Purchased a 93 twin turbo as a father/son project car recently and am trying to diagnose the following problem:

If I drive the car at low rpm like under 3000, it does not blow blue smoke. If I take the rpms past 4000 for a while and then back off on the throttle, it billows blue smoke.

I had the compression checked by a rotary engine mechanic and he said the compression is fine. He thinks the blue smoke is being caused by leaking seals on the 2nd turbo but said he's just guessing.

I've started taking items off the car to get down to where I can remove the turbos for rebuilding or replacing. As you all know, it's a lot of work to get them off and I started thinking it may be wise to ask you all if you think that the blue smoke is indeed happening because of the turbo's being bad. I can't test drive it now because the trans is pulled, (replacing the clutch) and I've got a lot removed on the engine, so...what do you think? There are oil drips from the 2nd turbo aluminum housing bottom and the turbo intake hoses seem pretty oily.

Should I be looking at anything else before removing the turbos or do you feel the rebuild will solve the oil smoking issue? Thanks for your opinions!!!

 

well your mechanic is right... whatever it is, its when the 2nd turbo starts boosting (3500-3800rpm)

yea well.. thats all i can tell you its 3 in the morning and my brain hurts.

 

Yes the turbos are the problem.

But rebuilding the stock twins has a terribly low success rate. You might be better off buying a very low mileage set used, or just get a new set of 99specs.

Or if you want a big project ($$) go to a single turbo system.

 

Thank you for the response and insight to the issue. I'll probably go ahead with buying the '99 Efini turbos.

 

does buying the 99 spec turbos require ecu work???

 

no

 

From what I have researched on the forums, the 99 spec turbos appear to be a waste of money. The BNR turbos are only a little more expensive and are able to make higher numbers on high-boost applications.

 

no actually bnr stage 3's only cost 2350 dude, 99 spec twins cost 2595. the 99's are a waste if you want some badass twins go bnr, i got the 99 specs and i mean they're great turbos i'm over 300hp just with the turbos and bolt-ons and a few minor stuff. great turbos they seem reliable. but just for price sake and power wise i'd definately tell you to go bnr, i would've if i knew about them at the time.

 

well would I be able to keep the seq setup??and could u point me toward any reading about the bnr turbos?

thnx in advance.

 

I'm going off of what I have seen on FS threads.

 

here is the copy and paste on info for bnr from rx7store and yes they can be ran seq... but im having the same problem i know for a fack my secondary turbo is going and was wondering would it need a rebuild/ buy low mileage ones or is it a seal or something to fix?

The new BNR Stage 3's have many improvents over the factory HT12 turbochargers. The factory HT12's are not rebuildable in most cases. The stage 3's however are not remanufactured turbochargers. They have new CHRA's (Center Housing Rotating Assemblies) and the factory end housings are machined to fit the new CHRA's. The Stage 3's are not rebuilt or remanufatured.

The turbine wheels have larger inducer and exducer measurements over stock giving the turbine wheels more leverage to push the larger, more efficient compressor wheels while decreasing backpressure in the turbine housings. The turbine wheels have more blades giving it even more leverage than before and also the wheel casting is much thicker than stock. In an event of a blown apex seal, the turbine wheel (more than likely) will survive, unlike the stock turbine wheels in the stock twins or the 99 spec twins which are a very thin cast that will be heavily damaged. Apex seal damage will cause slow spool, inadequate boost, and lack of power. The shafts in the stage 3's are 1/4" in diameter compared to 5mm in diameter like the stock/99 spec twins. Also the shaft has left hand thread shaft nuts which eliminates the issues of shaft nuts shooting off like the stock turbos have a tendancy to do under high boost. It can lead to engine failure if cases are bad enough.

The thrust bearings are upgraded to a 360 degrees for proper lubrication of the rotating assemblies up to 180K rpm! This means you can run a tremendous amount of boost without killing thrust bearings. The stock thrust bearings are 270 degree bearings which aren't reliable to run over 15 psi of boost. 360 bearings are standard on BNR Stage 3's.

The stage 3 comes with an adjustable wastegate actuator. This allows you to turn up or down the boost mechanically w/o a electronic or manual boost controller. The adjustable actuator can also make the boost controllers more effective because you are working them less to turn up the boost.

The stage 3's can be ran sequential or in non sequential forms. When sets are ordered, please include complete Y pipe for modifications. Extra charges will be given to customers who want a full non sequential conversions. A one year warranty goes along with each set of BNR Stage 3's. We do need your turbocharger cores on purchases!

 

Well, we got the stock twin tubo's out of the car. It's definately quite a bit of work. Anyway, I think I'll call RX7 Store to discuss the BNR Stage 3 set as I'm going to take the advice given from the replys and not try to rebuild the stock twins. Wish me luck getting it all back together again!