Maximum CR
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
You will probably get away with 89 Octane in cool weather, if you run a 180 degree tstat. In hot weather or if you are in heavy traffic you will need 91+ octane.
Are your pistons zero deck, with a dish, or are they flattops 'down the hole'?
If they are zero deck, you will have quench, and will be able to get away with 89 Octane under most conditions.
Are your pistons zero deck, with a dish, or are they flattops 'down the hole'?
If they are zero deck, you will have quench, and will be able to get away with 89 Octane under most conditions.
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Mountain Pass
Joined: Dec 2006
Posts: 190
Likes: 40
Originally Posted by danlee
You will probably get away with 89 Octane in cool weather, if you run a 180 degree tstat. In hot weather or if you are in heavy traffic you will need 91+ octane.
Are your pistons zero deck, with a dish, or are they flattops 'down the hole'?
If they are zero deck, you will have quench, and will be able to get away with 89 Octane under most conditions.
Are your pistons zero deck, with a dish, or are they flattops 'down the hole'?
If they are zero deck, you will have quench, and will be able to get away with 89 Octane under most conditions.
Thanks for the information.
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
You want a set of zero deck pistons from Tim Meyer. They will allow quench which will help to reduce detonation. You should be able to go to the light side of 9.5:1 CR and get by with 89 with Aussie heads and zero deck pistons.
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Joined: Mar 2005
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From: western montana
Listen close folks, as you know I just built that basic engine with aus heads, tims kb pistons and 9.5:1 ( what is atuallymore like 9.3 +-) I use the roller cam that is just a bit later IVC...not much diferent than the 255 and more forgiving if i remember correctly... I have to run retarded with 91 and lucas additive. The dynamic is pretty high with the 255 and even with quench heads and the right pistons there is no freaking way I'd go with that cam. And if you run into the 3k rpm range on the road it isnt the best cam anyway. Using the DEH 255 I'd not go over 9:1 CR.
Maybe I'm doing something wrong but even the basic guide states 95 + octane for that build...right? Hope my memory isn't going with the paint thinner i've been using lately. I'm still looking to propane the thing someday....need parts
Maybe I'm doing something wrong but even the basic guide states 95 + octane for that build...right? Hope my memory isn't going with the paint thinner i've been using lately. I'm still looking to propane the thing someday....need parts
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Joined: Nov 2005
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mr roger, paul. for what it is worth, it is always good to hear from you in our house.
regaurdless of the issue and or the subject matter. we like your level headed stlyle, as always, it is about the MOTOR, carry on, these hillbillys are LISTENING. good luck in OUGHT 8.
quietely and respesctfully.
paul &nick kiernan berwyn MD.
regaurdless of the issue and or the subject matter. we like your level headed stlyle, as always, it is about the MOTOR, carry on, these hillbillys are LISTENING. good luck in OUGHT 8.
quietely and respesctfully.
paul &nick kiernan berwyn MD.
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Mountain Pass
Joined: Dec 2006
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Originally Posted by roger dowty
Listen close folks, as you know I just built that basic engine with aus heads, tims kb pistons and 9.5:1 ( what is atuallymore like 9.3 +-) I use the roller cam that is just a bit later IVC...not much diferent than the 255 and more forgiving if i remember correctly... I have to run retarded with 91 and lucas additive. The dynamic is pretty high with the 255 and even with quench heads and the right pistons there is no freaking way I'd go with that cam. And if you run into the 3k rpm range on the road it isnt the best cam anyway. Using the DEH 255 I'd not go over 9:1 CR.
Maybe I'm doing something wrong but even the basic guide states 95 + octane for that build...right? Hope my memory isn't going with the paint thinner i've been using lately. I'm still looking to propane the thing someday....need parts
Maybe I'm doing something wrong but even the basic guide states 95 + octane for that build...right? Hope my memory isn't going with the paint thinner i've been using lately. I'm still looking to propane the thing someday....need parts
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Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
According to my calculations 9.3:1 static in a 400 with a 255DEH cam will give you 8.02:1 Dynamic CR. This should be OK with 91 Octane and Aussie heads with quench.
Look at www.edyno.com
Look at www.edyno.com
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