Any progress on V8 engine swap options?

[strombomb]

Looking great Escy, I can’t wait to see those rs6 turbos in action. It’s going to rip!

According to my measurements on the mock engine in the Boxster bay, the charge coolers should fit, but it will be tight for sure (the coolant fittings stick out towards the front and will be close to the front of the bay). With the air-water intercoolers, how big of a heat exchanger are you running up front? Are you satisfied with its size/capacity?

[Escy]

Originally Posted by strombomb

Looking great Escy, I can’t wait to see those rs6 turbos in action. It’s going to rip!

According to my measurements on the mock engine in the Boxster bay, the charge coolers should fit, but it will be tight for sure (the coolant fittings stick out towards the front and will be close to the front of the bay). With the air-water intercoolers, how big of a heat exchanger are you running up front? Are you satisfied with its size/capacity?

Yeah, hopefully it'll make good numbers. It's on the dyno the 13th of August but I'm not overly optimistic.

I've copied and pasted a bit on my build thread on another forum about my charge cooler radiator. It was a Chinese special, off ebay, it's large and only just fits. It's really heavy. I don't think it's particularly good at cooling. Compared to OEM stuff the core design doesn't look as good, plus it's so thick I couldn't mount it with as much angle I wanted for the air to easily escape behind it. I feel like with this stuff you are better off using OEM parts where possible, cheap aftermarket is typically ****************e.

I monitor the inlet and outlet temperatures of the coolant (pre and post turbos), I thought my system was performing quite well but since I had my engine out recently I'm not so sure. My current usage isn't ideal, it's currently about 20c ambient and I'm tuning it which means make a pull, then pull over for 5 minutes while I go through the logs making changes. The whole lot heat soaks. I've got no fan on the radiator at the front but I do turn off the pump when the car isn't under positive boost pressure or at low speed to try and stop heat soak. During a pull I'm typically seeing between 30 - 35c for the coolant entering my charge coolers, so 10-15c over ambient, not awful but I think room for improvement with a better radiator. The coolant temperature coming back from my charge coolers can go as high as 65c but there is a lag on it, during the pull it's similar numbers to the inlet temperatures (my sensors aren't that close to the coolers). It seems to show the Mercedes charge coolers are doing their job, putting heat into the coolant (the ones you are using will be more efficient than mine). Constant throttle around a track, I think this system get's overwhelmed fast but it's alright for street driving. My IAT's aren't brilliant typically around 50c at the top of a pull, did see one where I turned the boost up to 28psi which is probably past the efficiency of the turbos and saw 90c which is crazy.

Am I happy? Not really, think there is room for improvement in all aspects of my system but the gains are marginal and not worth re-doing everything for. I think the reality is air to water systems disappoint in nearly all applications I've seen. Even OEM systems over-heat and end up in reduced power modes. One thing I've looked at are systems like the interchiller which uses A/C to cool the liquid. It looks good but I think the same rules apply, you'll over heat the system with hard use, you just start from a lower base temperature.

I've got water/methanol injection (not used it properly yet), this should take care of my charge cooler shortfalls. I sometimes wonder if I'm better off with just this and ditch all the weight of the charge coolers.

--------------------------------------

I fitted the radiator up front. Everything on the 987 is slightly different so like pretty much the rest of it, I had to start again with mounting this and making brackets. One benefit of the differences are the radiator ducts on each side are smaller so I didn't need to cut them like on the 986.



The pump hidden away and mounted nice and low. After having the radiator inlets and outlets mounted on the passenger side I realised there wasn't enough space to run the coolant lines down the sides and behind the wheel arch liner/down the side of the fuel tank like it'd done before on the 986 so I had to work it out a different route.



The charge cooler tank is going to be mounted inside the front boot, there was a handy rubber blanking plug just above the radiator so the hose feeding the radiator runs through there. Then it goes through the rad, to the pump, back over the top of the rad and down the drivers side chassis rail and into the engine bay. On the way back there was another handy little blanking plug, I hadn't noticed it before as it was covered in seam sealer, the hose comes back into the front boot through that and back into the tank. I do my best to not cut holes all over the place, I'm pleased with the pipe routing.



Here is the tank mounted in the front boot. I spent a bit of time making up some brackets to raise it up and angle it slightly. I raised it as the higher it is the better in terms of any trapped air making it's way back into the tank. I angled it slightly so it looks better under the cover.





All hidden away, you'd never know.




The next big job was the tank for the meth injection. Having fitted the charge cooler tank where I initially planned to mount a meth tank I could now put the meth tank on the battery tray where the charge cooler tank was on the 986. I added in the fitting for the meth line.



My meth tank and the little race battery both fit on the battery tray. There were no mounting points on the tank so I used a battery clamp I'd bought years ago and never needed. The battery is held in place with a metal bracket. I bought another of those Battery Brain's the first one I had seemed to be playing up so I returned it. It took a bit of fiddling to get it all in place without needing to cut the battery cables which I wanted to avoid. I had to move the alarm siren to the other side where the original earth point used to be.




All hidden away. I'm happy with how it's turned out, it's been really time consuming planning where to put things and make the best use of the available space but I think it's worth the extra effort.

[1thenaton1]

^ psyched to share a page on the internet with you two.

My shakedown runs went well, no problems to report. Ahead of the first track day I sent the car in for a corner balance alignment at a well known race shop in town. On the very first lap at the track, something came loose in the suspension, the car went super squirrely and I limped it to the pits. Turns out the rear right adjustable lower control arm was left finger tight and that pulled the stud out of the inner piece, ending my day before it started. Did technically hit the track though, for 2 laps lol. Back to fixing ****************.

One thing I haven't sorted yet is oil pressure switch. The Porsche cluster expects to see a reading btwn 0.3-0.55 bar according to the sensor. The Audi oil pressure switch uses a higher resistance. Since you can't remove resistance, is anyone aware of a sensor that would fit the Audi oil pan location and run at the lower resistance? Or another creative solution to getting the oil switch to work?
I know I can just unplug it and the light will go off - seems like a good thing to have in place in case oil pressure is lost.

[Qingdao]

Originally Posted by 1thenaton1

^ psyched to share a page on the internet with you two.

My shakedown runs went well, no problems to report. Ahead of the first track day I sent the car in for a corner balance alignment at a well known race shop in town. On the very first lap at the track, something came loose in the suspension, the car went super squirrely and I limped it to the pits. Turns out the rear right adjustable lower control arm was left finger tight and that pulled the stud out of the inner piece, ending my day before it started. Did technically hit the track though, for 2 laps lol. Back to fixing ****************.

One thing I haven't sorted yet is oil pressure switch. The Porsche cluster expects to see a reading btwn 0.3-0.55 bar according to the sensor. The Audi oil pressure switch uses a higher resistance. Since you can't remove resistance, is anyone aware of a sensor that would fit the Audi oil pan location and run at the lower resistance? Or another creative solution to getting the oil switch to work?
I know I can just unplug it and the light will go off - seems like a good thing to have in place in case oil pressure is lost.

Why not use the Porsche pressure switch that came with the car?

EDIT: I see you got a different thread pitch/design. Brass adaptors, with thread sealant.

[strombomb]

I agree with Qingdao, thread adapt to use the Porsche sensor. I think I’ll go that route too.

[Escy]

I'm using this, fitted my Audi and is the right resistance for the Boxster. FACET Oil Pressure Switch 7.0108

[ike84]

escy - a couple of things about your intercooler setup.

1 - you'll notice the difference in spacing between fins on the oem and your ebay one. way bigger gaps on the cheapos. thats why theyre cheap though. not trying to criticize, just pointing that out.

2 - what boost pressure are you running? you should be able to run a setup like this up to 7-8 psi without any raise in temp above ambient. If youre running low to mid teens and only seeing +10C on your temps then I would consider this to be a success. i noticed in one post you mentioned 24psi? if youre running anywhere near that routinely then you will absolutely see intake temps rise, no matter how good of a setup (water-air or air-air) you have setup.

3 - what flow rate is your water pump? slow pumps can cripple a system like this. often underestimated how important that is.

4 - are all your data coming from stationary pulls? im assuming that youre using a big ass fan when you do that, but even still your data on the street at 100mph will be vastly different.

5 - you already figured it out but water meth will help. (beautiful work on the setup, btw) im sure you already know all the details about its pros and cons but I will say that it always makes me nervous to use it to "fix" a suboptimal setup rather than using it to "improve" an already good setup (unless, again, youre running high teens and low 20s, then its going to be almost mandatory.). what concentrations are you planning on running?

[strombomb]

Escy -

You’re spot on with using OE parts. That is the theme of my build. OE quality and reliability is definitely not always present in the aftermarket, but can be pretty cheap in the used OE part market (dismantlers). So I started by sourcing the 750i intercoolers (about $40 each)… I’ve since sourced the circulation pump from a 750i (a Pierburg CWA50 which states 25 l/min @ .53 bar back pressure for $55)… being that I’ve source these other parts from the 750i, I think I’ll also use the heat exchanger too. With that, I’ll be using the whole intercooling system from the 750i (4.4l hot vee bi-turbo) which seems like it should be ok for my measly 2.7l bi-turbo running at 18-22psi. Only difference being the distance the fluid has to travel through lines from the engine in the back of the box to the heat exchanger and reservoir in the front.



Thanks for posting the pics of your intercooler heat exchanger setup. Very helpful.

Also, at 26 psi, you should be seeing 500 hp at the rear wheels (being that the b5 S4 guys with rs6 turbos are easily seeing 450 at all wheels). I can’t wait to see how your dyno session goes. I’m sitting in the edge of my seat!

Also having now fabricated my custom exhaust manifolds, here’s a pic from below of the turbo placement of the passenger side ecoboost turbo in the bay. I really like the placement, though the stock engine bay cooling fan won’t fit, I will need to source thinner fan. Now I’m on to determining air intake and filter location. Are you satisfied with you air filter location in the bay? You have your intake filters down low right?

[Escy]

I also really like you turbo placement. Would have done similar myself if I had a bit more skills (happy to modify a manifold but wouldn't like to make them from scratch).

I should see 500 at the wheels in theory but I'm not holding my breath. Will find out soon. It didn't make the power I expected last time.

Air filter placement has been an issue all along. I did have them low mounted in a few places but they get soaked when it rains. I've recently moved them up to the side vents, one per side. Should be colder air there plus they sound great with the windows down. The downside is, I have no engine compartment fan at all. This isn't something I'm too happy about, I'd like one but can't find a spot to put one that'll do any good. Airflow through the engine compartment is the real achilles heal of this platform.

[Qingdao]

Originally Posted by Escy

I also really like you turbo placement. Would have done similar myself if I had a bit more skills (happy to modify a manifold but wouldn't like to make them from scratch).

I should see 500 at the wheels in theory but I'm not holding my breath. Will find out soon. It didn't make the power I expected last time.

Air filter placement has been an issue all along. I did have them low mounted in a few places but they get soaked when it rains. I've recently moved them up to the side vents, one per side. Should be colder air there plus they sound great with the windows down. The downside is, I have no engine compartment fan at all. This isn't something I'm too happy about, I'd like one but can't find a spot to put one that'll do any good. Airflow through the engine compartment is the real achilles heal of this platform.

I got air flow for days.... I just don't put the cover back over the engine.

[Escy]

Originally Posted by strombomb

Also, at 26 psi, you should be seeing 500 hp at the rear wheels (being that the b5 S4 guys with rs6 turbos are easily seeing 450 at all wheels). I can’t wait to see how your dyno session goes. I’m sitting in the edge of my seat!

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.

[strombomb]

I hear you! I have lost a lot of sleep trying to figure out how to get air into the engine bay. I’m currently considering putting a high output 6” fan (maybe two?) in between bay and trunk, pulling from the trunk blowing into the engine bay… then maybe having some sort of vent to allow air to be pulled into the trunk. Idk. I will probably talk myself out of that too haha.

I’ll run 2x MAF’s (2x 1.8t units and read them in with Arduino and feed out a single signal to the ecu) and place cone filters right inside the side vents (symmetric). Like the UK, it rains A LOT here in Oregon, so I don’t like having low filters either.

[Escy]

Originally Posted by strombomb

I hear you! I have lost a lot of sleep trying to figure out how to get air into the engine bay. I’m currently considering putting a high output 6” fan (maybe two?) in between bay and trunk, pulling from the trunk blowing into the engine bay… then maybe having some sort of vent to allow air to be pulled into the trunk. Idk. I will probably talk myself out of that too haha.

I’ll run 2x MAF’s (2x 1.8t units and read them in with Arduino and feed out a single signal to the ecu) and place cone filters right inside the side vents (symmetric). Like the UK, it rains A LOT here in Oregon, so I don’t like having low filters either.

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.

[strombomb]

I like it!!

[strombomb]

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.

[ike84]

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.

Sent from my SM-G970U1 using Tapatalk

[strombomb]

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?

[strombomb]

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!

[ike84]

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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[strombomb]

Originally Posted by ike84

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.



Sent from my SM-G970U1 using Tapatalk

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