Potential Z3 2020 challenge build

I just picked up a BMW Z3 to be a track car.  It happens to be under the challenge limit.  I am debating setting it up for the challenge before doing a more serious build later in the year.

I already own a set of 10 year old Rial Nogaro wheels that came with my 318ti when I bought it.  How do I go about figuring out the market value for those wheels?  They are old enough that prices no longer exist online.  I could pick up some cheap 5x4.75 steelies but I would rather not mess with wobble bolts.

The big question I have is how roll protection works on an open car.  My head is about 3" taller than the windshield.  I am familiar with autocross rules but drag racing is all new to me.  The stock car has a ~15 quarter mile time.  I just don't know if the safety rules were written for someone looking over the windshield to see down track.

The wheels I’d try and find completed auctions on eBay. If not then I think you have to ask us and get 3 of us to agree or something. I “think” you’re ok being that slow but I could be wrong on that. Can you even drive it with the top up?

You won't need wobble bolts for 5*4.75

5*120 = 5*4.75 within a gnats ass. Get some c4 or Camaro wheels for cheap.

In reply to Stampie :

If I scrunch down, I only push up the top a little with my hair.  A helmet would be right out.

In reply to ojannen :

Maybe bolt a cheap used aluminum race seat right onto the floor?

In reply to ojannen :

The way I read the NHRA rules are that you don't need roll-over protection (read roll-bar or cage) in a convertible until after you're fast enought to run a 13.49 second pass.  So you're good to go as-is for the challenge.  It'll take something radical to get the Z3 faster than 13.5

I can always drag race it for you :).

One of the reasons I picked this car even though it is close to the cap already is it has pristine door panels in a desirable color.  I found one completed auction for a set of brown over black panels on ebay for $830 and a number in the $300-$500 range.  That is enough to pay for suspension so I am happy.  I started looking over the build book and budget template rules and have a question.  On the budget spreadsheet, on the Example Recoup tab, what does the "Actual or FMV" column mean?  I think it means, "I screwed up and forgot to get a receipt so now I have to calculate the price" but it could also mean "here are 5 ebay listings and $500 extra into my budget after I take the part off the car".

I am debating whether I skip the concours or attempt the Radwood class.  Will a Vic Lee Racing Teal/Listerine livery with a big bag of powdered sugar in the trunk get me past 12 points?  I am planning on keeping the car stock except for suspension upgrades and weight savings.

What are the rules ramifications of cutting off the windshield?  I found the NHRA wind deflector rules.  I can't find any NHRA rules saying I need a real roll bar if I cut the windshield off.  Depending on how quickly the weight savings goes, I am going to buy a roll bar so I can run SCCA autocross in the Prepared category.  I am going to need something custom to pass the broomstick rule.  I don't have the skill to bend or weld one myself.  My current plan is to take it off for the challenge to keep it out of the budget. 

NHRA says open car needs full bar faster than 13.50

No real updates from my end.  A couple times this week, I got home from work to see a big wet spot under the car that smelled vaguely like coolant.  I checked the hoses, thermostat, water pump, and radiator and couldn't find any evidence of dripping fluid.  I was about to give up when I noticed the right front sway bar bushing was leaking.  After a little detective work, the pump on the windshield washer reservoir had a leak.  The level is now under the leaky o-ring so I am going to call it fixed.

What year is that car? I have some Z3 leftovers that have been sitting around since I sold my 2001. I have a new set of Brembo brake pads, maybe a DISA and possibly some other stuff.

If you're thinking about a roll bar, I'm pretty sure that the Hard Dog ones won't fit cars that have a power top.

The car is a 2000 with a power top.  If I decide to keep the car after the challenge, I am going to setup the car for F Prepared autocross.   I will need a rollbar there but at that point, the top will be optional.  If I can get a low enough seat, the Hard Dog one looks ok.  I am afraid I am going to have to do something custom to pass the broomstick test though.

I've got a 2000 M Roadster that I don't fit in either (I'm 6'5"+), so I'll be interested in how this goes.  One tip if you haven't heard it is there is a styrofoam hump behind the seat under the carpet, at least on the M.  If you remove this you can get the seat back a little more.  I did this and it helped.  The other one I've read about but haven't done is putting some washers under the front of the seat rails to tip seat base back a little.  These things could really have benefited from a tiltable steering wheel.

It’s also worth noting that hardtop stuff is really expensive for these cars. I think the bracket kit is around $700. 

In reply to GoIrish89 :

I removed the stryofoam piece in my last Z3 and it helped a lot.  I haven't gotten to it yet on this car.  I am curious how low I can get if I remove the seat bottom foam from the driver's seat.

I went to pull the stryofoam from behind the drivers seat today.  After I got the seat out, I sat on the floor and it is the most comfortable I have ever been in a car.

I debated bolting the seatbelt female end to the floor and driving it like this.

Common sense took over a few minutes later and I pulled the carpet instead.  I am going to sell it to fund my suspension and figured it would be worth more in one piece.

Maybe try one of those custom-poured seat kits.  We did them in these porsche kit cars we drove on ford v ferrari.  Just poured them to fit right in the pan of the car and cut holes for the seat belts to pass through.  The bottom of mine had spots where the lowest part of my tush was just barely on the floor. 

"After I got the seat out, I sat on the floor and it is the most comfortable I have ever been in a car. "

Now that's funny!

I ran into a problem after I put the rest of the car back together.  My head rests on the roll bar with the rear carpet/styrofoam removed.  At this point, is it safer to take them out or leave them in?  I am going to daily drive the car for a month or two until the interior is fully gone.

Leaned back: https://imgur.com/cdhV13D
Sitting up straight: https://imgur.com/Yn2GPud

After a long Coronavirus break , I finally got back to an autocross in my Z3.  It looks pretty cool.

I met pimpm3 at the event and his black M coupe too.  He gave me some tips for the challenge i hadn't considered, especially for the interior.

During the break, I almost fully stripped and sold the interior, removed the AC on the interior and exterior.  I picked up some cheap low offset wheels, a set of second hand A7s, and cut the fenders to fit the wheels.   I bought ebay suspension for $350 because the car was partially cheap due to blown shocks.  I don't think I could have gone to oem for $0 aginst the budget.

I need to cut a little more off the front left fender because I am cutting a tire under full braking.  With about $350 of budget left, I am not sure what to do next.
I would love to cut off the windshield, gut the doors, remove the top, and run the bottom half of a Z3 at the competition.  The big problem with that is I don't think the local autocross groups will let me run with that little rollover protection.  I am already in a sort of sketchy place.  I don't have the skill or tools to build a safe rollbar so I would need to pay someone for a custom bolt in rollbar and remove it for the competition.
The car definitely needs more spring and I might be able to get some second hand 2.5" OD springs from friends.  I think I could spend $100 on a set as long as I can get rear springs that are long enough.
I believe I could get an M3 or 328i front sway bar which is a little bigger than the Z3 bar.  Junkyard prices are around $100.

Where are you in FL? I  might be able to help you with a rollbar. Measure your car and start looking at universal roll bar hoops on Summit and Jegs. I have a tube bender but buying DOM tubing locally can often be more expensive then buying a prebent hoop online if you are able to get free shipping. Then having me weld it in or make it bolt in for you should be pretty minor ordeal.

We got lucky and found a whole universal cage kit in Tampa for $170 that fits our E36 perfectly, still have to weld it together but that doesn't count in the budget for us of course

In reply to cruisermatt :

I may take you up on the offer.  I totaled up my budget after letting the car sit for a month or two and i have another $300 to play with.  The top priority is obvously to cut off the windshield but I don't want to do it without passing a broomstick test.

In reply to ojannen :

Make sure you have the minium NHRA windscreen of 5x12 inches.  It has to be of nonflammable material.  Read the rule for yourself as I didn't stay at a holiday inn last night.