924Board.org

[Carrera RSR]

[Cedric]

He is working with efi, and kpa in absolute pressure is the standard setup. So about 1.5bars of boost. I think you are running out of both compressor flow and are getting high back pressure from the small turbine housing. Time for a new turbo?
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1980 924 Turbo
www.instagram.com/garagecedric/

[Fasteddie313]

[Carrera RSR]

6.10 with either 2664 or the 951S 2670 compressor
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[Cedric]

With the big lack of #6 turbine housings, there is reasons to go with a more modern turbo if you want to go nuts. The 2670 is nice, but wills start to be seriously unhappy above 1,5 bar, as most compressors designed for production engines. But that will probably be above 300hp, so it will move.



Otherwise I think an adapter like the one i have in my storage would be a good solution, and maybe put a TD05 mitsubishi charger on there. If you are really serious about it I can pick up my engine simulation model and we can try finding a good match.


[img]https://www.bildtagg.se/file/thumb/6tj1ctwqsbp4tfrzctqt9wss[/img]
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1980 924 Turbo
www.instagram.com/garagecedric/

[Mike9311]

That is a neat adapter. Very straightforward even to play around with ideas as apposed to Joakims first build with the welded on adapter which is a bit more permanent

This just requires boring out the inducer inlet of an S1. Very likely something like it on Ebay without the taller exducer tips to make the cold side modding easier of the 944 housing. But Cedrics adapter would easily open the door to lots of things easier than this


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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

[Cedric]

There are several options for the compressor side on the k26, the issue here is the lack of turbine housings. There are of course non 931 turbine housing for the k26, but then you need an adapter and could aswell go with a more modern turbo instead.
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1980 924 Turbo
www.instagram.com/garagecedric/

[Fasteddie313]

Really wanna stick with original 931 hot side and bearing housing stuff..

The k26/6 comp is really smaller than the 2664 931 comp?
Man, I really thought I remembered it being a bit bigger when it was in my hand..

I’m pretty convinced that this engine can handle pretty serious cylinder pressures.. Haven’t even blown the HG yet..
Think everyone is scared of all the non-intercooled and/or non-AFR controlled horror stories..
Isn’t this engine originally a diesel bottom end?

IDk.. I know I shouldn’t but I’m addicted..

Wonder if Borg Warner still makes/sells compressors to fit k26s..
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80 Turbo - Slightly Modified

[Cedric]

the K26/6 compressor from the 944 is 2667, so in between the 2664 and 2670. A good intercooler can mask the compressor getting into the wall, but it will demand a massive ammount of turbine energy when it tries to keep the boost out of the efficiency range, which means the wg is closing and building alot of backpressure. This is combination with a to small turbine housing is not the best combo,so ideally you would go with both of them larger. There is a plethora of hybrid K26/k27 variants, so alot could be done if you would like to go nuts, only your wallet and head gasket will put the limits on the fun, or maybe some detonation
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1980 924 Turbo
www.instagram.com/garagecedric/

[Fasteddie313]

Look at that AFR line tho...
Whew thats smexy..
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80 Turbo - Slightly Modified

[Fasteddie313]

[Cedric]

Ill throw out a WTB on the local transaxle board, maybe someone have something laying around.
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1980 924 Turbo
www.instagram.com/garagecedric/

[924RACR]

Yeah, that AFR looks nice, but I have to say I think the RPM trace is still a little wobbly... I forget, are you using the distributor still?

Mine was really wonky/bouncy when I still had the stock ignition and distributor; after switching to direct coil fire no moving parts it's now smoother than that.

No image hosting, I'll send you a pic on Messenger Eddie...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Carrera RSR]

[Cedric]

My turbo was like new, probably less than 100km on it, already cracked. A new casting would be nice, even though its a niche product, so miniscule volumes=high price. But if i remember correctly that was discussed not that long ago in a thread on here.
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1980 924 Turbo
www.instagram.com/garagecedric/