Tail Section Part 2

It is raining today and it is supposed to rain tomorrow but Friday was beautiful so I took a vacation day from my real job so that I could work on the tail section.  Actually, my boss said that I could take off Friday if I updated my blog on Saturday so I'm now updating my blog!!  :)

I did decide to join the small part of the tail section to the large part.  The changes that I'm making affect both and the large section was getting too flimsy without the small part fastned to it.  The small section had a U-shaped edge where it joined the large tail section which was about a quarter of an inch thick.  The purpose of this edge is to give the piece ridgitity but I couldn't effectively join the two pieces together with that edge -- so I cut it off.  However, by cutting off this edge it meant that I had up to a quarter inch step between the surface of the small tail section piece and the surface of the large piece.  So I had to figure out a way of spacing the edge of the small piece of the tail section to the flange of the large piece.  It also had to be flexible due to the curves in the pieces.  I could have layed a bunch of bondo but it would have been messy and heavy.  So, I turned to balsa wood and high strength epoxy.

I used cleco fasteners and to hold the pieces together and then pop rivetted them together and I again used the high strength adhesive to join the two pieces.

Since the two pieces were joined together, I could now cut out the hole on the left side.  A big percentage of the tail is now missing!

Now it was time to go through the process of filling in the hole on the left side with the same procedure that I did on the right.

I then needed to lay some fiberglass over it and I chose to use some very light (4 lb) fiberglass cloth that could be layed and wetted out easily.  I layed a piece over the foam and then traced it and cut it out.  Once I had that template, I then used it to trace two more pieces of fiberglass so that I could put down three pieces of cloth.

In order to prevent the fiberglass resin from sticking to the foam, I put a very generous layer of mold release wax on the foam and removed any wax that I got on the bodywork with a wax/oil remover.  Here is a pic of the foam with the wax on it.

I then layed the fiberglass and pryed the foam away from it.  Here is a pic of the inside of the bodywork just after I seperated the foam from the newly hardened fiberglass.  You can see that there is some foam around the edges which was intentional and actually turned out to be a great technique because it held the foam in place while I sanded it.  There were some challenges working with the left side because of the foam moving around too much.

The left side came out really good but the fiberglass is a little flimsy so I will strengthen it with some fiberglass mat on the inside.

I went through the same fiberglassing process on the right side but after I was finished I found out I had a problem.  I didn't have enough clearance.  Dang it!!    Here is a pic that shows where it was hitting.

I decided to make a smaller bubble and the blue lines in the picture show the size and shape of that bubble.  I went through that process and I still had clearance issues!!  So, this guess work was clearly not working.  It was now Friday evening and I was tired -- it was time to get away from it for a little bit.

This morning I got up and took a look at the shape of the hole and I decided that the hole needed to be bigger and it was best to start over.  I cut away what I had done and stuck the tail section back on the car.

I'm glad I did this because I also found out that the bodywork was also hitting a heat shield -- it is the flat piece of metal underneath the spark plug coils.  So the hole needed to be even bigger -- and the black line shows the extra material that I needed to cut out.  While sometimes doing a task multiple times is just part of the process, I definitely didn't wan't to do this one over again so I needed to figure out a way to work smarter and ensure that there was enough clearance between the bodywork and the engine after I fiberglassed over the bubble.  So, I created a couple of templates out of cardboard so that I could use those when sculpting the foam.

The templates came in handy because after I pulled the cardboard from the foam, I found out that the bubble was not thick enough.  I could have spread a bunch of bondo over the foam but the bad part about that is the bondo does not sand nearly as easily as the foam.  More foam was the right choice but making a "bowl" was going to be very difficult so I decided to go with something totally different.  I used a cheap brush to spread it over the existing foam before it really started to expand.  I didn't have much time to spread it but it worked reasonably well.  It did seem to create bigger air pockets in the foam but I found out that I could pack those with mold release wax.  Here is a pic of the bubble ready to be fiberglassed -- and the fiberglass is drying as I type this.  Hopefully there are no clearance issues tomorrow!!

Tail Section Part 1

First, I took all the other bodywork that I worked on to get painted and here is a sneak peak of what the car is going to look like!

The car came with two different tail sections, one with an air scoop on driver's left that was built into the tail (which is the one that was last used on the car) and one with the ability to take in air in the center even though it had an air scoop that attached to the left side as well. 

The Honda Fit engine has the air filter in the center so it made sense to use the tail section that has the air intake in the center. 

The HPD kit came with a fiberglass piece that is supposed to be bonded into the RF99 Van Diemen tail section which is quite a bit different then my RF97.  It didn't take me long to figure out that that piece wasn't going to work well with my car and this tail section.  For one thing, it is too narrow at the roll bar for my car which is a shame because it is a nice piece.

So now it was time to cut up a perfectly good tail section so that I could see what needed to be changed.  I expanded the cut out section for the roll bar and cut out a section of the tail on driver's right where the engine is.

My tail is actually two pieces and I'm debating about bonding the two pieces together again.  Nevertheless, I needed to see how the smaller piece was affected so I joined the two with the zeus fasteners and some screws and proceeded to cut out a section on the right.

In regards to the left side, I had the exact opposite problem.  The Ford engine that was in the car had the carburator on the left side so the bodywork is much wider on that side.  The slot that is there is for the air scoop which I don't need.  The lines that I have drawn give you an idea of what I plan on cutting to modify that side.

Getting back to the right side, I really had to think about how to make the bubble in the tail section.  First, I taped pieces of cardboard to get a rough shape.

To be honest, I threw away my first attempt.  I tried to go straight to making a rough fiberglass piece by laying a bunch of duct tape on the inside of the cardboard and then putting mold release wax on it so that I could pull the fiberglass piece off of it.  But the piece turned out to be way too rough.  I would have had to use a lot of bondo to make it close to useable.  So, I decided to go with plan B which was too use two part expandable foam which can be sculpted.  First, I needed to make a "bowl" for it.  Again, I got out the cardboard and the duct tape.  Btw, the tape that I use is Gorrilla tape which has to be the strongest tape around and can be bought at Home Depot.

After applying some mold release wax, I then poured the foam and after it set I was able to pull the foam out of the hole so that I could remove all of the tape and cardboard.

I then inserted it back into the hole and used more tape on the backside and even some toothpicks to hold it in place so that I could shape it with.  I even used some strips of tape on the front side and sculpted around them and re-located them as needed.  I did most of the sculpting with my palm sander with 80 grit sandpaper.  Here is where I left off and I think this is good enough to fiberglass over.  I'm crossing my fingers that I didn't take too much off!!

Wiring Part 3

I'm happy to say that I'm done with the wiring!  However, I did change some things since the last blog.  The more I thought about the terminal blocks, the more I didn't like them because I think they would be too exposed to moisture.  So, I decided to run everything through the Weather Pack connectors.  For the ground connections, I just connected 6 pins together and then plugged them all into the plastic housing.

I did the same thing for a couple of the power connections (like for the data acquisition switch) but the other connections were signals coming through the HPD wiring harness so I just had to make sure that they matched up to the appropriate dash wires.  I also had to include a couple of two pin connectors using this approach.  Here is a pic of the finished dash.

You may have also noticed that the indicator lights on the dash have changed.  The LED lights were protruding a little too much from the dash for my liking and I was concerned that my fingers would hit them.  Plus, I had dropped the rain light indicator LED light and that stopped working so I used a blue light that I had already for that and went to radio shack and bought a couple of flush mounted green LED lights.  One being for ignition and one being for the fuel pump.

The other thing that I ended up changing was the location of the wiring harness.  I did have it going through the inside of the car next to my left knee but I discovered that it would fit between the chassis and the bodywork so that saves me some room inside.  Here is a pic of the wiring with the dash mounted.  The only thing that I did after this shot was to wrap electrical tape around the ignition and fuel pump switches.

Btw, in order to check the wiring, I did as many continuity checks as I could think of to make sure everything would work when power was supplied.  I didn't take pictures of this but the connection to the data acquisition system uses very small pins that plug into a HPD supplied connector.  The pins are very similar to the Weather Pack pins except they are much smaller.  My crimper didn't work with those so I crimped as best as I could with needle nose pliers and then soldered the wires to the pins.  I made sure that I plugged them into the right spots because they are apparently very hard to remove once they are plugged in.  I was able to install my AIM EV04 Data Acquisition System hardware (minus all the non HPD sensors) and test a few things as a result.  I could see that the ECU was talking to the data acquisition system because I was able to see things like oil temp, water temp, throttle position, etc.  So, that tells me that I have probably wired it correctly!  Here is a teaser photo of the AIM EV04 system with a separate data hub and a channel expansion unit -- there is lots more on this to come!

Wiring Part 2

Ok, so I'm still wiring!!  The last thing I want is bad connections so I'm taking my time with it.  I did get all the lights and switches installed in the dash (pictured below).  The switch on the left is for the data system and the switch on the right is for the rain light.  I like to have lights on the dash so that I can actually see when something is on so I ordered some LED lights (the ones with the chrome bezels) to tell me when the ignition is on (green light), the fuel pump is on (yellow light), and when the rain light is on (blue light).  The small red LED light was given to me by a friend of mine and is an ECU error code light.  It flashes a number of times and the amount of times changes based on the problem.  The large red light is an low oil pressure warning light.  My data system dash (which will fit on the steering wheel) also has warning lights but I wanted an extra big and bright warning light for low oil pressure and this one actually came with the car.

I also decided to change the small change panel a little bit.  It was a little busy for me so I bought a military style switch that will turn on the ignition and will also turn the starter over -- it is a 3 position switch.  I used the ignition switch that came with the car (also a military style switch) for the fuel pump.  Since I'm not using the push button starter switch, I needed to remake the panel.  I made it out of 1/8" aluminum and used the old one to trace the shape.

Since the Honda Fit engine has an alternator, I had to buy a different type of master switch than I have used on my Formula Vees.  This one has a resistor and a number of blade type terminals.  You can see the resistor tie wrapped to the roll bar tubing in the pic below.

The good thing about the HPD wiring harness is that every wire labeled.  Getting back to the dash, all the items in the dash need power and ground wires so I velcroed some terminal blocks with jumper strips to the back of the aluminum panel that holds the ECU.  The terminal block on the left is for power and the one on the right is for ground.

There was going to be a lot of wires coming from the dash and I wanted to be able to remove it without undoing a bunch of wires so I decided to go with Weather Pack connectors.  I have never used these before but they are pretty slick.  They consist of male and femal pins along with rubber pieces that fit into plastic housings.  You can then connect and disconnect the plastic housings.  I will be using two 6 pin connectors and a couple of single pin connectors.  You do need a special crimper to crimp the metal pins to the wires.

Here is a pic of a male pin along with the rubber piece that goes with it.

And here is a pic of them installed on a wire.

And here is a pic of 6 ground wires installed in a housing.

I need to order some more stuff but I should be able to finish up the wiring next weekend. 

Fuel System Revisited

One good thing about creating this blog is that people are looking at it and ended up getting some good advice about the location of my fuel filter.  It turns out that I had it too close to the exhaust so I needed to move it.  I really wanted to keep it before the fuel pump but I just couldn't make that work so I moved it to the top of the engine so that I could still get to it.

A know other racers that have if after the fuel pump so it shouldn't be an issue.  Concerns were also voiced about the location of my fuel pump.  Ideally you want an external electric fuel pump at or below the fuel exit point from the gas tank since electric fuel pumps push fuel better than pull it.  I really wanted to put the fuel pump lower but again, I just couldn't figure out a way to do that so I mounted it as low as I could.  However, I emailed a picture to Walbro (the fuel pump manufacturer) and a technical expert responded and said that my fuel pump location was fine which at least gives my some piece of mind!!