N62 Z3 Part 22: More reassembly & Final touches

Yeesh. I need a bigger DME box

Bought this strut bar for a 4 cylinder Z3 on the off chance it would fit, was very happy (and surprised) that it did. I will need to do something about the CCV hose though. I am thinking I might notch the strut bar

Although not all was good news... in my excitement to attempt a test start, I forgot to install a couple grounds and this happened. I couldn't find the other backup I had so had to order another one

But that did give me some time to tidy up some other things with the car and one of the main things I wanted to tackle was the headers. I really wasn't happy with where the flanges ended up sitting once everything was installed. So I cut them off and ended up routing a new pipe which ran closer to the engine. The flange will be spliced in somewhere on this segment of pipe, with the main consideration being to ensure I can still remove the transmission with the headers in place

The main problem previously was that this flange ended up being too close to the framerail but now the clearance is very nice. I bought some brand new V-bands, I'm sure I'll repurpose the ones I chopped off for some other project in the future


After determining where to put the flange I got to work prepping and then welding the new v-band on

The main goal of the flange placement was to ensure the transmission could be removed without removing the headers and there is ample clearance to do so

I then focused on trying to get the midpipe sections oriented properly. I wanted them to be close to the transmission due to the limited clearance under the car and I also wanted both sides to be flowing straight backwards where they terminated. To accomplish this required cutting the pipes midway through and rotating them to change the output angle

The exhaust is now pointing straight back, parallel with the driveline

Then after repeating the process for the other side

Eventually I will merge these into the X-pipe you can see on the left in the below picture, but at least up until the first test drive I plan on leaving them like this

Getting the header flanges done now means I don't have to remove the engine to finish any exhaust work in the future. I am also hoping the midpipe section I started to build will save me some time when it comes to finishing the rest of the exhaust although I guess time will tell on that one


Next there is one chassis modification left... I over-corrected slightly when I relocated the steering rack and it is now hitting the oil pan very slightly. It had to be re-adjusted again, third time is a charm I suppose. I also welded the top nuts to the subframe to keep them locked in position. This is how it looks finished and with everything reinstalled

I'm kind of killing time at this point in the build... I am waiting on the secondary air system pipes. I've had them dropped off at a fabrication shop for quite awhile at this point and they haven't made much progress, so I've been doing other things such as painting the transmission output flange while waiting for them

I was going for a shadow chrome-esque finish, I think it came out fairly well


I then decided to reinstall the engine to make sure the exhaust was sitting in a good position. Looks good so I will continue to build it out from here while waiting for the SAP pipes. Most of the exhaust will be constructed of new 2.5" mild steel

Because the engine was also reinstalled I plugged everything in for a test start. This is a big milestone I have been *somewhat* avoiding because I get pretty anxious about this kind of stuff especially since last time I did this I fried a DME. I sorted that issue out but in the back of my head something was nagging me saying maybe something else was wrong from the engine rebuild. I'm always a little afraid something will go wrong when that deep in an engine even as extremely careful as I was. Well luckily, today it was smooth as butter. I have a new DME now so re-synced the DME/EWS and went to start it. Cranked, started and idled right away

A few things to sort out and the response was a little lethargic but the MAF wasn't plugged in which I expect was a contributor to that. I later plugged the MAF in, cleared adaptions and throttle was very responsive. The oil was just above the minimum mark which is why the lights came on under load

Now that everything seems good and is ready for a test drive it was time to do final preparations. First step was plugging the SAP ports


This open port was what I needed to plug, this opens into the exhaust so has been a minor exhaust leak

My original plan was to cut the SAP pipes and then weld them shut, so they'd look like below when installed. While I was eventually comfortable aluminum brazing the shift carrier, I was afraid the SAP pipe area would get too hot. The brazing rods melt at 700F and exhaust can get hotter than that. I didn't want to risk the SAP pipe getting so hot the brazing melted out and it "opened" again


An alternative along this way was to use the full length SAP pipe and a blockoff plate. However once I bought those and got them in I realized they were just way too big and cumbersome. I needed another solution

My first thought was to tap a freeze plug in there, and if needed build something I could screw into the back of the engine (where the pipe is) to keep pressure on the plug to keep it from blowing out. I wasn't able to find any freeze plugs the right size so kept thinking


Eventually I ended up tapping the port itself to be able to thread in these exhaust plugs to fill them. Looks like OE if you ask me and doesn't add any extra length out the back of the engine like the other solutions I thought of would

This has something that has been bothering me for almost the whole build and the solution ended up being a lot simpler than I anticipated


Next with the engine out was to construct the midpipe. I did not want to be crawling under the car a million times to test fit, cut, re-test fit, etc pipes a million times. So last time the engine was installed I took some careful measurements of everything and knew where the midpipe needed to go. Below is the finished product, sans a short length out the back

And installed ...pardon my messy shop lol