Porsche Boxster 986 - engine swap project

[Escy]

JordanTurbo said:

Great progress.

Love the little and large tailpipes. It's the kind of thing a proper petrol head would notice when it's parked and give a little hint that something special is inside.

Thanks, I'm glad you said that. At first glance it looks a little odd but I think a petrol head will twig the smaller one is a screamer pipe.

ikarl said:

Absolutely fan-bloody-tastic

Exactly what it should've been from the start.

Is this the only build thread, or have you a more detailed one?

I've got one running on the Audi SRS and Boxa.net forums but the content is pretty much the same. Is there anything specific you want me to be more detailed on?

[Zombie]

Escy said:

I did look at that one but I've gone for a Zeitronix ZT-2. I like the fact it can display everything in one display. EGT, AFR, Boost, charge cooler water temp, IAT, etc. It means I don't need to have loads of gauges inside the car which it's the look i'm going for, I thought it might cheapen the interior with gauges all over the place.

I have to say i'm a little disappointed with the LCD display, I think it's been out for years and it looks it, it's the same height as a din slot which means I couldn't recess it in nicely into a spare din slot, the cable comes out the side so it can't be hidden and there is no provision for mounting it which means it's a velcro job. It's a shame they don't update it with something smaller than can easily be recessed, I could have made a slicker job of fitting it. I do like the fact it uses an RJ11 plug for the wiring (small broadband style plug), it means I can mount the main unit in the rear boot and make the wiring easy and just run a small cable through the car to the dash for the display.

The interior in this picture is a big bogging, a cat has been spending time inside it.

Edited by Escy on Wednesday 6th July 22:45

Ha! Our cat (a bengal) is the same. Any excuse to climb in and investigate and he's there... There might be something to kill after all.

It's definitely a much neater install and the ability to display more than AFR is a distinct advantage. I've never looked into it in any real detail but I was always impressed with this install by one of the Alfa guys;

http://www.alfaowner.com/Forum/ice-andamp-blueanda...

There's a fault code diagnostic program for FIAT products that has morphed into Multi ECU scan. The OP developed the output, which was a standard line graph, into an infinitely configureable dial display;

[Escy]

Zeitronix offer something similar to that. I don't think it'd really suit the 986 interior, the basic LCD display i've got is quite understated in comparison. http://www.zeitronix.com/Products/dashdaq/dashdaq....

[Zombie]

Escy said:

Zeitronix offer something similar to that. I don't think it'd really suit the 986 interior, the basic LCD display i've got is quite understated in comparison. http://www.zeitronix.com/Products/dashdaq/dashdaq....

Aw christ! Don't! I'm supposed to be buying a house!!!

• Thinks of the colin chapman mantra*

[marky911]

Awesome project!!
Glad I've arrived late to the thread as it means I don't have long to wait to see the finished article. Top work!!

[ikarl]

Escy said:

I've got one running on the Audi SRS and Boxa.net forums but the content is pretty much the same. Is there anything specific you want me to be more detailed on?

nothing specific, I'm just surprised I've never read of many other swaps for the Boxster as the engine is what puts me off.

I wouldn't be surprised if other people wanted to copy your project - it looks just so... "right"

Hope you don't mind me asking, but how much do you reckon you've spent so far? (if you want to ignore this question, totally cool)

[M3ax]

What does the screamer pipe do? Apologies in advance for what could be a bumpy question...

[Fastdruid]

It's a pipe straight from the wastegate. So when on boost it's not used, when you back-off the wastegate opens and exhaust goes out the screamer as well as the normal pipe. Normally this would be fed back into the exhaust downstream of the turbo.

[M3ax]

Fastdruid said:

It's a pipe straight from the wastegate. So when on boost it's not used, when you back-off the wastegate opens and exhaust goes out the screamer as well as the normal pipe. Normally this would be fed back into the exhaust downstream of the turbo.

Thanks for that. Love these build threads. Especially this one.

[MaximumD]

M3ax said:

Fastdruid said:

It's a pipe straight from the wastegate. So when on boost it's not used, when you back-off the wastegate opens and exhaust goes out the screamer as well as the normal pipe. Normally this would be fed back into the exhaust downstream of the turbo.

Thanks for that. Love these build threads. Especially this one.

My Understanding is different to this - I believe you may be confused with the blow off valve which regulates pressure in the intake side of a turbo system (when you release the throttle usually) and bleeds to atmosphere.

Essentially the wastegate functions to bleed off excess exhaust gases to regulate boost pressure by controlling the speed of the turbine in the exhaust side of the turbo.

As a function of this the wastegate is only open at (or very near to) full boost.

This can also be used to "get around" cases where the exhaust is causing a restriction by being a bit undersized by dumping the excess gases out meaning you have better control of boost. Hence a screamer pipe also being known as a dump pipe.

[JordanTurbo]

Fastdruid said:

It's a pipe straight from the wastegate. So when on boost it's not used, when you back-off the wastegate opens and exhaust goes out the screamer as well as the normal pipe. Normally this would be fed back into the exhaust downstream of the turbo.

Not quite.

When OFF boost, the wastegate will be closed and all of the exhaust flow will be going through the turbine.

When full boost is reached the wastegate opens to bypass the turbine and prevent the turbo creating more boost pressure than is required.

A reserculation valve (or dump valve) is the one that opens when you lift off. It sits on the intake side between the turbo and throttle plate and opens to prevent the boost spiking when the throttle is initially closed.

Hope that helps

[Escy]

ikarl said:

nothing specific, I'm just surprised I've never read of many other swaps for the Boxster as the engine is what puts me off.

I wouldn't be surprised if other people wanted to copy your project - it looks just so... "right"

Hope you don't mind me asking, but how much do you reckon you've spent so far? (if you want to ignore this question, totally cool)

I'm also surprised there isn't more Boxsters with engine swaps, considering how well designed the chassis is and the fact that the original engines are failure prone and expensive when they do go.

There is a guy in the US that's been inspired by my build and he's planning on using the same engine in a 914.

As for the build cost, it's reasonable considering the i'm going to end up (hopefully) with a 550+bhp mid engine Porsche.

[Escy]

Moved onto the fuel pump. Went for the DeatschWerks DW300 (340LPH). On the Boxster the fuel pump basket has tabs on the bottom that lock it into the tank. That meant I couldn't use the pick up that came with the DW300. I was scratching my head trying to work out the best way of fitting it, I decided to hack up the old fuel pump so I could use the top and bottom sections of it. Turned out better than I thought.

[Escy]

I've turned my attention to the wiring. It took me ages working it out, both the Porsche and Audi wiring diagrams are a different style to each other which made comparisons difficult. Neither manufacturer has pin-outs for their wiring plugs and they aren't shown in one place, they are spread out throughout the various wiring diagrams which is time consuming to find. Other manufacturers list pin-outs for their various plugs, not sure why the Germans need to be so difficult? I've not retained the AC and I didn't have cruise control on my car so that's saved me some work. I've enjoyed every stage of this build except for working out the wiring, it's been a tough slog.

It's done now and i've started doing the soldering. Luckily, like I expected at the start of the project, as both cars use Bosch ECU's from the same era, lots of it is similar so there aren't really any major conflicts (famous last words). The Porsche ECU controlled the fans and the Audi one had a separate fan controller (which I didn't keep) so I need to go aftermarket but that's straightforward. Hopefully I might be able to fire it up soon.

[Escy]

It's been ages since the last update. I've been really busy doing things but not lots of progress worth taking photos of.

The engine as it currently sits no i've connected everything up. I still need to sort out the breathers. You can see a neighbor's cat quite likes sitting on it during the rain.



I've fitted the turbo oil feed and return lines, that was a load of hassle. Also made a heat shield for the return pump as it's a bit close to the exhaust.


Progress is quite slow with the wiring. I worked out how to get around the Porsche immobiliser, the alarm control unit talks to the engine ECU and needs a signal back before it'll power up the various relays to run the engine.

The Audi ECU had an immobiliser also so I needed to get that removed. Luckily my mate Adam knows his onions with computers and electronics. We had to open up the ECU, short a pin on a chip to ground and connect the battery so the ECU went into boot mode. Then we could wipe the immobiliser chip which was done using a program that required command prompt. It was all past my comfort zone so i'm lucky Adam sorted it all for me. We were running out of time but we quickly coded in the 750cc injectors and the 4 inch maf housing so at least I could have a crack at getting it running.

I spent lots of time scratching my head wondering why I couldn't get the fuel pump to prime, turned out to be a poor connection on the plug inside the tank. With that sorted I was able to try and start it up. I was turning it over and it hydraulic locked on the starter motor. Pulled the plugs and found a cylinder full of petrol. One of the (new) Bosch injectors was stuck open. The fix was to take it off and give it a love tap with the hammer.



Once that was sorted I could finally start it up. It started up but I couldn't run it for long as the revs were high and climbing. I should be happy but the fault codes logged on VAGcom will keep me busy. The serious one is the throttle isn't happy, i've worked on the assumption that as the Bosch ECU's, throttles and pedal sensors are similar and from the same generation of car that they will all work together. The wires and their functions match. I'm getting these codes

18039 - Accelerator Position Sensor (G79)
P1631 - 35-00 - Signal too High
18042 - Accelerator Position Sensor 2 (G185)
P1634 - 35-00 - Signal too High

Looking around google, these commonly seem to be linked to earthed out lambda sensor wires. If that is the case it sounds like the damaged caused to the ECU is terminal.

I've also got

17834 - EVAP Purge Valve (N80)
P1426 - 35-10 - Open Circuit - Intermittent
17938 - Camshaft Timing Adjustment
P1530 - 35-10 - Short to Ground - Intermittent
17955 - Boost Pressure Regulation Valve (N75)
P1547 - 35-10 - Short to Ground - Intermittent
17695 - Boost Pressure Control Valve (N249)
P1287 - 35-10 - Open Circuit - Intermittent

I've also seen these described as terminal to the ECU. I know what's caused them, I am trying to keep the wiring nice and tidy and logical so trying to re-use the original Porsche relays. There is a relay that controls the O2 sensors, Injectors and coils on the Porsche, i've used this feed to power up the powerbus circuit on the Audi which powers these sensors. It turns out, it's 12v with the ignition on but switches to earth when the engine is cranking. So that's how everything has ended up shorted out. I've changed the power feed but the codes come back every time the engine is cranked. I'll have to crack open the ECU and check for signs of damage.

I'm going to forget about trying to get it done before the summer is over and just take my time with it and spend more time with the family. The wiring is grinding my enthusiasm down.

Edited by Escy on Tuesday 16th August 01:47

[VerySideways]

Ecsy said:

I'm going to forget about trying to get it done before the summer is over and just take my time with it and spend more time with the family. The wiring is grinding my enthusiasm down.

Wiring will do that. Enjoy your summer!

[djdest]

Have you joined or searched on audisrs forum?
There are some very knowledgeable people on there for the B5 S4 engines and electronics

[Escy]

I'm on Audi SRS, it's a good forum. I have the same build thread running on there.

[C70R]

Escy said:

I'm going to forget about trying to get it done before the summer is over and just take my time with it and spend more time with the family. The wiring is grinding my enthusiasm down.

To your absolute credit, this is one helluva build, moreso given that it's been a largely one-man job.
However, given what an absolute pig of a job the electronics are likely to be, might this be the instance when discretion is better part of valor? Might it be worth getting in an expert/specialist to get you over this hump and renew your enthusiasm to finish off the build?

[Escy]

I'm not stuck on the wiring, just not enjoying it as much as other parts of the build. I've got around the immobilisers, it starts and runs so all the hard work has been done plus i've identified a highly possible cause for all the error codes.

It's the realisation that it won't be seeing the road this summer that's pissed on my chips.