My brother is currently looking to purchase an Evolution IX and a local tuning shop just ran a compression test and the results are 125, 137, 137, 140. Cylinder 1 is a bit worrisome but the shop said it could be buildup in the valve and could be cleaned by running e85? Note that the car has a protune for e85 but I think it was running mainly only a separate 91 map.

He's getting the leakdown test done right now but just wanted to throw these numbers out there to see what you all think?

Per the Evolution IX manual, the standard value is 145 PSI and the minimum limit is 92 PSI (these are lower than the VIII's). Just want to make sure the 15 PSI variance isn't something that could cause him the need to shell out money for a rebuild in the upcoming year or two.

 

How many miles on it?

 

73K miles on it.

 

Pending a leak down test, I would be ok driving it. How much boost is it setup for?

 

Do a leak down test to see what is causing the compression loss.

 

Leak it down. Compression test is kind of generic; your really just looking for a variance in values. As cylinder 1 is low and its tuned for e85... My guess is that it was poorly tuned which in turn hurt cylinder 1. Per leak down you cohld be buying an expensive project for yourself.

 

I'd rock it not problem. Low compression does mean "wear" but doesn't mean bad.

Make up for that compression by running more boost.