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Looking to see if anyone has messed with the CADD models on sevenesque for the 442 frame(Dave King-Synergy Tech file). Looking to make a set of drawings for a rear bulkhead that will bolt up the factory Mazda Miata rear sub assembly. I have the PDF's and 3D model from the website. I'm running into an issue with them not matching for the rear bulkhead. I get that slight differences in modeling can stack up but this 3D model is out over an inch from the PDF.


Dimensions are weird. I have "cm[in]" on the model and the PDF is "[mm]in". Anyone know if this has been documented. I wasn't really planning to make a whole new frame model but an inch short matters.

I guess the 442 and book PDF both show the same so the 3D model must be whats wrong.

It's a general guide and errors have been noted. Have you considered your na miata irs inner tire bulge clearance to the 442 chassis width?

Miatav8,MstrASE,A&P,F wrote:It's a general guide and errors have been noted. Have you considered your na miata irs inner tire bulge clearance to the 442 chassis width?

Looks like 1" per side or less . I started the 442 frame long before I had the Miata donor. I wish this forum did a better job organizing by build type. I see there is a sticky for the Miata sub frame. I'll write up my details and add them to that thread.

On of the bigger frustrations with this forum is there is "too much" information buried in the individual build logs. Why can't someone just re-write the book based on the Miata donor!!

Miatav8,MstrASE,A&P,F wrote:It's a general guide and errors have been noted. Have you considered your na miata irs inner tire bulge clearance to the 442 chassis width?

Looks like 1" per side or less . I started the 442 frame long before I had the Miata donor. I wish this forum did a better job organizing by build type. I see there is a sticky for the Miata sub frame. I'll write up my details and add them to that thread.

On of the bigger frustrations with this forum is there is "too much" information buried in the individual build logs. Why can't someone just re-write the book based on the Miata donor!!

scott322 wrote:. . . On of the bigger frustrations with this forum is there is "too much" information buried in the individual build logs. Why can't someone just re-write the book based on the Miata donor!!

We just need a volunteer. Sign you up? [WINK]

Cheers,

scott322 wrote:

Miatav8,MstrASE,A&P,F wrote:It's a general guide and errors have been noted. Have you considered your na miata irs inner tire bulge clearance to the 442 chassis width?

Looks like 1" per side or less . I started the 442 frame long before I had the Miata donor. I wish this forum did a better job organizing by build type. I see there is a sticky for the Miata sub frame. I'll write up my details and add them to that thread.

On of the bigger frustrations with this forum is there is "too much" information buried in the individual build logs. Why can't someone just re-write the book based on the Miata donor!!

There is no harm in asking for points of view beforehand, then do what you want even if it is completely different direction.

Since it is a 442, you should be able to narrow the entire rear chassis two inches yet also set the engine further back in the chassis to aid intake manifold clearance to the bonnet . Another option is to fit an appropriate width, light duty solid axle to the 442 (since you've included the offset for the trailing arms in the chassis already) or widen the irs subframe and fit custom length axles but I assume you want to keep it locost and straight forward. A 442 seems a bit large for a miata power train.

I'm using the NC rear end and there is enough space. I have a 17"x 8" wheel.

scott322 wrote:

Miatav8,MstrASE,A&P,F wrote:It's a general guide and errors have been noted. Have you considered your na miata irs inner tire bulge clearance to the 442 chassis width?

Looks like 1" per side or less . I started the 442 frame long before I had the Miata donor. I wish this forum did a better job organizing by build type. I see there is a sticky for the Miata sub frame. I'll write up my details and add them to that thread.

On of the bigger frustrations with this forum is there is "too much" information buried in the individual build logs. Why can't someone just re-write the book based on the Miata donor!!

I will submit one reason. I have been on this forum for over 15 years. My how the time flies! Most of us are not building our cars per spec. That is, not 100% to any one set of plans. We take ideas from various plans and other builders' build logs, mix and select what we like, and eliminate what we don't. Following plans is just a step up from building a kit car where all the parts are shipped to us and all we do is assemble them. Not that I am looking down on those builders. it does take fabrication skills to do so. However, the next step up is to design parts to get where you want to end up. We are a mixed bunch; we cover all levels of skills.

I would ask you this, who would spend their time to rewrite the book where the only financial benefit to them is the proceeds from the sale of the book. And as we have seen many times, there are still errors in any of those books for builders to find. This is why so many other car mfgrs sell kits and parts, not DIY plans to build their inspired creations. Ron Champion, for obvious reasons, is excepted of course.

scott322 wrote:On of the bigger frustrations with this forum is there is "too much" information buried in the individual build logs. Why can't someone just re-write the book based on the Miata donor!!

What's stopping you? If it's "not your job" who's is it?

I've shared my COMPLETE Miata based 3D frame model in my build thread for anyone to use/modify as they see fit. I've completed the car and proven it is viable. Is there some other obligation I'm not fulfilling? Pro tip: Entitlement won't get you nearly as far as gratitude. There's a LOT here to be grateful for.

I just did a Voodoo rear section on my 442 build. A couple things I ran into was needing to raise the diff an inch, and taking into account that I am not using 13" wheels and raising the pickup point for the control arms a little over 2" to account for the 15" wheels. As long as your mindful of wheel width and offset the miata stuff will still fit a 442 chassis.

I often come across threads that not longer have working pictures, but I understand how some info can be lost to time on account that these builds take a long time and often don't get completed. I have considered trying to do an occasional voice/video chat to discuss builds, or posting and revising documents on the facebook group maybe

I have re-written the book It is over 130+ pages with suggestions and improvements, less the pictures and schematics, for building a Locost with a Corolla donor. But a good 50% would only apply, if you are using a Toyota power train.

The books, the generously shared plan drawings, the painstakingly developed 3D models, the builds, and the extensive advice offered here for the sole purpose of helping others create a functioning vehicle will only apply if you, by some rare chance, are going to follow the specific example and use only the exact combination of donor parts used in these other builds.
Anyone on this website by now should really appreciate the massive amount of information and corroboration that has been shared here on LocostUSA. The essence of all this is that each individual can experiment and create a vehicle in a direction and configuration that they conceive as the “right way to do it” !
Yes, you can have a differing approach to solving a problem, yes, there will be something you want to do that isn’t like others. That’s all part of the experience. Build your unique and amazing sports car, or hot rod, or deviant vehicle. That’s what this Locost craze is all about !! Use your brain, listen to your visions, learn from each others’ struggles . Build your own unique dream, but don’t whine about someone else not figuring it all out for you.
It’s called “Do It Yourself “ bubba
Humbly yours,
Skidzzz

I think if 1 or a few builders could come up with a NA/NB single donor supplement to the Haynes roadster, it would be a lot more attractive to new builders. If I wasn't so motivated to build a locost, I might have walked away from locosts due to the confusion of which plans to use, and the amount of "self engineering" required. I'm using the Saturn plans for my build, which are UK RHD plans, and not totally comprehensive. The Vodou plans i think are even less clear. Considering that almost all of the plans are UK RHD based, and reference donor parts not really available in NA, I think are enough to turn away most, except the super motivated.

I was also considering the fact that the NA/NB Miata are aging platforms, maybe pairing the 442, and the NC Miata would be the next "mainstream" locost layout. Modifying the rear of the 442 to accept the complete NC rear end, just as Tibimakai has done, and probably some others. I can see the 442 as being the future standard chassis, as people get bigger, it's more "comfortable", and has fewer compromises as far as packaging. I could see that attracting some more people to locosts.

The rear NC fits very good to the 442E(there is a 442 as well). I wanted enough space for myself, that is the main reason to go with that size.
Here is my inspiration:
https://www.locost.ozcarnut.com/index.html
The back came out a bit heavier, but it saved me some much work and calculations. Mazda engineers made all this work, why not just use it.