losing power, give me a list of things to do to find my issue
#1
Evolved Member
Thread Starter
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
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
#3
EvoM Guru
iTrader: (1)
Sounds like the turbocharger is on its way out.
#4
EvoM Community Team Leader
You running a cat? I know those things start to get kinda nasty.
#5
EvoM Guru
iTrader: (1)
A cat going bad wouldn't cause smoke and liquid oil to come out of the exhaust.
#6
EvoM Community Team Leader
#7
Evolved Member
Thread Starter
Trending Topics
#8
EvoM Guru
iTrader: (1)
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.
#9
Evolving Member
iTrader: (6)
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.
#10
EvoM Guru
iTrader: (1)
Would you assemble an engine without checking bearing tolerances?
#11
Evolved Member
Thread Starter
#12
Evolving Member
iTrader: (6)
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.
#13
Evolved Member
Thread Starter
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
#15
EvoM Guru
iTrader: (1)
Compression won't cause sudden noticeable drops in power, and then the power comes back.