Your password will probably need resetting - don't panic. We have upgraded a few things and improved the hashing of passwords. Just use the Forgot Password link.
Page:
Home > General Chat > Is lowering the cr on the head ok with standard pistons ?

billmccorry

74 Posts
Member #: 9148
Advanced Member

LAMBEG , LISBURN

9th Dec, 2010 at 12:13:33am

Searched the threads and can’t find this

Can anyone tell me how much i need to take out of the chambers on my 1275 head
To lower the cr
as I’m running a turbo with standard pistons

and what the best gasket is to use
is AF470 thicker than AF460?
And will a thicker gasket make any difference

Only learning so be gentle

many thanks


best_stig

User Avatar

453 Posts
Member #: 6449
Senior Member

Brisbane, Australia

9th Dec, 2010 at 01:17:21am

You need to find out the original size of the head, then use a bit of maths, the dish of the pistons, the thickness of the gasket and your desired cr.
Once youve got those the maths has been covered a lot.
http://www.csgnetwork.com/compcalc.html
Theres one i prepared earlier.
A thicker gasket will lower the cr.

In boost we trust

billmccorry

74 Posts
Member #: 9148
Advanced Member

LAMBEG , LISBURN

9th Dec, 2010 at 07:27:12am

thanks best_stig
can the Cr be to low ?
And is there a desired shape for flow / swirl


scott the joiner

461 Posts
Member #: 9229
Senior Member

newcastle upon tyne

9th Dec, 2010 at 07:38:43am

Hi bill you pm me about pistons I havnt been on the comp & can't pm from me fone for sum reason iam sure I have a set of std pistons on rods


wil_h

User Avatar

9258 Posts
Member #: 123
Post Whore

Betwix Harrogate and York

9th Dec, 2010 at 07:43:23am

Yo can go too low with the CR, but you're unlikely to manage it with standard pistons.

Keep the shape as much as possible in the chambers.

At a guess you'll be looking at 26 to 28cc chambers depending on piston dish and piston to dec clerance.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph



On 2nd Jan, 2013 fastcarl said:
the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


billmccorry

74 Posts
Member #: 9148
Advanced Member

LAMBEG , LISBURN

9th Dec, 2010 at 01:08:27pm

thanks scott
my mobile is 07747805748
regards Bill
Home > General Chat > Is lowering the cr on the head ok with standard pistons ?
Users viewing this thread: none. (+ 1 Guests)  
To post messages you must be logged in!
Username: Password:
Page: