couldn't find any feedback on the rotorsports racing rebuilt stock twins... anyone using these? they're only $1300 compared to $2300 for the BNR's. i'm assuming they're just old cores with new bearings/seals thrown in without any other new parts. they look nice and shiny in the picture, though!

 

I dunno , but I have both some stuff to that guy and they works perfect , they have a special water seals that claim that they are better than the mazda ones, I have build 2 engines with that kind of seals with no poblem (well only the instalation that they are a pain in the ***)

 

I think Bryan (BNR) told me parts for the stock turbos are just about impossible to find....not sure where Bryan (Rotorsports) gets his stuff from

 

The stock twins are very difficult to rebuild properly due to lack of quality parts. more times than not you are going to get oil leakage into the intake or exhaust.

I recommend you spend the extra grand and get the new BNRs, they offer many many advantages over the puny stock twins.

http://www.bnrturbos.com/3rdGen.htm

 

Rich gets a $20 check for each set of BNRs sold on this forum

j/k....maybe he should, tho

 

rotorsports rebuilt my engine and did a pretty good job

 

We do not rebuild the turbos "in house" we use a turbo specialist since they have a large stock of parts for rebuilding/servicing and the turbos are guaranteed for a year. Plus we build engines-they build turbos! The turbos include new "wear" items such as bearings,seals etc. plus new compressor wheels and the turbine shaft and exhaust wheel are carefully cleaned and inspected and refinished. The assemblies are balanced before final assembly. We've never had a problem with leakage or premature failure. The only issue we've encountered was due the actuators for the turbos containing oil and needed cleaning.
We can also replace the turbine housing assembies with new parts (at extra cost of course) if needed since rewelding the inevitable cracks just doesn't hold.
Bryan
Rotorsports Racing

 

Bryan,

I've heard the quality with most of these turbo rebuilders (turbo city, etc) tends to be very hit and miss...how many sets have you had rebuilt and how many miles have they lasted?

thanks

 

We've had at least 10-12 sets done without incident (not certain of the exact number) and since none have been returned I'm not sure of mileage -but they have been in use for a few years. I know I'd have heard of any issues by now. I trusted his opinions and abilities enough to have him build my T-88 based single turbo for my personal triple rotor RX7. I've been pleased with the results.
Bryan

 

thanks for the response. so, welding/resurfacing of cracks on the flanges is included in this rebuild service? that's been my major concern in finding a good core. on that note, do you require a core? i've got several

 

We do not recommend welding since they simply do not last. We usually recommend replacement of cracked partsevn though it is more costly. Yes we do require a core -we usually have a few that are in great shape on hand.
Bryan

 

Has anyone used the BNR's with the bearing option? supposted to faster spool up, and better life. But they cost $3000.

 

ah, i didn't know they offered the manifolds as a seperate item. i'd definitely be interested in getting them with new iron parts. how much extra is that? it doesn't say on the site. out of curiosity where do you get the new manifolds?

you mean ball instead of journal? sounds fun

 

Bryan at BNR is working on my set now

 

agreed. I have had several rebuilt turbos (I had a service contract) and all I can is rebuilt OEM turbos really suck. 10k miles and they start smoking again.

I've heard this from several sources too, so it's not only me.

 

well this is promising. I'm at the point where I'm tired of having my turbos rebuilt. So either I get me a set of BNR's or go single.

 

i keep hearing this... but there's never a reason. i can't see why it's so hard to get it right and i'm probably headed down the path to find out, lol.

 

like I said, the stock turbo parts are just about impossible to find anymore....I'm not sure if Mazda stop producing them

I'd get the 99s if you want to stay "stock"

 

Mazda didn't ever make the turbo parts, they're a hitachi turbo.

What wears? There is s groove in both the cartridge and the shaft that a metal seal rides in. This is to keep the oil out of the exhaust. Over time the groove in the cartridge wears and the seal no longer has a good surface to seal against, hence the burning oil.

I rebuilt mine with a turbo city kit about 40k miles ago. They are still doing ok but my primary turbo is starting to slightly smoke for the first hard run then it's fine. The turbos now have about 160k total miles on them so I guess I'm lucky.

 

good point...."supplying them" then

 

that's my whole thing... i want to run in stock class at auto-x. that's the main reason for building up this car. i'm trying my best not to deviate from this plan... but it i really want to run TC-W3 and put on a downpipe for the sake of the engine bay.

"There is a groove in both the cartridge and the shaft that a metal seal rides in. This is to keep the oil out of the exhaust. Over time the groove in the cartridge wears and the seal no longer has a good surface to seal against, hence the burning oil."

I've had a couple CHRA's apart and have not seen a groove in the shaft. I don't have one around right now, though. Are you talking about that crusty black thing on the exhaust end of the shaft? The surface it rides on in the cartridge is integral and can't be replaced? What stops oil from getting into the intake side?

 

On the attached picture, you can see the groove on the shaft near the turbine wheel. The seal is the ring directly below the shaft.

The compressor side is sealed via spring loaded rubber/plastic seal that rides against the back of the compressor housing, IIRC. It's the round piece directly above the compressor housing.

 

thanks for clarifying. so the hard part isn't getiing the compressor side to seal, it's the exhaust side that's a pain.

perhaps there is a point of no return, when the bearing gets enough slop in it that the exhaust side seal begins to take the force that the bearing once did. at this point it would abnormally wear away at the groove in the cartridge and a rebuild does nothing but empty your wallet and get you a cloud of smoke. does this sound feasible?

 

oh yeah, and i can't even imagine what the cracks in your manifolds look like after 160k...

 

If you look in my engine bay, you'll see what appears to be stock twin turbos and stock fuel rails