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931 custom in need of some love
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Mclaren924  



Joined: 13 Oct 2021
Posts: 259
Location: Oceanside CA

PostPosted: Wed Apr 08, 2026 2:31 am    Post subject: Reply with quote

Wilwoods mounted up to 924 5 lug hubs to get rough idea of where all the brake lines will run. Converting to a stepped 944 master cylinder as well as F+R brake line routing instead of the X-split that is standard on the 924/931.

Will be converting to 924S front hubs and rear trailing arms/hubs/ The aluminum rear saves a lot of unsprung weight.

Installing a tilton Proportioning valve alongside the passenger trans tunnel and will finish off the brake upgrade with stainless steel hardlines, and braided soft lines to wrap it up.

Just got it all mocked up and time to mount the valve and booster/master and start bending brake line




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1980 931 "Salt" Bucket wannabe racer (Dreaming)
1979 924 Sebring "Pepper" -Sold
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Cedric  



Joined: 27 Aug 2004
Posts: 2801
Location: Sweden

PostPosted: Wed Apr 08, 2026 6:38 am    Post subject: Reply with quote

Slowly getting there! Do you make the adapters yourself? I really recommend the carrera discs up front while you are there, they cost very little and add quite a bit of extra cooling with the extra 3mm width.

I think the 944 MC only use the large piston normally if i remember correctly, so it will only act with the smaller area in case of brake failure. But with the bias valve you should be able to get it working, what pistons did you chose?
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Mclaren924  



Joined: 13 Oct 2021
Posts: 259
Location: Oceanside CA

PostPosted: Wed Apr 08, 2026 7:19 am    Post subject: Reply with quote

Just the wagenwest kit, it's the 944 setup and fits our 5 lug hubs perfectly. Will look into the carrera discs upfront, thank you for recommendation.

https://wagenswest.com/product/porsche-944-wilwood-caliper-kit-front-rear/

Got booster and master mounted up and intake mounted and started bending drivers side brake line now. Slow progress for sure.


The wagenwest kit is really a no brainer for the price and fitment. Really really easy and nice setup. Would only recommend different if looking to really dial in a track setup.

Couple pics



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1980 931 "Salt" Bucket wannabe racer (Dreaming)
1979 924 Sebring "Pepper" -Sold
1977 924 Slicktop "Pennie"-Most likely parts
1979 3/5 gt clone 924- Shop Test Car
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Cedric  



Joined: 27 Aug 2004
Posts: 2801
Location: Sweden

PostPosted: Wed Apr 08, 2026 7:31 pm    Post subject: Reply with quote

Really cool with the GTS intake, though having a more generic compresor cover would have made it a bit easier to rotate it around, the reason i swapped to 951 compressor housing Its really a huge casting with the built in bov, very modern for its day in that sense.

I think i had a look at that kit, the balance is a bit wonky, and pushes the bias rearwards quite a bit, which i didnt want. But since you do the F/R+bias valve that is not an issue. Maybe its because they do aircooled stuff Nice that there is a kit out there at least, not much to chose from if you dont want or have time to do stuff yourself. For the carrera discs it might work depending on the caliper design, if i remember correctly all measurments are identical bar the outer rotor surface which is 3mm further out, and of course the inner air channels that are much larger.

Fun to follow the build, not so many 931 build out there these days!
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924RACR  



Joined: 29 Jul 2001
Posts: 9061
Location: Royal Oak, MI, USA

PostPosted: Thu Apr 09, 2026 3:00 am    Post subject: Reply with quote

Damn, I need to make one of those intakes...
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Mclaren924  



Joined: 13 Oct 2021
Posts: 259
Location: Oceanside CA

PostPosted: Thu Apr 09, 2026 5:22 am    Post subject: Reply with quote

The intake is from mittelmotor and is high quality, going to get it 3d scanned by a buddy of mine with a very nice scanner. Was tempted to make one myself but there's no way to replicate the factory looking finish like this does.

The 951 housing was something I brought up to my turbo builder and he was firm with idea of using machined out stock housing, the exact reasons why truthfully went in one ear and out the other. I think it was a slower spool time and less efficient but I really could be wrong there. Going to have to push the steering rack mounts back half an inch on the crossmember and do some cutting and welding to the coldside inlet. I think also he has a specific turbine setup he mills for and uses and to put a 951 inlet throws a wrench in this I think more specifically the inducer is shorter on a 951 setup? Will take a look in the next couple weeks first hand as I also have a 88 951S were doing headstuds and cometic and boost controller on. Nothing too crazy

The proportioning is def a little wonky on the wagenwest kit, truthfully I was imagining anybody going to such effort already planning to add one as getting the right bias with just piston choice alone is a nightmare unless you have deep pockets.

A little sad to see how quiet the board has been recently. I'm sure this isn't the only 931 being sent to the moon right now but it sure feels like it.

Got front and rear brake lines routed yesterday. Time to mount proportioning valve and rear lines. Hopefully get all this knocked out today.
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1980 931 "Salt" Bucket wannabe racer (Dreaming)
1979 924 Sebring "Pepper" -Sold
1977 924 Slicktop "Pennie"-Most likely parts
1979 3/5 gt clone 924- Shop Test Car
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Cedric  



Joined: 27 Aug 2004
Posts: 2801
Location: Sweden

PostPosted: Thu Apr 09, 2026 5:21 pm    Post subject: Reply with quote

Mclaren924 wrote:
The intake is from mittelmotor and is high quality, going to get it 3d scanned by a buddy of mine with a very nice scanner. Was tempted to make one myself but there's no way to replicate the factory looking finish like this does.

The 951 housing was something I brought up to my turbo builder and he was firm with idea of using machined out stock housing, the exact reasons why truthfully went in one ear and out the other. I think it was a slower spool time and less efficient but I really could be wrong there. Going to have to push the steering rack mounts back half an inch on the crossmember and do some cutting and welding to the coldside inlet. I think also he has a specific turbine setup he mills for and uses and to put a 951 inlet throws a wrench in this I think more specifically the inducer is shorter on a 951 setup? Will take a look in the next couple weeks first hand as I also have a 88 951S were doing headstuds and cometic and boost controller on. Nothing too crazy

The proportioning is def a little wonky on the wagenwest kit, truthfully I was imagining anybody going to such effort already planning to add one as getting the right bias with just piston choice alone is a nightmare unless you have deep pockets.

A little sad to see how quiet the board has been recently. I'm sure this isn't the only 931 being sent to the moon right now but it sure feels like it.

Got front and rear brake lines routed yesterday. Time to mount proportioning valve and rear lines. Hopefully get all this knocked out today.


Maybe you should have a talk with the guy that recreated and cast all the GTS specific parts for his rally car, it was cheaper than buying them from germany. I can send you his contact details if you want, see some pics from the process.

Im not sure how Simon thoughts were going there, maybe he machines it larger than its possible to do with the 951 housing, im not sure. The 951 is pressure die cast so very light and thin.

There are actually some 931 projects going on here and there, there are a few guys i have contact with that searched me up for discussing performance builds. Since the FB groups are really awful to keep any long discussion ongoing. Sadly with the lack of forum activity there arent any collection of car build threads anymore.




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Cedric  



Joined: 27 Aug 2004
Posts: 2801
Location: Sweden

PostPosted: Thu Apr 09, 2026 5:25 pm    Post subject: Reply with quote

Oh btw, could you measure the GTS inlet length if you have time? Good reference data to have to understand their intentions.

Heres a pic from my intercooler thread:

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924RACR  



Joined: 29 Jul 2001
Posts: 9061
Location: Royal Oak, MI, USA

PostPosted: Thu Apr 09, 2026 8:50 pm    Post subject: Reply with quote

Yeah, I would indeed be interested in a number on a GTS intake. I assume it is still set up to use the stock S2 throttle body?

I have a stock S2 intake we lopped half of the plenum off of, with an eye to welding a new plenum with the right shape onto the stock runners... but it'd probably not look quite as nice or correct as the GTS version.

Hate to admit it, but all of my effort in the last year or so has been on cosmetics; other than a little bit of maintenance including new CVs over the weekend, I've been putting all my build money and effort into making the car pretty and special, since it's been mechanically pretty up to snuff, enough to just drive and enjoy.

Last big project was recovering the seats (see thread elsewhere), and cleaning up the paint some... next up, I still need to get around to installing the 968 wing from Marco (as well as resealing the hatch), plus 951 drip rails and 968 Cup car mirrors... but need to also hopefully today pull the POTD #77 out of winter storage - now that I think the snow's finally gone - and prep it for race in a couple of weeks! Also trying to get back to Karl's S1 931, figure out what's up with the clutch/pressure plate geometry on that, then swap out the blown turbo and cracked manifold. Thankfully,, he already has the spares, but will be a good bit of a wrench to get those going.
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