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My "Rat rod" 924 NA turbo conversion.
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Cedric  



Joined: 27 Aug 2004
Posts: 2807
Location: Sweden

PostPosted: Thu May 15, 2025 4:52 am    Post subject: Reply with quote

Good work with all the upgrades, nice that the pinto bolt fit well!

Whats the plans for this season, just drive around, or try something more advanced like autocross (with the wheel on this time maybe ) Will the car stay here or in the south?
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safe  



Joined: 18 Mar 2017
Posts: 703
Location: Sweden

PostPosted: Thu May 15, 2025 5:08 am    Post subject: Reply with quote

Cedric wrote:
Good work with all the upgrades, nice that the pinto bolt fit well!

Whats the plans for this season, just drive around, or try something more advanced like autocross (with the wheel on this time maybe ) Will the car stay here or in the south?


Main thing is to get the MOT done, hopefully before our Transaxle meeting late this month. I still have issues from the brake upgrade that need fixing.

I would love to do some Autocross, but the gearbox and linkage are just too bad for that, maybe a trackday.

My amin focus right now is to get the 911 -69 ready, new front fenders, painting them, painting the wheels and some emergency rust "fixing".

The 924 will return to Stockholm in the summer probably.
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/Magnus, Stockholm Sweden
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Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe
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Raize  



Joined: 18 Sep 2013
Posts: 447
Location: Scotland

PostPosted: Sat May 24, 2025 6:52 am    Post subject: Reply with quote

Not sure if it was posted but is the gearbox in this one the snail or the Audi box?

What brake issues are you having? I did my own brake upgrades with the inspiration of yours which are now just finished so might be interesting to compare notes.
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safe  



Joined: 18 Mar 2017
Posts: 703
Location: Sweden

PostPosted: Fri May 30, 2025 1:40 am    Post subject: Reply with quote

Raize wrote:
Not sure if it was posted but is the gearbox in this one the snail or the Audi box?

What brake issues are you having? I did my own brake upgrades with the inspiration of yours which are now just finished so might be interesting to compare notes.


NA snailshell.

I had problem with genuine poor performance, worse than original. The pedal was spongey and it didn't want to stop good, could not get the wheels to lock up at all.

I made one mistake, I put the front brakes on the forward part of the master brake cylinder, which is the secondary port. You should connect the front calipers to the primary port, the one closest to the pedal.
I also had problem getting the air out of one of the rear calipers. Didn't get it out until out of despair I removed it and tilted it and released the air.

So with a hard pedal (this is 2 days ago) The brakes still sucked, they didn't grip at all !!
So I just gambled and changed my new brake pads to some new pads, EBS yellow stuff in this case. Finally I got usable brakes, one day before my inspection/MOT.
I checked the pads I removed, and they must have glazed, they are rock hard on the surface and shiny.

I still got rejected by the inspection for silly things like side marker, that I don't need, torn steering rack boot and a loose removable tow hook.

Hopefully I have fixed all this now and can it thru inspection tomorrow.

Oh, and I have removed the turbo for the inspection. So that will have to be installed again
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Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe
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safe  



Joined: 18 Mar 2017
Posts: 703
Location: Sweden

PostPosted: Fri May 30, 2025 4:28 pm    Post subject: Reply with quote

Inspection done!
Clear for another 24 months

Putting the turbo-stuff back on tonight!
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/Magnus, Stockholm Sweden
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Porsche 924 -79 NA, EFI and Turbo.
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Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe
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morghen  



Joined: 21 Jan 2005
Posts: 9095
Location: Romania

PostPosted: Fri May 30, 2025 7:01 pm    Post subject: Reply with quote

nice! enjoy!
Hope i can say the same soon.
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Beartooth  



Joined: 05 Apr 2022
Posts: 314
Location: Roberts, MT

PostPosted: Sat May 31, 2025 5:47 am    Post subject: Reply with quote

Very good, it's got to be a relief! I'm so glad I don't have to deal with any of that; obviously there are people who either have no clue mechanically or no ability to think through consequences, and that's why vehicle inspections are mandatory in many places. But for us, we all probably have a good idea of what's a real hazard and what's just nitnoid stuff. I can register any old heap and be legal, but I won't take a car on the highway until I'm confident in the tires, brakes, steering, and suspension - which is a large part of the reason my 931 didn't see the road until over a year's work (intermittently) had been done to it. Anyway, I bet the car feels like a slug without the turbo! Any idea what went wrong with the brakes? It sounds like the pads didn't bed in and glazed over instead, but I have no idea what could cause that. Hopefully the new pads do the trick!
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Raize  



Joined: 18 Sep 2013
Posts: 447
Location: Scotland

PostPosted: Thu Jun 05, 2025 5:54 am    Post subject: Reply with quote

safe wrote:
Inspection done!
Clear for another 24 months

Putting the turbo-stuff back on tonight!


Good job!
I had the EBC yellow on my stock NA brakes, they were OK but not the best cold, but at least they didn’t have fade problems like the stock pads when hot. They also “warped” the rotors (ie, uneven rotor thickness from deposits) and only lasted 10k miles. I hope with my new oversized brakes that OE or something slightly OE+ like Mintex 1144 will be plenty.

I can see why your rear caliper would trap air, the angle of the bleed screw is not good where it intersects the piston bore.

The nice thing about the style of 4-bolt brake conversion we have both done is the front rotors are separate from the hubs so much cheaper and easier to change. And unlike a 944/931 you don’t have to take the hub off to change the brake disc (idiotic design!).
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safe  



Joined: 18 Mar 2017
Posts: 703
Location: Sweden

PostPosted: Mon Mar 02, 2026 10:29 pm    Post subject: Reply with quote

Winter fun, fixing nagging things that is really annoying.

There is an exhaust drone around 3000 rpm. Trying to fix that with a better quality rear muffler, also bigger. Its not a loud exhaust otherwise, just makes it unpleasant on longer drives.



Looks the same.


Hopefully that will make the issue smaller.

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/Magnus, Stockholm Sweden
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Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe
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safe  



Joined: 18 Mar 2017
Posts: 703
Location: Sweden

PostPosted: Fri Apr 24, 2026 7:01 pm    Post subject: Reply with quote

I've been slowly working on a G31 gearbox for the ratrod.
I had a 911/915 LSD I could fit to it also.





Had to rearrange the disks inside the diff and change the direction of the ramps to fit the 924, or a front engine car really.
A 911s diff is set up to lock up more on engine braking to stabilize the cor into a corner, while most other cars lock up on power to grip up under acceleration.
Its the ramp that puts pressure on the clutch disks making them lock up. I also moved around the individual disk to decrease the lockup from 80% to 40%, you essentially takes one of the friction disks out of play... Its all in the set up manual for the diff (Kaaz diff, Japan)





Decided to strip down the gearbox to to install a one piece bearing retainer and have a look at stuff.




Here I found trouble...
The dog teeth on 1st gear was compleatly worn down.
Not only that you can basically call them hens teeth because you can't find replacements... So here it stopped for quite a while until Cedric mentioned that he had replaced his long ago an still had the old ones and they were in much better shape than mine! Lacking pictures of that...



Hopefully it will soon be ready for installation. Torque tube gear linkages are ready.
I just need to get the fly wheel balanced and machined. Only unknown is how the clutch release bearing will interact with the new twindisk clutch.
I need to get some time on a lift in my other workshop.
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/Magnus, Stockholm Sweden
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Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe
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Cedric  



Joined: 27 Aug 2004
Posts: 2807
Location: Sweden

PostPosted: Sat Apr 25, 2026 2:28 am    Post subject: Reply with quote

One mans trash is another mans treasure Especially when it comes to G31 parts

How did you do with the ramps, just swapped around acceleration and braking side? What will the end result be on this diff do you think for the ramps, how much lock on braking? Since its mostly a road car i think its good to not have so much locking i general, it did grip up surprisingly well without the diff.

that poor G31 has no clue what its going to have to suffer through
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924RACR  



Joined: 29 Jul 2001
Posts: 9073
Location: Royal Oak, MI, USA

PostPosted: Sat Apr 25, 2026 2:57 am    Post subject: Reply with quote

Now that you're prying into the details... how do you go about changing the ramp angles, looks to me like you'd need to remachine that housing or replace it with one with the desired angles?

How about spring rates, do those want changing too?

Very interested since a certain one of my projects (day job) is pursuing some changes in that area, the design is virtually the same I believe, and I don't usually get to get my eyes on those details..
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safe  



Joined: 18 Mar 2017
Posts: 703
Location: Sweden

PostPosted: Sat Apr 25, 2026 5:09 am    Post subject: Reply with quote

You just flip around the piece with the ramps and it will work in the other way.
It switches from 1.5 reverse to a 1.5 standard.

It could be set up as hard 100% locking (as it came), medium 65% or soft 35%.

I set it up to 65% as that was the recommended setting for street and auto-x.

I actually don't know how the diff locks up. if its 65% on acceleration and something less on breaking. Or if its 65 on braking and more like 100% on the ramps. The original ZF diff with 40% lockup didn't really have any ramps.

The Kaaz USA guy was very interested in how I fit a 915 diff in a 924, he didn't realize the 931 had a special gearbox using 915 pars

The Kaaz diff is pretty high quality with 6 (3 disks) friction surfaces per side, more than the original ZF.
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/Magnus, Stockholm Sweden
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Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe
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