Need opinions on blue smoke issue.
Need opinions on blue smoke issue. Hey guys I bought a twin turbo car from a member on here a few months back that was kind of in the final stages of being done. I have been taking care of small things here and there and now I am going to start working on the random blue smoke issue. This is my first turbo LS1 so I am learning on the way here.
The problem seems to only happen when I am pulling up to a stop sign or red light but I will get a nice little blueish cloud around the back end of the car for a second and then it goes away. It seems to be less noticeable if I start slowing down sooner and use the brakes less and it doesn't do it every time but once or twice out of maybe 10 stops.
From what I have researched I am thinking it is a draining problem and that I might need to add a scavenging pump? Am I on the right track or does this sound like something different? I don't know what size my drain lines are but I do know my turbos are mounted really low so the lines don't slope down very much.
The problem seems to only happen when I am pulling up to a stop sign or red light but I will get a nice little blueish cloud around the back end of the car for a second and then it goes away. It seems to be less noticeable if I start slowing down sooner and use the brakes less and it doesn't do it every time but once or twice out of maybe 10 stops.
From what I have researched I am thinking it is a draining problem and that I might need to add a scavenging pump? Am I on the right track or does this sound like something different? I don't know what size my drain lines are but I do know my turbos are mounted really low so the lines don't slope down very much.
We see tons of problems on boosted cars with poor PCV systems. Make sure there are NO lines that vent to the intake. You need to run a catch can and a vacuum pump on the car. If you still have a problem check compression. The next common problem is breaking ringlands or rings with bad tunes. If all cylinders are within 10% you should be ok. If not check the cylinders that are out of the 10% for the problems.
I don't think anything vents to the intake but I am not sure. I do have a catch can and it only has one line going to it and it looks like it goes towards the back of motor around the intake but can't tell. I don't know if it has a vacuum pump on it or not.
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There are 3 things you need to look for if the turbo is smoking (pushing oil past the seals). The very first most common issue is the oil drain, make sure you run as large a drain line as possible and make it as straight and steep as you can with no sharp bends or kinks and no flat spots it needs to be running down hill the ENTIRE length. Once you sort that out and if it is still smoking, like others have said check your pcv set up and make sure it is routed correctly and adequately. Last thing to look for it there is still smoke is the oil feed line, this is more important with ball bearing turbos as they are more sensitive to oil pressure/volume then the journal turbos are. You may be able to use a restricter if they are getting too much oil. Hope this helps.
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Check for stupid things.. things that will make you facepalm yourself after. I had a similar issue where I would notice a little bit of smoke at a stoplight coming from under the car, turns out my return line was leaking at the fitting, the oil was all over the K member and every now and then a drop would hit the exhaust. DOH! Having done two turbo builds now, it always seems to be little oversights that have you chasing your tail. Worth a once over or a second set of eyes. But like others have said, check the normal things, crankcase vent and drains. You shouldn't need a vac pump if you have good drains/crankcase vent.
Check for stupid things.. things that will make you facepalm yourself after. I had a similar issue where I would notice a little bit of smoke at a stoplight coming from under the car, turns out my return line was leaking at the fitting, the oil was all over the K member and every now and then a drop would hit the exhaust. DOH! Having done two turbo builds now, it always seems to be little oversights that have you chasing your tail. Worth a once over or a second set of eyes. But like others have said, check the normal things, crankcase vent and drains. You shouldn't need a vac pump if you have good drains/crankcase vent.
Run a compression test. My crankcase was getting pressurized because I had a cracked ring land...it was backing up my return line. It would smoke when I came to a stop, and around corners sometimes.
Mike
Mike
