Sunday, August 30, 2009

Fuel tank removal

One of the challenges we faced was mounting the wing. There are two spars running the length of the wing that carry the load to the fusilage. They are the logical place to attach, but drilling through them presented a problem: the fuel tank. Fortunately the tank is not too difficult to remove in spite of the many seized screws.

I even made some art in the process of their removal.

Saturday, August 29, 2009

It works! It really works!

The wing is mounted and we all took the car out for a spin around the block.

We mounted the wing so that it would pivot around the front. In the back it is supported by a gas spring like those used on a rear hatch to help lift. We used a gas spring because they have an interesting property: once their initial force is overcome, the force does not increase. Thus the gas spring almost acts like a resettable fuse, limiting the amount of downforce.

Why would we want to limit downforce? To reduce drag. Both forces, downforce and drag, increase with the square of speed. It's worthwhile to have downforce and drag at slow speeds, when we're in a turn. When we're in a straight we don't need downforce, and by letting the wing change it's angle we can limit the drag.

Thursday, August 27, 2009

Sweet Ride

I drove the car around the block a couple of times this morning. No doubt waking up the neighbors with the lack of muffler.

The car is fast. The steering felt a little uncertain, but the engine revved smoothly, the transmission shifted and the brakes worked. It's going to be a great car to drive on the track.

The wiring is still a little flaky. The car didn't turn on at the first turn of the switch. We also need to check the alignment since most of the suspension parts came out of the Integra.

Now we need to get the wing mounted and decide on a theme.

Sunday, August 23, 2009


We started the engine tonight. It took a litle finagling to get the starter to work. We had to bypass our start switch and just jumper the starter to the positive lead coming off the battery to get it to turn over. I think we have something wired up wrong as the brake lights are on except when the pedal is pressed.

We also had the distributor wires plugged in wrong. We didn't have a service manual to tell us the correct order when we put the distributor on. Fortunately Jeff remembered that they were just random and we got them plugged in correctly.

The engine seems to run well. There's no exhaust and the car is still on blocks so we didn't drive it, but tranny and clutch seem to be working!

Thursday, August 20, 2009


Dick of Carrera shocks was able to hook us up with some better springs on Tuesday.

One way of understanding suspension is through the natural frequency. Natural frequency us the rate the car will bounce once disturbed and can be calculated as the square root of the ratio of spring rate to mass. Production cars generally have a natural frequency of about 1 Hz. This is driven more by comfort than performance as 1 Hz is similar to a walking pace. Non-aero racecars have have a natural frequency closer to 2 Hz. If mass is held constant the spring rate would need to increase by a factor of 4 to double the natural frequency.

Dick has a huge collection of old racing springs. We were able to put together a motley collection that would get us significantly closer to that fabled 2 Hz

Liquid clutch

One of the problems with getting the engine from a '95 is that they come with hydraulic clutches. The usual fix is to buy a doohicky that attaches to the end of the clutch cable and converts the pull into hydraulic pressure. Unfortunately those doohickies cost money. Money that we don't have.

What we do have is the clutch pedal assembly that came out of the Integra. Unfortunately we can't just bolt the whole thing to the firewall because the clutch master would end up poking into the wheel well. What we needed to do was reverse the direction of the master cylinder so that it pointed back into the cabin.

Some pounding, cutting and welding later we have a working clutch pedal. Now we just need to plumb some hydraulic lines.

A little bit scary

Craig and I put the wing on top of the car to see how it looked. The answer is "intimidating". I can't wait to have this thing out on the track.

As a bonus we saw that this 172 had electric flaps and the motor is still in the wing! Now we just need to rig the car with an extra battery to get 24 volts and we can have push button flaps.

Wednesday, August 19, 2009

Wings over the Civic

With no intrepid souls wanting to follow me into the chasm of madness that is suction downforce, I needed to find a kinder, gentler path to the banned technology award. Preferably one that didn't involve an extra motor and a 100lb fan. The solution? A giant wing.

A fully loaded Cessna 172 weighs about the same as a Civic and travels at similar speeds depending on which way the wind is blowing. A chunk of Cessna wing should be able to produce some serious downforce if turned upside-down on the roof of the car. Thanks NASA, for making FoilSim available. I used the camber and cord thickness from the Cessna wing (it's a NACA 2412 profile) and plugged them in. At 65 mph and 15 degrees, the angle of maximum downforce, we get over 1000 lb!

A trip to the local aircraft salvage produced a 6ft chunk of 172 wing with just a few dings. It even came with a flap.

A special thanks is in order to John and Blake at Atlanta Air Exchange for helping us out with our insanity.

Shift Linkage

We can shift now. Mark's finished modifying the shift linkage using parts from the '95 Integra as well as some parts from a '93. He also doubled the mass with weld.

Monday, August 17, 2009

Time is running out.

Less than a month to go. We've still got a lot to do, but there's light at the end of the tunnel. The current task list:
  • Get the Integra wiring harness installed and test the engine.
  • Bleed and test the brakes.
  • Build a battery box in the back of the car.
  • Build a bracket for the hydraulic clutch master cylinder.
  • Plumb the hydraulic clutch.
  • Find some stiffer springs.
  • Finish cutting out the extra weight in the car.
  • Get a better seat.

Wednesday, August 12, 2009

The Motor is IN

After the motor mounts didn't line up the second time we gave up on them. We decided that the rear mount would remain unmolested, but that the driver and passenger side mounts would have to be cut and rewelded. So cut them we did.

We put the motor back in with just the rear mount holding it and used jacks to support and level the motor. Once we were satisfied with it's position the mounts were cut, ground and tacked in place. We also took the opportunity to check to see if the '95 half shafts were going to work (they did) and to see if we'd have clearance for the suspension (we didn't). So the mounts were welded up and we were able to get the motor sitting in the car without something else holding it up.

There's one tweak remaining. The front crossmember needs to drop about .5" to clear the exhaust and give us some more clearance between the engine and the radius rods.

Friday, August 7, 2009

Stupid $@*# Motor Mounts

Having gotten the appropriate mount for the hydraulic clutch transmission, we giddily hoisted the motor up expecting it to drop sweetly into place.

It didn't.

Pretty much everything was wrong. The driver side mount was 15 degrees off and the rear motor mount "T" bracket was trying to punch through the firewall. A little more research and a question on Honda-Tech confirmed that we had no idea what we were doing.

The motor had come from a '95 Integra. Even though it's the same motor as the '93, the mount brackets are different. The driver's side bracket and the rear "T" bracket needed to be replaced with '93 versions to use the mount kit that we had.

We tried to get the bracket and some other things at the Pull-A-Part, but most of the engines had already been pulled. We found one '91 with the motor intact, but it was a automatic and the T bracket wasn't the same. It did provide us with the driver's side bracket that we needed.

Couldn't find the T bracket at M&R, the salvage place near my house, so I ended up driving to Honda Parts Connection. It was like the elephant graveyard for Hondas. They hooked me up with the bracket and the guys there had some great advice on some of the other questions we had (thanks Chris).

So with our new array of brackets installed we hoisted the motor again. We were a bit more somber this time. Even with our lowered expectations we were still disappointed. We were able to get the transmission side and driver side mounts in with some effort, but the rear mount was at least 1/2" off. In addition, the motor was crooked in two different planes. The transmission mount needs to move back 3/4" and the drivers side mount needs to move up 1-1/8" relative to the motor. Time to get the welder out.