Squish on M8 turbo

[Catman 42]

How much squish is recommended for an M8 turbo?

 

[RACINSTATION]

I like to see them around 68thou "

 

[Boyko]

What is stock set at?

 

[RACINSTATION]

Cat shows .059" for squish clearance in the service manuals.

*This is on 2007-2009 M8s.

 

[Catman 42]

Squish

I am actually working on a Bikeman 700 to 800 bored engine with a garrett and the squish was about 62 so I had it milled anther 10 but it turned out to be about 75 when I put it together and checked it. I ran it today and it seemed to work very well at about 3000' 10-12LBS 100LL. We didn't make it to 6 or 7 or get to make any climbs due to reed failure on the M12T.
Thanks for the input.

 

[RACINSTATION]

That should be fine at 3-5000 feet.

 

[snownman]

squish...

.075" will be good with high boost pressure to help control detonation, backlash is you might loose 2% on bottom end throttle response.

 

[Mseven]

Do you have to get the chambers milled in deeper or can you run a thicker base gasket?

 

[RACINSTATION]

It is always best to machine the domes. Base gasket thickness will raise the port timing, which on naturally aspirated may not be a bad thing...but on the turbos, I like the stock or even a pinch lower on the port timing.

 

[Boyko]

A thicker base gasket will open up your port timing, not the way to set up engine for a turbo. Mill the cylinder base and cut the squish band, open the dome for high boost or cheep fuel. JMO

Opps The Racestation beet me to the post, faster than me.

 

[Timber12]

How much can you mill the heads to go from race gas to say 75 premium 25% race gas? What are the downsides to this?