rx7 SE

iTrader: (5)

Before I get started, I love the stock twin setup on my FD, not going single and will probably never go single since I have a very nice 6266 single on the FC. That being said, when I purchased my FD in March-April of this year the twins, I believe, were sucking oil due to the fact that there was a significant amount of oil built up on my intercooler couplers and intake crevices and the car constantly smoked. No problem, replaced them while changing out my coolant seals . Got about several hundred miles with no smoking but now the car smokes during start up for about 10-15 seconds which didn't bother me at all until I pulled a coupler off and saw a hole bunch of oil built up on them yet again. This leads me to believe the turbos (which were used, low mileage) are sucking oil again.

The car is down for the winter so I can swap them out again but I want to know if maybe there's something I'm doing wrong or don't know about keeping the fd twins going or are they just that unreliable?

I don't track the FD per say, but I live on the Blue Ridge Parkway so about 90% of the 3500 miles I've put on it have been through the mountains in boost. I keep the boost on the low boost setting which is 10 psi.

Before I go tearing these turbos off again, any advice on what I can do differently this time or maybe something else leaking?



P.S. Like I said above, not going single

Thanks,

~Anthony

silverTRD

iTrader: (37)

Do you have a catch can? Sounds like that could be your issue since you're driving in the mountains so much.

IRPerformance

iTrader: (41)

The stock PCV system vents into the front turbo inlet and basically doesn't work. Get a catch can and it should help greatly. If it doesn't you have a bad oil seal in the turbos and they will need to be replaced at some point. If you are insistent on staying with twins, a set of BNR Stage 3s will be your best bet. Otherwise a known good used set of stock twins. I have two or three sets laying around with low mileage.

rx7 SE

iTrader: (5)

I don't have a catch can and the thought never crossed my mind, I think that's exactly what it is .

You'll be the first one I contact if I find these turbos to be shot again.

Would love the BNRs, but they seem a little too pricey for such small gains due to the restrictive exhaust manifold, IMO... Or are they just more reliable?

Tem120

iTrader: (5)

I was / am a die hard twins fan . You can make alot more power out of the BNR reliably .

Lots of people are in the 400 whp mark with the BNR twins , and they are quite reliable as they can run pretty high PSI ,

ofcourse you'd need injectors that can support the power , Fuel pump as well , and a good tune ..

Now .. the third and actually Better option is going single .. I know I know BLAH BLAH BLAH !! LAG TORQUE take a look at this https://www.rx7club.com/single-turbo...d-dyno-956766/

thats what modern BB turbos are capable of if done correctly

DaleClark

iTrader: (55)

+1 on catch can. Turbos may be fine, actually.

Also, many times rotaries smoke a bit on startup, that's probably not the turbos. Bad oil seals on turbos usually mean a smoke show or strong oil burning smell after boosting them.

My catch can is always about 1/4-1/2 full at an oil change with nasty crap. That's all crap that would have gone in the IC and intake plumbing.

Dale

rx7 SE

iTrader: (5)

Thanks for the advice guys, installing a catch can will be the next project on the list.

Fritz Flynn

iTrader: (263)

These cars don't need catch cans

Don't over fill the oil and you will be fine.

Don't go any higher than 1/2 way up on the dip stick fill indicator marks. It's really that f#cking simple.

DaleClark

iTrader: (55)

I only fill my car up 1/2 on the dipstick with oil, catch can still gets crap in it. A lot of it is emulsified water/oil mix from water vapor in air.

Stock, this is all going to be sucked through the primary turbo inlet duct. I'd rather trap it and dispose of it than have it coat my IC.

BTW, I have used these catch cans with great results -


It's reasonably priced, small, has a proper filter, and easy to mount. I have a bracket on my master cylinder this attaches to, then I have 2 lines running from the 2 oil fill neck nipples to the 2 nipples on the catch can. Super easy.

Dale

IRPerformance

iTrader: (41)

It really depends on the car. The higher boost you run, the harder you drive the car, the more g forces you induce when cornering, the more oil gets pushed out of the oil neck. The stock system dumps it into the primary turbo inlet, which is why you get oil in the intercooler piping and sometimes smoke. Engine health, seal clearancing, etc all affect the amount of blow by and crank case pressure an engine has. I rather run a catch can than run the car low on oil. An oil soaked intercooler isn't as efficient as a clean one. Cheap insurance.

ArmitageGVR4

iTrader: (13)

If you're making a lot of hard right turns on your mountain runs, it's a common issue that oil gets sucked right out of the filler neck through the PCV systems and into your turbos, intake, I/C, etc. In addition to a catch can, installing a baffled filler neck can help to mitigate this problem.

Fritz Flynn

iTrader: (263)

Can only base this stuff off my own personal experience so as always YMMV. I'm just saying I don't need a catch can on my daily drivers and only on my track car if I put too much oil in or have some sort of fuel delivery issue which just happened with the new build but that has now been corrected.

Every single time I buy a car the oil is over filled or they put in 4 quarts and f#ck me up and the car is blowing smoke and filling the charge tubes etc... Once I change the oil myself and put in 3 quarts no more issues.

These cars have lots of problems but oiling the engine is not one of them and you don't need much oil. If you enjoy filling your oil to the top to contribute donations to your catch can and throwing oil all over your engine bay no worries but I don't recommend EVER filling over the 1/2 way mark.

Fritz Flynn

iTrader: (263)

Yep

If you need a catch can I'd get this one

Tem120

iTrader: (5)

at what point does a catch can become necessary , I've had that whole oil in primary turbo issue for a long time and I just kind of ignored it since I knew where it was coming from . sort of just figured it as normal

neil_jdmr

Strange!! I think you have just been unlucky with your used twins tbh. I have ran at 1.2 bar or 17psi on standard 94 twins for the last 2 years and they have been ran hard for the past 7 years at 1bar and are still going fine. Very little oil in ic pipes and no smoke at all. All in they have done 30k miles from a rebuild

rx7 SE

iTrader: (5)

Really? When u say ran hard is that just in a straight line or track days as well?

After putting on my Hankook Ventus RS3 tires I was curious about the g forces I was experiencing due to the increased grip so I did some datalogging and found that I'm seeing an average of 1.0 g's, sometimes more, around these mountain roads. You mix that up with elevation changes and I suppose it would accumulate a lot of oil.

Fritz Flynn

iTrader: (263)

Too much oil means the oil will run up the neck and into the intake and there is no way to avoid it other than a catch can or fill neck/oil pan baffles etc... OR run 3/4 to 1 quart low. If the extra oil is running out of the engine there is no need to put it in to begin with. If the oil was constantly running out of your engine you wouldn't have any oil. You only fill the catch can when you overfill your oil.

I attribute this catch can over fill thing to people being scared to death to run low oil BUT why worry if the oil is just running out of the engine anyway. It just makes no sense at all.

You want an easy solution don't fill your oil up

If you are getting oil in your catch can still you have an engine problem. I've been tracking this car at VIR for 10 plus years and I don't fill my catch can AT ALL and t3 is a fast nasty left hand turn.

Banzai-Racing

iTrader: (11)

Checking the oil is part of my checklist prior to putting cars on our dyno. Most come in over-filled, which causes the catch can to fill up after a couple pulls, then puddle up on the floor if not monitored. I have just started dumping 1/2 before we start.

I have a theory that the over-filling is brought on by the idea that the rotary uses a qt./1000 miles, so "why not throw a little extra in?". The problem with this thought process is a lot of the people are running premix without an OMP, which means the engine will use no oil. Not to mention the other issues that arise, from developing oil leaks at the pan seal to filling the intake with oil even with a functioning OMP.

neil_jdmr

Mostly road but as I live in the country hard corners are regular plus more recently I've been going all out on trackdays. My oil is always full on the dipstick and tbh doesn't ever really use any either. I use cheapo 10/40 mineral and change it after a trackday or 3k miles whichever come first.

I can honestly say I have never had oil in the pipes from twin pack to tb. A light amount of black gunk on the joiners from time to time but I mean light amount. Also never had any smoke on boost either tbh bit of flame but never been smokey.

Tem120

iTrader: (5)

Do you run the factory PCV system ?

BLUE TII

iTrader: (9)

Another thing to check if you have oil in your charge pipes is check for boost leaks.

IDK why but whenever I have had a boost leak and was overspeeding the compressor wheel the turbo would puke oil into the turbo inlet/charge pipes/intercooler.

rx7 SE

iTrader: (5)

Interesting, yes I found my primary turbo charge pipe fasteners had worked themselves loose creating a massive boost leak. Learning some good stuff here

neil_jdmr

Yes,

I run it completely stock aside from boost, fuel, ignition. Stock twins stock injectors blah blah