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N62 Z3 Part 28: Even More Driving & Koni/H&R's

With the power steering working it felt like a whole new car... it felt like a real car

The color combo matches the tan/green colors of the desert pretty well, lol

The day after that little cruise was my birthday and the roads were a little more dry, I set out with a goal to get a sub-5 second 0-60... I drove around for about an hour doing a few runs at a few different private roads, I work in a construction related field and know of a lot of roads closed to the public where I can do runs safely. The main problem though was most of these roads were covered in dust, gravel or the road surface was just overall very poor. Meaning very poor traction... I beat it harder than I've ever beat any Z3, here are just the runs that I saved

As you can see from the last run of the day, I hit the sub-5 seconds with a 4.88. Accounting for the 1 foot rollout (how magazines review cars, for some reason) it did a very respectable 4.64 - so I was very happy with this

And the run wasn't even perfect, it definitely has a little more to give. The launch was well done in this run, but it spun a considerable amount into second. I am starting to suspect I am becoming somewhat limited by tires - I do have good sticky Yokohama Advan A052's out back, but at only 255 wide it seems the V8 torque just overwhelms them. 275 or 285 wide tires may be in my future...

I'm going to experiment a bit with getting a bit easier on the throttle when getting it into second gear to see what I can do with it as-is

Here is another run where I spun even more dramatically into second

When building the car I wasn't too concerned with 1/4 mile times or even 0-60 but now that it's finished, I am definitely interested in seeing what it is capable of. And on that note, I was talking to a friend of mine who said he would be impressed if it got into the 12's in the 1/4 mile

So, that is my next goal. I think with it setup like it is now, 12's would be very difficult as I'd have to shift three times and each shift risks losing precious seconds - but after running some calculations, it seems like a 2.93 rear diff ratio (it currently has a 3.15) would put it right around the ~108mph range at the top of third. A few sources seem to indicate that a 105mph trap speed is approximately a 12.98 quarter mile. A 2.93 diff ratio does exist that fits Z3's but it is quite expensive... if I can get away with a 3.07, that would be much better, but I'm not sure

But first is something I've sort of been putting off... and that is the struts and springs. Right now my front suspension has non-M stuff everywhere but with M strut mounts which adjust the angle of the strut. The car also sits much higher than stock (despite having springs meant for the iron block engines) and I realized after a recent drive that the outside edge of my tires is wearing. At first I thought my toe was wrong, since I did a string alignment myself. The toe seems good, but closer inspection revealed I actually have positive camber. I attribute this to the M strut mount and the raised ride height. So, I am going to tackle both of those issues at once with new non-M strut mounts as well as brand new Koni strut inserts and H&R springs

There is a slight complication to this though and that is because my front wheels don't actually fit properly. I bought them from an enthusiast advertised as fitting Z3's so I didn't check the specifications as closely as I should have, but as it ends up, the wheels poke. Pretty badly too. The offset is et30 and they really should be more like et40, they stick out about 10mm further than they should. At the raised ride height this isn't an issue. But once lowered, the tire will be rubbing straight into the hood... so I will need to address that as well

But first I had to install the Koni struts and H&R springs. These were the "cut a strut" Koni's so I had to remove the stock strut insert from the housing

I couldn't find my strut nut socket so just made one. A hex key has to go through the middle in order to counter-hold the strut shaft

Cut and removed the stock strut insert

Koni's installed!

New strut mounts arrived, stock non-M in the front and upgraded E46 M3 rear shock mounts

Rears installed first

Tire is wearing surprisingly evenly, though once lowered the camber will likely wear the inside more than the outside, as BMW's typically do. You can also see the diff mount here, I've been monitoring it and had the fender liner off as well. All looks good for the most part, though in the trunk I do see a small popped weld where I didn't observe one previously. I've marked it with the date I observed it and will monitor it to see if it propagates any further

I dropped the car and was surprised at how little it seemed to lower the car. It does seem lower than my stock M but I was expecting it to be just a little bit lower. Maybe I will need to dial it in with some different spring pads. Maybe this is just how it is... maybe it'll settle a little bit more after driving it. Below is it compared to my stock Z3M

Stock Z3M

V8 Z3

And another Z3 I own on Bilsteins (not even sure what springs, it's been years since I installed them). This is more the height I was looking for - in person, it's pretty much perfect fitment

This isn't a 1:1 comparison either due to different tire sidewall heights. They do look pretty close in person though

There's a chance I adjusted the struts wrong too but not sure if that would even make a difference here. Most people seem to prefer a half a turn from the softest setting, but my Koni's didn't come with instructions and counter-clockwise from one perspective is clockwise from another perspective. I've never had Koni's before so didn't know which way was correct. So there is a chance I did them backwards, at half a turn from the stiffest setting... when pushing down on the rear fender, it does seem like it's quite stiff

Got the fronts all finished too, these are quite a bit more work than the rears and I spent a lot of extra time cleaning everything, painting and refreshing the hardware


The front sits much lower, this height looks very nice. May need to dial the rear in with some shorter spring pads but I'm going to drive it a bit and see if it settles on it's own at all

The stock strut caps don't fit over the adjusters, but leave the bearing in the strut mount exposed to the elements so I drilled out the stock cap and put a little electric tape over the hole to cover it for now. Not the most elegant solution but it'll work for now

After a short drive the rear settled and I am quite happy with the ride height front and rear. Car is filthy though, I'll clean it sometime soon lol

I am very happy with the ride height, will need the rear fenders rolled to keep the rears from rubbing and the front I might have to trim the fender liners, but it's worth it as it looks so good

If you are wondering why I only really photograph it from the front, it's because the rear is still a work in progress

Then I picked up some new wheels

I was so excited I ended up putting them on that night and while I was pretty happy with how they looked in the front, I was really disappointed in the rear fitment. I went to bed happy, but not content

The the next morning I realized this was actually an opportunity to have even better looking wheels. Sitting this far inwards meant I could fill that space with a front lip, to give an even more aggressive look. So I went to my storage unit and grabbed all my spacers. I used to part out cars and got in the habit of keeping all the spacers from part outs so I had a lot to choose from. The lips only come in .5" increments though and my eyecrometers told me I'd need a lip 1" deeper than what I had

These spacers are all in mm so I was hoping to piece together a 25mm (.98") spacer from this batch, but as it ends up, I could only get a little over an inch or a little under an inch. I tried a few arrangements and what I liked the most was the fitment that was about 32mm. This was great news because this means I could use a 1" lip and fine tune the fitment with small spacers

Short little test drive - tires are totally shot but I am very happy with how they look

Currently working on sourcing the lips/barrels I need. The wheels came in staggered E36 M3 fitment, 17x8 and 17x8.5 with 2" lips - when I first test fit them I put the 8.5 in front to make sure it'd clear the strut and it did with room to spare. So my plan is to run the 17x8.5 in front and rebuid the 17x8 with new lips and barrels, a 3" lip and a 7" or 7.5" barrel to make for a 10" or 10.5" wheel

I hadn't done much to the car for awhile after trying on the Fikse's, but it started warming up so I wanted to get the car back out to enjoy the weather before it got too hot here. I took it out and got a more complete 1/4 mile run, hitting a 13.50 which isn't bad as previously my only 1/4 mile run I had was 14.20 after letting up very early

My 0-60 in this run was over .4 seconds slower than my best 0-60 run, my 1/8 was slower too... and I still let up early. I think low 13's are very achievable, but to break into the 12's would require pretty much a perfect run. I think the car can do it, but as a driver that's going to take some practice. My shifts are still pretty slow too particularly the 1-2 shift

Anyways, I'm in pretty good company on the leaderboards even with this run - between N/A and supercharged E46 M3's for example. I still want to work on improving it though as I know it has a bit more to give. I think two things will help - first will be adding some fuel as a weight ballast as I was pretty much on an empty tank this run. Second will be some wider rubber out back, I spin launching at a mere 1500 rpm. On that note, I think finding a better road to run on would benefit me a lot, but this road is safe for me to run on as it's a private road, but unfortunately it's near a construction site so trucks are always tracking dirt onto the road

As far as the build goes, the car is pretty much finished so not sure where to go from here. I do want to paint it someday and do some custom interior work, but it's not a priority at the moment as I am saving to buy a house. One thing I do want to work on is possibly getting the A/C working this summer so I can enjoy the car over the summer, the main obstacle for that is the fact that for some reason it doesn't seem to recognize the A/C on signal. I may work on. I do also need to finish the exhaust, but



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