Proximacentauri's Mid-Engine Exocar

[JonW]

You're an inspiration man. Keep plugging. I wish I had your energy, day after day.

I'm a step behind you in the PCM/immobilizer battle. Just received a good scanner today. I'll trailer the car to the dealer if I have to.

I hope you won't be bored at school. Why don't you skip school and just start a computer company in your garage? Just kidding.

You've placed an enormous amount of pressure on your shoulders with the deadline. Success can not be measured at one instant in time. The hundreds of steps in your journey have already proven that you're a success in the car building game.

I hope you are entering engineering school. The country needs more engineers. The smarter and more resourceful, the better.

[proximacentuari]

IIIIITTTTT RRRRUUUUNNNNNSSSSS!

After sending the ecu and immobilizer to a guy in California to be reflashed, and troubleshooting the fuel injector circuit, it started up. I didn't have anything on the head at that point so it was really loud. I bolted some of the exhaust to it, the flex connector and my vibrant metal core catalytic converter. It wasn't much quieter, but now sounds really good. The addition of a high flow muffler can only improve the car's sound.


After weaning the wiring system from my 12v supply and removing all the wires and things hanging off the bottom of the car, I drove it for about 2 minutes with 1 hard acceleration. This crate moves like nothing I've ever driven. Doesn't stop too shabbily either. Of course, the rear brake circuit leaks a little. The fuel pressure isn't being regulated well. My fuel pump died. The engine temperature went too high. MIL light is on.

However, I can read OBD codes so it's only a matter of time until I get it working.

[a.moore]

The cars looking good. Nice work.

[chetcpo]

Awesome! You should be very proud of yourself. And how old are you? 18-19? Incredible.

[dhempy]

That's AWESOME!!!! You built this in what...about a year? Lookin' great. I can't wait to hear your progress.

Now that it's on the road, PLEASE be careful. What a waste it would be if you went and wrapped yourself around a tree or something.

-dave

[JSullivan]

Where do you live? It's beautiful. Looks like fun roads!

Congrats on the driving!

[JonW]

Congratulations. Nice job.

So, when you get a chance, can you give me the info on the CA reflasher?

You just made me much more anxious to drive mine.

[proximacentuari]

Update: 8/2/08

I drove the car more today including 1 reasonably hard acceleration (hard enough to spin the rear wheels anyway). In the process I broke my tack welds on the fuel tank. I welded it back on with my brother standing there with the fire extinguisher in case of accidental special effects.

A bunch of stuff broke the first time I drove it. I found that the coolant wasn't circulating. The engine kept cutting out after a couple minutes. My fuel pump committed suicide. The fuel pump was a new model bosch but was un-take-apartable. Went to a junkyard and got a cheap pump for $15 which they assured me would work. Which it didn't. Fortunately it was the crimp type, so I pried apart the fuel pump and discovered that one of the magnet brackets was somehow bent into the vanes of the stator. Bent it back but got confused about the orientation of the pump mechanism. by the way, if you guys ever want to see a really beautiful mechanism, take apart a fuel pump. It took taking the pump apart twice in order to figure out the correct orientation of the pump mechanism.

Then, we tackled the fuel pressure issue. Before, I was running the pump --> fuel pressure --> fuel filter --> fuel rail --> injectors. After looking at the honda dealership at the fuel pressure regulator, I had one of those moments where all became clear and I understood how the fuel pressure system works. On some cars, there is a fuel return line from the fuel rail. On the honda k20, the fuel pump and return lines are inside the tank. So is the pressure regulator. Therefore, the fuel pressure regulator (in the honda) maintains a constant pressure inside the internal tubing in the tank. The pump keeps a loop of fresh gas flowing at 50psi. The engine only takes a little bit off that loop.

So I'd been trying to figure this out for the past week or so. So the final setup, including a "water pressure" gauge from home depot is:

Tank --> pump --> FPR --> tank and pressure gauge --> filter --> fuel rail.

Not having this setup was the reason that the first pump died...it was running against a blocked pressure and stalled.

So that's the story of the fuel system.

Coolant wasn't that much more complicated. I got a 11" reversible fan off ebay that seems to work great. My dad removed the thermostat from the engine while it was cold and we jacked up the front of the car around 2', raising the radiator above the engine. Then we filled the water until the whole system was full as best we could tell. I used the obd code reader to tell the coolant temp. When I ran it yesterday, the temp went to 98 C or so...today it hung around 80 C. So I think coolant is working.

JonW or others with honda immobilizer problems...send an email to Edgar at qfactor85@hotmail.com. He reprogrammed my ecu to pair with the immobilizer and matching key for $100. However, Jon, I believe that you only need an immobilizer key cut and programmed to match the immobilizer. This (at my dealership) is $50 if you bring it in. It's more if you call a locksmith, but they'll come to you.

I'm gone next week to go canyoneering in Zion NP. When I get back I should have the muffler/o2 bungs/ other fuse box and can put the rest of the exhaust together. Reverse engineering is fun, but not that reliable.

Since I'm pressed for time, I don't think I'll be driving it that much. Now, with the engine running, I need to finish adding all the parts and bodywork with tack welds. Then, I rip everything apart, put on some por-15, and reassemble. Then I get to drive :p. (And register)

For those wondering what it's like to drive:
Acceleration: scary. I haven't gone above 1/2 throttle and I got wheelspin in 1st.
Braking: reasonably fast. I don't have much of a standard of comparison. Braking effort doesn't require a strong leg at all.
Steering: instantaneous. When you move the wheel, the car jumps instantly. This seems to be the biggest difference between this car and everything else I've driven. Steering effort at low speed is fairly high. I'm still dealing with the problem of not enough caster. What really bugs me is that the centering works when moving in reverse. hmmmm
Suspension: stiff. But what would you expect? Body roll is undetectable in the light turns that I've done so far.
Grip: I haven't done any really tight turns at speed yet.

[horizenjob]

problem of not enough caster. What really bugs me is that the centering works when moving in reverse. hmmmm
Suspension: stiff. But what would you expect?

KPI is providing self centering too, and that would work in reverse. SO you must be getting more from KPI then Caster.

The suspension will feel stiff but shouldn't be too bad. Maybe as you start driving a little faster you will use more suspension travel and it won't feel so hard or it will feel more in proportion so to speak...

[a.moore]

Rather than KPI causing centering, could it be the KPI is causing the scrub radius to do something weird and thats causing the centering?

What do your mechanical trail and scrub radius look like?

If the mechanical trail reversed, it could cause the car to center really well in reverse.

[chetcpo]

Looking at the pictures it looks like the steering arms come off the top of the spindle. Is this because they have been reversed right for left? If so, that could be your problem. The center of rotation may be in front of a line projected through the top and bottom balljoints, when in fact it should be behind this line slightly.

[proximacentuari]

After several drilled holes, the front suspension now has a caster of 12 degrees instead of 4. This seemed to have some effect...the car now steers reasonably straight with no hands on the wheel. However, I haven't dispensed with the car's curious propensity to go to full lock while moving with about 3/4 lock. I'm going to put this off as some sort of strange interaction between ackerman and my extreme KPI and not care about it (actually, it's kindof nice because the car holds itself at full lock for turns which would otherwise hurt your arms.) Anyway, i'd never go 3/4 lock at high speed so I'm not going to worry about it.

Thanks for your advice guys..

Btw, now my KPI is 16.5 deg, caster 14 deg, mechanical trail 2" or so. Pretty wonky suspension. It turns so fast though....

[chetcpo]

Dude you should fix that. It sounds dangerous.

[Ryan In Melbourne]

Hi first post, I joined up just to say what a wonderful job you have done. I was actually thinking of doing something similar with my front suspension steering arm, so your design is some form of proof for me. I will probably end up using different uprights and angles due to my differing requirements and availability in Australia.
http://www.oz-clubbies.com/forums/index ... topic=8873

Where did the civic/Honda take its original steering arm from?

Looks like you have the steering wheel boss on upside down or something. If it’s the removable type its normally keyed so that the wheel only goes on at one orientation, did you weld it onto the coloum correctly?

[a.moore]

Btw, now my KPI is 16.5 deg, caster 14 deg, mechanical trail 2" or so. Pretty wonky suspension. It turns so fast though....

With those KPI and caster numbers, are you sure your contact patch isn't moving from one side of the king pin axis to the other when viewed from the front? This would cause the scrub radius to change and go from wanting to center to wanting to end up on full lock as you describe.