Potentia Build Thread

[sony1492]

I'll christen the Build Thread page with a "locost"

First the name, its Latin for force, power, or ability, deeply pretentious I know. Calling it the,"Lotus" or,"locost" all the time feels a bit awkward, its not added lightness like Collin Chapman originally designed nor is it particularly,"low cost" so I googled up something vaguely relevant in Latin and sent it.

What is it? Haynes, the company that publishes repair manuals for everything you can think of published a book on how to build your own car many years ago, there are various editions but the core concept is the same. A space frame made out of 1x1" 16ga square tube mimicking the design of the Collin Chapman Lotus 7 from the 1960's, its not a 1:1 copy but very similar. The book goes through how to build the chassis, suspension, and body using parts from a Ford Sierra, some common tools, and alot of time. Like all Haynes manuals there are missing steps and/or poor explanations, no two locosts are the same as everyone finds different ways around problems.

So after an expensive project blew up one too many times I gave up and scrapped the car, or course saving all the fancy bits. This left me with a spare engine, standalone ecu, 4 turbos, a bunch of wiring supplys, brand new fancy brakes, and a bunch of other expensive yet worthless parts lying around. Decided to double down and build a locost around all the parts as an -initially- cheaper way to make an awesome project car.



Started by mounting the turbos as close to the headers as possible, then went about making a wiring harness. In my infinite wisdom all inputs(every coil and injector) got a seperate power wire, the loom is unnecessarily thick but thats how it went for my first standalone loom. After that work started by measuring all the parts and roughing it out on a computer to decide on chassis dimensions, it ended up being 2" wider then the book with a 2" lower frame for turbo clearance. Some fiddling around with suspension geometry until my free trial ran out, decided how the front end would look.

Building the frame; after the basic structure was made the drivetrain decided everything else. The frame ended up being different then most locosts because the engine weight required alot more bracing along with the transmission being very large requiring a different footwell design.



After 6 months of chipping away at it, there's working steering, front suspension is done, and the chassis is 70% complete. Plenty of bits are in rough form though, the steering rack isnt properly mounted and the shock mounts on the LCA are wrong.

Overview: Toyota 4.0L quad cam v8, twin ebay gt28 turbos, ms3x ecu for sequential spark and injection, 550cc injectors, walbro 255 fuel pump, Nissan 6 speed using a Collins adapter, Ford s197 7.5" axle. Weight should be around 1,600-1,800lbs wet, though that could rise if/when it gets a closed wheel body. Horsepower will be 370whp and 400ft/lbs at 8psi.(based on previous dyno runs on the same drivetrain and turbos)

[RacinBob]

I presume the power to weight is similar to an old indy lights car......

[sony1492]

@racinbob thank god for modern tires

[interstate366]

Nice! I’d read up on your Locost build a bit on Kinja, but didn’t realize you were throwing your old 1UZ in it.

[sony1492]

@interstate366 this was a spare engine that had bad compression.

It made sense at first to build this using everyrhing that was already lying around

[Qaaaaa]

Whooooo. All that and a solid rear axle. Good luck!
For real though, I'm very excited to continue to follow this.

[interstate366]

@sony1492 that it does. I’ve still got my old donor H22 lying around if I ever have another Honda engine swap to do.

[sony1492]

@interstate366 2 months after our get rid of the h22 it an integra will present itself ready for a swap. Its the rules

[sony1492]

@qaaaaa not sure how updating a build thread will work on here but I'll definitely continue to harass the community with hackery

[interstate366]

@sony1492 said in Potentia Build Thread:

@interstate366 2 months after our get rid of the h22 it an integra will present itself ready for a swap. Its the rules

As my Prelude’s license plate says...

[rctothefuture]

Incredible! I'm always amazed at folks that can build chassis like these. It's my dream to some day build a Factory Five Cobra that can fit my 6'7" frame.

[sony1492]

@rctothefuture its pretty do-able if you've got the space and patience. This is by no means a professional effort, This frame is off in some areas but in my eyes its okay as long as its still "safe". When this gets finished, building a second chassis will go alot smoother with everything learned from the first.

You could probably get away with just lengthening the chassis by a few inches and mounting the seat on the floor. Bodywork to match would be less fun.

[davesaddiction]

@sony1492 Moved to Best of OPPO.

[sony1492]

@davesaddiction