My Forever Car: '89 325i Touring

[-J-]

Nice Touring! Been a long time since I heard the name Grattan. As a kid, used to go with dad to Porsche club events there, and caught a number of bass in the pond next to the main straight. It's a small track, but a lot of elevation changes make it trickier than one might expect. Good Memories!

Thanks! Grattan is hands down the best track in Michigan, and second only to Pitt Race as my favorite in the area (Pitt Race is basically just a faster, longer Grattan).

Very nice. In the early '90s I had a RHD '76 2002. It was really weird shifting with my left hand but getting in & out on the curb side was nice.

Shifting with the left hand (and working all radio/climate controls for that matter) is definitely weird at first. But after daily-ing this car for the past four months as a manual I find myself becoming more and more ambidextrous every day. It's kinda neat.

As a small update, the parts hoarding continues:




I also pulled the trigger on a set of Apex ARC-8's and Kamotors flares so I can have big fat tires and everything.

[moatilliatta]

Cool to see some form and function!

Subscribed!

[Poorhouse]

Great build!

[-J-]

Cool to see some form and function!

Subscribed!

Great build!

Thanks dudes!

Christmas in July continues:



Looks like I've been working with GM performance cars (who's rear tires are routinely 305 and up) a little too long when I think a ten inch rear wheel is appropriate for an E30, haha.

[-J-]

So I got married.



I went with a titanium/carbon combo because I'm a basic bitch car guy.

Planning and making decorations was a lot of work (and took away a lot of car time), but it was 100% worth it. The day was perfect and I couldn't ask for a better time.

Now that the wedding has come and gone, back to E30 work. I finally got around to installing LED headlight bulbs into smoked Depo's I've had lying around for close to five years.

I used the R4 bulbs from the Shadowline Motorsports group buy. The bulbs, while quite bright, are too long to fit with the H1 style E30 headlight housing. You can run them with the caps off, but that's jank and leaves the headlight interior exposed to the elements. I opted to drill the caps and use the included gaskets to seal them up.



The full bulb. It clearly wasn't going to fit.


Drilled and notched to allow wire connections to come out.


Gasket trimmed and installed.


The connectors here are pure chinesium. They'll be replaced with Deutsch connectors shortly.


Bulbs installed and secured. When the Deutsch connectors go in the wiring will be cleaned up further.


The result. LED bulbs aren't perfect for E30 projectors, as evidenced by the scattering above the cut line. I'll have to have someone ride in front of me and tell me whether or not I'm blinding on coming traffic.


And the aesthetic effect. The camera picks up more blue than in person, but I'm happy with the color.

[paynemw]

Awesome build man. Contemplating my purchase of a touring myself.

[wworm]

oh man oh man. Do you have any idea what the spring rates on those kw's are?

[-J-]

Awesome build man. Contemplating my purchase of a touring myself.

Do it. The practicality is nice and all but the long roof line is what really keeps me smiling every time I walk up to it.

oh man oh man. Do you have any idea what the spring rates on those kw's are?

Not yet, but I'm going to measure them with a scale pad and my shop press. I believe they're progressive though.

[AWDBOB]

Those forged spindles are an incredible step forward for the E30 world. If they did that for the M3 spindles/ackerman arms we'd be in business!

[wworm]

Do it. The practicality is nice and all but the long roof line is what really keeps me smiling every time I walk up to it.



Not yet, but I'm going to measure them with a scale pad and my shop press. I believe they're progressive though.

yeah I'm pretty sure all of their springs are progressive. Just curious really.

Love what this car is becoming btw

[-J-]

You guys.

The KWs. Are. Awesome.

The parts are very high quality and the install went smoothly, although I did find some small cosmetic knicks on the rear adjusters when I went to install. They don't affect operation though. Because I am the engineer that I am (and the fact that the KW website doesn't list the spring rates clearly) I went ahead and disassembled the fronts and measured the spring rates.


Don't mind me, just doing sketchy nerd shit

And here are the results:


Fronts at a very linear 47N/mm (268lbs-force/in) and a progressive rear with a 70N/mm (400lbs-force/in) rate at ride height.

The discrepancy in measured height and spring rate fall well within the measurement error of my jank setup so I'm confident in saying that these springs are dead nuts consistent. The sharp change in the rate profile occurs when the center coils bind, which is at roughly 35mm. From there the conical design dictates that it's a non-linear curve until coil bind, but the travel on the calipers ran out before the whole curve could be captured.

Once they were back together the old parts had to come out. The only parts going back in were the front strut mounts and rear damper mounts. Ground Control plates and mounts will go in later, but I wanted to do an A to B with the soft stock parts to eval NVH. New C-Tek front wheel bearings were used on install. No dust shields were used because I straight up forgot and my old ones were hanging on by a thread.


Ready for the new legs


Fair thee well, 200,000mile struts

Also replaced the manifold gasket and rear rubber hanger while I was under there. This is after a year of use:




Needless to say the first guess at ride height was a little low... It looked sweet but the oil pan would have become a maintenance item at that height. It was so low that the low profile jack wouldn't fit under the front frame rail, haha. Also worth noting that the front spring can sit lower depending on adjustment and a 5mm spacer was needed to prevent tire rubbing.


Oktoberfest, bitches



And here's where the setup landed. 50% cross is ideal but the suspension will definitely settle so being perfect here is irrelevant. Luckily it didn't take much work for the ride heights and cross to come in. Well, way less work than the Spec Miata at least... Rake was set to near-stock level. The rear toe is a little aggressive but it's currently not adjustable so it'll have to do. The front toe was set slightly out to compensate. Suck it, tire wear!

It's also worth noting that at a slightly higher ride height in the front there is more negative camber now. To me that says the spindles are cast at a slightly higher angle to give more negative camber without needing offset bushings or camber plates. Pretty neat. Unfortunately the camber isn't even so plates will be necessary anyway.

Onto the burning question: "how does it feel?" I'm still dialing in the damping for these shitty Michigan roads but the ride is way better right out of the box. The ride on pitted earth of US23 now feels better than stock, with a slight increase in harshness. This can be attributed to the high speed blowoff valves that allow a digressive damping curve (less stiff at higher damper speeds). This let's the dampers soak up the big bumps.

The whole chassis is way more composed than before, despite being on original 30 year-old bushings and stock mounts. The cornering confidence is also way higher, and the balance has gone away from soul-sucking understeer to just a hair loose of neutral. I can't wait to get fresh bushings in to see the improvement in response.

Every adjustment of the damping can also be immediately felt. I didn't think it'd be that apparent for 2-click adjustments, so I'm pleasantly surprised. So far I've adjusted fronts and rears down two clicks for both compression and rebound. It feels like it could use some more control in heave so I'll keep iterating.

And lastly, here's where the ride height ended up:


Nice and comfortable.

Next up are the Ground Control front camber plates and rear damper mounts.

[kronus]

nice job. you've clearly full-assed this whole thing.

It's also worth noting that at a slightly higher ride height in the front there is more negative camber now. To me that says the spindles are cast at a slightly higher angle to give more negative camber without needing offset bushings or camber plates.

FYI it's more complex than measuring static camber. There is a point in the e30 strut design where it loses camber on compression, which causes some wacky handling. You generally want to set it a decent bit higher than that point, because you want to gain camber on the outside tires in a corner to keep contact patch as the car is pitching over and compressing the outboard suspension. Otherwise it will fold the wheel over and you'll understeer more.

[-J-]

FYI it's more complex than measuring static camber. There is a point in the e30 strut design where it loses camber on compression, which causes some wacky handling. You generally want to set it a decent bit higher than that point, because you want to gain camber on the outside tires in a corner to keep contact patch as the car is pitching over and compressing the outboard suspension. Otherwise it will fold the wheel over and you'll understeer more.

Interesting, I've never heard of non-linearity like that in production Mac strut designs. Anything is possible though, and the E30 isn't without its (many) faults.

When I install the camber plates I'll do a travel sweep to measure the camber gain and report back with the data.

[-J-]

Managed to get the Ground Control plates and mounts installed last week. I went with the "Street" camber plates and "Sport" rear damper mounts. Both have polyurethane within the mounts and feel roughly like 80a hardness, which should match the rest of the bushings I picked up from Revshift.

As most have documented on this site, the Ground Control parts are pure pornography.






The install went smoothly, as expected.


To pull the strut apart I used a 1/4in deep well and the Craftsman "Max Axess" socket. I got the Craftsman set as a Christmas gift and figured it was another gimmick kit, but it quickly became my favorite socket set. It makes PITA jobs like this trivial.


Since I neglected to take an installed picture of sexy new KW spindle


FYI this is what's required to access the rear damper mounts on a Touring. That includes rebound adjustments on the KWs...

Once installed I set the front camber to -2.6 in the front and with questionable confidence in my abilities, I proceeded to drive across the state. Luckily this car is a champ and I didn't screw up, so it made the 600+ mile round trip no problem.

I only had a chance to drive on them for a week before the snow (read: salt) set in, but the NVH hit is certainly noticeable. I had to dial back the damping even more to reduce the harshness but it has a comfortably firm ride now. The most noticeable improvement, however, is to the steering response. Holy hell does this thing turn in now. As a result I've had to dial back the turn in points to my most familiar local corners. The steering precision has absolutely gone up a notch with these plates and mounts and I couldn't be happier with them. Buy Ground Control stuff. It's worth it.

[pipeuy]

Amazing build! I'd trade my coupe for a touring in a heartbeat

Do you think that KW V1 would be a good choice for a street driven car? Or should I wait till I can afford the V3 variant? Looking for good handling and somewhat of a comfortable ride since roads here are similar to what you mention.