Most liked posts in thread: The Phoenix - The GP Roadster Project

OK, my homies. I'm back from purgatory.

First, I'll answer the obvious questions.
"Paul, Where in the actual f!@# have you been? And what the h377 happened to you?"

Well, back in August, things were going swimmingly well. I had done several track days in 2016, car was well sorted (I thought), I was getting more confident and faster. That's how one always feels, I hear, right before the bottom drops out.





Happened about 5 laps into the first session of the first day of a two-day track weekend. Oof. Car was feeling squirrelly and I was trying to figure it out. I felt like I was driving well off my normal pace, but back end of the car came around when I turned in on a high speed sweeper... and before I could correct or even go two feet in, the car had assumed a new trajectory and I was just along for the ride, into the Armco.

Sadly, I my video recording didn't start properly that session, so I didn't have much to analyze. I KNOW I had the car set up VERY loose... but I had the same settings for two days at CMP a month earlier, with no issues. When I was rebuilding the car, I found that one of my inner CV joints had failed... either in the crash, or before. I'm thinking before, and perhaps that was what I was feeling with the car, prior to the crash. And that would explain why my usual car control skills didn't do what they usually do...

So, broke my car. And bought VIR $1200 worth of new guard rail. But I was able to spot my newly painted guardrail on the TV the next weekend when the pros raced at VIR. So that was cool, I guess.

Anyway, I let the car sit for about 5 months, because I just couldn't get in the right frame of mind to work on it. Then, I did.

Left engine/bumper frame rail was mushed. So I replaced it.






Gave me an opportunity to learn some new skills, and improve my welding technique.

Now, back to normal programming.

Got things pretty well patched up. Straightened out the mushed bonnet to "good enough" and re-used my spare partially screwed up bumper cover. I decided to switch to an Aero grille instead of spending $$$ on buying and painting a new slatted grille and related trim. I like the way it looks. Kept a little Armco Green paint for street cred.




Been driving, and rebuilding my confidence in myself and the car. I had been testing much stiffer springs. While it would actually work on the track (and did at CMP last summer), it's too stiff for bumpy roads. Every bump is a car control event waiting to happen. So I've backed way off on the sway rate, and I'm backing off a bit on the spring rate. I think the new setup will be about perfect.

Hood latches had been wonky since I helped my wife ripe the nose off the car a year ago... and remained wonky after the recent fix. So I replaced them with something better... Aerocatches.





Today, fabricated a spoiler.

I'm trying to figure out how to make the backend just a bit more stable at speed. The front sticks well with the RMW splitter. The rear got a bit better (I think) with the GP2 diffuser. But I want a little less lift back there... I really want the car to sit down at speed. Since my car has more in common aerodynamically with NASCAR trucks than other MINIs, I decided to try a variation of the NASCAR type spoiler.

Ordered some 3/16" smoked Lexan, and mocked up a spoiler in cardboard to get the shape and profile right. Originally I was going to mount this with stainless hinges and turnbuckles, but then had a brainstorm on bending tabs in the Lexan and trying that. Turns out that worked well, so it simplified the whole project.

Marked and cut Lexan using the cardboard mock-up as a template.



Started off 5" high, plus 2" for the tabs.

Marked the size/shape of the tabs. Drilled holes for stress relief. Cut the tabs with the jigsaw.



Bent the tabs, using a simple jig, flat pliers, and heat gun. You have to get this stuff HOT to bend it, about 300F. Took a few tries and test fitting to get the tab angles close enough.





Then drilled holes for hardware, removed the film, and screwed it into place.




I love it. It seems plenty stiff, I can add turnbuckles later if needed. Need to sand the edge a bit to smooth it out, but it's pretty much done.

 

So last year I fabbed a prototype "bikini" top for the GP Roadster. It was quite effective, and kept me and passengers mostly dry during a drenching trip to the Dragon, and other times also. But I thought it would be even better to have a removable hardtop that didn't flap in the wind, that could be faster to fit in the rain, and that folded to stow in the back. So I've been thinking about that for about a year.

Given the curvature of the roof, the best way to accomplish this would be to start with an OEM roof skin. Sadly, I thought of this shortly after I had sent the GP donor chassis to the shredder last year. Because I would have loved to have had the roof of that car as a starting point. Well, water under the bridge.

New roof skins are about $600... so I searched for a good deal on a salvage roof. Found one about an hour away, for a couple hundred bucks. So I started with this...


There's a lot of steel in the roof assembly. The perimeter of the roof has up to four layers of steel reinforcement, spot welded into various sandwiches with air gap in between, to make the roof strong and stiff. I knew some of this would need to go, to fit over the cage... but also knew it would be trial and error to figure it out.

First, chopped off the C-pillars and hatch mount... I knew I didn't need this part.


Then I made a template of the curve of the windshield header seal on the cabrio, traced this onto the roof, and rough-cut it using the nibbler. I intentionally cut it a bit large, knowing I'd probably need to trim it down later. But I just wanted to be able to lay it in place, so I could start strategizing on the fitment.


Took several hours of iteratively trimming and test fitting, to finally determine that ALL the structural stuff needed to come out to make it fit, just leaving the single layer skin. I had also thought I might be able to retain the flange that held the upper window seal, to use the OEM seal from the GP... but eventually determined that wouldn't work... just not enough clearance for the cage. So after hacking on the roof some more, I finally had something that would lay in place. Then was able to determine where the cut needed to be to best mate to the header seal, mark, and cut it again. Success!


Then time to figure out the length and shape for the rear. I played around with some different concepts, but eventually decided to leave it "flat" but cut it to the same curvature as the top of the new duckbill spoiler. So I copied that curve onto a piece of cardboard, made a template, marked the roof with about 6" of overhang in the center, and cut it with the nibbler.


The view of the overhang, from the driver's seat:


So it's fitted!
Next steps: pull some dings out of the skin, cut it down the middle so I can either fold it or stow it in two pieces (to fit in the rear), prep and paint, and install edging and mounting hardware. I found the hardware I want to use, and ordered it today, along with the edge trim. I'll start on prep and paint tomorrow. Hopefully I'll have the hardware in a week or so, and will finish it up then.

 

Thanks! It probably won't stay red for long, though I kinda like it too. But GPs have silver roofs...

 

Yeah, I'm fond of the CR also. It was a poor quality respray of a factory white (I think) roof, and clearcoat has failed... so it's gonna need paint regardless. So I haven't been careful to try to preserve it. While I'd like for it to look nice, the reality is it's gonna get banged up no matter what I do, hauling it around when it's off. So I'll probably end up doing something that's easy to touch up... single stage, no clearcoat. I'll see what I have left in my paint bin... I think I may have gotten some silver plasti-dip type stuff that I experimented with (but didn't use) for the cage...

Once I split it and paint it, the whole thing will get edging all the way around. I have a 4" wide neoprene rubber strip coming; my thought is I'll bond that to the inner surface as a foldable seal. I'll see how that works and adapt as needed. I may add additional structure to the inner surface to stabilize it... I'll see how it behaves once I have it hinged and mounted with the latch hardware, and go from there.

 

Yup. I did a rear fit today. Plenty of room, since I don't have the meth cell in there anymore.

 

Pretty busy week, working on the roof.

Sand and prime the roof panel. Not going for perfection; it's gonna get banged up anyway. Just want it "decent" for now.


Measure, mark, and split the panel with the nibbler.


Applied a few coats of silver wheel paint, which is a pretty close match to the Pure Silver. Painted the underside with satin black chassis & roll bar paint. Just going for "good enough" for right now... if it all works out, I'll take it apart and refinish later. Added edge trim all around both panels.

Now, to attach it... I spent the better part of a year searching for the best attachment approach for the roof. I looked at hundreds of different types of hardware. Things that were designed to hold on roof panels... and just about everything else you could imagine. Dick suggested last year that I use hood pins. I was headed that direction, but really didn't want pins sticking up through the roof. I looked at several kinds of flush-mount latches. The Quik-Latch latches looked perfect for the application... but they are $300 a pair! And I was probably going to need 8 of them...

Then I found a source for Chinese knock-offs of the Quik-Latch. Yeah, I know. I'm not usually into such things... I buy the real deal whenever I can. But there's no way I was going to buy $1200 worth of latches for my roof. $100 total, shipped from China, was more in the budget.



These are pretty slick. Billet aluminum latches have a ball bearing ring that snaps closed around a ball-top adjustable hood pin. Push the button on the top to release, it stays released until you press it back down on the ball.



Spring tension in the latch should help dampen vibrations. At least that's the theory. I measured and identified locations where I'd have enough clearance for the "stack height" of the assembly, and where the roof skin was flat enough for the latch.

The adjustable pins are designed to mount through sheet metal with nuts and washers. But that's not appropriate for mounting on the roll cage. So I drilled the cage and installed 8 M12 outserts. Yeah, I know... holes and roll cages aren't a great combination. If it was a wheel-to-wheel race car, I'd be concerned about it. But it's not... and I'm not. I avoided bends and junctions that will see highest stress in a catastrophic incident.

Measured and cut down pins to an appropriate length to provide the necessary adjustment range in each location.



Fit the roof panels in place, adjusting the pins to hold it at the desired ending height. Lined everything up, including the center seal for the panels, and taped into position. Checked, double checked, triple checked, and then marked the center points for the latches on the bottom of the roof where the pins touched.



2" hole saw to cut holes for the latches... install latches... and the moment of truth!






OMG! It actually works!

I'm most excited about the tight fit against the factory convertible roof seal at the front. Should be leak-free!







I'm actually a little surprised how well it came together. But the first real test... how secure it is when driving?

I did a total of two hours of spirited driving, over smooth and rough roads, at speeds up to 90mph. Zero wind noise, zero whistling, zero rattling. It's just on there, solid. Relatively quiet, calm, and civilized in the cockpit. With the windows up, the heat actually works and makes the car quite livable for four-season use.

I can install and remove the roof in about a minute, maybe less. Stows in the boot; I need to work up a secure storage method so it's protected and doesn't shift around back there. That's next.

I'll be able to test it in the rain this coming week, to see if I'll need to make any adjustments, or add any window seals, or add any "wings" in the rear to prevent blow-back. But judging by the airflow in the car today, I don't think it's going to be a problem. Very calm inside with the windows up.