Engine/Transmission (1994 - 1998) Oil in coldpipe?

[JStieger]

Some interesting news. JStieger wrote me today and said that he had the same problem with his BD twins. He said that it has been mentioned to him that the small charger can spool so much faster than the large charger that it can create a vacume and suck oil past the seal on the 3B. makes sense I guess.

It somewhat still doesn't make sense to me to me though!



I've corresponded with a few other folks that have BD twins. Some have no oil leaks while some have so-called oil leaks in the cold-pipe. These folks went insofar as contacting BD about it only to be told it's "normal". I even found a couple threads on my search of various boards where a BD guy responded to the same effect.



The BD twins come with a 4" AFE, whereas most other twin sets use a 5" inlet. I thought this was a problem so I tried a bigger filter (in theory) of the Amsoil Ea variation.



I've had the primary turbo rebuilt by HTT and they said the compressor side seal was perfectly fine as were all the bearings, but the exhaust side seal was leaking slightly.



During the time the AFE was installed, the oil leak was fairly small, but just annoying enough to make me worry. There was also air filter oil being pulled into the cold pipe too.



After the primary was rebuilt I strictly ran the Amsoil Ea dry filter and there was definitely more oil in the coldpipe. While the oil analyses were great and the surface area was Length x Width x Height bigger than the AFE, I think the dry filter has to be more restrictive hence the larger oil leak.



I'm installing new twins this weekend with a huge AFE filter so it will give me a chance to go through everything in greater detail. The oil drains on my current BD installation point straight down and are 7/8".

 

[Forrest Nearing]

Some interesting news. JStieger wrote me today and said that he had the same problem with his BD twins. He said that it has been mentioned to him that the small charger can spool so much faster than the large charger that it can create a vacume and suck oil past the seal on the 3B. makes sense I guess.



Could that mean that

A. You need a smaller housing on the 3B so it spools faster and is pushing air instead of having air sucked through it at low RPM's.



and

B. I need like a 14WG housing on the 35 so that it spools at a closer RPM to the 3B?



I put a 23 housing on there while I had it all apart. Noticed a small increase in boost from the 3B itself and maybe a small increase in spool... . not too much.



Forrest, other guys with twins experience want to chime in. I'm getting tired of this.



Jamie



P. S. anybody that wants to trade a 22 housing for a 23 and a 26 let me know.

that makes a lot of sense actually... I'm sure you don't want to redesign your twin setup, but a K31 under there would help spool up

 

[JHastings]

OK, here is NEW idea that I had never though of before. If the oil is a result of the vacuum between the two turbos, then this would probably work if I could find the right parts.

If there is vacuum, then the restriction is air going past the compressor blades of the 3B or the 3" outlet of the 3B so... . why not BYPASS it with a single tube and CHECK VALVE going from near the air filter to the coldpipe? Anybody know of a say 1" or 2" check valve that could do this? This would simply add another intake port that is still filtered, but bypasses the 3b and then closes once it gets positive pressure from the 3B.

Or If I "T" into the coldpipe with whatever size pipe and check valve and give it its own little filter. I dunno just a thought.
Jamie

BTW this is an idea from my buddy Nick Negranti who just joined TDR.