Proximacentauri's Mid-Engine Exocar

[defo1]

proximacentuari,

Regarding the front suspension. I used the existing McP strut for my Locost, which I have driven for two years now. I cut it to a certain height, and drained out all of the oil, so I then had a hollow tube. I then welded a 3/4" bolt to a disk (Same diameter as the tube), which was then welded to the top of the cut McP tube (The bold head was inside the tube, not on the outside face). I then had a tube with threaded bolt coming up. My upper control arm connected to this. My upper control arm had a 3/4" ID heavy duty rod end.

The advantage to this, is that I did not have to worry about the King Pin angle, as the donnor strutt already had this. My lower control arm used a balljopint with the same taper as the donnor one. Therefore I could use the same calipers and spindle.

How do you plan to attach the steering? If you use the rear spindles from the Civic they won't have the steering arm attached. Also, the hand brake attach will then be in the front. Can the spindles be swapped?

Good job on the frame. You've come a long way

defo1

[Miatav8,MstrASE,A&P,F]

I seen no reason not to use front spindles all the way around. Machine the cup from the front outer cv "spindle".

[proximacentuari]

1/22/08 - Playing around with Solidworks, I'm absolutely regretting not buying it in the beginning. The extrusion function has the ability to essentially do tubing joints automatically - I usually had to guess, degree by degree, to get two tubes to match up for a junction.

1/20/08 I deviated from the At-om design here - I added an additional rectangular bar about 6" in front of the front of the seat. This allows for people to get in/out without stepping on the seat or the fiberglass pan, which will likely be non-structural (at my skill level with fiberglass - none). This way I can avoid an additional aluminum floor.

1/15/08 - I followed an ad on craigslist to a pile of military surplus bolts - I picked up around 50 3/8 solid stainless steel bolts which will work wonderfully for the inboard suspension mounts and engine mounts. These bolts really are a thing of beauty, polished stainless and all. Also, I grabbed a box of rubber grommets, a bunch of bolts with holes in the top for wiring (anti-vibration for aircraft), several rod ends made out of some strange alloy that rings like a tuning fork, and all sorts of other stainless stuff. Not bad for craigslist. Probably saved me 50$ in fastener parts.

I am now planning to use front spindles all around. In the front, my addition will attach to the steering rack. In the rear, that addition will attach to part of the a-arm. In the rear, the top ball joint and toe-in angle joint just need to be at the same level in order to prevent twisting on bump.

Attached is how I plan to modify the front spindle. I would go with the weld-on bolt approach, but I don't know the material of the spindle (probably aluminum) and I like the additional adjustment that I get from choosing the length and angle of the steering arm.

Nice looking frame. Is that exhaust tubing? What is the wall thickness and tube diameters?

The large dia tubing is 2.5" .065 ERW tubing. It's essentially DOM without the drawn-over mandrel part. Half as expensive.
The roll point/roll suspension points are 2.5" .120 DOM tubing.
The med dia tubing is 2" .083 ERW
Everything else is either 1.5" or 1" tubing.

The fuel fittings should be as large as the original fittings for the civic. Trap door baffles would be a good idea too.

Is a sump a replacement for fuel tank baffles?

How do you plan to attach the steering? If you use the rear spindles from the Civic they won't have the steering arm attached. Also, the hand brake attach will then be in the front. Can the spindles be swapped?

For the steering plan, see picture. Also, I plan to use front spindles all around. Hopefully, the rear brakes will fit on the front spindle. If not, then i'll use front brakes all around and install an aftermarket parking brake.

[Glen]

1/22/08 - Playing around with Solidworks, I'm absolutely regretting not buying it in the beginning. The extrusion function has the ability to essentially do tubing joints automatically - I usually had to guess, degree by degree, to get two tubes to match up for a junction.

If you like that try the weldment mode and the structural members, you could have a whole frame done with a few simple lines sketched along where the tubes will go.

[Miatav8,MstrASE,A&P,F]

Is a sump a replacement for fuel tank baffles?

It can be, although it generally is not as effective. Many stock tanks have baffles. The fiero is one example, with a plastic insert sitting in the spot welded and soldered tank.

[proximacentuari]

1/23/08 - I bought the two front struts off a 2002 civic si. This will give me something to do while I work out the donor car, and will give me the four front spindles I'll need for my car. Also I identified a possible issue: the track of the Civic SI 2002 is 57.9", whereas the At-om's is 63. This means that the At-om is using custom half-shafts. Five inches is a lot when it comes to suspension, so I can no longer trust the values from the real car.

http://cgi.ebay.com/ebaymotors/2002-Honda-Civic-Si-Brakes-Suspension-Spindles-Acura_W0QQitemZ140199423618

[98 gt]

i thought you said it could be +/- 5"... 63" is only 5.1 inches wider than stock.
also, you could go to an axle shop and they could fab up the axle "rod" with machined ends to fit the inner and outer joints. thats what we did in a honda that needed some custom axles. also make ure to get an extra set of outer cv cups to put into the front uprights. you need them to keep the bearings inside their races.

[chetcpo]

Is it possible that the 5" comes from zero or opposite offset wheels rather than from longer halfshafts?

[JonW]

My Civic wheels were 45 mm offset (IIRC), and I bought 10 mm offset wheels for the rear so I widened the stock rear track by 70 mm or nearly 3". I'm still a bit narrower than I wanted so I might add some spacers to widen more. I'm not going to pay to lengthen driveshafts. The gain isn't worth the $.

(No, I'm not worried about increasing stresses on the wheel bearings since I put the Civic on a 1500+ pound diet.)

[proximacentuari]

Build Log Entry 2/4/08

I'm currently trying to negotiate the buying of a donor car. There seem to be two wrecked Civic Si's in utah; One at an Insurance Auctions Location and one slightly dented one at a salvage dealer for 5800. A price like this is making me consider buying an engine and everything on ebay. Although shipping would be exorbitant, so would the fees required to bid on an Insurance Auction. This thursday, I'll drive around to several junkyards and other possible places to get a salvage Civic Si.

On the frame, I've begun welding in earnest. I seem to have figured out how to produce pretty and strong welds. If there's a gap, I use low power to fill the gap. Then, I go over it again with a higher power/wire feed speed using a fairly quick back-forth movement (2-3 times per second). This produces a smooth weld.

Also, I've been looking at heim joints - I think i'll invest in four Aurora 5/8 cro-moly PTFE lined heim joints for the top ball joints on all four wheels. These are the same joints used in the At-om 2, I believe.
~$35 from pitstopusa

My dad said that it's possible to use bondo to smooth over ugly welds. Is this a good idea? I won't be entering this car in any regulated racing.

Will a knotted wire brush smooth out welds? I'm thinking about buying one to redo some of these welds.

Attached is a picture of the extra body tub tube that I put in for ease of getting in/getting out. Otherwise, the driver would have to step on the fiberglass tub.

[tomtom]

Dont worry so much about the appearance of the welds as much as their structural integrity. If you wont be entering any concours type events, I personally would leave ugly welds as is, provided they are strong. Pretty wont help you when the chassis fails at 90 miles an hour!

[violentblue]

once its done, primer your chassis, and see how it looks, if you don't like the welds at that point then use a little bondo to make it look nice. its more important that its strong than pretty.

[e30sho]

It’s tough not to be ashamed of ugly welds. Unfortunately, they’re part of the learning process. As long as they are strong, accept them as a stepping stone and move on. I like the bondo idea as long as you don’t need scca, nhra or some other sanctioning body’s blessing. When I have a cage that goes to SCCA I never alter the appearance of the actual welds.

Peter

[proximacentuari]

Gaaah...I can't believe this is so difficult:

Finding caps to weld on to the end of several of my chassis tubes.
Mcmaster Carr won't sell me anything thinner than a 1/2" disc. Help, locosters, where can a find 1.5", 2", 2.5" diameter thin steel discs for covering tube.

On the positive side, I'm about 95% finished with major tube welding. I probably should have payed for some gas to do MIG instead of FCAW, but it's done now.

[chetcpo]

Gaaah...I can't believe this is so difficult:

Finding caps to weld on to the end of several of my chassis tubes.
Mcmaster Carr won't sell me anything thinner than a 1/2" disc. Help, locosters, where can a find 1.5", 2", 2.5" diameter thin steel discs for covering tube.

On the positive side, I'm about 95% finished with major tube welding. I probably should have payed for some gas to do MIG instead of FCAW, but it's done now.

Buy a set of hole saws and some 16g sheet and go to work. You can always weld fill the drill hole.