How do the manufactures "take compression out"

[snowmanx]

Stock M1000 runs 12.1:1 compression ratio. Sounds like Twisted/ovs take compression out to the tune of 10.1-10.5? How is this accomplished? So they cut the dome out?

 

[Snowstar]

Twisted does not take any compression out of the head. retains stock C/R.

 

[snowmanx]

Twisted does not take any compression out of the head. retains stock C/R.

Does he do any porting of the cylinders or open up the cases any more? Or is it just stock? Thanks

 

[Snowstar]

No case work is needed. Twisted alters the port timing of the cylinders, which requires you to send in your cylinders and head. The head is machined to compensate for the cylinder machining so you retain the stock C/R.

 

[Rixster]

Really? 12:1 seams a little high to be able to run 87 octane. I dont have any idea what it is stock, I am just saying I think that is high.

 

[snowmanx]

Really? 12:1 seams a little high to be able to run 87 octane. I dont have any idea what it is stock, I am just saying I think that is high.

I could be wrong, I believe that is what I have been told by Jeff at Dekota Performance, but I may be mistaken?

 

[Dam Dave]

you could do that a few ways, some that come to mind, custom head, thicker gaskets, custom pistons

 

[jijohans]

Some rework the head with bigger/deeper domes, some cut the squish down 4/10-6/10mm...

 

[snowmanx]

Some rework the head with bigger/deeper domes, some cut the squish down 4/10-6/10mm...

If you cut the squish down you would be adding compression wouldn't you?

 

[jijohans]

If you cut the squish down you would be adding compression wouldn't you?

? If you remove 4/10-6/10mm of the squish band at the same angle...

 

[snowmanx]

? If you remove 4/10-6/10mm og the squish band at the same angle...

Sorry, as thick as mud