Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

100% DEFINATIVE TURBOCHARGER PART NUMBERS 931 S1-S2 AND 951
Goto page Previous  1, 2, 3, 4, 5, 6  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Tech.
View previous topic :: View next topic  
Author Message
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Sat Feb 20, 2021 4:08 am    Post subject: Reply with quote

C�dric wrote:
I meant something much simpler, something like this. Joakim had this setup for years with a garret turbocharger, of course the EFR and twinscroll worked better, but it was still good for alot of power with the good ol log manifold.

btw, i think i have that manifold+adapter and the WG behind it in my stash nowdays, aquired it when i bought a bunch of 931 spares.

[img]https://www.bildtagg.se/file/thumb/wf9i52ti7endw65tk4df2yyj[/img]


A joakim pic I don't have, thanks. I remember and have pics of his welded up log and I think I have seen this adpater from different angles. Easy enough obviously.

I'll try this HF wheel first and see how it goes. Its only because I needed to rebuild the turbo (it needed major rebuilding) and I had this damaged S1 housing to play with. I have been welding a head now for 6 weeks straight (a topic for another thread) so I am now sure these housings could get similar treatment. I have also thought about a billet 924 inlet homage attached to another turbo so it sorta looked like a 924 k26. This is just a thought though and I like to let the mind wander

Anyway, this HF wheel mated to #6 housing will be the for fun play for the summer. Previous set up was a S1 2664 / #6 which worked plenty fine. Its only because the turbine and bearings needed replacement due to eating something it shouldn't have.

Edit: Also adding this link here to help link all K26 turbo talk

http://www.924board.org/viewtopic.php?t=15595&postdays=0&postorder=asc&start=45
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Sat Feb 20, 2021 9:25 am    Post subject: Reply with quote

Scanning now but will need to process...

Concerned that I will need a slight radius. So I need to pull back and check on everything before completing my cuts. Nothing hurt yet

K26/8 is on the table now...

Can't work on it tomorrow though.
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Sun Feb 21, 2021 12:36 am    Post subject: Reply with quote

Ordered a 2667 housing. My mistake throws my original idea out the window and I will have to do the curve to make it right. At least this beat up housing will be totally saved and no signs of damage will remain.

CarreraRSR - if you do a 2670 mod to a stock housing, pick a housing that isn't core shifted. In other words, the bore of the wheel curve should have equal amounts of material all around or else you will have to do some creative porting.

The 44.5 (45+mm) is already touching the valve side (top) of the bore when I increased the bore size. There was still material on the bottom side.

I looked at another good S1 housing I have and some are better centered than others. Core shift was a common problem when searching out American v8 blocks back in the day. Had to watch the cam journal entrance for evidence of core shift

Scans turned out great. Need to quit for the day. Headed out to ski

Here is a teaser K26/8 (2670) housing process pic


_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Mon Feb 22, 2021 1:44 am    Post subject: Reply with quote

Alright, I'm going to try and show this in as many ways as possible. I used the "housing" outside flat on both housings as reference (where the screws for the retaining tabs screw in). This means I also have to measure the distance from that flat to the mating surfaces on each housing to see if they are the same. As it stands now without that measurement but with outside flat to outside flat being the same, there is a almost 2mm difference between the two internal flats.

See here in the ghosted picture. The 2664 starts out from its entrance cylinder inside the 2670 but then passes through to the outside. At one point they meet at one spot in their respective curvature. The 951S 2670 does not have the long straight angle to the outer flat while the 2664 comes off its inducer curvature and travels at an angle linearly for a bit before hitting exducer flat section at left side of pic

Edit: They do in fact share identical inner mating surfaces


_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Mon Feb 22, 2021 2:03 am    Post subject: Reply with quote

2670 in RED / 2664 in GRAY


_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Mon Feb 22, 2021 6:39 am    Post subject: Reply with quote

It would seem now that if you are not careful, you may end up with a significant gap around a different wheel. This gap would be twice the original gap and maybe even more in the areas the shapes don't match

From that I conclude that this is the reason a previous attempt at a HF wheel swap caused issues. At least this is a possibility had there not been compensations in the attempt to more adequately match the new wheel.

The surprise for me is the 2mm difference between exducer exit plane height to mount flange of housing to compressor main plate

I am going to find an elegant way to make this work correctly and I suspect I will be checking my work carefully in the end with a bore scope camera

Edit: I'm have an online conversation with myself.

Anyway, this is what I am seeing when I drop my HF wheel into the now 44.6mm opening. This CAD shot is showing new HF wheel in stock 2664 42mm housing. I can drop the wheel in but it rests somewhere on the curvature but isn't following the surface. So either find a way which includes closing that 2mm gap and modifying the curvature or 2670 wheel.


_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Fasteddie313  



Joined: 29 Sep 2013
Posts: 2224
Location: MI

PostPosted: Mon Feb 22, 2021 8:21 am    Post subject: Reply with quote

Could you deck the backside of the comp housing enough as to bring the wheel curve in enough to then machine it to match the new wheel??

As in, remove enough material from the housing-backplate mating surface so the wheel would sit deeper into it, therefore being able to remove the gap..

Mike9311 wrote:
2670 in RED / 2664 in GRAY



Make the housing sit deeper into the backplate far enough that the GREY overtakes the RED, then machine from there..

Kinda like when you would line bore a cam journal in a head, first you would need to remove enough material from the caps and bases to make the old hole smaller than the intended new hole..
Right?


Don’t feel too bad... I have conversations with myself often too..
_________________
80 Turbo - Slightly Modified
Back to top
View user's profile Send private message Yahoo Messenger
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Mon Feb 22, 2021 8:51 am    Post subject: Reply with quote

Fasteddie313 wrote:
Could you deck the backside of the comp housing enough as to bring the wheel curve in enough to then machine it to match the new wheel??

As in, remove enough material from the housing-backplate mating surface so the wheel would sit deeper into it, therefore being able to remove the gap..

Mike9311 wrote:
2670 in RED / 2664 in GRAY



Make the housing sit deeper into the backplate far enough that the GREY overtakes the RED, then machine from there..

Kinda like when you would line bore a cam journal in a head, first you would need to remove enough material from the caps and bases to make the old hole smaller than the intended new hole..
Right?


Don’t feel too bad... I have conversations with myself often too..


That is the one idea I was thinking too. Its by far the easiest idea. You could do it from either the compressor back plate or the housing.

I haven't seen the UK thread but I am sure fixturing the S1 housing is one of the topics. In order to machine the housing step deeper I would have to build a better fixture or at least change around this one.

I switched afternoon efforts to my GTS center console for the CS since I can't do much on this turbo until my 2667 housing arrives for scanning

This whole thing started with me simply wanting to get the turbo ready and have something off my list. Instead more things to work through
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Fasteddie313  



Joined: 29 Sep 2013
Posts: 2224
Location: MI

PostPosted: Mon Feb 22, 2021 8:59 am    Post subject: Reply with quote

Mike9311 wrote:
Fasteddie313 wrote:
Could you deck the backside of the comp housing enough as to bring the wheel curve in enough to then machine it to match the new wheel??

As in, remove enough material from the housing-backplate mating surface so the wheel would sit deeper into it, therefore being able to remove the gap..

Mike9311 wrote:
2670 in RED / 2664 in GRAY



Make the housing sit deeper into the backplate far enough that the GREY overtakes the RED, then machine from there..

Kinda like when you would line bore a cam journal in a head, first you would need to remove enough material from the caps and bases to make the old hole smaller than the intended new hole..
Right?


Don’t feel too bad... I have conversations with myself often too..


That is the one idea I was thinking too. Its by far the easiest idea. You could do it from either the compressor back plate or the housing.

I haven't seen the UK thread but I am sure fixturing the S1 housing is one of the topics. In order to machine the housing step deeper I would have to build a better fixture or at least change around this one.

I switched afternoon efforts to my GTS center console for the CS since I can't do much on this turbo until my 2667 housing arrives for scanning

This whole thing started with me simply wanting to get the turbo ready and have something off my list. Instead more things to work through


Well...
The back side of the compressor wheel is located on the shaft via the step in the shaft, spacer washers, thrust bearing surfaces, comp side piston, etc..

Basically, if you took the material off the backplate, you would then have to move the comp wheel back to the backplate..

Or...
If you were to only remove it from the edge of where the backplate sits against the housing, that might work.. But then you will probably have to remove some from the housing where the locking tabs go over the backplate so it would still clamp..


What about scroll volume list because of this??

What about a 2660 housing instead is a 2664?
What about the scroll area differences between the 60 64 and 70?


Why do you want to use a 931 housing anyway?
_________________
80 Turbo - Slightly Modified
Back to top
View user's profile Send private message Yahoo Messenger
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Mon Feb 22, 2021 10:43 am    Post subject: Reply with quote

Fasteddie313 wrote:
Mike9311 wrote:
Fasteddie313 wrote:
Could you deck the backside of the comp housing enough as to bring the wheel curve in enough to then machine it to match the new wheel??

As in, remove enough material from the housing-backplate mating surface so the wheel would sit deeper into it, therefore being able to remove the gap..

Mike9311 wrote:
2670 in RED / 2664 in GRAY



Make the housing sit deeper into the backplate far enough that the GREY overtakes the RED, then machine from there..

Kinda like when you would line bore a cam journal in a head, first you would need to remove enough material from the caps and bases to make the old hole smaller than the intended new hole..
Right?


Don’t feel too bad... I have conversations with myself often too..


That is the one idea I was thinking too. Its by far the easiest idea. You could do it from either the compressor back plate or the housing.

I haven't seen the UK thread but I am sure fixturing the S1 housing is one of the topics. In order to machine the housing step deeper I would have to build a better fixture or at least change around this one.

I switched afternoon efforts to my GTS center console for the CS since I can't do much on this turbo until my 2667 housing arrives for scanning

This whole thing started with me simply wanting to get the turbo ready and have something off my list. Instead more things to work through


Well...
The back side of the compressor wheel is located on the shaft via the step in the shaft, spacer washers, thrust bearing surfaces, comp side piston, etc..

Basically, if you took the material off the backplate, you would then have to move the comp wheel back to the backplate..

Or...
If you were to only remove it from the edge of where the backplate sits against the housing, that might work.. But then you will probably have to remove some from the housing where the locking tabs go over the backplate so it would still clamp..


What about scroll volume list because of this??

What about a 2660 housing instead is a 2664?
What about the scroll area differences between the 60 64 and 70?


Why do you want to use a 931 housing anyway?


I'm imagining this will be an active in process play calling sort of thing until I figure it out. Changing the housing sounds like the right approach at least for now.

I hadn't really thought about scroll volume differences since all along I was under the strange impression the 2664 S1 and 951/6 were nearly the same. This is a mistake I have been beating myself up about for 24+ hours since I carried this impression for years. So originally I thought if I just buy a modern billet wheel and tweak the housing entrance slightly I'd have a nice little upgraded stock appearing turbo.

The 2660 housing has the most meat for sure but I have yet to compare volume differences. The little angled flat section on the 924 turbos wreaks havoc on all this and requires more inventive machining.

Since I am in this deep, I'll see it through some more steps before finalizing something. I have a lot to do and I feel like I am running out of time.

Probably could check volume difference between the "8" housing and 2664 S1 easily. The scans picked up some of that even though I wasn't shooting for those sections
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Fri Feb 26, 2021 1:17 am    Post subject: Reply with quote

As expected... I will continue to see this through but now I am wondering if I will be reducing volume with any required and/or needed axial shift

The 2667 housing is a nice piece and I can tell its a modern casting that just happens to be the 951 housing PN

2667 in BLUE (apparently this one runs the tightest I have ever seen at the inducer 44.8 which I now feel the need to confirm manually)

2664 unmodified in GREY


_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Sun Feb 28, 2021 12:35 pm    Post subject: Reply with quote

I'm beginning to think this is doable with some tweaking.

Obviously turning in a lathe would be great but building a custom fixture with balance compensation didn't sound like fun

So it continues and its getting somewhere. That odd angle from curve to flat messes with the HF wheel extended tip geometry but really only at the extended tip once the curve is machined. Wheel fits so much better

Tool-path to simulation to video of machining... whenever the upload completes

Link to when it finally uploads
https://vimeo.com/517666663

Oh and the best part? I had the entire kooky set up broken down. I put it all back, probed, and the z height was exactly as before. A testament to the work holding idea






_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Fasteddie313  



Joined: 29 Sep 2013
Posts: 2224
Location: MI

PostPosted: Mon Mar 01, 2021 1:19 am    Post subject: Reply with quote

So it’s going to work?

Amazing modeling..
_________________
80 Turbo - Slightly Modified
Back to top
View user's profile Send private message Yahoo Messenger
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Mon Mar 01, 2021 4:27 am    Post subject: Reply with quote

Fasteddie313 wrote:
So it’s going to work?

Amazing modeling..


Thanks! I actually think it will if I tweak things a tad. It would be easy if the 924 Turbos had a straight or I should say flat plane that the curvature meets.

Right now the curvature is correct except the last 8mm or so of the extended tip. The angle is different. I am no wondering if I push it deeper and compensate elsewhere that it might work

The plan is get the curvature right first and see where the rest falls

Hopefully I can get a better idea tomorrow after pushing the curvature down a bit
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Mike9311  



Joined: 14 Dec 2004
Posts: 1102
Location: Chicago-ish

PostPosted: Mon Mar 01, 2021 11:48 am    Post subject: Reply with quote

Quit trying my 24+ hour upload to Vimeo and moved on to Flickr

https://live.staticflickr.com/video/50990983027/4434543c57/1080p.mp4?s=eyJpIjo1MDk5MDk4MzAyNywiZSI6MTYxNDU2NDA3OSwicyI6ImU2YjE4MDllZjFmYmI2ZTE4MGY0YmE2ZWQ5NDY4YWE2NzBiMjliNmQiLCJ2IjoxfQ

Will need to improve surface finish a bit which is easy enough
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA M650 Herausnehmbares Dach
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Tech. All times are GMT + 10 Hours
Goto page Previous  1, 2, 3, 4, 5, 6  Next
Page 5 of 6

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group