Poor Man's Z8 Project

[JimLev]

3 steps forward and 1 backwards. It sounds like it’s missing on a few cylinders.
I’m sure you’ll figure it out.

[BimmerBreaker]

Yeah I'm not going to drive it again until I can actually get it firing properly on all 8 cylinders lol

Peeled back the wiring harness a bit and saw this on the bank 2 VANOS solenoid. I've been having errors on that bank so I suspect this may be why. I don't know if it was totally broken before I got there or not but with how brittle and cracked the wire was I imagine it wasn't a very solid connection



Repaired it by cutting the wire up to where it had some fresher, more pliable feeling insulation and then spliced in some compatible connectors I had off an M52TU engine harness. So it's keeping a little bit of it's M52TU heritage after all. Also very glad BMW did not use some weird proprietary plug here



Installed the proper lock washer on the pedal linkage too, so if I do get to a test drive again any time soon the linkage won't separate and leave me with no gas pedal
Really eager to fire it tomorrow and see if she idles any better with the VANOS wiring repaired

[George Hill]

Is your temp sensor fault the outside temp sensor, the one you use to display the temp in the instrument cluster? Some cars will definitely throw a fault for an issue with those.

[BimmerBreaker]

I added on an ambient air temp sensor but am still getting that code. I'm not sure why, also not sure if its part of the issue

https://static.wixstatic.com/media/d...a7e65~mv2.webp

I've moved past that a bit though, as I am currently suspecting other things after fixing a few of the running issues. This is where I'm at now



No more VANOS codes, throttle is much better but still a little laggy. I was getting misfires repeatedly on a few cylinders and inspected those and after re-seating the coils it got a little better. It makes me think the coils may be part of the issue, the new ones I installed are a newer "upgraded" design which a few of the reviews said don't seat properly. Might throw the old coils on to at least rule them out

It also looks like the alternator may not be charging properly - or at least the DME doesn't seem to think it is as it is throwing a "Generator" engine error now. The battery maintains a charge but runs under voltage when the engine is on (ie. it will idle forever, and it will always restart after running, but it is below 13.8V when running - fluctuating closer to 12v). It idles ok ok but once I rev it and ask the engine to start coilpacking, DIVA'ing and Valvetronic'ing, maybe it's sucking the battery juice out faster than the alternator can shove it back in and it can't supply enough voltage for everything and I'm beginning to wonder if that's at least part of why it feels a little sluggish. I'm not entirely sure but I have room for a bigger battery in the trunk so I'm gonna try that and see if it helps at all

I'm also thinking it may be time to upgrade the fuel pump too... not that I suspect it's part of the current issues but it would be nice to not worry about fuel starvation in the future

[BimmerBreaker]

With a new voltage regulator installed it hasn't misfired once... took it around the neighborhood earlier on a little shakedown run. It's a lot of fun and upon my return there were no engine codes or anything weird, everything feels pretty good. A thing here or there looks like it'll need some tweaking but it felt great to drive. Hopped back in and took it down the street and back to have a documented drive. Thought if I just said it happened nobody would believe me because it's April fools day



Next I am going to work on the power steering, I have some of the lines figured out - I was pretty deep into getting those mocked up awhile ago so just need to finish that up. I was a little afraid to get too into the throttle, I was only on the top 5% of the pedal... I didn't want to send it sideways on accident without power steering
I also want to finish more of the exhaust out. I need to re-do the midpipe because it is hanging too low. I was open headers in the video

[JimLev]

Those open headers sound great.
Maybe get 2 minimal mufflers, nothing that would kill all that good sound.

[BimmerBreaker]

I do like the sound but it gets very loud right now as you get on the gas. The Valvetronic means that valve lift varies from about .3 to over 9mm. At idle it's at minimum lift and thus isn't aspirating 4.4L worth of air and the exhaust is not as rowdy as a result. Under load though, the valve lift starts increasing and at max lift the exhaust will get very loud... Even just 10% throttle at 3000 rpm starts to get very loud. I like the noises it makes I just want them a bit quieter so I'm not afraid to step on it. Currently deciding between a classic style muffler or a cherrybomb. The N62 produces this insane high pitched wail with cherrybombs. Very exotic sounding

[JimLev]

Well then go Cherrybombs!

[Venom13132]

nice to see it running!

[mellostock]

Glad to see it running congratulations

[BimmerBreaker]

Thanks guys!

And Jim, if you liked the exhaust note before... I think you are gonna dig this... (I sure as heck do!)



This is just with the midpipe on, X pipe and resonators. I don't want to change the exhaust note too much from here, I really like it. Has that sort of "exotic" note to it. I just want it a tad quieter, I'd like to be able to leave my neighborhood at night without waking up all the neighbors haha

ch-ch-ch-ch-ch-cherrybomb!

[JimLev]

Sound perfect. Just keep it under 2K when you leave the hood.
That 6500 shift was music to my ears.

[BimmerBreaker]

Sound perfect. Just keep it under 2K when you leave the hood.
That 6500 shift was music to my ears.

It's louder in person than the videos suggest lol, especially when the engine is cold. It calms down quite a bit once it gets up to temp though


Dang wind noise... I just can't seem to get a decent video can I...

[JimLev]

Sounds great. That’s probably what guys are looking for when they swap mufflers but aren’t going to get anywhere close to your sound.
What’s up with the steering wheel being upside down? By design?

[BimmerBreaker]

Sounds great. That’s probably what guys are looking for when they swap mufflers but aren’t going to get anywhere close to your sound.
What’s up with the steering wheel being upside down? By design?

Thanks! The sound of true dual exhaust is hard to beat - the N62 naturally has that "exotic" type noise to it and the free flowing exhaust and X pipe really accentuates it. I have a friend who just bought a 550i manual with a full dual exhaust and it sounds great, very similar to my Z3. Those 550i's btw are IMO the best kept secret among BMW enthusiasts... those are SO much fun to drive, so light on their feet

The steering wheel I didn't keep fully centered when I was building the custom steering rack and haven't taken the ~5 minutes it would take to flip it back the right way around. Have a 3 spoke in storage I thought I'd put on but I don't think I want to dig through there - I'll probably just flip it the right way round

The clutch master is also leaking a little bit, brake fluid light came on at the end of the drive. I need to figure out why - I suspect the supply line isn't fully seated, I'll look at that next time I work on the car as well but it doesn't seem like a big deal. If I have to replace the master I'm glad I made it easy to service! lol

[BimmerBreaker]

Just for you Jim...





And I was pretty close with my initial suspicions regarding the low brake fluid. The supply line had popped off the nipple. I oriented it in a different way and got it installed into place. Will top up the fluid before the next drive

[BimmerBreaker]

After a drive a few weeks ago I noticed the differential bushing was mangled and it was sagging at rest. Further inspection revealed the subframe bushings had cracked. These were in reasonable shape (no visible cracks or weird sagging) before I ever test drove the car so I suspect they got destroyed after the test drives...





There were no discernible issues with the trunkfloor yet so it seems the rubber bushings took the brunt of the damage...



Dropped the subframe out to replace the bushings





Also noticed a broken spring, so a fellow Z3 owner brought over some good ones he had on hand



I used solid aluminum for the subframe bushings to prevent it from being able to move which should prevent the trunkfloor/differential mount issue from occurring, or so I hope anyways. I also used a different subframe I had on hand as the one I took off the car had a bit more rust than I would have liked to see



OE rubber for the trailing arm bushings as well as differential bushing. I'm hoping this should somewhat mitigate the NVH from the solid bushings



Also took this time to install a 3.15 Torsen differential instead of the 4.27 Torsen I had in there (I thought it was a 4.10 until I took it out and saw the tag). This should allow for a lot more usability. Previously, it was zipping through gears... I could hardly enjoy the power, I spent all my time shifting lol

The manual 545i uses a 2.93 and the manual 645i a 3.23 so I am hoping the 3.15 will be appropriate for a car ~700 pounds lighter than either of those models. Worst case, I can swap to an even lower ratio if it really seems necessary but this should be way better than the 4.27

I repainted it and refreshed the differential seals/lock rings as well as filling it with some new fluid



Ready to go back in...



Applied a coating to the undercarriage out back as I had applied some in the front previously and wanted to finish off the entire undercarriage. It needs a few areas touched up but nothing major. I was running low on coating so I focussed on the areas that will be inaccessible with the assembly in place. I also masked off the area near the differential ear mount so I can monitor that area without it being covered up



May end up removing the spare tire carrier as it's quite ugly and blocking the M differential cover I also installed at this time

I also installed the DME cover at some point along the way which really cleaned up the engine bay. Once I am happy with where it is at mechanically I will focus on cosmetics including re-installing the dual intake



Just a few loose ends to tidy up such as replacing the e-brake cable, the ones I took off the car were rusted through so I bought new cables... they are already in place in the car, just need to pop the rotors off and install that end of them

More shakedown runs coming soon!

[GZilla]

Man, I almost forgot about this thread. Dude, I applaud you on your work. That is amazing and definitely something different than an LS or M62 swap. Simply stunning engineering so far. I bet when everything will be aesthetically taken care of the car will be a Mona Lisa.

[BimmerBreaker]

Man, I almost forgot about this thread. Dude, I applaud you on your work. That is amazing and definitely something different than an LS or M62 swap. Simply stunning engineering so far. I bet when everything will be aesthetically taken care of the car will be a Mona Lisa.

Thanks haha. I don't know if I'd call my cardboard engineering "stunning" but it seems to be getting the job done which is all I can really ask for



Forgot to post in here but while the rear end was out I was idling it a few times and it was still smoking so once the rear end was back in I wanted to try to sort the smoking before driving it again and ended up re-doing some valve stem seals on the bank that is smoking. Nothing seemed to be wrong and it still smoked immediately afterwards while idling which was annoying but at least now I know I can do valve cover gasket jobs with the engine in place. So pretty much any maintenance can be done with the engine installed which is great



Also one keeper got lost and I spent about 40 minutes looking for it, was a bit of a nightmare to be honest. It actually got lost twice. I found it pretty early on and flicked it out of the area it was stuck in (between the spring and part of the eccentric cam assembly) with a ziptie. Then I couldn't find where it went...

After cursing at the engine profusely didn't help I ended up using my shop vac on "blow" mode and after blowing out all under the eccentric cam area, I saw it fly out and rest on one of exhaust springs. I very carefully grabbed it with a magnet tool and breathed a sigh of relief
This keeper is the 2022 Hide and Seek Champion



Of course, I decided to rip it around afterwards and a few big puffs of smoke came out, then it was smoke-free... shoulda done that beforehand. Oh well. I still get a little puff here and there but really nothing major. It's not enough to worry me at this point. A little smoking is just part of the N62's charm



That was all a couple weeks ago - when I got home from that drive and was looking underneath to check for smoking I noticed some coolant dripping. I had previously repaired a small crack in the expansion tank with JB Weld and to it's credit it held for quite awhile...

I got a new one in the mail today, installed it and got it back out for another test drive



Here's a little glimpse of how it's moving these days...



I got to say, it's a blast with the 3.15, I can actually enjoy the engine instead of just shifting all the time! I love the feel of the rear end with the solid subframe bushings and rubber trailing arm bushings as well, completely planted but the car still has nice OE like compliance on rough roads

[JimLev]

Wow, it revs to redline pretty quick.
Whats up with that front bumper?

[BimmerBreaker]

I did some custom work to it to shave the corner markers which is why it looks a little funky, it isn't even sprayed in primer yet. The front bumper, trunk lid, rear bumper, hood side vents and side mirrors all need to be painted, I am converting to M body stuff except the hood vents which will remain non-M but will be body color. I am planning on doing them all together, cosmetics have not been a major concern up to this point but I will focus on that soon

[Laminar]

Awesome work!

[BimmerBreaker]

Thanks man


It's really hard to drive this thing slow I'll be honest. It just keeps wanting to go, go, go. Here's a pull from earlier today

[BimmerBreaker]

Since getting the dual intake back on hasn't been a major priority, I decided to paint this radiator core support because I got really sick of seeing that silver standing out like a sore thumb. I really dig how everything being black seem to really nicely accent the engine





Launched it earlier, but was very slow shifting into 2nd. Trying to nail down the best 0-60 possible, getting used to driving it hard but going to take some practice to get that perfect launch and perfect shift

Also had it on the highway a bit, it was at about 2800 RPM at 75mph, so I may end up dropping the rear diff ratio down a bit, not entirely decided at this point

[BimmerBreaker]

Finally got around to getting the dual intake back on. But the A/C condenser doesn't fit, so it had to go - not a big problem because the A/C wasn't working, but it did mean the stock aux fan no longer had anything to mount to.

I happened to have an electric fan that fit perfectly in the space, so I swapped over a harness from the Z3 so it would have the same plug as stock. I then wired in a resistor (like the stock prefacelift Z3 aux fan setup) on the low speed input to power the 2-wire fan at a lower speed when the temp switch triggers the low speed. Works perfectly so the aftermarket aux fan has both low and high speeds just like stock



Intake installed - bought a 4 foot segment of 3" diameter tube and cut it to size. It fit exactly as I envisioned it, it's nice when a plan comes together without a hitch. Only modification was trimming the 45 degree elbows to move the filters "rearwards" slightly to fit behind the bumper. I plan on adding some mounts to hold the tube in place in the near future









I plan on installing the fender liners as well as some mesh in front of the filters at the brake duct openings to protect the filters from getting damaged by rocks, but I'll take it on a few test drives like this just to get a feel for it and monitor the IAT's

Everything all together and installed, the hood closes and latches properly which is a relief lol. I also finally ordered some paint and I am excited for it to finally get here so I can paint the bumper and finally have the front end pretty much finished



I don't plan on keeping it this color forever, but at least having the car one color for now will be great