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heinke 06-06-2018 01:40 PM

Modern-day Miura
 
This is a build diary for my home/scratch built Miura car project. I’ve been gathering information and planning the build for a few months now. I thought it was about time to share the project on a public forum as I’ve found comments and questions raised in this type forum are helpful to me and hopefully you’ll find the project interesting as well.

The overarching goal for this project is to complete a high performance oriented but comfortable street drivable car that has the beautiful looks of the Lamborghini Miura SV. I have made various car body pieces from scratch before, but not a complete car body. I plan to scratch build the Miura body myself in aluminum. This won’t be a replica or re-creation per se, but hopefully will look like a Miura to the average person on the street.

For those not already familiar with the Miura, here’s what a well preserved Miura SV looks like.

http://www.allmetalshaping.com/pictu...ictureid=18811

Miura with clips opened and as a cut-away.

http://www.allmetalshaping.com/pictu...ictureid=18812

http://www.allmetalshaping.com/pictu...ictureid=18813

A brief history is that the Miura was the first mid-engine, street oriented V12 powered “supercar” sold to the general public. It was built by Lamborghini in Italy, first available in 1967 to 1969 in what is known as the P400 model and 275 of these were built. It was upgraded to P400S model from 1968 to 1971 with 338 cars built in this model. The Miura Sprint Veloce or SV model was produced from 1971 to 1973 with 150 of this model built. What is fairly unique to the Miura is the transverse orientation of its 4 liter V12 engine that is located just behind the cockpit. The Miura came equipped with a 200 mph speedo and independent testing showed it to be the fastest street car of its time with a top speed of 172 mph.

My previous scratch built car project, a Ferrari 250 GTO, is almost complete (getting painted now) and has been 15+ years in the making. I’m hoping to complete the Miura much faster than that. A combination of not trying to do everything myself and now having more time for my car hobby should help. From the GTO project, I’ve found metal shaping to be the part I find most rewarding so I plan to do all the Miura body creation myself. The Miura is a very complicated car so my expectation is that this project will not be easy. I do think the resulting car will be very unique and I’m guessing the build journey will be as well.

Kevinb71 06-06-2018 03:03 PM

Looking forward to seeing how you tackle this! Should be very interesting.

Gareth Davies 06-06-2018 04:02 PM

One of the nicer looking Lambos, I think. Be nice to see this progress. What engine is planned for it?

Charlie Myres 06-06-2018 05:23 PM

Good on you Joel!

One of the prettiest cars in the World!

Looking forward to seeing how you do it,

Cheers Charlie

RockHillWill 06-06-2018 06:09 PM

Nice choice of projects. That is a gorgeous car. Keep us posted with lots of pictures.

csdilligaf 06-08-2018 07:49 AM

The Miura has always been one of my favorite cars. A friend of mine is the lead mechanic at a shop here in San Diego that's specialty is restoring Miura. Its really something to see 10 of them at once in different stages from bare chassis to finished all under one roof. Good luck with the build, looking forward to watching.

heinke 06-08-2018 09:42 AM

Quote:

Originally Posted by csdilligaf (Post 146815)
The Miura has always been one of my favorite cars. A friend of mine is the lead mechanic at a shop here in San Diego that's specialty is restoring Miura. Its really something to see 10 of them at once in different stages from bare chassis to finished all under one roof. Good luck with the build, looking forward to watching.

Chip,
Just out of curiosity, what's the name of that shop?

Thanks,

heinke 06-08-2018 11:55 AM

Forming a high level project plan
 
In a project of this size and complexity, it’s important to define priorities and from there form a good plan.

My top priorities are:
  1. Build a high performance car that I’ll want to keep and use for a long time. In other words, make a car that will be thrilling to drive but also comfortable to drive both around town and on extended trips. I’ve never owned a “garage queen” and don’t intend to start now.
  2. Stay true to the “spirit” of the original Miura but don’t restrict project choices to the ones Lamborghini engineers made over 50 years ago. To me, the Miura spirit includes a powerful transverse engine (i.e. capable of propelling the car up to 172 mph) placed in the middle of the car and with a body shape that could easily be mistaken for an original from 15 feet away.
  3. Take advantage of automotive technology advances by including them where it will make for a better driving experience but won’t take away from the Miura spirit in priority 2. Some modern technologies that quickly come to mind are things like EFI, ECM, and performance tires. The Miura was a very technologically advanced car for its day and there are still some areas where today’s factory cars (USA made anyway) and OEM parts are still catching up. I’ll want to strike the right balance between sticking to technologies used in original Miura and modern ones.

From these priorities, a few top level questions came to mind:
  • Can I comfortably fit in a regular sized Miura or do I need to go for a plus sized car?
  • What engine and transmission package should be used?
  • Will I need to build a chassis myself or is there a source where I can buy one at a reasonable price?

As it turns out, the answers to these questions are very inter-related. I’ll provide my thoughts and conclusions in subsequent posts.

crystallographic 06-08-2018 12:29 PM

Hi Joel,
You are approaching this new project with a clear sense of needs, fits, design and history.
Was interesting for me to note, years ago, that Lamborghini built very nice Italian farm tractors, and being very successful in the 1960's, went to buy a Ferrari. No luck - have to wait 6 months after placing your order.
"If the super sports car business is this good, I should get into it," he was reported as saying ...

csdilligaf 06-08-2018 07:22 PM

Joel, The Shop here in San Diego is Bobileff Motorcar. I have been friends with them for 15 yrs and do some machined parts that need recreated now and then. Gary, the owner is a Ferarri judge at Pebble Beach among others. They turn out some award winning cars. They once had the Muira there that was special ordered by the Shah of Iran. Always have 6-10 at a time for the last 15 yrs.

heinke 06-09-2018 02:32 PM

Regular or plus sized Miura?
 
Ok, so first off, I’m not your average sized guy. I’m taller than most at 6’ 5” and 225 pounds. But if I were an average sized guy, I’d build a regular sized Miura. The real question is if a regular sized Miura will be comfortable for me (at taller than average) to drive.

The most obvious way to answer this question is to find a Miura and take a seat. In reality, this is much easier said than done when you’re talking about a car whose value is around 2 million dollars. Well after working hard at this for a few months, I finally this week was able to track down a Miura and check out the fit.

Before answering the fit question, I’ve got to say that the Miura is even more beautiful in real life than in pictures. The car I found just happened to be a finely restored Miura being prepped for show at Pebble Beach Concorso Italiano this year, but still what a beautiful car. It even further strengthened my resolve for this project. I’d like to pass along my gratitude here to Geoff Provo of GP Enterprises (www.gpenterprises99.com) for getting me access to this Miura. He’s a real nice guy and quite knowledgeable about Italian sports cars.

Well the answer to the fit question is that I fit well enough that I could drive it but not well enough to safely drive it or call it a comfortable fit. The input from those in the know is that a 5’ 8” person fits a Miura very comfortably and people up to 6’ fit alright. Above 6’ and the angles in your ankles and knees becomes too great to be long trip comfortable.

So it’s a plus sized Miura for me. Now the question becomes 103%, 104% or 105%? Since the answer to this question is inter-related with the other top level questions, those questions need to be moved along in order to completely answer this question.

heinke 06-09-2018 06:02 PM

What engine/transaxle to use?
 
Absent other constraints, I’d use a V12 for this project. Given the original Miura had a V12, the smooth exhaust note of a 60 degree V12, and the distinctive scream at revs, I was really hoping I could make a V12 work. So what realistic choices of V12 engines are out there?

Using an original Miura engine is out of the question as they’re just not available. That’s too bad because they are very unique in that the engine and transmission are cast together in a single alloy block.

http://www.allmetalshaping.com/pictu...ictureid=18814

So while finding a workable V12 is already hard, finding one that can be hooked up to a transverse transaxle makes the level of difficulty go up considerably.

Of the modern OEM made V12s, the BMW M70 engine is still readily available and makes decent power. The downside is that the engine is fairly long at just over 29 inches, rebuilding costs can be high, and adding horsepower over the 325HP it came out of the factory with is quite expensive. The chassis I was evaluating (more to come on this later) has an opening 33 inches wide where the engine will go. 4 inches of space for a bellhousing, etc. was just not enough space to work with. The Jaguar and Mercedes V12s were even less amenable for various reasons. In addition, I’d like to choose a power plant that has a large, active community of people using and modifying it as well.

Hmmm…so after a few weeks of research, the V12 route wasn’t looking very promising. In addition, I needed to take into account the mating up of the engine with a transaxle. I really like the notion of transverse engine transaxle package because all the rotating parts, from engine out to wheels, are operating in a parallel plane. There is no power loss from needing to turn the rotation 90 degrees like in a standard hypoid differential. Also a transverse engine is needed to fit the spirit of the Miura.

So I started to seek out options for factory built cars that have transverse engines (both front and rear wheel drive). Transverse engine packages in front wheel drive cars and Fieros are common but almost all are either v6 or inline 4 and fall short on the power criteria (i.e. must push a 2,800 lb car at least 172 mph). I looked at Fiero V8 conversions using the F40 manual transmission but these make for a wide engine transaxle package given the transmission is basically inline with the crankshaft. Yes, people make this work in a Fiero chassis but that’s not the chassis I’ll be using for this project. I looked at racing oriented, sequential transaxles and the $16-20K price tag quickly scared me off.

The next path of investigation was to use a V8 along with a custom built transaxle. I have a friend, Pete Aardema that is a diehard DIY car guy with a soft spot for mid-engine transverse platforms. Pete had already built a couple street rods with transverse V8s in the back seat so he has both the interest and experience. Pete teamed with master machinist Kevin Braun to build the Chevy LS3 SOHC conversion on the engine in my GTO so I know they have the knowledge, experience and machinery that surpasses most prototype machine shops. Pete cranked out a pencil drawing with the concept and offered to scout up an engine for mockup purposes. His question back to me was, “What engine do you want to use?”

So what V8 both fits to the spirit of a Miura and is short in length? Well it needs to have alloy block/heads and overhead cams just to equal the 50 year old Miura technology. The Ford 5L Coyote has this plus 4 valve heads so some advanced technology to boot. The BMW and Mercedes V8s are also technically advanced (more even than the Coyote) but don’t appear to be separable from their OEM ECM/PCMs. I’d really like to emulate the Weber carbs visible through Miura back window with an 8 stack EFI system so this brings an aftermarket ECM into the picture. I checked and yes, there’s an 8 stack EFI for the Coyote that uses very realistic looking Weber like throttle bodies.

So there you have it, the plan is to use a Ford 5L Coyote engine, most likely a new Ford Motorsports crate motor as they look reasonably priced. The factory output of 435 HP with 400 ft lb torque should propel a Miura up to 172 mph and beyond. For the transaxle, we’re mocking up a custom bell housing/transfer case mated up to a Tremec TKO600 with a shortened output mated up to a Super 8.8 limited-slip differential carrier from a 2015+ Mustang IRS all these components meshed up with custom made helical gears. Ok, so I’m sure your heads are spinning from that last sentence. I’ll be posting pictures for the transaxle mockup after answering the chassis question in a subsequent post.

cliffrod 06-09-2018 07:55 PM

Very, very cool to hear Pete Aardema will be tangent or more to your build. I've only read about his engineering creativity, but really like what he does and can do.

I had the opportunity to look over a real Miura rebuild/reconstruction at Rick's shop last year. Pretty amazing work and equally amazing machine. the lines between complexity and simplicity are not as obvious as one might think.

I'm looking forward to your build.

Edit- especially now that it will have a Ford engine and more.

Charlie Myres 06-09-2018 08:40 PM

Quote:

Originally Posted by heinke (Post 146845)
A... I’d really like to emulate the Weber carbs visible through Miura back window with an 8 stack EFI system so this brings an aftermarket ECM into the picture. ...

Sounds great Joel!

Have you investigated Megasquirt? http://megasquirt.info/ programmable fuel-injection and ignition maps, plus a host of other useful functions, at a fraction of the price of most of the competition. It can be made to work on most engines and for those who want carburettors, Megajolt fits the bill and is the ignition part of Megasquirt,

Cheers Charlie

skintkarter 06-09-2018 11:43 PM

Great project Joel. I know it doesn't have a heap of horsepower, but what about a Lancia Thema 8.32 engine and transmission? Basically a 3.0l Ferrari V8 in a transverse front drive configuration. Sexy looking engine I gather based on the Mondial/308engine. They messed around with it according to Wikpedia and gave it a cross plane crank and smaller valve (4 valve heads). One presumes that a proper flat plane crank could be installed and the heads opened up or swapped out. Plenty of people around with experience of extracting more power from the small Ferrari V8's. Solves the transmission problem with no engineering.

neilb 06-10-2018 03:57 AM

Quote:

Originally Posted by heinke (Post 146845)
Absent other constraints, I’d use a V12 for this project. Given the original Miura had a V12, the smooth exhaust note of a 60 degree V12, and the distinctive scream at revs, I was really hoping I could make a V12 work. So what realistic choices of V12 engines are out there

how about a vw w12? this would also give you choices for a transverse gearbox

Marc Bourget 06-10-2018 09:43 AM

Heinke,


Considering what can be done with "additive" (3D Printing) machining, consider a "custom" transaxle. Use the 3D to create a pattern and have it cast up!

Superleggera 06-10-2018 01:04 PM

https://www.modenawest.com/HAMB/JoelMuira.png

Here is a quick example via digital restyling of lengthening the wheelbase on a Miura. A few inches in the engine bay (offsetting the internal firewall/bulkhead rearward for more cockpit space is an option), longer cockpit and 17in and 18in Campy style wheels (versus 15in original).

FYI: One negative of the Coyote engine is width and especially in a traverse configuration. You will need to determine the transaxle setup with engine before you know where the firewall (rear bulkhead) will go. A narrower engine (or head configuration) might allow you some additional cockpit interior space.

On a current de Tomaso Mangusta project for a customer, the Coyote option was skipped and the engine selected was an old school 289 with Gurney-Weslake heads because it was dramatically narrower. (It will get injectors with an ECM to modernize along with ignition system)

Red lines show offsets based upon centerline of rear wheel forward. (top image is "stock")

hlfuzzball 06-10-2018 03:44 PM

Speaking of Supercars:

Sold at Auctiion: 1963 Ferrari GTO for $70 Million ! Wow !!!!!

https://www.hemmings.com/blog/2018/0...ar/?refer=news

Methinks I've been priced out of the market !

heinke 06-10-2018 05:45 PM

Quote:

Originally Posted by cliffrod (Post 146848)
Very, very cool to hear Pete Aardema will be tangent or more to your build. I've only read about his engineering creativity, but really like what he does and can do.

I had the opportunity to look over a real Miura rebuild/reconstruction at Rick's shop last year. Pretty amazing work and equally amazing machine. the lines between complexity and simplicity are not as obvious as one might think.

I'm looking forward to your build.

Edit- especially now that it will have a Ford engine and more.

AC: yes, Pete Aardema and Kevin Braun are not only part of the project but are contributing a very key piece of the puzzle that I would not be able to do otherwise. I know they appreciate the recognition, so thanks for calling them out.

In addition Rick Mullin has also helped me out with some Miura cockpit measurements that I needed but couldn't find anywhere. His help was key in moving the chassis selection process forward.

Thanks for watching and thanks again to those who've already contributed with a helping hand with the project.


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