Giving the ZHP 330i some much needed TLC.
Having an actual daily driver is both refreshing and irritating. On the one hand it’s nice to have to have a car you can just hop in and use, but on the other hand it means demonstrating self control to not go completely ham on modifications that add more “fizz” behind the wheel. After a solid year of driving the ZHP e46, it was time to address several items that were making the car feel a little tired—along with its driver.
Tickets to Koni Island
With over 100k miles on the clock, I knew the stock suspension was on borrowed time. Not wanting to go overboard with coilovers, replacement struts and shocks were in my future. Once my eyes were glazed over from reading forums and various product reviews, I decided to give the Koni Active line (formerly FSD) a shot.
The selling point with the Koni Active is that they are cushy over rough roads, while firming up when you want to hammer the car through a corner. Unlike the ubiquitous Koni Sport, the Active shocks are non-adjustable, so you install them and that’s it. In the E46 application they are also offered with the option to use Eibach lowering springs, but I opted to stick with the stock ZHP springs since they’re plenty stiff for a stock setup, and the car can barely clear the arms of the lift as is.
The rears install easily just like most BMW of the era. The only deviation I made here was adding some leftover Rogue Engineering rear shock mounts that utilize a reinforcement plate with exterior accessible hardware. This eliminates the need to remove the trunk liner when installing the shocks.
Replacing the front struts was a little more fiddly. The main hiccup with the E46 front strut replacement is that it takes some careful maneuvering to clear the strut assembly from the knuckle. With the factory sport suspension there’s just enough room to swing the assembled strut out of the wheel well, but on some cars it may require popping control arm or tie rod ball joints to give more suspension droop angle (I can confirm this as true on the e46 M3 models after a similar install). A good “while you’re there” addition is the tower reinforcement plates. These sandwich plates slide over the mount to add an extra layer of metal to the towers so you don’t have to cry the next time you hit a pothole and worry that you’ve mushroomed the strut tower.
Not wanting to repeat this job, I also installed fresh strut mount bearings and front sway bar endlinks. Something to note is that the e46 stock style springs have a specific orientation where the end of the coil sits relative to the spring perch. The easy way to keep track of this is to mark where the stock spring sits on the rubber spring pad before swapping parts over to the new struts.
Weldy Wonderland
Less than five minutes searching e46 problems on the internet will leave you scared that the rear suspension will eject itself from the car while ripping the trunk floor out in the process. Sadly this isn’t entirely untrue. There’s no shortage of companies willing to sell reinforcements, but some are more extreme than others. At least from what I gather, most of the reinforcement plates are fine, but to fix the root cause of the problem you have to tie the subframe shelf (the metal under the trunk floor skin) directly to the frame rails. Then select the stiffer-than-stock subframe bushings of your choosing.
There was zero appeal in attempting to do this job myself, especially trying to squeeze it in on a weekend. Instead, I had VT Motorworks in Pleasanton, CA perform the install. I simply dropped the car off and a week later it was ready. Like many e46s, mine had cracks hiding under the bushings, so it goes to show that even a pedestrian non-M e46 isn’t immune to the subframe cracking palooza.
On my car they went with Turner Motorsport subframe plates, paired with AKG 95a subframe bushings. In the process they also replaced the differential bushings as the original ones were torn, and as they say, “while you’re in there”. Additionally I had Vorshlag subframe to frame rail reinforcements installed as well, which seems to be a good compromise between zero upper reinforcements and going bananas with the CMP or Vince Bar setups that are more complicated installations.
If I were to do it again and wasn’t pressed for time, I would have added front trunk pickup point reinforcements, but these can be done at a later date if I’m willing to drop the subframe again.
The Wheeler Stealer
While enroute to the subframe appointment, I was greeted by a small crater on the freeway that blew out the sidewall of my front tire. The e46 sounded like a 747 making an emergency landing as it blared its emergency warning sirens until I was able to limp it off the freeway into a strip mall parking lot. Naturally this happened at 10PM on a Sunday night as Milton was en route to pick me up from the shop.
A very good friend indeed, Milton detoured home to pick up a spare pair of wheels that could be used to get the e46 to its destination for the subframe appointment. This soon led to a couple months of trying out different wheels on the car, which included the BBS RG-R and Kosei K1. Turns out the 17s ride a lot better than the factory 18-inch Style 135 wheels–and weigh nearly 50% less! However, eventually I did replace the tire and went back to the stock wheels and was greeted with the reality check of heavy, harsh riding wheels.
Boat Anchor Hangers
One of the bigger gripes I’ve had with the e46 is the aforementioned boat anchor wheels. Yes, they’re what give the ZHP its trademark appearance, but they’re incredibly heavy, which makes mounting them onto the wheel hub a real workout. The other problem with the stock “Style 135” wheels is the lug pocket is recessed, so fishing the lug bolt into the pocket as you’re trying to thread it into the hub becomes a circus attraction–all while trying to support the heavy wheel itself.
Having tried a few stud kits on other cars, I picked Apex for this go around. Their studs have a nice fit and finish and install easily thanks to the widened shank. Unlike other brands, the widened shank ensures the stud consistently threads into the wheel hub at the same length (whereas some studs can thread too far into the hub leading to mismatched stud lengths). The main advantage however is that the boat anchor wheels can hang off the studs while threading the lug nuts. Your arms and back will thank you, I know mine have…
Parts Pile = A Useable Car Once More
So how does the car drive with its first round of updates? On the suspension front (and back), the Koni Active setup is exactly what I had hoped. They ride like a Koni Sport without having to worry about adjusting them. Over rough pavement they ride smooth, but I never found the yellow Sport shocks to ever ride harsh either. Hammer into a corner and they firm up just as advertised. They’re not terribly expensive either, and fixed damping means one less thing to frett over in the middle of the night while trying to sleep.
The rear is where I most noticed the biggest improvement from the Koni’s, as the rear shocks were especially blown out upon removal. With a full set of fresh shocks, it reaffirmed that the stock ZHP springs and sway bars are quite sporty for most driving, so I’m glad I didn’t lower the car any further at this time.
Getting the rear subframe reinforced was mostly a preventative maintenance job, but the AKG poly subframe bushings do help the car feel an extra bit more composed under cornering, but I’m sure fresh rubber bushings with poly stiffening inserts would have been a nice improvement as well for street driving. At least I can be assured the rear suspension won’t rip itself out of the car.
Wheel studs were mostly a quality of life accessory, but having tried lighter 17-inch wheels was a real eye opener. Not only did the 17’s have less harshness over bumps due to the increased sidewall, but the ZHP felt noticeably lighter on its feet because the rotating mass had dropped by nearly 15 lbs per corner. I found 245 tires to be plenty adequate, but you can stuff 255s under a non-M e46 with some fender rolling and a bit of camber in case you wanted Arby’s fitment instead.
While I completely understand the appeal of the factory ZHP wheels, I’m a firm believer they’re one of the biggest drawbacks of the car in stock form. The excessive weight makes the car feel sluggish, not to mention the expensive staggered 18-inch tires. If you do nothing else to your ZHP—ditch Fred Flintstone’s wheel setup. On the plus side, you won’t have to buy a new set of weights for your home gym.
One more modification I made is the installation of a more comfortable driver seat, but that will be a separate write-up in itself. With everyone’s average attention span that of a goldfish these days, I figured this was long enough for one article.
-JC
