Page:
Home > Help Needed / General Tech Chat > compression ratio, what's safe? super charged

HUBBAHUBBA

9 Posts
Member #: 10951
Junior Member

9th Nov, 2014 at 08:26:37am

In a quandry, looking to ditch de compression plate. With out the plate and retaining 6cc pistons the cr is 11.3! (With plate it 8.5).
If I get my hesd chambers to 25cc then the cr is 10.27. It would take a whole 33cc in the chamber to get back to 8.5.
My question is, is 10.27 too high? FYI - It will be intercooled blow through and has got programmable ingnition curve reacting to boost and revs.
Cheers

HUBBAHUBBA

9 Posts
Member #: 10951
Junior Member

9th Nov, 2014 at 08:40:38am

Oh and running at about 8 psi

apbellamy

User Avatar

16540 Posts
Member #: 4241
King Gaycharger, butt plug dealer, Sheldon Cooper and a BAC but generally a niceish fella if you dont mind a northerner

Rotherham, South Yorkshire

9th Nov, 2014 at 08:52:29am

I'm running 8.3:1 on 12psi with a suck through setup (efi etc). I've done a massive 30 miles without it blowing up or chewing the head gasket.

On 11th Feb, 2015 robert said:
i tried putting soap on it , and heating it to brown , then slathered my new lube on it

*hehe!*

wil_h

User Avatar

9258 Posts
Member #: 123
Post Whore

Betwix Harrogate and York

9th Nov, 2014 at 09:33:47am

The SC will make plenty of heat even at 8pis even with an IC. Yo can back the ignition off to compensate, but it's not ideal.

You need to find some cc in your pistons really. 9:1 is a a nice compromise for lowish boost. But you either need to machine the pistons you have, or buy some new. Otherwise you might as well stick with the decomp plate

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.


HUBBAHUBBA

9 Posts
Member #: 10951
Junior Member

9th Nov, 2014 at 10:51:57am

Thats a pain. Only rebuilt the engine 200 miles ago. Oh well. Any suggestions on high cc pistons for +60 thou, the only omega ones I can find seem to be +20 thou

Rob Gavin

User Avatar

6729 Posts
Member #: 618
Post Whore

Glasgow

9th Nov, 2014 at 11:14:51am

Not familier with the pistons so may be a daft suggestion but could you machine a bit out the crown?
Home > Help Needed / General Tech Chat > compression ratio, what's safe? super charged
Users viewing this thread: none. (+ 1 Guests)  
To post messages you must be logged in!
Username: Password:
Page: