Compression tests. 2.7T Section comments

This post is for making comments on the Actual test section. This is to not let the tech post get cluttered with comments and questions.

good idea… one misconception I see is that compression ratio of the motor is directly related to the cylinder pressure you see in the test. While it is, you also have to consider the cams and how much overlap is allowed.

See the stock 2.7T numbers the count posted, the pressures are higher than you’d normally see with a 4.2 despite the 4.2 having an 11.0:1 scr and the 2.7T having a 9.3:1 scr. The 2.7T cams have less overlap and therefore let less air escape before the valves seal up.

You beat me too it. Great post beem. This is why I was just going to start a 4.2 S4 thread. This way each member will be able to see a reference to there motor. I was going to do the same for each of the populated boards on the site.

great idea… I’ll post mine after i get done with the build.

thanks, and sounds like a good plan.

a cool idea would be a communal compression test kit, we could get lots of data if we had a test kit we could ship around instead of havin people pay for their own kits/getting the test done. I’d be interested to see rpm/sec vs compression numbers for similarly modded cars.

looking forward to seeing the ‘mint 4.2’ compression test numbers posted up, to be used as a standard when selling as ‘mint’.

I wont post mine again it is to painful.

Hansen your fine everyone loves you your safe to talk here…lol

160 155 155 150 155 142

Those r blue crushes compression numbers

Love you too buddy

I have one that’s just been sitting. I’ll offer it up if anyone needs it. Just need an address and I’ll ship it for free