Fit and finish

I had a busy Monday!. My goal was to get the top ready for real world testing. To do this I had to make the back able to take rain and to close of the C pillar area. I found out that after adding on rear glass I was no longer able to put the top on by myself. I was worried that I wouldn't be able to do anything since I wouldn't be able to measure and size things on the car. I decided to remove the rear glass and use a different hinge system for the hatch. With the rear hatch removed the top was easy to put on. I then welded on the outside of the wire frame that I'd be using for the C pillar area. Next I measured the frame that I was building for under the rear hatch. This frame will seal with the hatch making a channel for the water to go down and out the back when it rains. After I cut the metal for this channel I welded it to the top. I took the top off the car at this point. Next I welded on the new hinge system (pictures to come later) and then welded up the wire frame. I thought at this point that putting the fiber glass on would be not too difficult. I was wrong! Fiber glass is tough, its sticky and it gets everywhere and if you get it on your skin it will stay there forever. It looks like the catalyst that was in these packets from who knows how long ago had gone bad because only the one packet seems to have dried. In the end I had to reinforce the outside with duct tape to make sure that it wouldn't come loose while it sets.
Now that I have the top on and its driveable I have a few challenges to over come. I need to seal the windows to the top and have the doors be able to open easily and have the windows go up and down easily. The other challenge will be to make sure that everything else is sealed to get ride of some wind noise and for when it rains.

Order placed

I placed an order for some fiber glass supplys today.
I ordered:
6yards x 50" of triaxial weave fiber
8yeards x 50" of matt
2 gallons of vinyl ester resin
1 gallon general purpose resin
catalyst
release wax

This should be enough to finish the current roof and then build a mold from it and to build a fiberglass top with high strength and rigidity.

Plans for finishing the top.

To make the trunk water proof I will weld on a lip to go below the trunk on the sides and then use rubber to make a seal between this lip and the trunk.
After some discussion with James I've decided to create a wire frame for the C pillar and then lay fiber glass on top of it. I am going to have to mold in some brackets for attachments. I've watched some videos online about how to mold with fiberglass and carbon fiber.
This top I will finish with fiber glass and then after I've done some testing and any modifications that are needed. I am thinking that I will build a mold of the top and then create a top out of carbon fiber.

Besides making plans I did connect up a strip of red LEDs for a center brake light.

Rear glass

I got the rear lexan window partially installed today. The profile is starting to come together. To install the glass I had to cut it into a trapezoid shape to match the shape of the trunk. After that I put a bead of silicon around the whole frame then I placed the lexan onto this and put another bead of lexan onto the glass. I then used an L shaped metal to sandwich the lexan to the frame and welded that on.

Some more supplies

I got some more supplies today. I first tried to get a single piece of lexan for the rear view screen but Lowes and Home depot only had 36 x 48 sheets and I needed 40 x 48. I decided that I tried to see if I could fashion a 2 sheet window but after buying 2 sheets and bringing them back to see the fit I decided that it wouldn't work. I went online and found that the same place that I ordered the corrugated plastic for the underbody also had a 48x48 sheet of lexan.
After the Lexan came in I decided to get a few more metal supplies. I got another 24x24in sheet metal and I got a few more bars of metal. I'm also going to have to fill my CO2 + Argon tank before I do any more welding.
I was thinking that I might try to put a bead of silicon on the edge of the sheet metal where it will contact the body between the rear seats and the trunk, if that doesn't work I will look into rubber.

More hardtop work

The first thing I did was to add some support beams that have a curve to them. This has 2 benefits, first it adds extra head room. The second benefit is that it matches the slope of the rear hatch.

Once the support beams were welded in, I started to attach some sheet metal to fill out the roof. I had some sheets that werr a little big. I tack welded them to the perimeter and the interior supports.

After It was welded, I cut off the extra and its starting to look like a roof.

Hard top progress

Please click the pictures for a larger view
Today I worked on the frame of the hard top. I built the attachement points for the rear of the frame to the car. I had to shape these so that they matched the contour of the body and so tht they matched the shape of the molding of the outside of the soft top.



After I mounted these I welded a the beam that will make up the rear roof line to its edge .







On the side with the gas cap I made a cross member that attached closer to the front so that the gas cap can still be opened.







I attached the rear hatch to the top of the roof with 2 hinges on both sides. After that i finished createing the hatch.






Here is the finished frame of the hard top. I need to finish the mounting points to the top of the windsheild frame and to add the latch for the trunk. Once these are done I will put in the rear glass and attach the body panels.

Test results from tray

I've driven with the under body tray for a week and 1 tank of gas so far. My gas mileage was 30.8 and the speed down the "hill" was the same (around 68mph) . So there was no noticeable change plus or minus from the under body tray. I'm curious if more air is flowing out my vents now or if the air through the radiator is going out the side through the wheel well. I don't know if sealing the engine bay by closing off the wheel wells to the engine bay will have a positive or negative effect. I'll be looking into adding an under body tray to cover the rear differential and seal off the underside of the rear bumper.

Underbody tray

I installed a underbody tray to cover the bottom side of the engine compartment.
There is a small lip spoiler in the front so i took that off and then sandwiched the new tray in between that and the lip spoiler. There was a few solid chassis points that I bolted the tray to in the back. There is still an open area from the wheel well to the engine bay, so i wonder how effective this will be. I will be testing the effectiveness by the hill speed test and a weekly average mpg. I will be looking into a shield to seperate the wheel wells from the engine bay.

Progress

I got to work on the hard top today. First I bent a bar to form with the edge of the windshield. This requires a multiple bends in a 3D crescent shape.




Next I welded the 2 peices I bent to go from the body up from the windows to a bar across the top. This will form the top wear the hatch / trunk will hinge to.






Next I attached the windshield the bar to the window bars. After the welds this shape turned out to be a pretty strong shape.
I started to bend a bar from the window supports toward the trunk but this shape is very complex and I didn't have the time to attempt it.

Got Materials

I picked up the materials for making the new coupe style roof. I'm starting to bend the pieces and I will weld them the next time I'm at my shop.

Another Idea

I've had another idea to improve aerodynamics, to make a hardtop that is in the shape of a coupe. If the hard top goes all the way to the edge of the trunk it will be a Kammback style which is very aerodynamic. I will do some sketches soon to upload.

Results

I have 2 metrics that I will be using throughout my project, the first is gas mileage. Since I use this car to commute to and from work for a round trip of 70 miles a day, mostly highway, I should be able to get repeatable results as long as control my speed. The benchmark from when i first got the car has been a repeatable 28mpg every week and now I am averaging 30mpg. The other metric that I will use throughout this project is a rolling speed down a steep hill on my way home from work. There is a hill about a mile long that I usually enter around 65 to 70mph, after about 30 seconds the car has slowed to a coasting speed and will stay at that speed for the rest of the hill. I've also entered the hill with around 55mph and the car has speed up to the coasting speed. When I bought the car I would coast around 58mph with the top down and 60mph with the top up, after my modifications I have been coasting with the top down at 60 to 63mph depending on the wind and with the top up around 63 to 65mph.

Miata update

So the next thing that I wanted to do was to seal the gaps between the grill and the radiator. After the grill opening there was about a 3 inch gap between the radiator and the grill opening and shroud. To fix this I am using a product called Coroplast, it is corrugated plastic. I put a U shaped piece to direct airflow for the sides and bottom. Then i made inserts for the front of the grill to direct the air towards the grill as can be seen in the second pic. Now that the air from the grill opening can only go though the radiator i feel more confident that i won't have any cooling issues after I close up the bottom of the engine bay.

Project Miata

I have a 1999 Mazda Miata, its a great little car that gets good gas mileage for a sports car. I use this car for my daily driver during the spring, summer, and the begining of the fall. My goal with the mods that I'm planning is to enhance the air flow around the car. The first thing I did was to buy a magnehelic gauge off of ebay for about $10.



A magnehelic gauge can measure pressure differentials to a thousandth of a PSI. The importance of this is that a pressure differntial across a surface will insure that air flows through the surface. My plan is to seal the bottom of the engine bay to reduce the drag and also to reduce lift. To do this I needed to create an alternative path for the air to flow.




I decided to create a vent in the hood. First I measured the pressure differntial across diffrent points on the hood to find the area that would be optimal for air flow. The engine bay under the hood gets close to uniform pressure but the top of the hood goes from a high pressure zone at the front of the hood to low pressure along the flat surface and then back to a high pressure region at the base of the windshield. After i found the area that i wanted to cut my vents, i carefully measured and cut the 3 sides and then bent it down creating a vent. My next step will be to seal the area around the radiator so that the air that flows through the grill opening will be used for cooling and not just blowing through other openings.

Scuderia Toro-serratura

My 1984 GTV6 was a carrier of the Alfa bug and the infection spread quickly. I bought the GTV6 with a 3.0L heart transplant. The aim of this car is a cruiser / track car and I try to keep this in mind when buying parts and making modifications. At this date I've removed the air conditioning, added stiffer rear springs and replaced several bushings with the poly replacements.


After being infected with the Alfa bug I couldn't last a full week and sometimes more driving a "normal" car. I found a neglected baby in need of some tender care. After replacing the battery and the timing belt I got the eninge to start but it was far from running smoothly. It took a long time to track down a minor vacum leak inside of the cold start air auxiliary valve. The small air leak was wreaking havok on Bosche L-jet fuel injection keeping it from being able to be a driveable car. After fixing the air leak, I cleaned up many bad sensors. Now she's my daily driver during the fall and winter months.

The next car in the stable is the classic GTV from 1974. As you can tell the outside is in need of some attention. The inside is in good shape as all the seats have been reupolstered. The engine was rescently rebuilt and since the picture it has been given performance springs which really improve the apperance and the handling.



For my next car I went south from Milano to the town of Modena to a tiny manufacturer called Maserati. The 1985 Biturbo has classic elegant lines which mask its true character that really wants to go fast. When the car arrived the previous owner didn't know that the wastegate has been disconnected. Luckily i found this out and reconnected it. Since then i've installed a manual boost controller, liquid to air intercoolers, bypass valves, and a SPEC stage 2 plus clutch.