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Thread: Quick question on turbo hot side

  1. #1
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    Quick question on turbo hot side

    For the stock RS6 turbos, is the casting the same for the hot side on L & R? I believe it is, but just double checking.

    I'm getting ready to pull the motor on my RS6 to rebuilt the turbos...I have a smoker on the passenger side and also need to do cam chain shoes, etc. while I'm in there. I picked up a used pair of lower mileage turbos on a gamble, both need new CHRA's which I was planning on doing anyway, but I have 2 f'd studs on one hot side (other is fine). I wanted to rebuild while I have time before pulling the motor, but looks like I'll need to yank mine off first anyway to get a second hot side housing that is hopefully usable.

    Thanks for your replies. While I'm at it, what is the best way to set the waste gate tension on these? I was told that the ones on my car (thanks nubcake!), are not in sync...and looking at the ones that I got, neither are they...one had a nice tight tension with about 4-5 turns on the lock nut before free, the other you could spin the flapper as it sat. I feel like mine is probably doing the same thing based on nubcake's comments on my tuning logs and want to be sure to set correctly for the rebuild.

    Appreciate your inputs! EricD

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    Quote Originally Posted by Muggy View Post
    For the stock RS6 turbos, is the casting the same for the hot side on L & R? I believe it is, but just double checking.

    I'm getting ready to pull the motor on my RS6 to rebuilt the turbos...I have a smoker on the passenger side and also need to do cam chain shoes, etc. while I'm in there. I picked up a used pair of lower mileage turbos on a gamble, both need new CHRA's which I was planning on doing anyway, but I have 2 f'd studs on one hot side (other is fine). I wanted to rebuild while I have time before pulling the motor, but looks like I'll need to yank mine off first anyway to get a second hot side housing that is hopefully usable.

    Thanks for your replies. While I'm at it, what is the best way to set the waste gate tension on these? I was told that the ones on my car (thanks nubcake!), are not in sync...and looking at the ones that I got, neither are they...one had a nice tight tension with about 4-5 turns on the lock nut before free, the other you could spin the flapper as it sat. I feel like mine is probably doing the same thing based on nubcake's comments on my tuning logs and want to be sure to set correctly for the rebuild.

    Appreciate your inputs! EricD
    Hey Eric! So while I cant answer your question about the castings, I can say an easy way to set wastegate cracking pressure is to use a Mitty-Vac (something equivalent that provides pressure, not vacuum) and to connect it to the nipple of the wastegate valve.

    I actually t'd the line off and ran it to both wastegates simultaneously, and just adjusted accordingly (not 100% on what the cracking pressure is for the RS6 is, but I know I used to set them to about 5-6psi on my B5 S4)

    Cheers dude!

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    Thanks Joel, Looking like 5psi is proper pressure to crack the wastegate enough to be able to spin the flapper disk freely. Pair of turbos that I got had one set at about that, where the other one you could actually spin the flapper disk without any pressure. Nubcake mentioned that it looked like I had one turbo that is doing exactly this on my car by the tuning logs...seems funny that if both cars are set to OEM specs that one would be softer than the other. Just want to confirm that they should both be set at the same pressure or if there is something goofy that was engineered into different settings to soften the boost hit or something. Probably reading too much into this, but I want it set right when they go back in...I don't think I'd have the patience to pull my motor as many times as you have!

    Thanks for the input!

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    You can set the preload even without having a mityvac. Loosen the actuator up, then keep tightening until the flapper no longer spins and is "just snug". Then do 2 turns more. That's it. Usually by messing with it further you'll only make it worse.

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    Thanks nubcake....sounds like a plan. I'll set this way, and double check proper operation on the WG valves with a little pressure to confirm that actuators are operating correctly.

    On the castings for the hot side, can anyone confirm that they are the same (or not)?

  6. #6
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    Muggy, Sroll products is just up the road from you and they can go through the Turbos and set them up properly. They can even upgrade the CHRA's to the latest K04 design.
    https://www.scrollproducts.com/en/hybrids
    2003 White RS6 2013 Midnight Blue S5
    2013 Daytona RS5 2x944 Turbo's 1974 911 w/'91 3.6ltr motor
    Roy, WA

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    Thanks hahnmgh63, I disassembled the ones that I picked up and feel confident that I can do a rebuild with new CHRA's...picked up a fresh pair of Melett cartridges that are on the way from Turbo Rebuild Limited. I was just bummed that 2 of the studs were bunged on one of the turbines that I picked up as I wanted to get these put back together and set aside while I pull the motor soon. I "should" still have 2 rebuildable turbos coming off of my car, but I always worry about the unknown as far as running into the same problem with what I pull off of my car.

    As far as I can tell, the turbines are the same on both sides with just a difference in the compressor castings...if so, this gives me 2 shots to get a good hot side off of my car for a rebuild. Fortunately my car has been in the garage for years, and was a breeze to pull the intake off when I had to do the suction jet valve last year...no rust, corrosion, grease, or frozen bolts at all to deal with. BUT, as we all know, being on the exhaust, heat changes everything, so hoping to have some stud love on at least one turbine....

    On the turbo rebuild, does anyone have a favorite anaerobic sealant for the compressor? Research shows loctite 510 or 515 are good options...any input on this?

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    I used Loctite 518 because I read it was better for aluminum. I used the same CHRA's on mine and installed them myself. It was pretty straightforward, but I struggled quite a while disassembling the hotside off the old turbos. I finally realized that the way to break the bolts loose is to tap the little lock-lever under the bolt head. Using a wrench on the bolt itself was difficult and resulted in several rounded heads. I ended up replacing all the bolts anyway, but it took a lot longer than it should have before I figured out the trick. Let me know if you need more info or pictures of what I'm talking about.

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    Thanks GreggPDX, I appreciate your input on the 518. I know what you mean on the bolts...I got lucky and hit someone's K04 rebuild thread on Audizine and learned the tricks of bumping the tabs enough to get a screwdriver under the edge and then use a wrench in combination with a little nudge. At first try, I had a couple of easy ones on each side and decided to do a quick search before what would have been ruined bolts for sure!

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