RB25DET Smokey Exhaust

Discuss the RB20, RB25 and RB26 series engines.
redman1989
Posts: 1
Joined: Mon Aug 17, 2015 12:27 pm
Car: 1989 RB25DET 240sx

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Hey everybody,

I've been a lurker here for a while, but this is my first post. I tried searching past posts to answer my question, but I didn't have any luck.

So I have an S13 with an RB25DET swap. I drive it daily, and it has yet to let me down in any serious way. It runs as strong as it ever has, but I've recently noticed that the exhaust occasionally get's smokey. I haven't had the opportunity to drive behind it for a better look, but here's what I can tell from looking in the rear view. There's zero smoke when the engine is idling or if I'm just cruising around at lower RPM's. But most of the time when I start getting on the throttle at all, it'll shoot a pretty sizable plume of what looks like white smoke. The weird thing is that it doesn't seem to happen all the time. If I had to guess, I'd say it happens 70 percent of the time. My best guess is that the seals on my turbo are blown. My dad and I did most of the swap ourselves, and at one point we made a boneheaded mistake. When installing the turbo, we forgot to remove the dust cap from the line that returns oil from the turbo back into the engine. This obviously resulted in loads of oil being forced past the seals and dumped into the turbo and subsequently burnt off when engine temp started to rise :tisk: . At the time, I talked to the guys over at Precision, and they told me that the metal seals in my turbo should've survived the massive screw up just fine, but now I'm not so sure.

What do you guys think? Do I have a blown turbo on my hands? Or is it possibly something much worse?

Thanks in advance, and sorry for any noob violations of etiquette


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xracerx972
Posts: 110
Joined: Fri Sep 27, 2013 2:40 am
Car: 89 240sx
Location: New York

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Do a PROPER (engine @ operating temp, throttle plate wide open) compression test and then a leakdown test if necessary, you could have a blown headgasket that only leaks while boosting. Ive seen turbo cars that only leak coolant while boosting, the added pressure during the compression stroke is enough to cause the leak.

If all that checks out, then the chances of it being a major repair or anything to worry about at all are greatly reduced..


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