Any progress on V8 engine swap options?

[Quadcammer]

to bring this up, I've had a hard time finding decent audi v8s in my area. One engine that appears quite similar that has come up is the VW phaeton 4.2 v8, which I have to assume has the same bolt pattern and size as the audi v8, which I'm guessing is mostly identical. There are low mile versions of these motors for cheap and they make 330bhp

Any insight about this motor would be great.

thanks!

[ike84]

Originally Posted by Quadcammer

to bring this up, I've had a hard time finding decent audi v8s in my area. One engine that appears quite similar that has come up is the VW phaeton 4.2 v8, which I have to assume has the same bolt pattern and size as the audi v8, which I'm guessing is mostly identical. There are low mile versions of these motors for cheap and they make 330bhp

Any insight about this motor would be great.

thanks!

There are subtle differences between the audis and vw V8s, mostly in the internals if I recall correctly. You can find detailed factory manuals on both of them to read more (it's been a while since I've looked at them but I don't recall the specifics). One thing to definitely look at though is whether it is an fsi generation - if it is, it becomes much more difficult of a build because these require factory harness and ecu's to run (unless you are going to run motronic, which is hella expensive). This then complicates other issues such as transmission(phaetons weren't offered in a manual) and other peripherals (factor MAF, sensors, etc). The ecus can be modified (nefmoto is an entire community dedicated to this) but be prepared to dive balls deep if you want any chance of doing it right.

Disclaimer - I don't have any direct experience with these motors. This is just what I learned in researching the swaps a few months back.

Sent from my POCOPHONE F1 using Tapatalk

[Quadcammer]

Originally Posted by ike84

There are subtle differences between the audis and vw V8s, mostly in the internals if I recall correctly. You can find detailed factory manuals on both of them to read more (it's been a while since I've looked at them but I don't recall the specifics). One thing to definitely look at though is whether it is an fsi generation - if it is, it becomes much more difficult of a build because these require factory harness and ecu's to run (unless you are going to run motronic, which is hella expensive). This then complicates other issues such as transmission(phaetons weren't offered in a manual) and other peripherals (factor MAF, sensors, etc). The ecus can be modified (nefmoto is an entire community dedicated to this) but be prepared to dive balls deep if you want any chance of doing it right.

Disclaimer - I don't have any direct experience with these motors. This is just what I learned in researching the swaps a few months back.

Sent from my POCOPHONE F1 using Tapatalk

Thanks. This is not the fsi motor, i believe its a standard 40v audi unit with the me7.1.1 computer. Not sure about the intake srage count but i understand the tranny should bolt up. Not sure where people are finding good cheap audi motors.

[ike84]

Originally Posted by Quadcammer

Thanks. This is not the fsi motor, i believe its a standard 40v audi unit with the me7.1.1 computer. Not sure about the intake srage count but i understand the tranny should bolt up. Not sure where people are finding good cheap audi motors.

The audis are coming from eBay. An ABZ can be found for$500-600 pretty easily.

Btw, the main drawback of the 40v was the chain tensioner system for the timing chain. As with our ims, they are the achilles heel of the motor. They are an expensive fix though, even with the motor already out of the car.

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[Quadcammer]

Originally Posted by ike84

The audis are coming from eBay. An ABZ can be found for$500-600 pretty easily.

Btw, the main drawback of the 40v was the chain tensioner system for the timing chain. As with our ims, they are the achilles heel of the motor. They are an expensive fix though, even with the motor already out of the car.

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This is a belt driven 40v.

My plan, thus far is this:

TI dave cradle
phaeton V8
2001 A6 ECU with Immo off and s6 tune
Stock motronic for dash only
986 5 speed with drilled vss hole and 2mm spacer
No AC and electric powersteering.

Since I have a 99, I'm wondering what to do about my return style fuel system? I guess I could just run the feed line and cap the return near the tank?

Also, the 40v come with this goofy built in oil/coolant heat exchanger/oil filter thing. I'd like to delete that mess and just run an external oil cooler and filter. Anybody tackle that? Doesn't seem to be an off the shelf solution for the later v8s.

Thanks all. I'm getting more amped about this project.

[truegearhead]

I posted this on an Audi forum with no luck and can't find the info any where else. Long shot on this thread but do any of you Audi V8 guys know where the Audi brake booster vacuum port is on the intake manifold?

[1thenaton1]

Got mine started!

Having some trouble getting the tach sorted. My car is a '98 so no CAN. Can anyone confirm where the cluster gets tach signal? My notes say pin 15.

I have the Bosch crank position sensor sending info to this spot but it's not moving the tach. Anyone dealt with this successfully?

Thanks

[78F350]

I'm pretty sure that the tach signal is not from the sensor, but converted within the ECU. On the 7.2 ECU it is, but I don't have any reference handy for a '98/2.5L harness. There was some discussion with the LS swaps between John and VLad using a converter. Some of that is here: V8 Conversion

If I remember and have time, I'll track it down for you.

[78F350]

From the 986 Factory Service Manual, Audi A6 (C5) Bentley and a few old spreadsheets I made, here's a simplified diagram:


That's from the 1998 Boxster and 40 valve AWN engine A6. The 32 valve V8s will have a different ECM pinout, but I have that filed somewhere too if it's needed.
That same signal should also be run to pin 9 of the OBD port.

I have not tried it yet. I'm curious if the signal output by the Audi ECM is identical to the one put out by the Boxster's DME. I expect that it will work and not make smoke come out of the cluster.

[1thenaton1]

Thanks so much for that info. Your link above sent me in the direction of signal modifiers for tachs and think that may be the ticket, using the signal at a coil pack translated into what the cluster needs to see for RPM.

The Audi ECU that I'm running (2002 S8) sends tach signal to its cluster by CAN, and the 98 Porsche cluster does not use CAN.
[addit] Sending the Audi ECU signal (CAN) to the newer 986 cluster works straight away, confirmed by others using newer 986s for the swap. I am next going to try a tach adapter to see if I can match what the older 986 cluster expects to see for tach signal [addit]

I'll post after giving this a shot. Cheers

[strombomb]

Originally Posted by 1thenaton1

Thanks so much for that info. Your link above sent me in the direction of signal modifiers for tachs and think that may be the ticket, using the signal at a coil pack translated into what the cluster needs to see for RPM.



The Audi ECU that I'm running (2002 S8) sends tach signal to its cluster by CAN, and the 98 Porsche cluster does not use CAN.

[addit] Sending the Audi ECU signal (CAN) to the newer 986 cluster works straight away, confirmed by others using newer 986s for the swap. I am next going to try a tach adapter to see if I can match what the older 986 cluster expects to see for tach signal [addit]



I'll post after giving this a shot. Cheers

There is also some good info here (link below) regarding providing an early 986 cluster with usable speedo & tach signals.



http://914world.com/bbs2/index.php?showtopic=240315



I’m in the process of putting an Audi 2.7t into a late 986 (with CAN). On my bench setup with a spare cluster, I’ve got engine coolant temp, speedo, and tach working over CAN... but can’t yet control warning lights (CEL, coolant alarms, low fuel, etc). This info is out there for 987/997, but I can’t find anything that works for 986/996. Does anyone have info on controlling the various warning lamps via CAN on the 986/996 cluster?



Also, here’s a pic to keep the thread interesting. For anyone familiar with Audi 2.7t, this should raise some eyebrows.

[1thenaton1]

Thanks Strombomb for that link. I'd actually also stumbled on that page and think it explains why my recent attempt at using tach-adapt did not bear fruit - The early boxster cluster tach being powered and essentially wanting a pulsed ground signal. I am looking for a tach adapter that will provide that kind of signal modification.

But for now, I drove the car home! A joyous and maybe frightening experience but made it.

As a stop gap I am using Torque app to monitor RPM and coolant temp. It's not a great long term solution so will continue trying to figure out this tach, or maybe add a aftermarket physical gauge.

[1thenaton1]

Mine is up and running, though still working out plenty of kinks before she is track ready. Still workin on tach with a Dakota Digital tach adapter, need to wire coolant temp to the cluster, and having some trouble getting good O2 sensor readings for some reason. Spending lots of time correcting sloppy work from the shop that mounted the engine. In retrospect I would say this is a much better project to DIY than depend on any third party, ymmv

[Escy]

Yeah, I did notice the larger spacing on the fins compared to good OEM radiators. Would go with something else if I was to do it all again but finding something that fits in the space is hard. Bought it 3 years ago, there's more options now (electric and hybrid cars have good auxiliary radiators). My water pump is a Davies Craig EPB40, I think it's considered a decent pump, it wasn't cheap (although looks it). It's 40 litres per hour.

I'm running 50/50 water methanol (capacity rather than weight). Boost wise, actuator base pressure is around 10psi. Currently up to 26psi while testing although not sure I'll run this much in the end, depends on the power it makes on the dyno.

All my data is coming from pulls on the street. The last time I was on the dyno I found things actually stayed cooler as in-between pulls the fan was cooling the charge cooler system. On the street I stop to make adjustments and it all heat soaks.

[strombomb]

1thenaton1 - what sort of exhaust layout do you have? Any pics from the bottom of the car? I’ve been racking my brain to figure out how to incorporate a crossover but haven’t come up with anything very good.

[1thenaton1]

Exhaust is one thing the shop did a very nice job on. I provided them with downpipe flanges (from a 2.8, they are the same) to mount to the manifolds and they welded custom pipes to a set of mufflers another customer had taken off his car, 718 cayman I believe. Here's an in process pic before it was finished and wrapped, so you can see the approx routing.


What turbo setup are you thinking of on your 2.7? I saw your tease picture but couldn't make out what it was, some newfangled electric assist no doubt

[1thenaton1]

Was able to get the tach going with the help of Dakota Digital. The standard settings would not work, regardless of if we used engine speed sensor, coil, or injector pulse, but with their help we were able to get a workaround in place. Posting it here in case it can help anyone in the future getting their early non-CAN 986/996 tach working.

Using the SGI-100BT, we tapped into the Diesel input, and selected Flywheel. The TTV flywheel I and others have used is 58 teeth, and with that info the converter was able to send an accurate signal to the tach from the engine speed sensor. Other settings were low voltage and original engine cylinder number was 6 as expected.

On to some shakedown runs ahead of end of July track day.

[Gilles]

Cool, congratulations!

PS: I miss my white faced gauges..

[strombomb]

Glad to see the tach working, great job! Do you have everything else in the cluster worked out? I’ve got grand ideas about getting the oil level readout working, but that’s low on the list. Let us know what you run into in shaking out the box before your track day.

For my 2.7t, I’m going a direction I haven’t seen anyone take before (due to spatial constraints in the Audi engine bay)… I’m starting with OE 2011-12 f150 (3.5L) ecoboost turbos mounted tight to the cylinder head. They are k03 frame, but nearly RS4 k04 wheel spec with billet compressor wheel - there’s good aftermarket support to go bigger later on. Also, recirculation valve is integrated into the compressor housing which is great for packaging. For intercooling, I’m using OE BMW 4.4l turbo units mounted to the timing belt covers - directly between turbos and throttle body. The whole build is focused on using OE parts that are readily available. With these turbos and the tight layout, this setup should rip between 2-6k rpm. I’ve currently got the drivers side fab’d up and am transitioning over to the passenger side next.

Also, looks like the pic of your exhaust broke; can you fix it?

[Escy]

Impressive packaging on your 2.7t. Those charge coolers will be a tight squeeze. Interesting choice on the turbos. Interested to see how you get on, post updates.

Here is mine.