MISERICORDIA

07-25-2006 04:23 PM

How much higher should I aim for?

CamKing

07-25-2006 05:33 PM

What's the corrected barometric pressure where you'll be running?

JakeFusion

07-25-2006 05:44 PM

91 octane is probably a little weak for 8.5:1 DCR. I usually recommend that for 93 octane... actually I'm recommending upto 8.7:1 nowadays on 93 with a kickass cooling and a dead on tune. That being said, I would think 8.1:1 or so would be the max on 91 octane at sea level and about 8.3:1 on 92, so with the altitude, you might try for 8.5:1-8.6:1.

MISERICORDIA

07-25-2006 10:53 PM

Thanks for the help.

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