Lonnie's Mustang V6, "Steal with Both Hands", Locost
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Author:  Lonnie-S [ January 5, 2009, 10:54 pm ]
Post subject:  Lonnie's Mustang V6, "Steal with Both Hands", Locost

It’s definitely a start! After several years of dreaming, lurking, and yes, finally acting, I do have the start of my Locost sports car. It is a 1994 (A/K/A SN-95 or Fox-4) Mustang and it will be my single donor solution. After spending some months looking at different possible donors this one was the right one. It has the 3.8L V6, a T5 transmission and the Ford 7.5” live rear axle at the right price. My original plan was to have the drive axle be IRS, but I feel the advantages of the Mustang far outweigh the only real negative for this donor; a live rear axle.

The 7.5” axle is light enough to be acceptable performance-wise and the use of a Mumford link will give me a low enough roll center to get the kind of handling I want. It can handle the horsepower I expect to put out and you can get a brand new Traction Lock setup for less that $200 from Ford Racing; even less for a used one. My prior experience with the 3.8L V6 was very good and it’s tendency to blow head gaskets at higher horsepower can be overcome with the right parts and machining. It definitely pushes the 3,100+ pound Mustang briskly even in stock form (the SFI engine is real sweet), so I know it will be outstanding in a Locost, which should come it at 1,500 lb. or so.

My build log will start out slowly and first fill with revised chassis models. I’m basing my build on the Gibbs/Haynes roadster chassis. Obviously, since that design has a Sierra/Merkur IRS, some retro changes will have to be made. Yes, I could use a Thunderbird or Lincoln IRS instead, but that would take a lot more redesign and I think the 7.5”/Mumford Link combination will give me what I need plus be a simpler, one-donor solution. It also turns out that the Mustang front end can (most probably) be employed by using the spindle extensions available from Griggs Racing in Northern California. They have been using that solution for very successful Mustang race cars over the last few years, so I feel confident they are suitable for service in my case. That is assuming the resulting suspension geometry works out, and I think it will. Otherwise I’ll buy Mustang II front spindles and then use my SN-95 hubs and brakes.

I don’t plan to disassemble the Mustang right away. I’m going to solve all the known problems while it’s still in one piece and enjoy driving it while doing so. That way, I’ll start with everything known to be in good working order while it’s easiest to diagnose – in the original car. Boy, I may even try to use the bucket seats out of the ‘Stang. Man, they are really comfy! But, for right now, I’ll be doing lots of researching, designing, planning and re-arranging of my garage before I start creating the actual Locost chassis.



File comment: It's In There!
First-Build-Photo.JPG [ 171.93 KiB | Viewed 32967 times ]

Author:  Lonnie-S [ January 5, 2009, 11:18 pm ]
Post subject:  The Donor Unmasked

It's actually in pretty nice shape for a donor. In fact, it could easily be salvaged as a great project in it's own right, but it is destined to be much happier and prouder as a Locost 7.

Small-Build-2.jpg [ 139.87 KiB | Viewed 32949 times ]

Author:  IndyJoe [ January 5, 2009, 11:32 pm ]
Post subject: 

Great to see you getting started Lonnie. Wow that 'stang looks mighty fine, like you said almost a shame to break it up. Let the fun begin!

Author:  Blackbird [ January 5, 2009, 11:53 pm ]
Post subject: 

You've been stuck 8) .
Good luck with the build!


Author:  Thinkkker [ January 6, 2009, 5:03 pm ]
Post subject: 

So I take it that the unibody is the only thing to be left on the car. That looks like a decent start for a V8 to go in and make a CMC/AI car :).

Are you planning on 99+ heads and intake? I would think that this would be a sweet, simple, and NEEDED :) thing to have.

PS, I may be in the market for parts you want to get rid of :)

Author:  Lonnie-S [ January 6, 2009, 8:31 pm ]
Post subject:  Remainder Will Be Sold for Parts

Yes, after I remove all that I need, I do plan to sell the unibody, glass, interior, etc. for parts. I'm probably 3-4 months away from deconstruction, however. If someone wanted to make a race car out of it (road, drag, drift, etc.) the shell might be ideal. For those purposes, all the parts I need would be discarded anyway for heavier duty ones or for a V8 and heavier rear axle.

Author:  Lonnie-S [ March 31, 2009, 7:09 pm ]
Post subject:  March 31, 2009 Progress Report

It looks like nothing is happening with my project, but there's actually a lot going on that just doesn't photograph well. Here's the lowdown as of today.

1) I've got the evaluation version of SusProg3D and I'm learning it's capabilities. I'll need to redesign the front and rear suspension of the Gibbs chassis to suit my 1994 Mustang donor. It's a very interesting program and I think it will help a lot with the design tasks. I fully intend to buy the program when I get to the stage where I have all the critical measurements of the donor suspension pieces and can actually be doing it for real.

2) In the mean time, I'm busy reading the best suspension design how-to books by Allan Staniforth, Herb Adams, Len Terry and Collin Campbell. I love the stuff, but "my head runneth over" although it is starting to sink in little by little.

3) I thought I'd found a solution to converting the '94 Mustang strut uprights to SLA front suspension. I've not found a 100% certain solution, but one vendor has pieces that extend and convert the Mustang uprights to SLA and they have been used successfully in racing, so I think there's a solution out there. However, I haven't got the definite commitment of the vendor that it will work - yet.

4) When looking at the Renault Cleo radiator used with the Gibbs chassis, I know there is zero change a unit of that size will service a 3.8L, Ford V6 even stock, and I plan to get it up to perhaps 250 HP in the final, installed state. I need see what other have done for cooling with larger engines and see what impact that will have on the design of the front frame.

5) I'm half way through a great welding class at my local college and learning all 4 fundamental electric welding processes: stick, TIG, MIG and flux core wire feed. Stick welding sucks, but I love TIG and I know the cheaper MIG process will cover the basics of steel and aluminum for the Locost. I don't think flux cored is the way to go, so it's a choice between TIG and MIG, which I'll have to make in a month or two.

6) Last, but definitely not least, I'm proceeding along very well with my Advanced SolidWorks Class. It's been very challenging, but exciting as well. Thankfully, the instructor is a total car guy and he is letting me model the Gibbs chassis from the Haynes book as my final project for the class. That's not due until May, so I've got a pretty good window of opportunity to work on it. I'll attache a screen shot of what I did today, which is just the bottom, main chassis rails plus the front frame. Much remains to be done, but progress is being made.

15 April 2009 update:

7) The SolidWorks model continues to grow. It's been a very interesting process. Many of the dimensions given in the book are suitable for actual construction of the chassis in (real life) metal, but not that useful for SolidWorks modeling. Of course, the purpose of the book IS to make it possible to construct it, so it's working exactly as designed. However, when you need to make a 3D model from the book, a number of dimensions for the chassis members must be calculated and placed accurately. It's not practical to create every piece-part from the appendices and then assemble them together in one big model.

For example, constructing member D7 as shown in figure 4.8 takes some doing from a SolidWorks 3D sketch so that when trimmed to lower chassis rail BR5 the forward, upper end of D7 ends up lying 491.5 mm from the back edge of BR5. It can be done, but it isn't trivial. Hopefully, an updated snapshot of the chassis will appear below.

File comment: It is now just about at "second stage" as Chris calls it.
Stage2-Gibbs-Locost.jpg [ 174.19 KiB | Viewed 29849 times ]
File comment: It's a start!
Small-Btm-Rail+Front-Frame.jpg [ 36.84 KiB | Viewed 32602 times ]

Author:  SamM [ April 1, 2009, 10:04 pm ]
Post subject:  Re: Lonnie's '94 Mustang V6/Gibbs Chassis Locost

Why not just use Mustang II spindles to eliminate the problems? My donor is a 1987 Ford Thunderbird Turbo Coupe with the oddball 4-lug bolt pattern. The new Mustang II spindles cost me $164 from Speedway Motors. The rear 8.8 axle from my Turbo Coupe will be converted to the same 5-lug pattern as my front brake kit (also from Speedway) with Ranger axles. The car will use 2007 Mustang LX aluminum wheels. The brake kits use GM metric calipers and standard Ford rotors.

I'm not sure if it's Locost or not but my car will use parts that are easy to get anywhere.


Author:  Lonnie-S [ April 2, 2009, 9:22 am ]
Post subject:  Re: Lonnie's '94 Mustang V6/Gibbs Chassis Locost


The Mustang II setup is my fallback position. I'm trying my best to keep this a single-donor project. As you mentioned, switching spindles introduces other issues such as brakes, wheel bolt patterns, etc. If I keep the '94 setup then I can use everything including wheels, which should save $$$.



Author:  SamM [ April 2, 2009, 9:39 am ]
Post subject:  Re: Lonnie's '94 Mustang V6/Gibbs Chassis Locost

I understand completely. One of my first thoughts was a single donor build. I looked high and low for a Miata but they are hard to find where I live. The Miata is one of the better choices for a single donor. You made a good choice with the '94 Mustang too. My Turbo Coupe was also a good choice but my main concern was the huge T-Bird ABS calipers. I knew I couldn't use them and since I had to change them out, it seemed like the better solution was the Mustang II spindle and 5-lug axle swap for the 8.8 rearend. I saw some other parts ('07 Mustang LX wheels) that I wanted and switching over to the 5-lug wheels makes things easier for me. That comes with a cost though. All the T-Bird parts will be sold to offset the extra costs.


Author:  Lonnie-S [ April 19, 2009, 7:10 pm ]
Post subject:  Second Stage Chassis Complete

As of today I have the chassis modeled up to the part Chris Gibbs calls "Second Stage" in his book. Much remains to be done, but it's a real milestone.

Small-Second-Stage-Chassis.jpg [ 147.86 KiB | Viewed 32277 times ]

Author:  Lonnie-S [ April 28, 2009, 9:55 pm ]
Post subject:  Rough Visual Comparison of Gibbs and Champion Basic Chassis

My SolidWorks model of the (Haynes) Gibbs chassis is moving along nicely. I have it to the point where the main chassis only lacks the transmission tunnel and the various brackets and mounts for the engine/transmission and suspension. There is still lots to do, but the fundamental shape of the chassis is very apparent. I had an old model of the Champion chassis that I picked up from the McSorely website some time ago. I thought it would be interesting to load them up together and see how they compared to each other.

The Champion model that I have lacks some of the diagonal bracing between the main rails, but it's roughly at the same state of development given that one uses an IRS and one uses a live axle, and certainly complete enough to inform you visually. You'll see that the Champion chassis fits nicely within the Gibbs chassis; something like those Russian Babushka (sp?) dolls.

My Gibbs chassis model is in gray while the McSorely model of the Champion chassis is in red.



File comment: Some additional detail at the back where the biggest changes are evident.
Top-Rear-View.jpg [ 229.64 KiB | Viewed 29844 times ]
File comment: View from the top.
Top-View.jpg [ 169.83 KiB | Viewed 29839 times ]
File comment: Surprisingly close except for the length in this view.
Side-View.jpg [ 92.45 KiB | Viewed 29841 times ]
File comment: There are lots of differences aft of the seatback bulkhead that reflect the increased complexity of the IRS setup on the Gibbs chassis.
Left-3Qtr-View.jpg [ 219.05 KiB | Viewed 29837 times ]
File comment: The front frames, firewall bulkhead and the seatback all line up very nicely. However, the Gibbs chassis is longer and slightly wider.
Top-Front-View.jpg [ 192.77 KiB | Viewed 29846 times ]

Author:  chetcpo [ April 28, 2009, 11:48 pm ]
Post subject:  Re: Lonnie's '94 Mustang V6/Gibbs Chassis Locost

Wow, that's interesting and represents a lot of work. Good job!

Author:  JagLite [ April 29, 2009, 12:06 pm ]
Post subject:  Re: Lonnie's '94 Mustang V6/Gibbs Chassis Locost

Excellent comparison of the Gibbs frame with McSorely's version of the book frame!
Is McSorely's chassis you modeled one of his + size versions of the book chassis?

Author:  Lonnie-S [ April 29, 2009, 7:45 pm ]
Post subject:  McSorley Chassis

Thank you for the words of appreciation, gents. No, this example is "The Book" chassis not one of the enlarged chassis detailed on his website. As far as I'm aware those redesigned versions are are only available as PDF-based, drawing files.



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