URS6 Build

[coultl]

I reused the in tank lines and I agree, it’s probably a good idea to replace those. Especially since I will run some E85. I’ll add that to the list!

I’d like to also replace the soft lines going from the sender to the hard lines under the car. Then I’d have all new soft lines…but those might be impossible unless I drop the tank. Not doing that right now.

[coultl]

Quick update. I installed the external Aeromotive FPR and relocated the fuel pressure sensor onto the FPR. The new FPR does keep the fuel pressure a very constant 4 bar over MAP. The stock FPR was over pressure at idle and low throttle positions. That can be accounted for in the tune but it's nice to have a properly sized FPR. I also installed the flex fuel sensor which will allow me to run E85 in the future and it also gives me fuel temp.

The install was pretty straightforward. I could have made things cleaner if I messed with the factory hard lines but I wanted to keep those in place. The FPR is held in place by a zip tie right not but I'll make a mount soon. The FPR delete / blockoff is from Ebay. Marketed for BMW but it's the same FPR our cars use.

I'm not sure if this will help my vapor in the return line issue, but I suspect it wont. It's been a little cooler here and the fuel is maxing out at about 45C. The issue only occurs when the fuel is really warmed up.

Still working on the tune and making progress. Just trying to make sure I'm not knocking! Monitoring the knock sensors closely, but I think I'll build an audio knock system to make sure. Pulling the plug and see no sign of knock. Plugs are new and cylinder #2 is getting dark faster than the others. Not sure what the deal is with that...but compression is strong across all cylinders.

[coultl]

Below is my current timing table. I'm still running the stock K24. The idea is to get a decent tune in place and get familiar with things before I do the engine rebuild and big turbo. All parts are in hand, I'd just rather learn before going full on. I'm slowing upping the boost and right now I'm peaking at at 225 kpa.

[macof]

Hi, plase can you share your knock settings?

[coultl]

My knock settings are below. I have only run up to about 250 kpa of boost and I'm still working on it, so only use this as a base. It's not all dialed in! That said, I've done some work and it's getting close. Next up I'm going to build an audio knock detection system so I can listen for knock. That's supposed to be a much consistent way to spot knock. Hopefully the when I hear knock I'll also see it on the knock sensors, so I can trust that they able to pick it up consistently.

[macof]

Thanks for sharing your settings, after installing the ECU on my car i will test it with knockbox

[coultl]

Quick update. The car is running well with the ECU Master Black and the videos from Evan's Performance have been a huge help to getting the tuning right.

I'd really like avoid throwing a rod through the block so I've been spending time getting the knock sensing right. I wanted to add an extra knock sensor for audio knock detection. I first tried just stacking a flat response Bosch sensor on top of the stock sensor (also a Bosch flat response sensor). Tightened it down to spec (20nm) and...it didn't work. For some reason the stock senser picks up way more noise when you stack another sensor on top it. I figured it would do the opposite. It made the signal coming into the ECU too far off to be useful.

I ended up adding the sensor to the M8 boss on the block just above the crankcase vent. The block in the attached photo (not mine) actually has a knock sensor bolted up to this boss. That's not the correct location for the knock sensor...at least it's not correct for an S6. The correct location for the second knock sensor closer to the top of the block. It's the boss to the upper left of where they have the knock sensor installed. At any rate, the boss near the crank vent works great for the audio detection.

I am not using an audio knock tool of any kind. I just wired the sensor up to a headphone jack in the glovebox. I can hear it in headphones, but a cheap headphone amp makes it much louder. I spend an hour driving and learning the engine sounds during normal driving. I get a little knock at about 80 kpa and 3200 rpm. It's not bad, but I could hear it! Not louder but more of harsh sound. Like others have said, almost like shaking a glass jar with a few ball bearings in it. Now, hopefully I can hear it when the engine is at 7500 rpm!

[newsh]

I ended up adding the sensor to the M8 boss on the block just above the crankcase vent. The block in the attached photo (not mine) actually has a knock sensor bolted up to this boss. That's not the correct location for the knock sensor...at least it's not correct for an S6. The correct location for the second knock sensor closer to the top of the block. It's the boss to the upper left of where they have the knock sensor installed. At any rate, the boss near the crank vent works great for the audio detection.

Yes, up and left is the correct position for the rear knock sensor.
I must have seen that pic a 1000 times and never noticed that knock sensor bolted in the wrong position!

[coultl]

Making progress on the tune and added E85 maps. Seems to run well on E85 so far but I have not pushed the timing as much I probably can.

My driveshaft center support was worn and intermittently making a bunch of noise under high torque. I figured I should get that sorted before I pull the engine and up the power. Pulled the exhaust and drive shaft yesterday. Replaced both CV joints (boots were fine). As I've seen posted elsewhere, the front CV joint was very dry. The rear had grease but not much.

Then I cut off the old center support and installed a JXB center support. Nice piece of hardware and very thankful that I didn't have to break the driveshaft apart. I got the "street" stiffness rubber with the kit and it feel pretty soft. I'll report on how it all feels/sounds once I get the car back out.

While I was in there I also replaced the parking brake cables. It's such a ****** job that I just wanted to get it done while everything was out of the way. When pulling one of the old cables out it broke in half...totally rusted. They were not sticking, but I guess a failure was coming. Glad I got that done.

Next up is replacing the cat with a 3" Gesi G-Sport. The previous owner put in a EPA reg cat to pass emissions but it's not sized for any kind of power.

[coultl]

Quick update. The new Gesi cat when in today, ran new fuel lines in the tank, and finally took it for a drive.

The pics below show the new cat pipe vs the old one. The old cat was EPA approved making it expensive and restrictive. It was also a 2.5" and not 3" like the rest of the exhaust. The v-band threads stripped when I removed them. Common issue with stainless bolts so make sure you use anti-seize. My welds are not great, but they will work.

To try to resolve my air in the return line issue I installed new 5/16" submersible (and E85 compatible) fuel lines in the tank. I also added a small blocker in the fuel basket to try to keep any air in the return line from getting to the bottom of the basket. I don't think there was anything wrong with the old lines and I'll still have vapor in my return line when the fuel gets up to 50 C or so. I think it's normal and I probably would have never known it was happening if I didn't do all my early testing on very hot days.

Finally, the driveshaft with the GXB support feels great on the road. The old driveshaft was clunking so much that it feels like a new car now. So smooth! Huge upgrade.

[coultl]

Quick update. I've been wrapping up a few things before I pull the engine for the rebuild. Some recent work on the car:

- I switched to R8 coils but I'm still getting misfire around 4k RPMs. The strange thing is that more dwell only makes it worse. It's nearly gone when I drop the dwell down to 1.2ms @ 13V, which is very low for these coils. Something is going on there and I'm trying to troubleshoot it. Running FR5DTC plugs, AFR is ~12, peak boost is just over 20psi...pushing the stock turbo about as hard I think I should. Any ideas? Could there be an issue in the factory wiring that's causing voltage drop? Really strange bc there is zero misfires at high RPM. It's only around 4k RPM. This is really the last part of the tune that has me scratching my head...

- I installed a oil pressure sensor so I could get a decent baseline for oil pressure before doing the engine rebuild. Good piece of mind also to have the ECU setup to kill the engine if oil pressure drops too low.

- I keep adding in updates to the tuning file, dialing in a lot of things. It's getting there! More recent file here: https://www.dropbox.com/s/eqll942g91...3-22.emub?dl=0

- I have a 6 speed 01E from a 2.7T A6 on the way. That will go in when the engine is rebuilt.

- Found a great set of carbon interior trim on eBay and it looks killer in the car. Must add at least 20hp...

[coultl]

Almost forgot. I also installed the 034 short shift kit. I am so surprised at how much better it feels. Night and day from the mushy thing it was before. A few notes from the install:

- The spring that comes with the kit is too soft and it makes it feel like I'm going to go into reverse instead of 1st by accident. I put the factory spring back in and it's way better. I then added a 10mm 3d printed spacer and it's ever more stiff now. Better in my opinion.

- I saw others say that you don't need to remove the center dash and console. I did and I'm glad. Makes it much easer...less swearing. In removing the center dash, there are bolts hiding behind the center vents that I missed. Lucky I didn't break things...

- The kit says that the OEM retaining ring might not go back in. It does if you're careful getting it out.

- I can clearly feel I have some front to back slop in the bushings that connect the lever to the trans now, but that will get fixed when I pull the engine. I think that's a known issue. Anyone have info on what breaks down there and how to fix it?

- All in all, a great upgrade. Exceeded my expectations.

[coultl]

Quick update...

ECU tuning:

- I was getting a misfire at about 4k and spark dwell didn't fix it. After a lot of messing around it's related to the trigger setup. I fixed (I think) through changing some settings and it pulled great with zero misses. Felt great. With that I had things sorted enough to bring the next phase of pulling the rebuilding the engine for the bigger turbo.

Pulling Engine:

- So far it's a whole lot easier than pulling the engine on my B7 S4. That was such a beast with zero room to work.
- The front clip came off easily. No issues there.
- I couldn't get the viscous fan off and I couldn't even find a straight answer online if it's normal or reverse thread. I was horrified to see someone sawzall it off in another post....then I did the same after an hour of messing with it. I'm installing an electric can so didn't plan to reuse anyhow.
- Something I've never seen before, but the turbo impeller is bent. You can clearly see some of the leading edges are bent up in the photo. No sure how that happened. That turbo is getting pushed so hard, can't believe it didn't just fully fail.
- I'd like to replace the rotors on my 2Bennett kit but I'm guessing it will cost $$$ to get from them...and they won't answer my emails. Anyone have an idea of where these came from? Looked up the part number on the pads and they are from a Cayenne Turbo. No part number on the rotors.
- Need to do other stuff, but hoping to get the engine out next weekend.

[coultl]

more photos

[coultl]

Progress…