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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Tue May 20, 2008 12:56 am Post subject: Bolt-in off-the-shelf water-cooled turbo for 931 |
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Well boys, I've just confirmed it. The 951 K26/6 water-cooled bearing housing is part number 5326-151-0089.
Why should you care?
Because it is a direct, bolt-on replacement for the 931 bearing housing. Take your SI or SII K26 turbo, get the 951 bearing housing, send the bits to your favorite rebuilder, and voila, you now have a water-cooled 931 turbo unit. The unique 931 top and bottom oil lines / bracket fixtures are a direct bolt-on to the 944 bearing housing (John at Majestic confirmed this for me).
Of course, you'll need to plumb in the water lines and a pump. For this you can either source the stock 951 components (pump and relay, which operates the pump for 30 seconds after shutdown), or you can go aftermarket (for example, a Davies-Craig electric booster pump). The easiest way to tap into the coolant circuit is to tap the cold and hot side respectively of your rad. _________________ erstwhile owner of just about every 924 variant ever made |
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tuurbo
Joined: 08 Aug 2007 Posts: 1446 Location: East Windsor, New Jersey
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Posted: Tue May 20, 2008 1:05 am Post subject: |
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Excellent.
That is what I call an upgrade. Now I'll Google for the 951 bearing housing...no luck there. Lindsey doesn't list them.
So are these bearing housings available from the same people who sell rebuild kits? _________________ 1980 924 turbo, MSD, Meth. Inj, otherwise stock. |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Tue May 20, 2008 1:13 am Post subject: |
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Your best option would be to find a used 951 K26 unit, possibly from a Pelican or Rennlist user, or eBayer. The 951 crowd like to upgrade their turbos, so you should be able to find these used without too much difficulty. In my case, John at Majestic happened to have one sitting on the shelf. He didn't even know what it came from, so I took the part numbers, did some sleuthing, and found out it was from the 951 K26 unit.
I suspect that because orientation and oil line connections are completely different on the 951 unit, it never occurred to anyone to check to see how similar the bearing housings were between the 931 and 951. As it turns out, the oil ports and stud patterns are identical to the 931, so our oil fittings and brackets bolt right up, as do the hot and cold side housings, no mods required. The only thing to sort out is how to plumb in the water lines, but as noted above, this can be achieved pretty simply. _________________ erstwhile owner of just about every 924 variant ever made |
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Mike924
Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK
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Posted: Tue May 20, 2008 1:42 am Post subject: |
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...or to save time, you could buy a 951!
Seriously, good detective work, Dan. _________________ 1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd
'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Tue May 20, 2008 1:57 am Post subject: |
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Incidentally, I should mention that the Borg-Warner catalog part number for the 944 Turbo bearing housing is 5326-150-0020. That may help you source the part from a rebuild shop. However, that number is not stamped anywhere I can see on any of the units I have seen (in photographs) or heard of. I don't understand why the different part numbers, but it might be a useful cross reference. I've posted this info over in -nick's all-u-want-to-know-about-KKK thread. _________________ erstwhile owner of just about every 924 variant ever made |
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Rasta Monsta
Joined: 12 Jul 2006 Posts: 11723 Location: PacNW
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Posted: Tue May 20, 2008 2:02 am Post subject: |
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One thing that will be needed for this conversion (not a criticism. . .I am considering it, therefore thinking about engineering issues) is some sort of heat shielding for the water lines. Remember, the 951 unit dwells in relative luxury on the cold side of the 2.5. I think timed pump run-on will be mandatory for the same reaon.
For the source (because I can't bring myself to drill holes in my Davis rad), I would consider a short section of pipe with nipple spliced into the lower rad hose. For the return, I would consider epoxying a fitting to the overflow tank, 951-style.
Very interesting, Dan. Do Majestic have any more of these housings laying around? _________________ Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Tue May 20, 2008 2:18 am Post subject: |
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Rasta Monsta wrote: | One thing that will be needed for this conversion (not a criticism. . .I am considering it, therefore thinking about engineering issues) is some sort of heat shielding for the water lines. Remember, the 951 unit dwells in relative luxury on the cold side of the 2.5. I think timed pump run-on will be mandatory for the same reaon.
For the source (because I can't bring myself to drill holes in my Davis rad), I would consider a short section of pipe with nipple spliced into the lower rad hose. For the return, I would consider epoxying a fitting to the overflow tank, 951-style.
Very interesting, Dan. Do Majestic have any more of these housings laying around? |
Here's a couple of pix that John sent to me of the bearing housing uninstalled:
I won't know precisely until I get the built unit in my hands, but you can see from the photo that the water fittings are at 90 degrees to the oil fittings. In the case of the cold inlet, I believe it will actually be sitting directly beneath the large bracket that bolts the turbo to the block. It should be relatively easy to add a small heat shield on that side. In any event, I plan to use braided stainless for the water lines. Heat gain may be a bit of concern, but I think it can be adequately addressed.
Timed pump run-on is a no-brainer. Since I'm going with the Davies-Craig electric water pumps (primary and aux), I may opt to try their new digital controller. We'll see.
Yeah, I think your approach for plumbing would be just as effective. In my case, I'll just modify the stock rad.
You'd have to ask John if he has anymore, but I believe he said it was the only one he had laying around. I would think that these housings would be easy to find though. There are at least 8 or 10 different places throughout the US that specialize in sourcing used KKK stuff that I've been in contact with (including Majestic) so now that we know what to look for, I'd think we'd be able to find it, especially given the popularity of the 951. Heck, even a trip to a few boneyards might yield something...you could grab the whole turbo and possibly get trade-in value on the other components if they were any good. _________________ erstwhile owner of just about every 924 variant ever made
Last edited by ideola on Sat Jul 18, 2009 2:39 am; edited 1 time in total |
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bass gt
Joined: 02 Dec 2004 Posts: 971 Location: Johannesburg for now!!
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Posted: Tue May 20, 2008 2:24 am Post subject: |
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Dan,
If you are going with a decent ECU you can use a PWM output linked to the water temp value to drive the water pump. Saves money and you can fit a seperate switch/timer relay to override the ecu output to turn the pump on permanently. have serious concerns about the Davies Craig controllers and their robustness. If you went with my DTA for example, this is doable, as the PWM outputs list the water temp as a ref value
Steve _________________ Front Wheel Drive is the Devil's work. |
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peterld
Joined: 10 Dec 2006 Posts: 946 Location: Noosa Heads QLD Australia
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Posted: Tue May 20, 2008 11:05 am Post subject: |
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Brilliant work, Dan! |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Thu May 22, 2008 3:09 am Post subject: |
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Rasta Monsta wrote: | Do Majestic have any more of these housings laying around? |
Rasta, you have PM... _________________ erstwhile owner of just about every 924 variant ever made |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Fri Jun 06, 2008 7:22 am Post subject: |
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Just arrived (Click pix for larger photos)
_________________ erstwhile owner of just about every 924 variant ever made
Last edited by ideola on Sat Jul 18, 2009 2:40 am; edited 1 time in total |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Fri Jun 06, 2008 7:36 am Post subject: |
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Here are the components:
Stock 931 Turbine housing, shaft & wheel
Stock 944 K26 water-cooled bearing housing
K27 compressor housing (5327-101-5079)
- machined to accommodate wheel
- 2" outlet / 2.75" inlet
K27 compressor wheel (part number unknown)
Total cost:
- Rebuild: $335
- New compressor wheel: $125
- Bearing housing trade: $65
- Compressor housing trade & machining: $140
Total cost from Majestic: $665
(not including ceramic coating and shipping) _________________ erstwhile owner of just about every 924 variant ever made |
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macBdog
Joined: 16 Aug 2004 Posts: 1111 Location: Brisbane, Australia
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Posted: Fri Jun 06, 2008 10:26 am Post subject: |
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Good work, that looks incredible! Hardly off the shelf though... _________________ 1979 931 with a 350 chev
1973 911E with EFI
p-talk wrote: | I'm still convinced the word 'Porsche' makes people crazy in all kinds of ways |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Fri Jun 06, 2008 10:28 am Post subject: |
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For my hybrid turbo, the only thing not off the shelf is the machining of the compressor housing. Everything else are stock KKK parts that you can source from anywhere, including used turbos.
In terms of the original post, the point was: you can simply swap out the stock 931 bearing housing for the 944 bearing housing. Everything else is bolt-on. _________________ erstwhile owner of just about every 924 variant ever made |
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!tom
Joined: 28 Aug 2006 Posts: 1930 Location: Victoria, BC Canada
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Posted: Fri Jun 06, 2008 10:37 am Post subject: |
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ideola wrote: | you can simply swap out the stock 931 bearing housing for the 944 bearing housing. |
Shouldn't this be 951 rather than 944? _________________ 78 924 NA
5-lug |
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