fasteddie313

so I have my turbo at a shop and so far out of two turbine wheel/shafts ive sent them I guess both of them are no good because the rings on the turbine wore the notch/seat where the rings sit too much on both...

they say that the bottom of the seat is rounded out and that there is no way to fix this.. they cant turn in a new seat on a lathe I guess..

I looked up tolerance specs myself and I cant find anywhere where there is a depth spec for the ring seats, I can find width tolerances specs for the seat but not depth..

why wouldn't they make these tiny little rings in oversizes like piston rings? are you just supposed to throw away a very expensive piece of Inconel every time you rebuild these things? I would think not...

this turbo is a 5326-970-6407 off of a 1980 Porsche 924 turbo..

I either really need some help finding a good replacement turbine wheel/shaft for this because the turbo shop cant seem to get them..

I can only find new shafts made in china and I was highly advised to get an original kkk shaft and not a chincy china one..

they just want to sell me a new turbo but its not that easy because the turbine housing for this Porsche is the only one in the world that has this 3 hole mounting pattern and making a custom header to fit a garrett is just out of the question due to space confinement and budget..

not to diss on this turbo shop but they only seem interested in selling me something new other than rebuilding what I have....

the first turbo I sent them was supposed to be a good rebuildable core when I bought it but when they got it they said the bearing housing and the turbine wheel/shaft were toast..

so I sent them the bearing housing and turbine wheel off of my original turbo that got a nut or something in the compressor (wasn't me) witch ate the intake end of the compressor wheel up, not the tips of the fins, the end... they said they checked the turbine wheel and the ring seat bottom is eaten up on that one too but didn't even look at the bearing housing so they couldn't even tell me if that was any good....

then said things again about getting another different turbo for me but I don't want the nightmare of trying to customize a different turbo in there...

these turbos on these 924s are hard mounted to the manifold, and a bracket to the engine block, and hard mounted to the exhaust witch is also hard mounted to the wastegate dump pipe witch is hard mounted to the wastegate witch is hard mounted to the car body bracket and j pipe witch is hard mounted to the header again so to try to fabricate in a different turbo requires you to make all of that stuff all over again..

I have no need to change any of that, k26 is plenty big enough to up the boost to 17psi easy and its got a dual port wastegate stock so im satisfied with all of this...

if there were an easy good way to upgrade the turbos in these cars the 931 guys would all be doing it, and unless there spending tuns of money and wanting over 300hp there not, and I don't want to spend a tun of money nor am I after insane power like that so I don't feel I need to either....

and im already into the shop half the labor cost of a rebuild for there "inspection fee" just to take it apart and see if they can rebuild it so its not like I can just go retrieve my parts....

I just want to fix the car.. it cant be that complicated!!!

frustration

am I missing something here?

I need some explaining/reassurance...

anyone have a turbine wheel/shaft for a k26 they can sell me?

has to be either a 924 turbo shaft or 951 s2 shaft.... 951 s1 shaft is a no go..

I could really use a 951 s2 k26/8 turbo and just bolt my turbine housing to it but they are expencive and hard to find

no the k26/6 wont work or id have had it done ages ago.. they are so cheap.. uggghhh

Dougs951S

Like I said before, you are getting incorrect info. If you are able to just bolt a k26/8 minus the hotside onto your 931 Hotside, than you can do the same with the 26/6, they are identicle except the turbine wheel is smaller in the /6 and so is the hotside, which wont be used anyway.

fasteddie313

ok... is the turbine wheel in the 6 actually physically smaller or is it called smaller because of the attack angle of the blades or what?

since you know the 951 turbos well, what would happen if you put the 8 housing onto the 6 turbine witch would be similar to putting the 931 onto the 6...

if the turbine is actually smaller around in diameter or circumference in any area or not quite as long then that would create a gap between the turbine and the turbine housing letting exhaust gas pass around the turbine and not through it loosing all sorts of efficiency would it not?

if the 6 really will work ill buy one right now...

I moved this thread here (or copied) on the advice of someone that posted in the other one advising me to do so... sorry if that wasn't the correct thing to do...

Dougs951S

You are fine posting here, lots of times turbo questions go unanswered in the other forum because the turbo guys like our little hangout here. In any case, its all relative. The /6 turbine is physically smaller in diameter than the /8 and I suppose the 931 turbine as well, if the 931 is truly the same turbine as a k26/8. That being said, hotsides are matched to fit tightly to the turbine so yes you will "lose effeciency" running the smaller #6 turbine wheel but guys do it all the time with modern turbos. Oh, not reaching your power goal or turbo choking out at high rpm with say, a .63 hotside? Slap on a .82, leave the turbine. People do it every day.

fasteddie313

afaik we are pretty much stuck with out turbine housings and bearing housings (or 951 bearing housings) because of extremely tight turbo fitment, your 951 turbos are on the other side of the engine....

there is one other turbine housing option we have though... the standard is "4.10", but there does exist a "6.10" that is designed for the same turbine but it has a larger scroll capacity witch makes for slower spool up but reduces backpressure at high output so you can reach higher hp..

my goals are only to add an intercooler and plumb a boost controller dual port style to eventually get me to around about 220 hp.... staying within restraints of stock CIS K-jetronic fueling system..

what would you expect performance of the 2.0 to be with the 6 compared to a standard 931 s1 turbo? 931 s1 and s2 both have the same turbine as the 951 s2, the 931 s1 has a bigger compressor than the 931 s2 but the 931 s1 is still slightly smaller than the 951 compressor....

its a common upgrade to run a 951 s2 turbo on any 931, especially the 931 s2 due to its shortcomings in the compressor department, to get a bit bigger compressor...

fasteddie313

not that it would be exactly easy to change to a 951 compressor...

then I would have to plumb it all custom and buy and install a recirculating blow off valve because that's integrated into the 931 comp housing and I would loose it switching....

Dougs951S

Though I am mainly a 951 guy, I am familiar with 931 as well, I owned a 931 s2 with a fmic, a k26/8 from a 951s, and 15 psi of boost. It easily out ran my then stock 951, it was no contest and I doubt that car was much over 250 hp. Compared so your stock turbo, a k26/6 will have a bigger compressor but a smaller turbine. You should spool up nearly the same and make a bit more power lb for lb of boost.

fasteddie313

well I guess I could give it a shot and see how it goes...

for 75 bucks I could probably get my money back out of it for the most part...

i would much rather get an 8 tho... what would be a fair price on an 8?

or i could always just swap the turbine out in the 6 to make it an 8 later during a rebuild, i don't need any 951 turbine housing..

fasteddie313

im gonna hassle that turbo shop a bit more tomorrow before i make any decisions..

fasteddie313

how would lag be if i ran the 8 like you did but only at around 8 psi with no intercooler until i can scratch upp the stuff to install a fmic with?

what abouts rpm did boost come on with the fmic and your 8?

did you have any problems getting enough fuel out of the cis system at 15psi? or was yours efi?

what did or didn't you do with the water cooling of the 8?