losing power, give me a list of things to do to find my issue
 

Ok just got back from another track day, I now know I have an issue but its slight. The car is an Evo 9 with only 77k klms on the clock and I have been noticing on the road a very slight power drop which my timer on the track proved. I was down on top speed on the straights around 15 klm per hour. I was down 2 seconds a lap too. Also puffs of smoke were being seen behind the car on gear change at WOT. It also spits a little oil on start up in the mornings. The car is mostly stock. I also noticed one lap it actually lost about 20% power for half a lap then came good again which is weird and never repeated that.

ok so I understand about boost leaks and have been over the pipes and one of those boost smokers into the inlet tests and nothing was seen escaping. I want to also do a compression check, that's easy, I can buy a comp tester this weekend. I am also suspecting the journal bearing on the turbo, how do I test for that? Can I lose boost with a worn journal bearing?. Is there anything else I can check or test?

The car hasn't got that many miles on it which concerns me of what it could be.....thanks anyway

Compression/leakdown test and you can grab the compressor wheel nut and try to wiggle the shaft in and out/up and down to check for excessive radial and axial play.

Sounds like the turbocharger is on its way out.

You running a cat? I know those things start to get kinda nasty.

A cat going bad wouldn't cause smoke and liquid oil to come out of the exhaust.

true, but if he does have that stuff going out his exhaust its probably doing bad things to the cat, so still worth lookin at.

i think i sense this, so at the cheapest can i simple buy a rebuild kit for 100 bucks and diy ?

I wouldn't do a DIY rebuild on a turbocharger. There are some critical tolerances to measure, and they should be balanced after assembly. I would find a reputable turbo rebuilder to do it. Here in the states, Forced Performance only charges USD $275 for a rebuild.

I have rebuilt several of my own, no measurements taken of anything, the only thing I have done is marked the compressor/shaft/nut and lined them back up upon assembly and the evo is not the only car I have done that on. All of those turbos live to this day, make sure everything is clean when you assemble and prime the turbo with oil before the first start.

Would you assemble an engine without checking bearing tolerances?

i agree, if i pull the turbo is there upgrades to it worth doing if i payed a but more, that you would recommend?

LOL. That is critical, but obviously not checking clearances on a turbo is a lot cheaper to fix than an engine if there is something out of spec thats why I took the risk. To be honest I have never heard of turbos needing clearances checked. I only shared my first hand experience with rebuilding my own turbos, I haven't had any fail but that doesn't mean there isn't a possibility. So If you are gonna do it do so at your own risk, but I have heard/read of a lot of others rebuilding turbos without checking clearances and those turbos still live.

I just did a compression test, at first i did it cold and they were all just under 100psi then i realised i stuffed up and repeated with a warmed up motor, funny they all gave the same reading just under 100 psi, the plugs are all light tan color and were all dry. I read that bottom is 92psi, should i be worried as it has lost some power on boost, plugs look good though so i thought this wouldnt be the case, im going to boost tdst it next

The fact their all close together means it could be fine and just be the turbo thats a little low but depends on gauge and methods

Compression won't cause sudden noticeable drops in power, and then the power comes back.