Mojojo's Tinkerings


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I'd like to take some time and document some of the progress I've been making on my car. I've spent more money and effort on the car in the last two years than probably the last ten years combined. I've had a handful of 850s before this one, but this has been my favorite by a long shot.

So, I like my Volvo... and you guys probably know how the rest goes. 😄

The story of this particular car, a 1996 850 Turbo in Platinum trim goes a little like this:

~late 2010/early 2011, while in my black T5-R, I see a fellow Volvo owner filling up at a gas station. I pull in to the pump next to his to get some gas and strike up a conversation, "That's a really nice car that you've got there..." I ended up talking with the owner for about 45 minutes that night and discussed all sorts of details. He bought the car new from a local dealership for his wife. They loved the car even though it was nearing 210k miles, but were thinking of purchasing something else (ultimately a Prius). I gave my contact information to the owner and told him if he ever wanted to sell it, I would be happy to buy it. Fast forward about a year and I get an email out of the blue from the owner telling me that he hasn't driven the car (about) since the last time we spoke. It's been parked in his apartment complex, and management wanted him to move it. We did some brief negotiating over the phone and he insisted on selling me the car for scrap value since he hasn't been taking care of it. After some reservation, I obliged - the last time I saw this car it was in good condition, but need some TLC. We meet at his complex, and his wife (and my late wife) are both with us. We strike up our conversation like the last time we met at the pumps and he tells me he wants to give me the car, no charge. I offer to give the money that we had previously discussed but he refuses.

I drove away that day with a free Volvo 850 that needed some attention, albeit was still running well. Over the next couple months I got the car cleaned up and ready for another harsh Minnesota winter. Here's some of the only pics I have at the time I received it (with the snow tires):



Fast forward ~3 years...

We're back down in Georgia, and my wife passes away suddenly. As I'm sure you all can imagine, the car (and almost everything else in life) was neglected for the next year or so while I tried to pick up the pieces and raise my then 3 year old daughter.

~1 year later...

I finally get around to manual swapping this car, and do it on a super budget. I hooked up with someone who was moving and just needed to unload parts and bought two complete manual swap kits for ~$400(?). I saved the best stuff and sold the rest to recoup my money, plus some. The car was doing great, piling on the miles and just being a Volvo.



I've been daily driving the car up until this point. I just started a new job with a well-known Japanese company. About two weeks in, on the way home, the oil pressure light started flickering. I realized at this point I was going to need to pull the pan and replace the sump o-rings (again... lol). I gave some careful thought and decided now was the time for me to buy a new vehicle. I purchased my first new car, a 2018 Toyot Tundra... and the Volvo was parked in my shop where it lived for the next year or so as I found the intermittent motivation to work on it. 

The year(s) of the Covid...

Now I'm spending a lot of time at home (working from home) and saving a bunch of money by not commuting in a 14 mpg 4wd truck (fml...), and the seed for a new hobbie is planted - 3d printing. Of course I go in cautious and get a glimpse of the silly things I can make and then my wallet jumps out of my pocket, so to speak.

I'm going to do my best to document as many changes as I can that have occurred since 2020 and some of the things I'm still working on. As of today, the mod list on the car is extensive. At a high level, here's what I'm working with:

B5234T9 - '04 C70 T5 - refurbed
B5254T(?) dual VVT head - 2006 S60 2.5T
Aaron tune - in progress still. ~1,100 kg/hr
Ported Japanifold
Gasket matched N/A intake manifold
N/A throttle body
Hybrid K24, billet 11 blade 54.50/68 compressor and 9-blade turbine
DW 1000cc injectors
DW 300 fuel pump
Do88 radiator/fmic
KW v3
320mm front brakes
IPD sway bars
General refresh of maintenance and consumables

Pictures! (next post)

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The replacement engine was taken down to the block and rotating assembly for inspection/cleaning/maintenance. I shimmed the block and used an S60R MLS head gasket.


I spent a little time cleaning up the ports. No heavy changes, just smoothing out the rough casting.


With the engine out, and waiting on the UPS man to show up, I tackled the interior. I pulled all the carpet to clean with the pressure washer, pulled the dash to repair the mounts, and pulled the headliner to recover... and that's when I found the source of my leaking sunroof.



Engine is in and doing some tuning/driving/testing...


The car is missing a bunch of pieces but running well now...


Driving around on these old janky pegs leaves a lot to be desired. Time for new wheels.


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Posted (edited)

New wheels, old bumper, no spoiler.


After several logs and new tunes from Aaron, the car is running well. At this point, I focus on simple QoL improvements with the swap and getting everything to look nice-ish.

Bend your own fuel lines to go over the cover. You can also see the TME sway bar that I refinished.


This is as close to stock as the engine bay will ever look.


I drive the car for ~1,500 miles like this. I'm happy, the car is happy... and then the first failure occurrs. The K24 suffers a catastrophic thrust bearing failure. The engine/trans comes back out to pull the turbo and oil pan and make sure I get as much metal out of this thing as possible. 

Witness marks on the housing:



At this point, I've already collected two spare K24s, and this one is still under the 6 month warranty from LKQ. So, a quick phone call and they're sending out a replacement - that was easy. I get with Aaron and discuss how I want to proceed. The idea is a nice K24 now that can reach upper 300s (as I prep the fuel system for e85) and a large frame turbo later... which lends itself to the ideal 'while you're in there' scenario.

So, one of the spare turbos get sent off to G-Pop for rebuild and hybrid.

...while I'm here, probably should add a Quaife...


As I continue to wait for the rebuilt turbo, I look at what I've got on the shelf and grab the best exhaust housing and go to town cleaning it up.


Two weeks later...

The turbo comes in from G-Pop, everything looks phenomenal. Money well spent. Engine and trans are assembled and reintsalled. The K24 requires removing the compressor housing to get to the rear engine mount.



The turbo goes in and my first taste of traction in an 850 hits me. It's definitely a transformative mod. I love it... and need it. Even with the quaife, the car is spinning the tires as boost builds in first gear, but there's a problem. The new turbo is flowing too much for the 850 air box. My interim work around for this is a K&N pod filter directly on the maf. This works great when the car is moving, but the performance hit is serious once I hit traffic and the engine bay heat soaks. Time to work on another idea - get more air into the turbo, from outside of the engine bay. To be continued...

...but the car is lacking in the looks department. My buddy has had my replacement R bumper and R spoiler for a few months now, so time to get those back. Paint color is not a perfect match, but the price was good and I've come to the realization that in order to get everything on the car to match, I'll need to paint the whole car.



Now comes the 3d printing hobby. I've decided to improve on some aspects of what the 850 came with.

Edited by mojojo
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3D printing project number one: an air intake that allows for more, cooler air that the factory intake above the radiator. The plan is to utilize thhe bumper opening on the driver's side to get fresh air. I think I've seen an accessory at IPD that works for later model Volvos, but there's no off-the-shelf part that does this for an 850. My plan is to 3d print a part that can be fastened to the bumper and connect a hose to. This needs to be a good sized hose though. I think the IPD accessory is <2 in.? I started out with this concept:


and through ~30+ changes, arrived at the final product that's both easy to print and looks great.


With the help of some brass inserts, a face plate, six M4 screws, and a short section of 3 in. ID pipe, we arrive at the end result.


I'm also happy to say that once installed, it easily can go unnoticed:


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The bumper adapter only solves one piece of the problem though. The main issue was the 850 air box (used in combination with a C70 T5 lid and 3 in. MAF). From the data logs I could see that once the car made~ 850 kg/hr, the airflow would stall/drop as the engine speed increased.


During one of my junkyard trips, I found a fresh, 2006 S60 T5 with the B5244T5, K24 and P2R air box. I grabbed the turbo and air box thinking I may use them one day. The day is today.

The next step comes mounting the P2R air box in the 850. The larger filter used in that box should allow adequate flow. Along with the large opening of the air box, and proximity to the bumper opening, I should be able to get a straight shot into the air box from the bumper. This sounds promising... but also has obstacles - the battery, for one.

The battery is getting relocated to the trunk with 1/0 marine grade cable.

The first idea is to create a multipiece bracket that utilizes the old battery tray bolt locations and two locations on the frame rail. I printed the first piece and it does what it should.


However, I quickly realize that I'm being me and making this more complicated than it needs to be. I call an audible and create this:


I'll support this with a piece of aluminum stock underneath, so this really serves as just a spacer... but, it works like a charm.


(and you can see that I've got the cams locked in this photo. The VVT hubs are worn so the car is currently down.)

I've got everything lined up thanks to a 3 in. to 2.75 in. 90* reducer at the turbo and a 60* mandrel bent 3 in. pipe that is cut to length. I will braze fittings to this pipe for PCV hose and TCV reference line.


I've definitely overlooked some milestones in the progress on this car. This brings me to where the car is currently. I'm going to try and do better at photographing along the way.

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With the air box fitted, I was able to finish up the intake pipe. There's a 1/4 npt bung for TCV reference line and a 12an bung for catch can return. I'm going to take this opportunity to move up to 12 an fittings for the breather setup.


I've loosely designed a plate that I'm going to have laser cut from aluminum for the top of the PCV box - I'm using the RN box currently. I don't have a spare box that I can measure so I'll have to pull the one from the car and check it. I'll cut the outlets flush and braze a couple an fittings onto the plate, then glue/screw it to the box top. I've never been a fan of the solutions that I've come up with. This should put an end to any concerns with the system and serviceability of it.


I ran the positive cable for the battery relocation and working on a battery hold-down that accepts the factory-sized battery. I'm not a fan of Optimas, and not really up to paying the $400-500 for Li tech... yet.


And designed a plate for the laser cutter to mount my two service points in the engine bay for (+) and (-). This will mount on top of the piece of the car that holds the grommet for the air box.



I spent most of the day today getting some needed upgrades done to the 3d printer. I went with the BTT SKR mini E3 v3.0 main board and TFT35 3.0 display. I've got one more upgrade to do with a direct drive extruder, but that will wait for another day.

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Been loving your build, such a clean car and fast too.

I just got a resin printer, so let me know if you need anything aesthetic printed at very high resolution.

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Did you get around to measuring the airflow after your new airbox mod yet? Any appreciable difference? I'm curious to know, since I've drawn close to 1200-1250kg/hr through mine, and am wondering if the stock box was already close to capacity at 850kg/hr. My assumption would be not a lot of difference, still I'm interested what your measurements say.



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1 hour ago, Boxman said:

Did you get around to measuring the airflow after your new airbox mod yet? Any appreciable difference? I'm curious to know, since I've drawn close to 1200-1250kg/hr through mine, and am wondering if the stock box was already close to capacity at 850kg/hr. My assumption would be not a lot of difference, still I'm interested what your measurements say.



Not yet on the box, but I haven't got the car on the road again yet. Still down for the VVT hubs.

The factory box was just over powered by how the hybrid k24 comes on, so I had to go to the open filter...

If I can fit this air box and have no issues, that would be great. My fall back is too just build a new air box behind the driver's headlight.

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Nice thread and nice car! ;)

I remembered you had some detail I think on SS about your pcv/catch can set up - I need to pick your brain on that soon.

Also, what fuel pump are you running?

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PCV setup takes a lot of what the guys making big power do, and just making it look nicer (and more expensive too...). I need to pull the manifold soon and take measurements of the can so that I can do a laser cut top. They're pretty cheap, I'll order a spare. ;) 

Fuel pump is DW300 with high-amp wiring kit from DW as well. Works great!


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Minor tinkering tonight. Started to remove the manifold to get dimensions of the pcv box top, and ended with finally cutting the corner off of the ported RN manifold I have. I've got the Deeworks adapter already, so maybe this is the opportunity I have to switch to this manifold. My understanding is that it flows more (+HP top-end), but has a smaller plenum (-mid range)... which has kind of been the theme of this car. It's pretty sleepy and docile below 3,200 RPM, but after that, power comes on like a light switch. I like it.

Some cutting was required at the passenger side of the plenum in order to clear the PS resevoir, but I don't see that making much difference. It should be a good comparison flow-wise because this manifold and the N manifold it will replace were matched using the same gasket... and grinder. lol


The old with a comparison to N turbo manifold.


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  • 2 weeks later...

I decided to put the RN manifold project on hold so that I could get the car back on the road. Unfortunately, I'm not sure how long it'll be on hold. Seems like it may be a better idea to figure out a custom manifold setup with the combination of short runners and large(er) plenum. We'll see.

Nonetheless, the P2R air box is in, battery relocated to the trunk, PCV system upgraded to 12AN hose.... and new cam hubs installed. I took the car out for a test drive last night and I'm happy to report no more flow restriction through the air box, like was the case with the 850 box. 👍


Still to do: work on the inlet adapter for the air box to accomodate the 3" hose from the bumper inlet.


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