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11:1 Too Much For DD?

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Old 05-13-2011, 08:43 AM
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pcressey
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Default 11:1 Too Much For DD?

I am in the process of taking off my S/C and putting in a Stage 1 NA block. My question is... Is a 11:1 compression ratio too much for 91 pump gas? The last thing I want for my DD is to have detonation issues.

If you think 11:1 is too much, are there any aftermarket pistons around a 10.5:1 or stock 10.3:1? I can't seem to find any.

Just a note, there is no 93 available in SoCal.

Thanks for the input.
Old 05-13-2011, 09:55 AM
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Blu_Blur
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Originally Posted by pcressey
I am in the process of taking off my S/C and putting in a Stage 1 NA block. My question is... Is a 11:1 compression ratio too much for 91 pump gas? The last thing I want for my DD is to have detonation issues.

If you think 11:1 is too much, are there any aftermarket pistons around a 10.5:1 or stock 10.3:1? I can't seem to find any.

Just a note, there is no 93 available in SoCal.

Thanks for the input.
You could always bring back the timing to prevent detonation, right?

I'm in Cali so I know what you are talking about in regards to gas. A good resource to speak with is GT Motorsports in Rancho Cucamonga. Ask for Sam as he is the lead tuner.

He tuned my Turbonetics 350Z and he is very knowledgable on the VQ engine.
Old 05-13-2011, 10:21 AM
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str8dum1
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you can have pistons made for any compression that you want, so dont let in stock ratios be the only thing you are looking at.
Old 05-13-2011, 11:03 AM
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pcressey
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Thanks for the info.


Originally Posted by Blu_Blur
You could always bring back the timing to prevent detonation, right?
That is true, but I would worry about the timing being too retarded and causing other issues... like being sluggish and running too hot. I will give Sam a call.


Originally Posted by str8dum1
you can have pistons made for any compression that you want, so dont let in stock ratios be the only thing you are looking at.
Good to know, you have any links for custom pistons?
Old 05-13-2011, 11:04 AM
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kacz07
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I drive my 11.5:1 w/ UpRev very often.
Old 05-13-2011, 12:46 PM
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Originally Posted by kacz07
I drive my 11.5:1 w/ UpRev very often.
Yeah but you're in New Jersey. What octane do you fill-up with?
Old 05-13-2011, 01:59 PM
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Zazz93
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11.1 is still relatively (keyword relative) conservative. Granted its a push up from 10.3, but I would imagine you wouldn't have too many issues DD'ing a well tuned setup provided your tuner doesn't push too far for all out numbers.

But the question you should ask is why? NA power is cool but what is it your really looking for?

BTW: I'm at 11.3 and have had no problems on CA's 91.

Last edited by Zazz93; 05-13-2011 at 02:01 PM.
Old 05-13-2011, 03:49 PM
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Originally Posted by Blu_Blur
Yeah but you're in New Jersey. What octane do you fill-up with?
True, I forgot. I think I have a 91 map, but yea, I use 93. Still, as long as the tune was good, you should be straight.
Old 05-13-2011, 09:09 PM
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boostedforlife
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I am at 11:1 in cali. 91 octane.

I think the new 37's are 11:1 from factory so no worries.
Old 05-14-2011, 09:31 AM
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pcressey
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Originally Posted by Zazz93
But the question you should ask is why? NA power is cool but what is it your really looking for?

BTW: I'm at 11.3 and have had no problems on CA's 91.
Taking the FI off and just going back to a somewhat stock NA setup. Getting a new block and it comes with 11:1 compression. Just want to see if anyone else was running that safely on 91 octane, or had knowledge pertaining to it.

The car will be tuned with UpRev; makes me more comfortable that you are at 11.3:1 and doing fine.
Old 05-18-2011, 03:50 PM
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why removing the SC?
Old 07-02-2011, 05:56 PM
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im fully built with 11:1 DD'n my g with an osiris tune......using 93 octane here in SC
Old 07-02-2011, 06:00 PM
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wish 93 was an option around here
Old 07-02-2011, 06:23 PM
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05Z33
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You guys don't have E85 in Cali? 11:1 with the Vortech on E85 would be nice.
Old 07-02-2011, 06:55 PM
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terrasmak
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Originally Posted by 05Z33
You guys don't have E85 in Cali? 11:1 with the Vortech on E85 would be nice.
Been thinnking about that for a while, but doesn't look like i'm going FI .
Old 07-02-2011, 07:34 PM
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I'm also 11:1 for the past year or so with no problem. That being said i'm going to be adding a direct port water injection very soon to achieve something else as well as potentially venturing into E85. There are a few stations here in the bay area.
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