Mid engine homebuilt supercar (Gruppe B meets Group 5 meets Grassroots)

Hi all; long-time listener, first-time caller.

I'm a Capriquarius born under a full moon, I like long naps on the couch, sitting around campfires, eating steaks and drinking rum.

This is an on-going monologue that I would like to turn into a conversation with the brain-trust, dreamers, skeptics, cynics and pragmatists of the community.

Having just hit middle age, I have an itch that must be scratched.

That itch is a self-built mid-engine "supercar" of my own design. When I say design, I really mean "a lil of this, a lil of that" but done cleanly, correctly, affordably and reasonably quickly.

I'd rather spend the time in the planning than the build. Not that I want to rush the build, but for me the build isn't the sole journey, the finished product is the inspiration for even more building, modifying, refining and tinkering. Basically this car is my early "retirement" project and life-long (what's left, that is) "love" interest. Don't worry, the wife already knows, and is actually supportive of my hobby.

I've been a fabricator and machinist most of my adult life. I have lots of cool tools, would like to continue filling up what little space I have remaining with even more cool tools. But most importantly, I have a real need to build something that comes from my heart and my mind through my own hands.

My first job after the Army was for a NASCAR team, back in the early 2000's. Since then, I've been chasing $$$ in the oil patch, building everything from gas compressor stations, CO2 injection units, downhole tools, to medical implants and satellite components.

I've never actually built a tube chassis before, but I've bent, coped, fitted and welded pipe for pressure vessels, steam-fitting, hydraulics and injection manifolds, so I'm pretty sure I can handle the fabrication end.

I've never built an engine from it's base components before, but I've swapped intakes, exhausts, cams and heads before. I'd like to try my hand at building my own engine, for my own car.

I've rebuilt and modified manual transmissions, quick-change and pumpkin rearends for dirt track cars before, but never a transaxle. I'd like to try my hand at building the transaxle for my car too.

I've built Cup car bodies to templates, fire-truck cabs, made patch panels, and sheet metal enclosures but never designed or shaped metal for my own car before. I'd like to build my own body for my car.

I've done some very minor projects with composites, a fairing for my Buell X-1, an airbox for an engine-swapped project, and a surfboard for one of my army buddies. I'd like to build some fiberglass bumpers and air dams for my car.

I've made patterns, modified and sewn several projects for myself...a vestibule for my canvas tent (elk camp), some purpose-specific packrolls, a rifle and shotgun scabbard, some storage panniers for my Jeep, and some sail-cloth shades for the back patio. But I've never done any interior work before. I'd like to upholster the interior of my car.

I guess what I'm trying to say is that my experience is broad in many respects, deep in several, but I'm not a master of any craft or trade. I'm competent in enough areas that I've managed to build my own business using those skills, but I've never had a "calling card" that I could specifically point to and say "I built that...that is what I'm capable of."

This is that and more. This is the car that I could never buy from a manufacturer...at any price...at any time...for whatever reason. Mostly because I have non-mainstream tastes, mostly because I'm a fan of very niche activities and goods, mostly because I'm part OCD, part introvert, part anti-bandwagon, and part masochist. I usually do things my own way, once I understand what I want, then decide how I'm going to achieve it without just throwing money at the problem.

This won't be a low-budget build, but it also won't be some narcissistic, bottomless-pockets, trend-chasing, tech-heavy build. Based on past experience, this will come somewhere between a used C6 Z06 and a C7 Grand Sport. The goal is a (mostly) analog driver's car, decent power (I really don't need and can't use 500hp...the nearest racetrack is 650 miles away), manual gearbox, overbuilt (possibly heavier than necessary), very little aero development, fast, fun, easy to drive, yet capable sports car of my own design.

Oh yeah...my inspiration is Group B/Group 5/Can-Am/Pike's Peak/Drift/Time Attack/Sandrail/KOH. This build will incorporate many attributes from all those diverse areas, while attempting as much as I can to be cohesive in my overall design and finished product. And more than a bit of my own personal eccentricities...mostly because I just dig certain elements.

Hopefully you'll follow along, interact, give feedback and shoot the poop with me over cars/motorsports. Can't say as I follow any one team, particular niche, or style, but I'm a gearhead through and through. I have a very diverse interest of the automotive variety and the only common denominator in my tastes is build quality, quirkiness and ESPECIALLY rebelliousness.

MY VISION:

Group B meets Group 5 meets Mad Max meets Grassroots.

RAW...not rancid or rotten.

Ruggedly handsome, not dainty and pretty.

Stout like a 4th generation Skandahoovian Minnesotan, not delicate like a hipster millenial snowflake without Starbucks, wifi and safe spaces.

Daily driveable without being a daily driver.

MY INFLUENCES:

Lancia 037. Ferrari 288 GTO. Porsche 956. BMW M1. DeTomaso Pantera. Bowler Wildcat. Milner R5. GMC Syclone. Herb Adams' FireAm, Cheverra, and SilverBird. Dallenbach's Coyote chassis Pike's Peak racers. I could go on and on and on and on...

MY GOALS:

Excellent handling. Dead-nuts reliability. Exhilarating acceleration. Eye-straining deceleration. Affordable maintenance, replacement and upgrades. Bare maximum overkill on chassis rigidity and survivability. Maximum use of OTS parts, no custom parts unless they can be made in-house. 

MY PLAN:

Chassis;  Semi-monocoque/space-frame chassis. Welded steel members, firewalls and floor. Removable panels for maintenance access. Appropriate materials for appropriate tasks (no bling for bling sake, no CF, no titanium, no exotic materials). Integrated roll-cage.

Suspension; IFS & IRS. A-arm only, no trailing arms, no radius links, no multi-links, no strut-based suspension.

(I'm struggling with what I want vs. need on this one. I have some options that I'm mulling over currently.

Corvette C5/C6/C7:  Plusses-proven components. Minuses-availability over time, stock geometry leaves a lot to be desired for mid-engine repurposing.

Repurposed/modified circle track parts:  Plusses-proven components, massive availability, affordable components, virtually unlimited geometry adjustability. Minuses-limited selection of appropriate spindles, lower arms, and increased maintenance regimen.

Custom built: Plusses-can be whatever I design. Minuses-will be whatever I design!

(Rocker-arm/pushrod/pullrod suspension has intrigued and infatuated me since their discovery.) 

Drivetrain;

Engine: Coyote V8 vs LS V8. Only 2 options I'm considering. Not open to other alternatives.

Gearbox: Mendeola S5 vs. Weddle HV-25. Sequential vs. H-pattern. Basically comes down to engine choice in this matter.

Axles: Sway-a-way sand car axle shafts, 930 or 934 CVs.

Unit hubs: C5/C6/C7 vs. 5x5 Ford F150 (mid-90's). Depends on CV choice - 930 vs 934.

Ancillaries: Dry-sump. Mandatory. AC/power steering - depends on numerous factors, nice to have, not must-haves.

Brakes: C5/C6/C7 vs. Wilwood. Depends on suspension choice. Extravagance - ABS. Only 2 options here, nice to have, not must-have.

Radiator: Pantera vs. GT40 vs. Fiero vs. circle track. Depends on availability, cost and plumbing strategy.

More to follow.

Kindred spirits! I can't wait to see what you conjure up.

Welcome to the silliness, Gingerbeardman.

Looking forward to more details as you decided what you want.

Welcome to the hive...Your plan seems to have been fermenting for some time.  Does this post mean that you are ready to put fire to steel or is there a CAD phase that will happen first? That would help communicate the vision. Is there a timeline for this?

Pete

I'MA so Happy you dropped in. We Think Alike But I'm on the Cheap, So I Have Lots of Ideas for someone with a Vision and some Cash, Gotta run right now But your On!.

You have a Buell. We can be friends.

Oh, and I can't wait to watch your plan unfold here.

You're more adventurous than I, but I would start with the easy one: I would say LS over Coyote, given your plan.  It's smaller, and makes great power (add turbo?) - I'd go with the aluminum block version.  If you went with the LS, what dependencies does that entail?

This is going to be cool.  Sounds like the concept is remarkably close to a Palatov D2, which isn't a bad thing at all!

Looking forward to it! And welcome to the madness. 

A wild challenger to the Ferrari thread appears!

I will add for rebelliousness sake, forego the steel tubing as much as possible in the structure. Folded 5052 aluminum monocoque with just enough steel to make suspension mounting easy. The steel tube space frame has been designed to death by the Locost community. No welded aluminum, just rivet & epoxy. Look at sports 2000 class cars for inspiration, also McLaren M8.

In reply to Gingerbeardman :

Time

Im sure you can do it if you really want to but assuming you have everything on hand and the misc money that is always needed, you realistically are talking about 3500 man hours.  

That’s not time in the shop, that actual working time.

Professionals who do this all the time will and can spend less time.  

TurnerX19 said:

I will add for rebelliousness sake, forego the steel tubing as much as possible in the structure. Folded 5052 aluminum monocoque with just enough steel to make suspension mounting easy. The steel tube space frame has been designed to death by the Locost community. No welded aluminum, just rivet & epoxy. Look at sports 2000 class cars for inspiration, also McLaren M8.

I have to agree here. 

but first, welcome, and I look forward to whatever you come up with!

In reply to frenchyd :

Nobody said it had to be ready for this year's challenge!  Proof that it can be done is the Molvo; going to guess there is around 4000  hours into the project over 5.5 years calendar time. 2000 hours/year is ballpark for a  full time job. I see the proposed project in the same ballpark.

Pete

In reply to NOHOME :

Pete; I wasn’t suggesting a schedule, simply an idea of the time involved. 

What about an 88 Fiero with the Getrag F40 six-speed trans used in the Pontiac G6 and a mildly breathed on LS4?  Custom suspension based loosely on stock with custom control arms, whatever hubs and axles, etc etc, and then glass in some flares to cover it all.  

In reply to pres589 (djronnebaum) :

Original poster wants to build a car, not convert an existing one. He means to build the chassis.

In reply to Robbie :

Staniforth's source book 4th. ed. p 16. 

Can't link picture at the moment.

Add suspension and drive line to the bulkheads and tie together with a safety cage.

Done.

It was mentioned above, but I was going to suggest converting an existing chassis as well.  There's still plenty to do to make it 'your own' but it cuts out a bunch of details that aren't much fun to design and can really bog down a project.

In reply to NOHOME :

This HAS been brewin' & stewin' for some time...over a decade now. It all started with a Factory Five GTM that I grew increasingly frustrated with as my build progressed. That's a story for another time.

I'm an inveterate (or is that degenerate...I always get confused) planner. This will go through several renditions in CAD before any metal is cut. I'm past the paralysis-by-analysis phase, I'm into the pragmatic phase now. Best bang for buck. Whatever will be most hardy, reliable, affordable. Pretty much in that order.

In reply to GTXVette :

I have nothing against cheap (though I prefer frugal...cheap is the result of inferior source stock, methods and care) I'm just past the disposable toy phase of my life. Basically from here on out, I'm buying for the long-haul.

I know what I like and new, modern cars have gone sour on me. I like my tech stable & mature. Mid 90's to early 00's is the sweet spot for me, tech-wise. That and 70's iron. Mmmmm...IH Scout, Bronco (orig not II) and Jeep are my go-to's for offroading.

In reply to FSP_ZX2 :

I loved my Buell. Unfortunately after hydroplaning then high-siding it on I-95 after a brief squall, I realized my talent on 2 wheels was finite & limited. A severe reprimanding by my company command while in hospital provided all the encouragement I needed to gravitate towards a "cage". 
I still find myself browsing Craigslist for Buells occasionally, now that I'm home in the land of cows and deer. 

In reply to FIYAPOWA :

I'm very receptive to the LS platform. Between a few swaps I've helped with and my work DD, I've become an ardent admirer of that engine series. Bang for buck is where it's at for me.

Turbo...(where's my drool bib?!?)...an intriguing possibility as I live a mile above sea-level and my favorite driving roads are all in the mountains surrounding me. Downsides are added weight and complexity. Not totally off the table yet, but between a first time chassis build, first engine build, etc. building a functional, robust turbo system might be stretching myself thin. Definitely an option into the future however, as I intend to keep this car until I die.

The only thing causing me to vacillate between Coyote and LS is something visceral and petty...Coyotes rev and drive like a Euro engine with a much better torque curve...I want a Ferrari-esque scream. And yet, they ARE more expensive to build, and other than sound, I'm not finding many other reasons to go that direction.

In reply to Mndsm :

I only hope I could live up to the hallucinogenic fever dreams of that lunatic (the best kind) mk_e!