Interested to see what you end up doing. I did consider having fans on the outside of the air intakes and hiding them behind intake scoops. At the moment I've had no fans for over a year, I think it's been fine but I guess you never really know. Did have a cam chain tensioner fail, could have just been it's time or possibly be related to heat. I wonder why exactly Porsche used the fan in the engine bay compartment, I wonder if they ever released a technical document about it (similar to the Audi self study ones)? On a standard car the one vent is sealed up completely with the air filter, mine isn't so at idle I'm letting out more heat.

If you went standalone you can ditch the maf's, that's what I did. Depending on the year of your car there will be canbus stuff you probably need to take care of.

Escy - I wonder how much hotter the Boxster bay gets than the B5 S4? That Audi bay is jam packed and I bet airflow it pretty minimal too. I’m not really ready to worry about fans too much, I’ll save that for later on in the build, just thinking ahead a little.

And yes that passenger side cam chain tensioner gets mega hot being that it’s inches away from the stock exhaust manifold. I’m hoping I’ll get better life out of tensioners, scam seals, and valve cover seals with the turbos located a little lower.

If you ever find a SSP like document for the Boxster please share! Those VAG SSP’s are so great to understand how things work and why design choices were made.

I’m sticking with the stock ECU and am really trying to make it run at first on a stock tune, then turn it up after after things seem to be working right. My box is a 2003 so I will def need to feed CAN to the car; I’ve got a plan there too. I’ll share if it works like it should.

I got my passenger MAF and filter mocked up today. I’m pretty pleased with the layout. The filter will be just behind the side vent. I think I’ll make a cowl or something to direct air to the filter. I still need to plumb the recirculation valve to in-between the MAF and turbo inlet. https://uploads.tapatalk-cdn.com/202...b47c568484.jpg

I cut through the firewall between engine bay and trunk and have my short ram intake mounted there. It's hot in there though, and my intake temps on a NA setup are over 100F.

The OEM fan only comes on as a secondary cool down measure - it pulls air into the engine bay after shutdown if the compartment exceeds a specific temp. It's kinda silly and a lot of guys gut theirs (including myself). Others have wired the fan to a switch so they can run it on cool down laps.

If you're worried about a fan, I would probably think about cutting it not the engine bay cover and mounting them there.

And no, there are no Porsche SSPs. I agree that those documents are phenomenal and always wondered why Audi made them but Porsche didn't.

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Do you have a vent or a way to allow air into the trunk? Any pics? Wow, 100F NA. Part of the fun of making power in a Boxster, right?

The results are in, power was a bit inconsistent during the day because of temperatures, it made between 470 and 488bhp on pump fuel, when I added the water/methanol injection (50/50 mix) it made 530bhp and 540ft/lb of torque. These numbers are at the flywheel. A bit lower than I expected, on a Mainline dyno which apparently read a bit lower than others. It worked hard to make those numbers, raised the rev limit up to 7200rpm as it was making power at the top end and it was running 1.8bar on petrol and 2bar on meth.

The interesting bit is probably temperatures. The car made 83 pulls so things got hot. Ambient inside the building was about 20c degrees during the morning. All the pulls were on petrol only. My charge cooler coolant temperatures were consistently around 30c for the inlet, the outlet would go to about 40c after a pull. IAT's were 30c up to 55c by the end of the pull. Not brilliant but acceptable, maybe the pump isn't fast enough?

We stopped for lunch, in the afternoon the ambient temp was up at 27c and everything had heat soaked, my charge cooler coolant was sitting around 40c and not coming back down much. IAT's were climbing to 65c at that point.

Right at the end we did 2 runs back to back, one on meth, one without.

On meth IAT's went from 35c, when it kicked in they dropped to 22c, by the end of the pull they were 36c. The initial drop might be the sensor getting doused with it. The charge cooler inlet liquid went from 32c to 42c, outlet was 41c. The EGT's peaked at 815c.

The next run was 0.2 bar less boost, no meth. IAT's went from 35c to 65c, inlet coolant went from 32c to 37c. Interestingly a few seconds after the run the inlet coolant kept raising to 41c, I guess this is the heat put into the system from the 1st pull, it shows not enough capacity in my system (probably about 10 litres) and the radiator isn't efficient enough to cool it back down fast. The coolant outlet was 48c on that pull. My EGT's were 900c.

Going by the difference in EGT's you can tell the water/meth is definately keeping things cool and it's not just a case of tricking the IAT sensor. My timing was about 5 degrees more advanced on the methanol.

It's kind of exactly what I thought, charge cooler gets overwhelmed, it'll be interesting to see where it ends up after a 1/4 mile run, I think it won't cope, even with it starting at near ambient temperature. Definitely not up to a trackday (but is any water to air system?). Like I said before, improvements to the efficiency of various parts of it are going to be marginal gains, what's a 5c improvement if your at 65c to start with?

If I was to do it again, I might be tempted to sack off the charge coolers and go for a more fancy water/methanol set-up, a couple of nozzles pre-turbo and one in each port to ensure equal delivery.

Hey Escy, those are impressive numbers, great job. Sounds like you sorted out a few gremlins, that’s a win by itself.

What’s up with the misfires and FW version? That seems a little fishy. I bet you’ll be taking that up with manufacturer; hopefully they can help sort out the misfires.

The dyno graph you posted on pistonheads looks great. You are peaking at 30psi and tapering to ??. Looks well controlled. Are you using the 2.7t N75 valve (wastegate control valve)? How has it been tuning the wastegate control with the LPC8?

Your experience with the a2w intercoolers reinforces my concerns about intake temps. Having the a2w intercoolers in the engine bay means the intercooler coolant needs to not only cool the charge, but also overcome the heat soaking and ambient temps of the engine bay. To that end, more coolant flow, better cooling of the coolant, and lower ambient temperature around the intercoolers would be helpful.

I can’t wait to see some street numbers now!

FWIW, there's a guy named bisi ezerioha that did what was probably the first twin turbo 986 build. His turbos were remote mounted (where OEM muffler would be) and intake was plumbed into the trunk, where a large a2w intercooler setup was mounted with the heat exchanger being the front 3rd radiator. I've not gotten to talk to him directly about his experience but in an interview with Hoonigan, he said his setup resulted in IAT that never exceeded ambient temps on hard track days.



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So you’re saying it’s possible to have stable IATs! Is this build documented anywhere?

There is/was also a Subaru powered Boxster out there that started with a pretty trick a2a in the trunk but ended up with a a2w in the trunk. See the link below. This guy also (I believe) simply repurposed the 3rd radiator for intercooling. That would be great and easy, but I would worry that engine cooling would be inadequate. Anyone have any thoughts or experience regarding only using the side radiators for the 2.7t engine and using the 3rd for intercooling?

https://forums.nasioc.com/forums/showthread.php?t=2047734

Thanks. It isn't definately an issue with the FW, it's not been confirmed yet. He'd added a fueling schedule look ahead setting for the latest firmware, where it gets a timing value. I don't know if you saw my latest update but it turns out I messed up and got the cam chain tensioners on the wrong banks, when I've been stripping it down to fix, I've just noticed my cambelt is really slack (thinking maybe caused by the tensioners working in the opposite way?). This explains the inconsistent power with the timing being all over the place. It should hopefully do a bit better once I sort it all out and get it back down there. The suspected FW issue could be my end (there was a FW update a few months back which caused an issue on my car and it was a problem their end).

The graph should look better when I go back, thinking it might be around 80-100bhp better off at about 4000rpm once the inlet cam is advancing rather than retarding. There's no tapering of the boost at all, it's holding 30psi at the 7200rpm redline. That's impressive for a 2.7t isn't it?! I didn't want a power band that drops away so happy with that. Standard N75 controlled by the ECU. No issues, it's doing what we want when we want. I guess it's down to the experience of the tuner, I struggled to tune the PID on the road, I had it reasonable but he got it a lot tighter to our target. Just looking at my logs and PID isn't even working much to keep it at 30psi at the redline. That's down the the physical spec of the engine I think, probably mainly the larger exhaust manifolds.

Yeah, I had a charge cooler mounted in the boot before and it stayed cooler for a lot longer (it was also larger). You could touch it and one side was hot the other cool.

https://live.staticflickr.com/65535/...3de3fd5d_b.jpg20160925_174312

I never got to use the car properly hard as it wasn't tuned, on the road it stayed really cool, on the dyno, it eventually got overwhelmed. From a performance view this was definately a better set-up than my current one. One thing I'm quite proud of, with my current car is I've not made any sacrifices in terms of practicality. Everything is hidden away, meth tank, charge coolers, meth pump, etc. That's why I won't consider cutting away bodywork to improve airflow, my car isn't about that.

Like you say, just circulating coolant into the engine bay is going to heat it up. One improvement I can make is wrapping my exhaust manifolds and making some heatshields. My charge coolers are right next to them. My system might recover better on the road compared to the dyno, there's no airflow through the engine bay so everything is probably a bit hotter than normal. We got a load of runs where the IAT was <50c, for road use, it'll be fine.

He's a nice guy and he builds cool stuff. He's only running small boost (<10psi?), I don't think his system has as much demand on it as mine does. Also, the car is a tool to promote his business, not convinced he'd say it performed like **************** even if it did.

The simple fact with all charge cooler systems I've seen is they work well for a short period but eventually you heat the coolant up and it won't come back down until you are off the throttle. That includes manufacturers with proper development. All the improvements (larger radiators, better pumps, more capacity, etc) just move the window a bit. That's the way I see them anyway.

The standard 3rd radiator doesn't look a good design in terms of cooling for a charge cooler. No issue with just the side radiators, that's what I use (with a/c condensers in front of them), ever had issues with engine coolant temperature, even on the dyno.

.................opps

You are right, his setup is at low boost. The m96 is not setup well for anything over 5-7 psi. He did not do a detailed build documentation unfortunately, and he seems to have built a lot of walls around himself as he has become more successful so I can't seem to figure out how to reach him.

It's all about balance though. Air or water, you're never gonna have cool intake temps with 30psi boost. You pick your poison, so to speak.

Where do you charge pipes sit? You could put small bar and plate intercoolers in line on either side if they line up with the side vents. Put some scoops over the vents to really shoot air through them. There was a twin turbo boxster (if you can call it that) that used a V8 from a 968 which was setup like that, albeit their "side vents" were massive.

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If you follow him on Instagram he has live videos where he answers questions.

My charge coolers are at the sides of the engine. I looked into having intercoolers by those side vents, not enough space and I'm not convinced they draw enough air.

I'm not planning on making any changes to the charge cooler system at this point. The only potential idea I have is to plumb in a heat exchanger that uses the A/C to cool the coolant. Tesla use one for their battery cooling. I've got one on the shelf. Because you use the a/c to chill the coolant you can get it down to bellow ambient temperatures. All the same charge cooler limitations apply though, you'll put heat into it quicker than it can recover, if the coolant pump isn't fast enough might not improve things towards the top end of a pull, etc. You basically just start from a better base line. If I could plumb it in myself I'd give it a go but I haven't been able to find the fittings. Ultimately, with the WMI proving so effective, what's the point?

I'm not sure if I said it on here already so if I have please forgive, but I don't like the idea of using wmi to fix a problem. The issue there is that of you run dry or your system malfunctions, it may cost you a motor. I'm certainly not trying to criticize your setup, I think you've done a fantastic job.

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Btw, thanks for the heads up about the Instagram live feeds. I'm not on social media so I'm in the dark with that stuff, but I may need to sign up lol.

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I've got a level sensor wired into my screen wash light so I'll know when it runs low and have got a flow sensor which will flag an error if a pipe came off (set up as a boost cut) and also I have knock control which will pull timing so I don't consider it much of a risk.

The boost cut and timing retard are smart. Be careful though, running super hot not only predisposes to donation but also preignition, and that's what will get us in the end. Do you have a boost controller in the cockpit so that you can control the system while driving?

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Any progress on V8 engine swap options?
 

Well I’m going to test this theory; the red box in this image is about where the side vents are. I am hoping that the vents can supply some fresh air to both the air filter and to the area around the charge coolers in the front. I am thinking of augmenting with some slim 6 inch fans to increase flow. If I find a recipe for stable IATs without AC cooling or WMI, I’ll let you know. Though I do agree that WMI is pretty magical.

https://uploads.tapatalk-cdn.com/202...a5d02e3504.jpg

The stock ecoboost turbos should put me in the B5 S4 k04 ballpark with great low RPM spool, but there are some drop-in upgrades that I’m pretty excited about too. Here are some 42/56 units that should be comparable to the RS6 turbos that you are running. One step at a time though… need to get this embodiment put together before really pushing performance.

https://crpengineering.com/product/3-035-311/

Fueling is currently my bottle neck… I’ve still got stock injectors and fuel pump in my build. Which injectors are you running?

I'm not running super hot with WMI though, the EGT's are over 100c lower. I've got a switch with different boost targets assigned to it.

I've currently got my air filters sitting in the side ducts, I don't think they'd supply enough air for air to air intercoolers though.

I'm running a cheap 340lph fuel pump and Bosch EV14 550cc injectors. They are OEM fitment on some cars so can be had cheaply. I'm near the limit of the injectors, they are hitting around 85-90% duty cycle.

Thrilled to have gotten mine out for its first successful track day. No major hiccups, car did well. There is so much more in this car, I've barely scratched the surface. This somewhat rusty lap was almost 10 seconds faster than the last video of a lap I have in this track configuration.

<div style="padding:20.25% 0 0 0;position:relative;"><iframe src="https://player.vimeo.com/video/594405113?badge=0&amp;autopause=0&amp;player_id=0& amp;app_id=58479&amp;h=421135d6d2" frameborder="0" allow="autoplay; fullscreen; picture-in-picture" allowfullscreen style="position:absolute;top:0;left:0;width:100%;h eight:100%;" title="East track August 29th 2021 first laps after swap"></iframe></div><script src="https://player.vimeo.com/api/player.js"></script>

https://vimeo.com/594405113/421135d6d2

Wow great video, congrats! I love the few seconds with the Corvette in the rear view. Car sounds great too.

So what do you have next on your list? Anything remaining with the swap? More test and tune?

Wow thats super impressive you didn't have a single hiccup

^, ha, I didn't have any MAJOR hiccups. Of course there were some. You may have seen last month I got the car aligned ahead of a track day and made it exactly one lap before something came loose and ended the day. This event was good by all measurements, but definitely had some things pop up. A bolt on my engine cradle came loose, somehow stayed in place and was able to re-tighten it, but need to figure out why that's happening. In the last session my fuel gauge and engine coolant temp stopped reading correclty, showed lower than true, so I came in a lap early to check. Scanned w Vag-Com, normal readings to the ECU and after cycling the key the cluster showed normal again as well. Tore up a fender liner, need to find some replacements for both fronts.

As far as next steps, definitely more seat time on track and get used to the different setup. Need to get new fender liners, work out a better coolant temp monitoring strategy (likely additional sensor and external gauge), swap in the oil pressure sensor Escy recommended. Have been getting some belt squeal on startup, going to throw in a fresh belt and see if that helps.

Always things to fix/improve. But a successful day is critical in keeping motivated to push forward so thankful to have gotten there

Big thanks to Escy for the post a few pages back on the oil pressure sender; installed today and it works.

Repost for posterity - FACET Oil Pressure Switch 7.0108 fits Audi 4.2 thread pitch and has the correct resistance for the Boxster cluster

Glad it worked for you. I didn't work it out myself, I'm just sharing information. Credit to René Jansen who's doing a V8 swap in the Netherlands, he told me.

Wrapped up my track season with another good day out there, this time on the full and outer circuits which include a very long front straight. Had cool temps and epic scenery after some recent high elevation snow. Ran 2:22 on outer and 3:28 on full on 200tw tires, car is hitting ~137 on the straight vs about 120 with stock motor.

Since last time out I threw on a new/used set of Fikse FM10s, probably 5lbs lighter per corner, and tidy'd up a bunch of interior items, made some basic door cards to cover up the bare metal and make opening/closing doors less of a task.

[IMG]<img src="https://hosting.photobucket.com/images/uu26/nbsiegal/IMG_0241.HEIC?width=960&height=720&fit=bounds" border="0" alt="IMG_0241"/>[/IMG]

Here's a short vid of some track footy passing 5 cars on the front straight (click the video title for full screen). Is it more fun than the 2.5 liter? Ya maybe a little
https://vimeo.com/634569267

Btwn now and the spring I plan to throw on a new serp belt and hope that eases the squeal i am getting at startup, try to diag O2 sensors which don't seem to save fuel trims, maybe get on the dyno to better understand the engine power, new brakes all around (go figure, new setup eats brakes a little quicker), and work on a better engine cover solution to cut down on cabin fumes. And keep working on this nut behind the wheel.

Great video! Keeps me motivated to make progress and get mine back on the road. You were really picking up speed on that straight. I love it.

Hey crew,

I’ve recently got my 2.7t swap car running and driving and I’m now in debug and cleanup mode.

Regarding instrumentation… using the Audi ecu connected directly to the Porsche powertrain CANbus, tachometer worked out of the box (Audi and Porsche use the same hex addresses and protocol for tacho). Also, I’ve been able to use an arduino to read ECT via CAN from the Audi ECU, translate, transmit, and successfully control the temp gage in the Porsche cluster.

For my 2003 Boxster… I believe CEL (solid lit and flashing status), the over temp warning light (next to the temp gage), and some others lamps/functions are controlled via CAN. Does anyone have any address data for late 986/996 that could be shared?

I searched the web and have found some limited info… but nothing that solves my problems.

I achieved some of the maintenance items over the winter and kicked some down the road a bit. I did dyno the car this spring, 322 whp 311 torque.
https://hosting.photobucket.com/imag...runShare_0.png

I've had it out on track a few times this year, with no major issues. The way that I had coolant temp spliced from the Audi ECU into the boxster cluster worked, but was not optimal. Being resistance based, it read low on the cluster and the ECU. Not in a problematic way but I wanted to improve it. I added an aftermarket sensor in the coolant pipes from engine to radiators and a gauge for monitoring. It also blocks the Check Engine light!

https://hosting.photobucket.com/imag...l/IMG_2476.jpg

Have a few more track days this summer/fall that I am looking forward to. Thinking I will add an aftermarket oil temp/pressure gauge in the next offseason.

Wow those are great numbers - a really predictable power band… and congrats on the “reliability”. It’s pretty awesome you’ve gone without major issues.

I need to get my oil temperature hooked up too. I’ve got the Audi oil sump level/temperature sensor characterized using an Arduino… just need to hook up a display/readout at this point.

What tire setup are you running and how do you like it? I’m in the market for more traction and am interested in what you’re using?

I rewatched your track video and love the sound!!

Thanks man. Love the flat torque curve.

Tires I have been running a square setup 255 40 17 Bridgestone RE71r. With those discontinued I have my eye on Falken 660s next, very similar. For a track setup I am glad to be able to rotate tires, although realistically as long as the tires are symmetrical (right to left) it would have the same benefit. Even with camber mods I end up wearing out the outer shoulders but can then switch them side to side.

I think with your setup and wanting to keep the car streetable, I'd look for a wider rear tire. I prefer 17s for the extra sidewall and lower replacement cost, but wheel options in 17x10 are limited. I think you could stuff a 10 wide and 275 or 285 back there and come close to handling 2.7t torque

Make me one of them Arduinos?!?!

For anyone looking for an Audi V8 powered Boxster, I'm selling mine as I am headed overseas.

http://986forum.com/forums/boxsters-cayman-cars-sale-wanted/82568-2003-boxster-s-audi-v8-engine.html#post648877

Priced to sell, have at least $45k into this without my time being accounted for. Half what it would cost you to build yourself.

My loss is your gain - would love to see this car go somewhere it will be raced in anger.

@specboxCO - I've never seen a picture of your car (though have appreciated your many contributions here over the years) and its funny that ours have several similarities (color, wheels, race number referencing engine, others im sure).

I'm curious how you mounted your rear wing and whether you felt that helped on track, and about the accusump setup if you care to share.

Consider sharing your for-sale ad in the "swapped porsche" facebook group, or I can for you if you don't participate over there.