DCR and octane - Team Camaro Tech
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post #1 of 7 (permalink) Old Mar 27th, 08, 07:06 PM Thread Starter
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Brian
 
Join Date: Jun 2004
Location: Nassau County, Long Island, NY
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DCR and octane

Is 100 octane enough?



My info.

Cam http://www.compcams.com/Technical/Se...umber=12-771-8

Bore 4.060"
Stroke 3.75"
Disp 388ci
Pistons -5cc
DITH 0.015

gasket bore 4.166
thickness 0.039 (yeah i know my quench is too big)

victor jr heads 64cc

First of all, did i do the calc right?
Second, will 100 octane be good for me? I have a good source that can get it at his cost, but he can't get the higher octane stuff at the low price.

Thoughts?

Brian
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post #2 of 7 (permalink) Old Mar 27th, 08, 07:16 PM
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Jim
 
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Re: DCR and octane

I got exactly the same numbers using PatK's calc.

Are you sure you can't find a set of 70-72cc heads, or some d-dish pistons?
Or maybe a lil bigger cam even?

That's a lot of compression.





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post #3 of 7 (permalink) Old Mar 27th, 08, 07:30 PM Thread Starter
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Brian
 
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Re: DCR and octane

I can go bigger on the cam.
Could go bigger heads, but there's more money in that.
Pretty unwilling to change pistons.

The car is really going to be an occasional street driver, but mainly track time is what i see it doing.
How much will going with a bigger cam help me?
Using this cam http://www.compcams.com/Technical/Se...umber=12-704-8 will get my DCR down to 8.088 What kind of octane would i be looking at there?

Brian

Last edited by 67Builder; Mar 27th, 08 at 07:46 PM.
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post #4 of 7 (permalink) Old Mar 28th, 08, 07:39 AM
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Trevor
 
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Talking Re: DCR and octane

Hay Brian where did you get that calculator from?
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post #5 of 7 (permalink) Old Mar 28th, 08, 08:20 AM
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Mark
 
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Re: DCR and octane

Brian

Try plugging your values into this:

http://www.bid2race.com/DynamicCompr...Calculator.php

When you click 'calculate' it gives you a minimum octane for that comp. ratio.

Mark

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post #6 of 7 (permalink) Old Mar 28th, 08, 03:39 PM Thread Starter
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Brian
 
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Re: DCR and octane

Quote:
Originally Posted by osin68 View Post
Hay Brian where did you get that calculator from?
http://www.kb-silvolite.com/calc.php?action=comp

That's where i got that calc from.

with this cam http://www.compcams.com/Technical/Se...umber=12-705-8
my DCR goes down to 8.816.

That should be low enough for even the crap gas you get from the station.

But is the 100 octane enough to run this thing with a normal amount of timing as it sits today? I've got it started up on 93 octane running retarded and rich. Don't want to push it too hard till i get some better gas in the tank though.

Brian
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post #7 of 7 (permalink) Old Mar 28th, 08, 05:00 PM
 
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Re: DCR and octane

I use this one for DCR.

http://www.rbracing-rsr.com/comprAdvHD.htm

and this one for SCR.

http://www.campbellenterprises.com/R...alculators.htm

pdq67



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