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Transplanting 924 turbo engine on na
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safe  



Joined: 18 Mar 2017
Posts: 210
Location: Sweden

PostPosted: Fri Dec 25, 2020 3:34 am    Post subject: Reply with quote

Turbo head, custom JE pistons to get 10:1 compression, at least, ITB with EFI.
A good start. Stock rods are ok but heavy, should be ok with a little higher revs.

Mixing of the shelf parts from other engines on a budget requires that you really know what you are doing. If you need to modify parts and cant do it your self it quickly adds $$$.
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/Magnus, Stockholm Sweden
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Porsche 924 -79 NA, under EFI and turbo conversion
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Juho  



Joined: 03 Oct 2018
Posts: 160
Location: Finland

PostPosted: Fri Dec 25, 2020 4:42 am    Post subject: Reply with quote

there must be a car with right bore and compression height, but its hard to find specs of oem pistons
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2130
Location: MI

PostPosted: Fri Dec 25, 2020 5:08 am    Post subject: Reply with quote

924 bottom end is super strong, might need to refresh the head gasket, but it should be able to take a lot of nitrous..

Maybe like a 50 shot on a wot switch and another 50 on a button.. wet..
Whatever your trans can handle..

Way quicker, easier, and cheaper..

That’s probably what I’d do with an NA..
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Juho  



Joined: 03 Oct 2018
Posts: 160
Location: Finland

PostPosted: Fri Dec 25, 2020 5:18 am    Post subject: Reply with quote

engine is in parts atm, maybe il just throw rods and cheap forged pistons and make some boost. Going na doesent seem worth it for me atm
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safe  



Joined: 18 Mar 2017
Posts: 210
Location: Sweden

PostPosted: Fri Dec 25, 2020 7:32 am    Post subject: Reply with quote

Cheep forged pistons would still be custom JEs... I dont think you will get away with less than the 8-900~ish euros for that.

The 924 pistons have an unusual high compression height.

If there was a good option for cheep pistons you would find it on this forum.
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Porsche 924 -79 NA, under EFI and turbo conversion
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Juho  



Joined: 03 Oct 2018
Posts: 160
Location: Finland

PostPosted: Fri Dec 25, 2020 8:02 am    Post subject: Reply with quote

been thinking of vw flat tops but if they are forged is little questionable
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safe  



Joined: 18 Mar 2017
Posts: 210
Location: Sweden

PostPosted: Fri Dec 25, 2020 8:11 am    Post subject: Reply with quote

Juho wrote:
been thinking of vw flat tops but if they are forged is little questionable

They arent, if you thinking about AA, they are hypereutectic, which is pretty good for NA, but not great for boost.
There are Mahle flat tops that I think is forged, but they are much more expensive.
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Porsche 924 -79 NA, under EFI and turbo conversion
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Juho  



Joined: 03 Oct 2018
Posts: 160
Location: Finland

PostPosted: Sat Dec 26, 2020 1:48 am    Post subject: Reply with quote

what about grinding crank to use different rods?

like this http://www.924board.org/viewtopic.php?t=36293&postdays=0&postorder=asc&start=0
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Juho  



Joined: 03 Oct 2018
Posts: 160
Location: Finland

PostPosted: Sat Dec 26, 2020 2:46 am    Post subject: Reply with quote

finding the rods used in this setup wasnt hard but the pistons are hard to find, not sure if they are off the shelf anymore


found even better rods with less to grind away from crank but idk about offset grinding the crank
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safe  



Joined: 18 Mar 2017
Posts: 210
Location: Sweden

PostPosted: Sat Dec 26, 2020 3:48 am    Post subject: Reply with quote

Like I said, if you are going to use parts not made for the 924 you need to know what you are doing. If you cant figure it out for yourself, its not for you.

Grinding the crank and rehardening it, I think you are not in a cost effective mode anymore. Grinding the crank would only be something I consider for stroking the engine (offset grind).
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Porsche 924 -79 NA, under EFI and turbo conversion
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Juho  



Joined: 03 Oct 2018
Posts: 160
Location: Finland

PostPosted: Sat Dec 26, 2020 3:52 am    Post subject: Reply with quote

I know how the offsetgrinding works, but machine shops here wouldnt probaly do it, and the money spent on crank work could be put on custom pistons.
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Juho  



Joined: 03 Oct 2018
Posts: 160
Location: Finland

PostPosted: Sat Jan 02, 2021 12:51 pm    Post subject: Reply with quote

Found pistons off the shelf that would give high compression with the 931 head but the pin size is different, could they be machined to fit with 924 rods?
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