Drove a '97 Z3 six car... don't know if I should do this.

So, I must say, small interior, two seats, six cylinder all of which I absolutely love. The bonus is they're drop tops!

Now the responsible adult in me is having second thoughts about pursuing the thrill and intoxication of a sports car. A real one, not like those fake arse 240/280Zs I used to (and still do) love so much.

Yes, I really should get the 320i running. And I will, just not sure if once running I should sell it and the 2012 Focus and daily drive a +/- 15 year old car.

Having said all that, I have to say, the thing didn't accelerate or turn in appreciably better than my Focus (well, at low speeds). I suspect some suspension work would take car of all that. Plus, six cylinder, small, two seat sports car. Hello? Am I dumb? Yes, but that's beside the point.

Anyway, second up is the notorious "rear subframe issue". According the the bimmerforums Z3 section, if the spot welds are dimpled, there are issues coming. This one had probably every second or third spot weld in the trunk floor dimpled, despite being an 82K mile car, with an otherwise very clean appearance.

Anecdotally, according to bf, running urethane bushings underneath a solid car will eliminate the subframe tearing (bad bushings seem to be the cause, extra twist and flex over stressing the subframe/floor - seems fairly logical).

On one hand, I want to do this, really badly. On the other hand, I like to drive spiritedly, and autocross nowadays, but I don't want to wind up with rear subframe issues on what will become my daily.

What sez the brain trust?

Go for it.

Ya I am no help am I.

You looking for someone to talk you out of a BMW sports car on THIS forum , really ?

Yeah, go for it. A little dull stock but lots of fun a little further down the road.

There is a noticeable lack of these cars on this forum. You need to buy this and teach us everything we need to know about them. Be the guy.

Well said, Woody!

Hear, hear!

I've mentioned a few times in the past I would love to have a six powered Z3.

How about some pics?

buy/make subframe reinforcement plates and carry on

Might as well look into 98-00 M roadsters......last I checked they were selling for small potatoes compared to their much better clown shoe brethren.

I think the Z3's are great little cars and have really enjoyed my long term ownership experience. I've had my 2000 M (Z3) Roadster for 14 years now and a 1996 Z3 (1.9) for several years before that. They are not the lightest, nor fastest, nor best handling cars of that generation however, the Z3 rides/feels more like old school sports cars from decades earlier in a more modern, comfortable, and reliable package. Also, they can accommodate taller drivers like myself that can't be shoehorned into a stock Miata. Z3's need the typical BMW cooling system preventative maintenance but, otherwise are very easy to work on with excellent technical support from the online community. These cars respond very well to suspension upgrades. The front suspension comes from the e36 parts bin and as such all of their proven setups work here. The rear suspension resembles the e30 trailing arm setup and the faster cars have been ditching the rear sway bars along with running higher spring rates. Also, the Z3 fenders can swallow fairly wide wheels/tires. Upgrading to polyurethane subframe bushings makes a world of difference and eliminate some of that rear steering wet noodle feel but, I'm not so sure that they will prevent the subframe issues. The thin sheet metal mounts are simply not up for the recurring forces at work back there. I reinforced my subframe after finding a few failed spot welds in the trunk floor. Inspect the car and price accordingly if you should find any issues. Subsequent inspections of the trunk/subframe area should become part of your maintenance routine. The Z3 is not the only BMW model to have suffered subframe issues and I wouldn't let this stop me from enjoying these wonderful vehicles.

Boxster! It's a much better driving car than the Z3 w/ none of the idiotic BMW shortcomings (subframes etc). Well, except for the risk of IMS issues...

I'm still a little up in the air.

I can "hobby weld" but I'm not up to par for anything structural, nor will I necessarily "find the time" to try the upgrade myself anyways.

killeen_john, when you reinforced, did you a) DIY it, b) was it a "reinforcement kit" c) will running "bead" welds (as opposed to just spots) along the subframe help d) if you had done, what was the cost?

Also, is the "dimpled spot weld" a true indicator of pending subframe issues?

Finally, are the issues "solved" with reinforcement? Or does it prolong the inevitable failure at the trunk floor("Subsequent inspections of the trunk/subframe area should become part of your maintenance routine")?

I still need to look at a few more of these, and the appeal is strong.

amg_rx7 wrote: Boxster! It's a much better driving car than the Z3 w/ none of the idiotic BMW shortcomings (subframes etc). Well, except for the risk of IMS issues...

Hmmm. Several thousand in repairs one way or the other. Me likes inlines more than flats, anyway.

OldGray320i wrote: killeen_john, when you reinforced, did you a) DIY it, b) was it a "reinforcement kit" c) will running "bead" welds (as opposed to just spots) along the subframe help d) if you had done, what was the cost? Also, is the "dimpled spot weld" a true indicator of pending subframe issues? Finally, are the issues "solved" with reinforcement? Or does it prolong the inevitable failure at the trunk floor("Subsequent inspections of the trunk/subframe area should become part of your maintenance routine")? I still need to look at a few more of these, and the appeal is strong.

My welding skills are fairly basic so I employed Don Fields at Mr M Car in Farmingdale, NJ to handle the subframe reinforcement. He doubles the thickness of the sheet metal ear for the differential mount combined with welding in additional cross and diagonal braces to spread the loads of the mount across a greater area.

Randy Forbes of Sports Cars Plus offers a subframe reinforcement service as well as a DIY kit that converts the single ear differential mount into a dual ear mount along with additional cross bracing to further distribute the loads. The DIY kit is more involved than I would be comfortable taking on myself.

Dinan has a Z3 reinforcement kit as well.

At the end of the day, each of these options reinforce the differential mount and spread the loads across a greater area to avoid tearing the cross member/trunk floor sheet metal. These are not temporary band aids but, rather well engineered solutions that permanently address the issue.

The dimpled spot welds are generally an early indicator of the subframe issue. I would recommend taking pictures and posting on Bimmerforums for further evaluation from Randy Forbes and other Z3 gurus. I would carefully inspect the sheet metal cross member looking for any cracks or separation from the trunk floor. Also be on the look out for any cracks in the sheet metal mount that attaches to the differential ear. These last two items are the telltale signs of a more serious problem.

Hope this helps.

Great information on these. Any other information that you can provide? What are some other common problems?

I've been looking at another convertible and because I'm a 35" inseam, the miata is not the answer. god knows I've tried and just never got really comfortable in them.

I've always been interested in the 2000+ sport 3.0L models.

Stretch the budget/sell some stuff and get the M Roadster

This is a good read to learn about some of the other common problems affecting the Z3. The subframe and cooling system preventative maintenance are the major reliability concerns whereas the rest of these items are annoying but, won't leave you stranded on the side of the road.

I had the same challenge of being too snug in the other roadsters (S2000, Miata, MR2, etc.) when shopping at that time and didn't want to hack up the interior of a new car to fit.

The 3.0L with 230 HP was available from 2001-2002 and gets you very close to the performance of the 1998-2000 S52 M Roadster without the "M" premium price tag. Your next best bet is the 1997-2000 2.8L with 189 HP. More details about the different models and engines can be found here.

bmw makes a weld in parts kit for sedans and m3s with ripped out mounts. I believe later m3s had it installed from the factory.

BMW might make a similar kit for the z3s. I had mine done (about 5 years ago) when it was totally ripped out. I was recommended to a body shop by a trusted bmw specialist. They did everything for 1500 bucks. Never had another issue even with lots of autox and track work (and a v8 swap).

I also had a 'loose rear end' feeling when I first bought the car. New Rear Trailing Arm Bushings (RTABs) put a quick end to that, but mine was the sedan suspension.