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Discussion Starter #1
Hey ECU Gurus,
I just got my upgraded engine (rods and pistons, valvetrain) up and running, only to have the same smoking issue I previously had. I hoped it was bad valve guides, but it proved to be my turbo seal. The turbo shop quoted me $800 to rebuild my Garrett 2860, so I pondered just asking them to build me a 2871, since it uses the same housing. But given this new unanticipated cost and project, I don't know when I'll have the time to finish installing the LC-1 and Datalogit or the money to subsequently have the PFC retuned. Would changing the turbos drastically alter the driveability of the car without a retune? Sorry, I don't know much about tuning, so I don't know if changing the turbo without a retune is engine homicide or if it will just run sub-optimally.
Also, while I'm at it, anyone want to sell their tuning services for a date to be determined?
Also, while I'm at it, anyone want to comment on new turbo options? I briefly read on NC that some of the 2871s get pretty laggy. I'd like to keep my car autocross ready, but would like to get some additional benefit from the built engine.
Thanks guys.
 

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well... you can drive it.

i wouldn't drive mine MUCH and i would NOT go into boost with out the retune!

no i'm not a tuning guru...that is the advise pasted on to you from two tuning gurus to me.

glad to hear that progress is being made ,my friend. give me a call the #'s the same.
 

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Discussion Starter #3
Thanks Chris. I'll give you a call this weekend if I get a few minutes. Did you upgrade to a 2871 or did you go even bigger?
 

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take duskas advice
 

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If you stay a couple of psi below your past boost, AND your previous tune was well done, you should have no issues.
Why do I say so?

  • The "couple of psi below" is to ensure you don't get burned by the higher flow of the bigger turbo -- you could easily be flowing more O2 molecules at 8 psi than you were before at 9 psi.
  • Why "AND your previous tune was done well?" Well, if you think about a fuel map or a spark map, they are basically a 2-dimensional grid of rpm vs AIR (yes, I know it gets expressed in software as MAF voltage, or MAP, or AFM position or just "load"). Once your MAF voltage gets corrected by temperature and turned into an air volume, your EMS doesn't know (or care) if your turbo is a 2860, a T4OE, or a whatever. All that's really changing is where you are on the map. Now... I said "done well" for a reason. In normal operation, there are a lot of areas of the map that you'll never hit. If your tuner was careless about the rest of the map, guess what? You changed your turbo, it's possible (even likely) that you will now see some of those cells. Faster spool? That means you will likely see higher load ("air") cells at lower RPMs than before. Were they tuned, or just copied?
Bottom line -- go easy. Get to know it before you start to floor it.
 

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Get a new turbo. I had mine rebuilt. And lets say it didn't go so well. Ordering a new turbo at the end of the month:angry:
Do they even rebuild Garrett GT turbos? Or just replace the CHRAs.... I've only owned the ball-bearing variants of the GTs, to my knowledge they were not rebuildable.
 

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Discussion Starter #8
Evidently I misspoke by saying "rebuild." It would be a replacement of the CHRA. Thanks Mike, for your thoughts.

Driftings, sorry to hear your rebuild didn't go well. What happened?
 

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The seal in my turbo failed. Causing oil to be shot out the turbo and burnt. To say it caused me to eat through oil is an understatement. I had a shop rebalance the main shaft. Replace all the bearings, install new seals, install new gaskets, new fittings etc... It leaked less oil with the chewed up bearings.

I had originally a t25 turbo. I'll be switching to a t28 cause I just don't want to change out my downpipe, and exhaust manifold. If I intended on keeping this engine configuration for a long period of time I would have looked into getting a EFR turbo, and go air to water cooling.
 

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Discussion Starter #11
Chris, I remember you dialing it back a while ago. You've since figured out how to tame the beast, huh?

Driftings, so sorry to hear about your oil problems. I actually just read about an EFR turbo by Borg Warner yesterday. Though I didn't research it much, it sounded incredible. The price was a bit steep, though.

All, I decided to stay with the 2860, so thanks for helping with your comments.
 
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