LocostUSA.com

Hello All,

I thought I'd post up a build log of my project. I had one on Grassroots a while ago before their board switched, and haven't made any updates since then. I always meant to get one on here, so Now I will.

The car started out life as a 1978 MG Midget, and then got a rotary swap after it was in a flood. The suspension never quite worked right on it after the swap, and I never really got it fully sorted before I got married and moved to Wisconsin from Central Illinois, so the project stalled for 2 years or so. I'm a Mechanical Engineer fresh out of school and did the chassis/suspension/pretty much everything design on the U of I FSAE car my senior year and decided that when I got back to the MG using the stock chassis just wouldn't work. I finally got back to it last November, and took it completely appart, and hacked it all up. I cut the body off of the unibody, and disposed of the middle parts. My plan is to build a tube frame chassis and hand the origional body around it. The tube frame chassis is similarish to a locost frame, but honestly I've never even seen the book, the design is my own. I would say the car is being built with the locost ideology. The engine will be a Mazda 12a rotary, The suspension is from a 4 lug 2nd gen RX-7. Shocks front and rear are motorcycle sourced (R1 in the rear, CBR600f4i in the front), with pushrods front and rear. Front and rear suspension is double wishbone; I'll double check the numbers but from memory (120" VSAL, 3" RC, 4-8 degree adjustable Caster, 9 degree KPI front) (65" VSAL, 4" RC Rear). The Wheel base on the Car is 80" and the track width is going to be stock 2nd gen RX7. I'm keeping the Chassis within the bounds of the stock Midget body, and am adding ridiculous flares (almost 12" per side) to cover the wheels.

That's about all I can think of right now, but I'll be sure to answer any questions and post up more pictures as time goes on. I have quite a few old pictures of the chassis as it went along, and have most of the car In Pro/e. Chassis current weight is 165lbs, so it will be a little porky, but it includes an SCCA legal Roll cage, and I used .083 wall tube.

Thanks for looking, I know I've seen a link to my old build log on GRM on this website so I thought you guys might appreciate the build. More pictures are available at http://s33.photobucket.com/albums/d51/Nocones/midget/
Daniel

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MG midget bodied Locostish car in progress

Your front and rear subframes both look to be off center by at least 1/16 of an inch...You might want to fix that.

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-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

Hi Nocones!

I wondered what happened to you from GRM.
you are building a project close to my heart so I was disappointed when I lost your build. Glad to have you here.

I will be watching for regular updates and progress reports as well as lots of pictures. Keep 'em coming!

James

I do think you are correct. I'll double triple check to make sure.




Thanks a lot for the support. I'll be sure to keep the pictures coming. The project is a bit different than the standard locost. Not so much now, but when I get around to the body it will start to be different.

Oh and Thanks to Driven5 as he has been a big help on the project so far. I'll be sure to post up a picture of him making vroom vroom noises in the chassis soon.

Thanks,

Daniel

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MG midget bodied Locostish car in progress

Yes...Whatever would you do without me there to do things like taking three tries to make two little brackets.

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-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

I worked on the rear bulkhead area for a while tonight. I got what I call the 4 W tubes fitted. The upper crossbar is at the same 15 degree angle WRT the build table as the rear roll hoop. The outer W bars come in at a 35 degree angle to vertical, and to complicate the cuts they intersect the vertical tubes and the bottom at a 15 degree angle. Did I mention I don't own a compound chop saw.. I used my trusty HF steel compass, and calmy built the tubes up. I actually built both tubes at the same time and both fit really well. Now I can get to work on the lower rear tubes. I need to put a gusset in, as I don't want the lower tube loading into the middle of the W bars, with no support. The chassis is only 48" wide, To the outside, So I had tight clearance with the offset input on the RX-7 diff. The tunnel is only 7" wide, so I moved the vertical tubes to have a 7" inside clearance. This gives the input flange ~.25" clearance on the vertical tube.





Daniel

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MG midget bodied Locostish car in progress

Won't be long until the chassis will be able to hold that diff up, all by itself!

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-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

Which is no easy task! I have one of those heavy mo-fos in my car. It's what, about 75 pounds? If the budget allows you might be ahead to buy a torsen LSD from a Miata. I think they weigh about half as much and don't have a big ol long diff snout to package. The downside is they are a little tougher to locate because of that. (they were made to bolt to the Miata powerplant frame) They do however share the same aluminum carrier unless I'm mistaken. If it's not identical it's very close.

I know the axles should plug in since my RX-7 diff is running with 99 Miata axles.

Oh and is that plywood seat FIA approved?

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He is a wise man who does not grieve for the things which he has not, but rejoices for those which he has.

Very Nice Work!

This will be among a few inspirational builds I will frequent to keep me focused when suspension geometry design just isn't making sense...

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Eating a horse. one bite at a time... pardon me, do you have any HP?

The diff is right on 75lbs. I've thought about getting a Miata Torsen, but its really not int be budget. I also think the extra weight in the back might be a good thing. The car only has a 80" wheelbase, and all the reduction compared to a locost is in front of the engine. So basically I'm a locost minus 10-12" in the front. I'm thinking It will be a little nose heavy, so the 75lbs in the back might help. I plan to put the battery back there also.

And, Of course the seat is FIA approved. You just never know when you build table might get rear ended.

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MG midget bodied Locostish car in progress

Thanks for the kind words. I'm going to try to update the build as much as possible, but not put to many pictures of me doing trivial stuff.

Daniel

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MG midget bodied Locostish car in progress

Today I Cut all my suspension brackets at work during lunch and after work. I used Pro/E to plot the brackets in full scale, and then I used general trim adhesive to glue them to a sheet of 12 Ga. Steel. 2.5 hours later, I had 32 brackets.. My thumbs hurt..

Daniel

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MG midget bodied Locostish car in progress

Mmmm...Beefy.

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-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

I made some progress on the A-arms.
I constructed a jig out of 2 1" thick pieces of MDF to build the a-arms off. I plotted all 4 a-arms on the same sheet with the front bushing in the same spot. I just move the other block to the 3 positions required to make the 4 a-arms. The a-arm below is the Rear upper.



I'm not entirely sure what caster I want to run, and desire some adjustability, however I didn't want to affect Camber when I adjusted caster, so I built these little blocks. The tube is threaded to accept a 3/4" rod end, and I will have some spacers to prevent the flanges from collapsing. It allows 1" of caster adjustment (~4-8 degrees). If I settle on a certain caster, I might rebuild caster specific a-arms. But I like the adjustability, and thought the brackets came out well.




Thanks for Looking!

Daniel

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MG midget bodied Locostish car in progress

Nice work. What are you using to cut your steel. fab work looks great.

Andrew