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Learning how to build Lotus Seven replicas...together!
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PostPosted: November 19, 2016, 7:50 am 
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Joined: November 19, 2016, 7:14 am
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Hello all. Been lurking for a little while, thought I'd join and see what kind of pointers and direction I can get from anyone willing to lend a word.

I've been working on the side as a shade tree mechanic/ GM computer tuner for almost 2 decades. I know my way around just about anything on a car, at least fundamentally. I have limited welding skills, consisting mostly of being able to stick farm equipment metal back together. My son, however, has been welding for some time now and is praised for his abilities.

I have acquired a 2006 Impala SS in it's entirety, with a GM LS4/4T65E transverse mounted (AKA FWD). 303 hp/323 tq but a pretty heavy package. The car was a slide-off total, having experience a telephone pole after of the passenger side front wheel near the A-pillar. However, it still runs/drives perfectly fine, and all the damage appears to be confined to unibody and door/front fender. A nice custom chassis should make it much more enjoyable to drive, and I'm thinking we'll be able to save a bit on the 3700lb waistline.

Initially I was going to transfer the running gear into a good Impala body and sell. However, after seeing a home-built A-tom wannabe ( https://www.youtube.com/watch?v=m_aVLRuOg_o ), I was inspired to make something similar. Since then I've been poring over pages looking for aesthetics and design ideas.

I'm NOT looking to build a show car, or the fastest thing on the road, or the best handling SCCA car, or anything of that nature. I want to build a "fun" car that my boy(s) and I can say we built most of. That being said, as with anything of this nature, cost is a component, so I'd like to keep that down where possible.

I'm not against a pre-prepped plan, particular for sub-assembly aspects like the front suspension/steering arrangement. I would like to keep most of the running gear (uprights, brakes, etc) in easy-to-obtain parts. Of everything I've seen so far, something similar to the Palatov D2 front end styling on the chassis would be ideal. If I could get plans in hand for the D2 from rear-line/back wall of cab forward, and then fabricate my own rear engine mount, etc that would be ideal.

So - things I'm most interested in hearing about:

Shareware/low cost modeling software. I have Sketchup (and have limited experience with CAD from 15 years ago). Guides for suspension design, space considerations, minimizing structural tubing requirements.

Good discussions on suspension/steering geometry and the various tradeoffs. That said, a basic, pre-determined, easy to fabricate, durable front end that won't make a driver white-knuckle it everywhere would be sufficient. I would just love to learn more about it on the way.

Square tubing vs. round tubing. Keeping in mind costs and not making an all-out performance/competitive machine, square tubing seems the way to go for cost and ease of prep. I'm open to arguments against this. Also, I have no experience with relative strengths, treatments, etc - so choosing a size to adequately protect my occupants seems somewhat daunting.

Road-legalizing. I want to design with this as an end-goal, which I'm sure means there will be some compromises compared to some of the designs I've seen out there. I live in Kansas, which has very little published information for what makes a vehicle "roadworthy", but uses the term frequently. Any real-world experience would be nice. It doesn't seem to be too stringent, as the road-legal buggy crowd has plenty of dubious entries. I'd prefer not to present the same.

Any of what I'm sure can be a very long list of considerations that I haven't thought of. I have plenty of space in the form of a 64x80 shop and a two-post lift for those hard to reach places. I'm also fairly intimately familiar with GM LS engines and drivetrains, although this is my first transverse/LS4.

Sorry for the book as a starter!

Jon


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PostPosted: November 19, 2016, 12:21 pm 
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Joined: February 8, 2014, 10:47 pm
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Location: Cornholio OR "Where the magic happens"
I would consider only using the power train parts.

Doesn't the SS use struts? Ewww, not sexy and have lousy camber characteristics.

You need a goal so you can focus your choices. You also need time, space, and cash.
You goal should also be realistic within your reach and means.

My first goal is something I would not be embarrassed to be seen in.

My second goal would be to spank some Porsche/BMW/Corvette ass.

Third goal would be street legal, although not something you would be comfy taking a trip in.

A Middy offers up some interesting packaging challenges but it is do-able.

Pretty sure there area some plans posted on this site that you could fold and spindle to your needed specs.

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PostPosted: November 19, 2016, 7:43 pm 
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Joined: January 28, 2016, 7:59 pm
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Location: Omaha, Nebraska
I'll throw in a few thoughts here:

First you really need to find a design/shape/aesthetic that you like. If it doesn't look cool (at least to you and your boys), you'll get tired of building it, and even tired of driving it.

I liked drawing ideas on paper for the first step in design. It's fast, fairly unscientific, and allows you to quickly dismiss ideas that just don't look right. After that, I put the ideas on graph paper so that I could nail down the proportions that looked right. I personally didn't do any design on computer, but I think the time to do it would be either after the broad-strokes phase or after the graph-paper phase.

Seriously consider buying a bender and working with round tubing. You'll need it for your roll protection anyway, and when exposed, I think round tubing looks much better than square. Round tubing is actually easier when you're making connections at various angles in 3D space.

Second, I'd think about safety. An LS powered car that weights any less than 2500 pounds is a very fast car. I suspect you could end up with something under 2000 pounds if you prioritize lightness. I would highly recommend at least a NHRA or SCCA spec roll bar, sufficient frontal structure to absorb impact, and good quality racing seats and harnesses.

Third, I would try to use the entire stock front suspension setup for the rear of your build, even the subframe. I think you could make the geometry work well enough for your purposes by repositioning the tops of the struts. It will cut the build time for this car by a huge percentage, it will reduce cost by a lot, and the most complicated/expensive part of the car will be of modern GM quality. It's true that the camber gain of struts is not awesome, but there's also something to be said for very little camber gain in the back of a very powerful car.

That's a lot of benefit to give up for the possible improvements to suspension design and geometry, unless your intended level of performance is extremely high or you are interested in implementing your own design.

Have fun.

-Graveyard

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PostPosted: November 19, 2016, 8:45 pm 
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Posts: 149
Hi Jon,

First, congratulations on starting, and joining the mid-engine mayhem. There are several interesting middy builds on here, and we can always use another set of ideas.

Second, I am in awe that you are doing so with that LS4 piece of iron (OK, Aluminum) for motivation. I considered the LS4 for my build because, well, V8! :twisted: So I have cylinder envy. But donors were scary expensive here, and sourcing a manual was not in the cards. And as Dismantalus would attest, getting it registered in NJ on an ongoing basis would be tough. I envy you your state's common sense as well.

About your thoughts, yes, the Palotov is an awesome example. I think, if you squint really hard, you can see a way to go directly from Kurt's Midlana to a Palotov shape. I thought about that shape for my build too, but love the can am look and the short overhang of the Bauhaus style, so mine is going to look different in yet a different way. Probably train-wreck, but it will be a very fast train wreck, and it will be mine.

Square tube will work just fine, BTW. Since you are using body work, most of the tubes will be dead straight anyway, so not to worry. Round is good too. Pick your poison, or choose based on need for each part of the car. It will all work out in the end.

My single piece of useful advice is to buy Kurt's book "Midlana". It is breathtakingly expensive, but very well written and quite comprehensive. Worst thing that happens is that you get great ideas and inspiration for the completely bespoke approach you undertake. Money well spent.

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PostPosted: November 21, 2016, 5:34 pm 
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Bent Wrench - Yes the Impala has struts up front. While I have to agree that they are not sexy, I intend to eventually have them hidden. I'm also thinking that long-term I might be doing several "versions".

Can you define realistic? ;-P I have lots of space, lots of time (I'm not in any rush, but like many I'm quite impatient), and while I can't say money is no object, and I want to minimize cost, I make a good living so I don't expect there to be any cash crunch. I expect that in the end I will have $10-15k and potentially 1000s of hours into the project - which seems to be realistically in line with a lot of the projects that have posted estimates.

Omaha - I'm also a fan of the drawings, and have been working on some. I have my first few drawings done, not pretty, but giving me a good idea of what I want to do. I'm not as good at integrating all of the bits I want to do on one drawing, so I'm going to be fleshing out individual characteristics/angles.

Is there a good sticky/thread on benders? I'm completely unfamiliar with using them, so I don't even know where to start to get a good one and the proper dies. I was also looking at tubing pricing vs. square tubing, and while generally round tubing was preferred, it seemed to be more expensive. So my cost vs. benefit comparison seemed to favor square tubing since I didn't need any special tools really. I have a good chop/mitre saw and blades aren't an expense I'd likely even calculate in.

I like your idea on using the entire front end of the Impala including struts. I'm not overly concerned with making this the ultimate machine right out of the gate. I recognize there will be a significant learning curve, and trying to make everything perfect the first time out is probably not a wise choice on my part. Functional, sturdy, light, fast... and then maybe good looking once I get a hang of custom glasswork. One thing I was considering was to have 2 subassemblies to the chassis, the cab/front, and the engine carriage. That way, during a winter I can pull the engine sub assembly and mock up a better rear if I so desire (I bet I will, but I'd love the experience of doing multiple iterations).

Omterry - I have seen the midlana site, and have already considered a few manual purchases. Are there any others that you recommend? I will probably eventually do one of those types as well, particularly for the better weight balance.

Thanks guys for the replies, it's definitely keeping the gears turning!


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PostPosted: November 30, 2016, 10:42 pm 
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Joined: May 13, 2016, 9:28 pm
Posts: 29
If you don't want to re-create the wheel, This engine/trans combo has been swapped into the back of Pontiac Fieros. You'll need the ECU, harness and gas pedal (I believe that car is drive by wire). You'll have a helluva sports car when you're done. Just my 2cents. Vinny


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PostPosted: January 13, 2017, 3:34 am 
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Joined: November 19, 2016, 7:14 am
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Still researching and looking at ideas. I've been thinking more and more about using the entire front drive and suspension in the back, and came across the DFGoblin... a lot of good photos and information on that build. Basically exactly what I want to do, but with a Cobalt drivetrain instead of an Impala.

Also, after looking at the Factory Five kits, I'm thinking square tube for the basic structure and then some round tube for the few exposed areas. With limited round tube I think I can source it without having to get tube bending equipment.

I'll have to comb through some of the LS4 Fiero threads. I have PCM access through HPTuners, I'm interested to see if there are any BCM modifications that I will need to make with the system not being in the original chassis.

Jon


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PostPosted: January 14, 2017, 1:27 am 
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In our cars struts are more doable in the back than the front, but the height of struts is hard to work with.

If you don't use struts what I recommend for this is the old style suspension used in the 60's-70's with trailing rods on the sides and reverse wish bone for the lower arm and a simple radius rod for the upper. This setup means you only need one bulkhead to mount the suspension arms to. For a regular locost this is just the bulkhead behind the driver. For your setup I'm not sure how that works with a transverse engine. The GT40 and all the formula cars of that era used this.

If you decide to go past paper and start with SketchUp we have a library and other exanpls of cars that you can just grab parts from. Not a huge amount and maybe not the pieces you are using though. I found it helpful, but it can also chew up time. Some of the year it's pretty cold in my garage so that helped with the time.

Keep an open mind as you are drawing. Having parts on hand is good, but sourcing a strong diff and a transmission are pretty easy too.

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PostPosted: January 21, 2017, 11:48 pm 
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Joined: January 5, 2017, 9:19 am
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I'm not sure an LS4 drivetrain would fit into an unmodified Midlana build (likely too long), but I'd strongly recommend Kurt Bilinski's Midlana book. $100 isn't cheap, but it's totally worth the cost for such a concise A to Z treatment of building and fabricating a car.

He gives lots of drawings and ideas for the entire car, so I'd say you'll easily get your $100 out of it.

Also look at what Fiero guys do for LS4 swaps. Some might apply.


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PostPosted: February 14, 2017, 12:25 pm 
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Joined: February 18, 2013, 9:37 am
Posts: 33
I really like what this guy is doing, but I can't find a build log anywhere. not sure it would fit that design. I do like the ls4 option to try to do something.

Martinavayerd.com



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PostPosted: April 27, 2017, 12:33 am 
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I plan on purchasing the midlana book, I'm still in the planning phase but intend to start sometime late Summer. I have 3 other projects to finish and sell for starting funds (96 Tahoe 2 Dr that's all but complete, 92 Full size Bronco that needs and engine and paint, and a 99 S10 ZR2 extended cab thats 80% through a V8 swap). Then the build begins. In the meantime I've taken a few moments here and there to strip the Impala, and it is remarkably easy to disassemble.

I'm still torn on round vs. square tube. I'm intimidated by bending, but it seems strength and aesthetics are much improved with the round tubing.

I also like the martinavayerd concept, but I plan on mostly or fully enclosing the cockpit. The locost design will be hidden underneath a partial if not full body. I've been reading/watching a lot of fiberglassing information and will shortly be practicing with the materials for various small-scale projects.

As of now, it all seems so far in the future. I'm firmly resolved to doing this however (I was offered a significant value gain for selling the SS, and was not tempted in the least).

Jon


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PostPosted: April 28, 2017, 4:25 pm 
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Joined: June 5, 2016, 7:03 am
Posts: 119
Location: ontario
Hi Jon, welcome to this list.
Yours sounds like a remarkable project. 300bhp+ moving a locost that you could build under 2000 lbs. You won't have to make it "exciting" it will be exciting . If you are going to show the tubes (Ar-i-el? exoskeleton?) I would say go for the round tubes. A bit more trouble to miter (fishmouthing) but it will look better. Your power train is likely to be on the heavy side, so make the chassis accordingly. You may want to look at files that were written years ago by folks who wanted to plug large V8s in Seven bodies and had to upgrade the chassis.
My second Seven is a rear engine with IRS (from a 1965 Corvair). I had to spend a good deal of time looking at weight distribution, trying for instance to emulate the Porsche 911. Useless to say that behind the seats the engine bay does not look at all like Ron Champion's Book design. Useless to say too that I have moved as much weight as I could to the front end (fuel tank, spare tire, battery, etc) and move the seat forward by about 12". You are likely to face similar challenges. Your car too will be essentially a rear engine machine rather than a "middy" . Keep us posted. :cheers:


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PostPosted: May 31, 2017, 9:21 pm 
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Location: Mooresville, NC
merim123 wrote:
I really like what this guy is doing, but I can't find a build log anywhere. not sure it would fit that design. I do like the ls4 option to try to do something.

Martinavayerd.com



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He's actually responded on here, not too long ago about it. He has an Instagram with some updates as well.

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PostPosted: May 31, 2017, 11:19 pm 
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Joined: February 8, 2014, 10:47 pm
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Location: Cornholio OR "Where the magic happens"
A turbo'd banger would be easier to package.

The V8 will move the cabin forward over a banger which gets tricky when you want to keep the wheelbase short (proportional).

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and Hillary is the engineer!


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PostPosted: July 15, 2017, 1:58 am 
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Location: Washington and California
They install that LS4 motor in MR2's so should make a nice car. I am thinking of installing one in my Midlana. Rough measurements says it fits were my Honda K24 is now.
I would love if someone else started one.


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