LocostUSA.com

Okay, once again I am being drawn to the dark side and considering the Ar-i-el At-om for my build. They just look so much cooler than the locost 7. IMHO
I saw where some people were using 2 inch dom tubing but here in kentucky it is going for over 4 dollars a foot where welded steel pipe is about 1.25 a foot. Is the dom tubing a real have to or will the 1.90"OD X .120 Wall welded steel pipe work just as well. I don't mind spending the money when I have to but at four times the cost. Ouch

Brake lines and hydraulic cylinders are made of welded tubing. All square tubing like most 7s are made of us welded. It's fine.

The "seamless" and "DOM" specs some sanctioning bodies require for roll bars or cages is incompetent engineering. It was probably an attempt to prevent people from making load-bearing structures from muffler pipe, except they wouldn't come right out and say "don't use muffler pipe." Decades ago, when those rules were made, muffler pipe was grade-zero nasty stuff, prone to split along poorly-welded seams.

I paid $3/foot nearly 10 years ago. $4 doesn't sound unreasonable. You only need 2 lengths so this cost is small in comparison to the rest of your build costs. Why use something that weighs twice that to save $120+/-?

I don't think that many builders on this forum would recommend pipe for frame construction. How will you bend the 1.9" od pipe? Tubing-size bending wheels may be easier to source.

Not that I'm advising it, but there are hydraulic benders available that will do a good job on sched.40 pipe. Very common back in the jalopy days, but still much heavier than tube.

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Mike - Read my story at http://twinlakesseven.blogspot.com/

harbor freight has a nifty little jig that will bend up to 2" pipe. I've used one with pretty good success. they're not terribly expensive, and produce fairly clean bends. The trick is to fill the pipe/tube with sand. I ran into crimping issues with thinner walled stuff, and the sand in the pipe cured that. Makes it a bit more of a PITA, but I'd rather spend time than money.

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Tucker

The most recent 302's didn't have a distributor anymore. That was replaced by a little cap that covers the hole and has a position sensor for the ECU. Very tidy. The 302 is considerably smaller than other choices because of it's low deck height, 8.2" I think. The one on my build table is 22" tall from oil pan to top of intake manifold and that is a tall single plane manifold.

I was looking at that table of data and there are some other descrepencies, my 302 engine is 19" wide, not 22". I'm sure it's hard putting these tables together, so you have to double check things to be sure on your application.

I'm sure you can easily fit a chevy in too, SeattleTom is doing that in his build.



It's one of those good news / bad news things. The Ar-i-el is designed to show off it's frame and for it to be good looking. I don't think it's a as good a frame though and the lower part that hangs the drivers butt and the important suspension pieces seems like an after thought.

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

I tend to agree and I am looking at all options before I jump into it. I want something similar to a indycar but with seating for two. There is a car out there called a tramontana which I really like but by the time you put in the tandem seating and the mid engine it would be as long as a bus.
The complexity of the mid engine doesn't scare me as much as rolling the tubes for the Ar-i-el and making it all look right.

There was a how to description of bending those tubes written by "cheapracer" on this forum maybe about 3 years ago. I think that would be helpful I don't recollect a title for the thread. I remember some talk about the radius of the tubes etc.

Are you interested in older Indy cars? There has been discussion on some of the older roadsters, both Indy and a few others. I find them more attractive than newer cars, but admittedly less purposeful...

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Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.

Okay, I have decided to skip ate At-om and do the locost7.
I like the looks of the At-om but the seven just looks so much easier to build.
Would I gain anything (other than weight) by making some of the frame members (lower frame and suspension mounts) out of heavier wall square tube. I have even considered making the bottom frame from 1-1/2" x 1" tube stood up so the 1" side is on the horizontal.?

Round tube is lighter for the same strength, but square tube is so much easier to work with most people stay with that. There are some older threads here prosyletizing 1-1/2 or 2" tube instead of 1" tube; it's much stronger, but the extra width costs cockpit room. You could use a 1x2 tube for the top cockpit rail and fix that at a small cost of strength, though.

My system is to work back-to-front, starting with the flange-to-flange width of the rear end or transaxle. You take that, then juggle available wheel backspacing against cockpit width, noting room lost to the side rails and center spine. Then you decide how much room you need for your legs, the seat back, and pedal travel, and that gives you the front bulkhead distance. For a front-engine car, you then determine how much footroom you can give up to transmission and bellhousing intrusion before you can't operate the pedals any more, and that determines where the engine sits. To keep the wheelbase short, the rack and pinion goes close to the front of the crank pulley; most people use a "front steer" arrangement since most donor spindles are made that way.

The original Lotus 7 design had the engine pushed way forward. The little 1.1 liter flathead was absurdly small by modern standards; it was literally smaller than the Briggs & Stratton twin in my riding lawnmower. Since the driver sat right next to the rear axle, the engine was pushed forward to try to keep the weight balance near 50/50. That was important in the mid-1950s, for complicated reasons involving tires. Nowadays we shove our larger, heavier, more powerful engines back as far as practical since it's not a problem any more.

...helps to create a lower polar moment of inertia, as well...

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Scratch building, at continental-drift speed, a custom McSoreley-design framed, dual-Weber 45DCOE carburated, Zetec-engined, ridiculously fast money pit.

http://zetec7.webs.com/

TRX makes a lot of sense in his build strategy.
I am having a difficult time trying to decide which way to go with either a front engine or a mid engine. I think the mid engine is going to win out. Yes it would be a little harder to build but the advantages of having the engine behind the cockpit are many. Once I saw the midlana and the reasons he listed for going mid engine it really started to make sense. don't think I will be buying his book for 100 bucks but I might be building something very similar.
The 3.8 buick is a rock solid v6 and the front wheel drive buicks are cheap and plentiful.
Just soliciting ideas. All comments are welcome

It's hard to go wrong with the Buick... Brunton sure sold a lot of Stalkers set up for them.

The 4T60 automatic isn't particularly light, but it's reasonably strong. The FWD 3.8s and all 3800s had the "corporate V6" bellhousing bolt pattern and you can use any of the GM FWD five speed manual transmissions.

edit: the Wikipedia article below implies some of the newer GM four and six cylinder engines have different bolt patterns

Various other engines share the "corporate V6" bolt pattern; from https://en.wikipedia.org/wiki/List_of_G ... g_patterns that's

GM 60-Degree 2.8/3.1/3.4/3.5/3.9 L V6 (also used by AMC)
Buick 3300/3800 V6
Cadillac HT4100/4.5/4.9 L V8
Isuzu 3.5L DOHC V6
AMC/Chrysler 2.5L I4 found in Jeep Cherokee, Comanche, Wagoneer, CJ and Wrangler and Dodge Dakota
GM Iron Duke/Tech-4 2.5L I4
GM "122" 1.8/2.0/2.2 L I4
GM 5.3L LS4 V8
GM 3.5L LX5 "Short Star" V6

The Cadillac Northstar V8 doesn't *quite* use that bolt pattern, but it's close enough that you can modify the bellhousing or use a simple adapter plate; it's a common swap into Fieros.