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Learning how to build Lotus Seven replicas...together!
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 Post subject: The GWTFFM
PostPosted: August 3, 2015, 6:02 pm 
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Joined: August 11, 2013, 6:03 am
Posts: 305
Location: CNY
I've been working on-and-off on this for the past 7 years, mostly in CAD, with around 4 models "nearly finalized" before they were scrapped and restarted.

It's going to be a mid engine street legal car powered by a dry-sump S5 NA 13B mated to the 6 speed from a SE-R Spec V, with functional gull-wing doors (with moonroof panels), and maybe AWS if I can get it worked out properly.

Target weight is under 1500# with me in the seat (so really under 1355#...), and target dimensions are "Kei Car", on par with an AZ-1 or Cappuccino.

I have a full "build log" of all my fits and spurts with the CAD, the procurement of parts/engine/trans, and the rest on another forum, so I'm probably not going to retype everything here.

As of now, I have the engine rebuilt, the trans gearing changed out, and I'm 2/3 through designing the adapter plate. The dry sump is also coming along rather nicely.
Image

I do have some early partial frame renders, from a model that's in "cold storage" right now.
Image
Image
Image

Strong design cues from the DMC-12 and the AZ-1, more from the DMC though.

I have Miata front spindles for the front, and likely will use Nissan Maxima/Altima/Sentra front spindles in the rear.

Suspension is the sticking point, I can't start designing that when I don't have full powerplant dimensions, due to my ludicrously small track width requirements.

Sorry for the incoherent mass of text, like I said, I'm trying to distill 5 years of existing build log and 7 years total project time into one post.
If anyone wants, I'll link to the other thread if cross-site is allowed.
EDIT: Link to the build log

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Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


Last edited by 300D50 on August 5, 2015, 3:08 pm, edited 1 time in total.

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 Post subject: Re: The GWTFFM
PostPosted: August 4, 2015, 9:21 am 
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Joined: January 1, 2012, 12:44 pm
Posts: 220
Location: Boise, Idaho
Walt,

Welcome to the group. I went through your build over on HotRodCoffeeShop and love the acronym for your car. I'm running a turbo 13B in my car and have it setup with a dry sump pump doing the scavenging part and the stock pump doing the engine supply as you are planning to do. It works fine.

Ron


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 Post subject: Re: The GWTFFM
PostPosted: August 4, 2015, 3:06 pm 
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Joined: August 11, 2013, 6:03 am
Posts: 305
Location: CNY
Thanks for the welcome. :razz:
I used the "safe for polite conversation" acronym here because it's a bit bigger forum, and I don't know the admin(s) or how they would react. :mrgreen:

Any tips on scavenging port placement in the bottom plate? I can't seem to find your build log, my phpBB-search-fu is failing me....

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Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: August 4, 2015, 3:44 pm 
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Joined: January 1, 2012, 12:44 pm
Posts: 220
Location: Boise, Idaho
I didn't really have a build log because I had completed my third power train installation about 20 years before I joined the group. A summary of the car is at:

viewtopic.php?f=33&t=13185

There was a previous discussion on dry sump for a 4-rotor. It is at:

viewtopic.php?f=4&t=16194

On page 2 of this thread, there is a suggested drawing for a three stage scavenge pan. This would apply for your setup if you use all of the stages of your Weaver pump for scavenge as you mentioned.


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 Post subject: Re: The GWTFFM
PostPosted: August 5, 2015, 11:18 am 
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Joined: October 24, 2008, 2:13 pm
Posts: 3162
Location: Carlsbad, California, USA
300D50 wrote:
I've been working on-and-off on this for the past 7 years, mostly in CAD, with around 4 models "nearly finalized" before they were scrapped and restarted.

. . . .

I have a full "build log" of all my fits and spurts with the CAD, the procurement of parts/engine/trans, and the rest on another forum, so I'm probably not going to retype everything here.

. . . .

If anyone wants, I'll link to the other thread if cross-site is allowed.


Yes, please post the link. I did a little poking around on HotRodCoffeeShop, but mainly found info on your crashed Hyundai, not the CAD design.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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 Post subject: Re: The GWTFFM
PostPosted: August 5, 2015, 3:11 pm 
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Joined: August 11, 2013, 6:03 am
Posts: 305
Location: CNY
Here's the link to the build log.

I've also edited the first post to add it in.

Cross linking to "other car forums" can be a sticky point on some boards, so I tend to play it safe. It's mostly on the "we are owned by XYZ Advertising and Branding Corp" boards though.

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Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: August 9, 2015, 12:26 pm 
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Joined: October 24, 2008, 2:13 pm
Posts: 3162
Location: Carlsbad, California, USA
Thank you.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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 Post subject: Re: The GWTFFM
PostPosted: August 26, 2015, 2:29 am 
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Joined: August 11, 2013, 6:03 am
Posts: 305
Location: CNY
Nothing done in the past few weeks, working on the VR4 winter rat instead and setting aside for a full brake job on the RX8.

My brother has his truck with him at university now, so I need to get the winter rat going earlier than winter as a spare vehicle.

Cramps the budget a bit, but oh well.

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Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: August 26, 2015, 9:46 am 
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Joined: July 30, 2015, 9:05 am
Posts: 36
Location: Mooresville, NC
Having done FSAE all through college, onto doing racecars for a living; hold off on doing chassis design. You seem very chassis oriented and don't even know what your powertrain size or what your suspension is going to be.

Get your components (ALL of them) sorted out, design the suspension from the contact patch back inward, then start connecting the points...that will make up your chassis.

Just my $0.02.

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To Midi-exo or AWD Locost...


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 Post subject: Re: The GWTFFM
PostPosted: August 26, 2015, 7:25 pm 
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Joined: August 11, 2013, 6:03 am
Posts: 305
Location: CNY
Yep, good advice for sure.
Wish I had known that many moons ago when I started modeling the (very) first design, got it all done in wireframe, then tube, and then realized I could never fit wheels/suspension to it without it looking like a daddy long leg.

The frame render you see is from back before I committed to the 13B/MFA60 6 speed combo, and was going to use the drivetrain from my wrecked tiburon.
I did end up working back from track width/wheelbase/engine/trans dimensions when I made it, but there would be too much work involved to salvage the model and adapt it to the final engine/trans choice. I learned from it though, so there is that.

Now that I have the engine/trans that I will be using, it has became alarmingly clear that I can't do anything until I have the adapter plate made and can pull reliable points off the entire power plant assembly.
This is exasperated by my track width requirements (50 inches or under) for the rear, and the axle placement along the engine requiring a CV with a jackshaft (or an engine running on it's side). On the Hyundai setup, I could have got away with simple shortened axles and been peachy. Complexity, but worth it in the end for me.

Currently I have Miata spindles for up front and I'm debating if I go Nissan FWD spindles in back to match the trans, or Miata rear uprights, since I'm going to need custom axles anyways. I'm leaning Miata, because they look to be easier to work with, and I won't need to make strut adapters. I'm deciding that after the adapter plate is done though.

I've got an engine model off grabcad that I've been massaging with real world measurements, and I'm in the process of digitizing needed transmission features.

The bell housing patterns that make up the adapter plate were pulled using a Bridgeport mill with a DRO and an axial indicator, I just need to find time (and space again) to cut the MDF and do a proper test fit before the wallet comes out for aluminum. Then I need to find time to machine it...

The idea is to have the entire rear suspension and engine in as small and compact a subframe/subunit as possible, and then either bolt it in or build off of it for the rest of the car.

This is the state of the current model, from the rear. (click to link to larger image in the gallery)
Image

The subframe tubes are just there to give a bit of a boundry box at this point, since the dry sump needs to be completed and the adapter plate needs to be finalized.

I also need to refine my transmission model, since it's a bit off, and account for the intake/exhaust at some point...

The rear suspension is probably going to have to be multi-link with bell cranks and inboard shocks due to the track width constraints.

Anyways, starting to ramble a bit too much.

_________________
Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: October 5, 2015, 9:48 pm 
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Joined: August 11, 2013, 6:03 am
Posts: 305
Location: CNY
Absolutely nothing done on the build since last post.

But today I got a bug in my bonnet and ordered two 05 Altima wheel hub/bearing kits from rockauto.

They're WJB WA518516 29 spline, 5x114.3 pattern, 43mm ID on the wheel bearing.
Miata rear bearings are 40mm ID, so I may be able to coax the Nissan hubs into Miata bearings after some careful machining on the hubs.

I'm still stuck with the rear suspension design, since I don't have the rest of the powerplant stuff worked out, but this moves me incrementally forward.

With the VR4 taking all my time and major cash, this is back burner yet again.

_________________
Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: October 8, 2015, 11:50 pm 
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Joined: August 11, 2013, 6:03 am
Posts: 305
Location: CNY
Rear hubs came in.

Physically looking at them confirms that I have enough wall thickness between the OD of the spline and the OD the bearing fits over to machine them for Miata rear wheel bearings if I so choose.

Small victories.

Now to update my physical build log, and remember to put the receipt in the envelope...

_________________
Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: October 15, 2015, 8:01 pm 
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Joined: August 11, 2013, 6:03 am
Posts: 305
Location: CNY
After thinking everything over, and getting up close and personal with the Mitsubishi AWS system, I'm going to design the rear so that a Nissan R34 SUPER HICAS rack can fit in.

Worst case, I just use a lockout bar kit for an R34, and forget everything. Best case, I have one hell of a toy.

_________________
Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: October 23, 2015, 5:42 am 
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Joined: August 11, 2013, 6:03 am
Posts: 305
Location: CNY
Well, an R33 SUPER HICAS rack with the connector pigtails is on the way from Japan. :twisted:
Turns out the same rack is used for the R33 and R34, just slightly different control modules.

I wasn't really planning to pull the trigger and get one this early, but the price was right and things just slotted together.

This means that I won't be using Miata rear uprights, so at least one option has been removed from the table, and some progress has been made towards the end goal.

_________________
Walt
04 RX-8 Touring RIP
90 Ram 50 4x4 V6
91 3000GT VR4
Some people never have anything except ideas. Go do it.
Emissions & fuel economy haven't exactly been areas of strength for past rotary power plants, but absolutely no one with a soul has ever cared.


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 Post subject: Re: The GWTFFM
PostPosted: October 23, 2015, 8:13 am 
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Joined: March 30, 2011, 7:18 am
Posts: 1144
Location: central Arkansas
Well, that nails one rear suspension parameter - if you use the HICAS, you want a layout that uses toe links. Either A-arms or old-F1-style trailing arms.

Personally, I'd go with the trailing arms, even if I had to change the intake and exhaust for clearance. Spread the suspension loads out, feed the longitudinal loads directly into the main chassis or roll hoop, avoid the "forest of tubes" needed to provide eight A-arm pickup points...


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