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2005 Turbo Elise
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Discussion Starter · #1 ·
So since I am new to the forced induction gig and Lotus I will reach out here. As we all know I an the happy owner of @thangcu35 turbo swap Elise project. It has been running well and have not driven it much or driven it hard.... never even hit the 2nd cam until this weekend. Just exploring the car and tiding up some things on it. I was out for an hour run around town and decided to do a couple hard 4th gear pulls on the highway to see how she felt and hit the 2nd cam. I loved the power.... a bit strong for such a light car. Anyways drove a bit more and returned home. Lifted the clam to find a bunch of oil blasted out of the Tial QRJ BOV all over the clam wall and engine. I cleaned uo the outside of the BOV before I thought of taking pictures so you can't see much on it but it is everywhere else. I have not seen anything like this on the other drives.

So I need some guidance..... is this normal? Is the turbo shot already? Just blowing out the cobwebs or residual old oil build up in the intake track? The BOV is just upstream of the turbo. Cylinder compression was 205-210 psi across when I got the car in May. Interestingly the oil is dark black and stinks like 5yr old 20k miles oil....yet I changed it 3 weeks ago and if you pull the dipstick it is still crystal clean.

42,500 miles
swap was done about 7k ago
target boost is supposed to be 10psi on 93oct

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I'd say blown seal, but that's because 100% of the time I have witnessed oil in the intake, it was a blown turbo seal. I've only seen it once, but 100% nonetheless.
 

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2017 Evora 400
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I'm going with blown turbo seal also. Probably dumping that stuff down your intake as well. I would not drive it until it is addressed.
 

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2005 Lotus Elise
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Seals 100%. Time to rebuild the turbo or get a new one. Seals can fail for various reasons and may want to do a health check on the motor.
 

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Cmon guys you cant imagine the other reason there is oil in the charge piping? It's even in one of the pictures maybe.

Does the car still recirculate the crankcase vent into the intake? I see the hose coming off the valve cover, but not where it goes.
 

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2005 Turbo Elise
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211 Posts
Discussion Starter · #6 ·
Cmon guys you cant imagine the other reason there is oil in the charge piping? It's even in one of the pictures maybe.

Does the car still recirculate the crankcase vent into the intake? I see the hose coming off the valve cover, but not where it goes.
Atmosphere vent...the hose runs down to the bottom of the car...... been thinking I need to add a catch can but that is a whole nether rabbit hole I went down reading which is best vent to air or catch can then open or closed can system
 

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well catch can venting to atmosphere with a drain back to the sump through a filter is what I like best but every system has ups and downs. If you don't have vent to intake then the only source of the oil is the turbo seal unfortunately. You can try limiting pressure to the turbo but that's just going to mask the symptoms at best. Better to rebuild/replace the turbo probably.
 

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well catch can venting to atmosphere with a drain back to the sump through a filter is what I like best but every system has ups and downs. If you don't have vent to intake then the only source of the oil is the turbo seal unfortunately. You can try limiting pressure to the turbo but that's just going to mask the symptoms at best. Better to rebuild/replace the turbo probably.
You did catch me breaking one of my own rules, so I do appreciate that. When multiple failure modes can produce the same symptoms, I hate jumping to the “most common” with no addition evidence. If he was venting crankcase pressure to the intake, we would’ve steered him to rebuilding a turbo only to spew oil again, so it was smart to first check.
 

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2005 Turbo Elise
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211 Posts
Discussion Starter · #9 ·
What I have read is that venting to atmosphere causes pressure in the crankcase and causes leaking seals... which i have a pretty good leak. Venting to a catch can system with a return lint to manifold create a small vacuum on the crankcase and is supposed too be the preferred but can still allow some oil to make it into combustion. Supposed to be easier on seals. Then there is the catch can that vents to atmosphere thru a small filter like BOE markets.......

What I am hoping is that there was some oil accumulation in the intake track and when I dd a couple of Italian Tune Up pulls it just blew back on throttle closure..... wishful thinking o_O
 

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My first reply was wrong:

If you vent to intake you will be venting to a pressure somewhere between vacuum and atmosphere based on the throttle position, this is true. But if you have a properly sized vent to atmosphere it should be impossible to build any meaningful crankcase pressure and as such it doesn't matter that much.
 

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2005 Turbo Elise
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Discussion Starter · #11 ·
My first reply was wrong:

If you vent to intake you will be venting to a pressure somewhere between vacuum and atmosphere based on the throttle position, this is true. But if you have a properly sized vent to atmosphere it should be impossible to build any meaningful crankcase pressure and as such it doesn't matter that much.
Ok...My vent to atmosphere hose is the size of the port, whatever slides onto the valve cover port and about 3 ft long going right down to the bottom of the engine so any oil vapor and drip exits the engine bay
 

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We're getting off base here though.

1. You can only know if the vent is big enough with measuring pressure really.
2. The turbo seal sees pressure equal to approximately the engine oil pressure. Exactly how much depends on how well it can drain from the turbo, and one of the factors in this draining is the crankcase pressure. Regardless the pressure in is much higher then this restriction. If your turbo is badly leaking like it looks like then it is going to be a seal issue most of the time.
 

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I had this exact same issue with my turbo setup. It was related to two things: not enough/improper crankcase venting and an air filter that was too restrictive. Just venting to atm through the stock 1/2" port on the valve cover was not enough. I now use the rear port for venting and the front port for the PCV valve. I can send you a drawing so it makes more sense. Mine is all closed loop, nothing to atm.

Sent from my SM-G950U using Tapatalk
 
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