fasteddie313

Took another big hard run last night, everything went fine.. Ran awesome.. I'm approaching 1bar boost with my new big FMIC install.. The engine is taking it great..

Cruised for about a mile, turned around and went to go back, "HOOOOOOOT" like an owl and no boost..
It still ran awesome just lost all boost, I thought I blew a hose somewhere.. I started taking hoses off to find the leak/rip whatever and I find this..







The shaft nut backed off and was just barely on when I found it, that let the comp wheel slide up the shaft a bit and it ate the comp wheel against the comp housing, the shaft is even bent..... TOAST/FUBAR

Maybe it had something to do with its oil drain vibrating against my crossmember (chased a rattle but that fixed earlier), shook it up too much or something..
It's definitely my fault whatever happened, I put it together myself to the best of my ability, I guess my best isn't good enough..
This thing was all like brand spankin new guts a couple months ago, now I have to start from scratch.

Maybe she will live again next spring or something, It's going to take me a while to save up to put together another turbo and have it done proper..

I need to find a rebuildable 951 turbocharger core, preferably k26/8 but I may be able to work with a k26/6, the search is on.. Wish I could just buy a new one..

Then my engine will blow and I'll have to rebuild that..

This is for a 931, if I'm not supposed to be in this section with my turbo I apologise, it seems somewhat fitting..

V2Rocket

You got lucky to catch it when you did.
I've seen what the aftermath of the nut falling off into the blades looks like...not nice.

Voith

I have this if it interests you:

https://rennlist.com/forums/944-turb...l#post12453507

fasteddie313

Interesting for sure, not that I can buy it right now..

I'm concerned it may be a bit too big for my application though, how big is the compressor vs a k26/8? Any chance you have a map for the compressor? What do you know about it?

I'm running 2000cc displacement and won't be topping 300 hp due to fueling restrictions..

fasteddie313

Similar to the turbo that came on the car when I bought it I'd imagine..



You are very right, I did get lucky that I was able to diagnose before it fell all the way off.

V2Rocket

last one i saw didn't have a compressor wheel, just the back plate!

fasteddie313

Going through my options..

I'm pretty sure I have 1 good 931 turbine wheel/shaft left (same as k26/8), send that to a shop alongside a k26/6 with a good compressor and get back a water cooled turbo that will bolt up with a slightly larger compressor (I think) that I can spit upside down.. (with my FMIC setup I have to have a comp housing that doesn't have the integrated BOV like the OEM 931 so I can index it upside down to shoot at my IC plumbing)

Or I could use one of my 931 bearing housings, and shaft/wheel, and see if I can find a shop that has a suitable k27 coldside in stock (reasonably priced) to send them to to get a big compressor but I'd still not have water cooling..

Or possibly that k27 hybrid linked to above but I don't know if it's too big for me..

Maybe I'll find a deal on a good to go k26/8 and just bolt it on but that's unlikely.. Or a k26/8 rebuildable core..

A new 2664 comp wheel (931 S1) + my parts and rebuild kit should put me right back to what I had + a shop balance/rebuild, I doubt my Audi comp housing is hurt too bad.. But I wouldn't mind my boost coming on a few rpm higher for some more headroom and efficiency gains.. For the cost of a shop rebuild/balance I may as well upgrade to a 951 water cooled setup with a bigger compressor I'm thinking..

I was testing that thing up to 1bar (931 S1 compressor/Audi housing) and it didn't feel like it wanted to quit there, my intake never got hot that I could find, and I never heard a hint of pinging ever..

An OEM 931 compressor housing is out of the question, it must be a standard non-931 comp housing so I can shoot it down to my FMIC plumbing.. (I have both S1 and S2 comp housings anyway and a good (small) S2 wheel but there no good to me now)

What do I want to do now?
I'd like to end up with a 951 bearing housing for water cooling, and a bigger compressor be it /6 /8 or 27 but not too big.. I have to run a /8 turbine basically not a /6 turbine to fit a 931 turbine housing..

How much HP is the k26/6 compressor good for?
I'm shooting for 250-300 HP (depending on how much fuel I can squeeze out of my tweaked CIS) @ maybe 20 psi boost max on 2000cc 6000-6500 RPM with crap VE..
Will a /6 compressor be enough to get me there?

Humboldtgrin

The k26/6 is a stage 1 (small turbine and compressors wheel)
The k26/8 is a stage 2 (bigger turbine and compressor wheel)
They sell the turbine for the k26/8 on eBay but I haven't found any k26/8 compressor wheels or housings for sale there. The k27 7200 compressor side should work on these but your engine will kick in later. If you have a 2.8 or bigger this turbo is a better option. But honestly I would just get a new k26/8 turbo. Or send that one in for repair. Might be half the price to repair vs a new unit.

fasteddie313

What I have is a k26/8 turbine (basically/interchangable/same), I have to run the big turbine.. I have 1 spare turbine still..
The biggest compressor I have is just slightly smaller than the k26/6 compressor, that's what just toasted.. I think I need a bigger one..

This is what a k26/8 map looks like..

This turbo is 72% efficient at 1.22 BAR or 18psi, about 250 hp @ 6500 rpm, (lower lefter dot on map)

This turbo would still be 70% efficient @ 325 hp @ 5160 RPM @ 26.75psi/1.89bar and looks like I'd still have full turbo to redline at that boost level.. A whole lot of room to grow.. (upper righter dot on map)

Approximately.. Not 100% accurate.. Could be very wrong..



I think a k26/8 would be about perfect for me but a bit spendy.. If I could get away with running a k26/6 cold side and bearing housing with the bigger 931-k26/8 turbine in it it would bring my cost down substantially.. A k26/8 is basically bolt on for me though..

mahoney944

I lock tight that nut with the high temp stuff, plus a good balancing of the shaft to stop/ prevent any vibrations. I lost my first turbo the same way. And I said NEVER AGAIN! Lol now I don't have an issue with the nut coming loose, its trying to get it off when servicing lol.

mahoney944

The Lindsey turbos are basically bolt on, I had to change the cap screws that hold the throttle body spring to the intake with some flat head ones and some light filing of the return oil/ motor mount for clearance. But I switched to a dry turbo setup and that made life easy. Best decision in my experience. Never had an issue I run high boost often

Paulyy

IMO the best turbo for a 2L is a garrett gt2860rs (disco potato)
If you ever decide to get a new turbo, should look into those.

Check it out here:
http://www.924board.org/viewtopic.ph...r=asc&start=45