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I don't know if you've seen it, but there's a turbo tri-rotor bugeye that competes in SCCA autocross in E-mod. The thing is STUPID fast:

http://www.youtube.com/watch?v=n3dw9w6SbPk

www.acestainless.com for the weld els. They are so cheap its great!!!

J. R.

Are his hands that fast or did he not even shift it except to start off?? I love Rotaries!! Rev forever!!

KS

Hard to believe, but it's been nearly 9 months since I worked on the car. This crazy thing called "life" keeps getting in the way. Hopefully, that's about to change. I've got 4 sporadic weeks of vacation time coming up over the holidays, and I'm planning on spending at least a few of those days in the garage. I've got a lot of ground to make up, but for some stupid reason, instead of doing new work, I'm probably going to focus on re-doing some of the work that's already done. Specifically, I'm going to upgrade the rear end.

The current diff in the car is an open R160 from an early 70's Datsun 510. It's fine for 140hp Datsun engines (like I've run in the car before), but it will be no match for the 300hp/300lb-ft turbo rotary engine. I thought about simply dropping in an R200 from a Z-car, but the weight of those beasts are substantial. Also, I've already put Miata front suspension pieces in the car, and I've got the rear hubs, brakes, and axles from a second-gen Miata. Ergo, I went out last night and picked up a limited slip low-miles rear diff and driveshaft from a 2003 1.8-liter Miata. These rears are reportedly good for 350 horsepower, so I should probably be okay. The price was right, too (the guy I bought if from didn't know it was an LSD, or even what an LSD was). As result, here's the first thing I'm going to work on getting into the car over the Thanksgiving weekend:



Don't know about you, but I think Mazda created a work of art with the rear casting on this thing. Shame it gets hidden underneath the car, out of view.
-Bug

Your car looks sweet. I raced bugeyes in SCCA for 13 years. I made molds for running 20"x8" slicks for the bugeye some years ago and Rick Haynes has them now. http://www.sportsandimports.biz/. the rear quarters are full Quarters and have a nice shape. the hood is pretty sweet to- kinda proud of it. I have some pics of a street car that we did if you would like to see

Whats wrong with a R180? Strong enough and LSD's available.

You're not wrong about the R200's weight.

Nothing at all wrong with the R180, but I already switched the front spindles and brakes to Miata pieces, am now running a Mazda rotary, and had the rear halfshafts and hubs/brakes for the Miata pieces already. In other words, it made sense to just go Mazda for the diff, too.... and speaking of which, we made some progress this past week. Got all the old R160 diff mounting stuff cut out, and then got the new Miata piece bolted in (well, half bolted in; we still have to figure out mounting for the the front of the piece). IMHO, it looks like it belongs in the car. The cool thing, too, is we will be able to salvage three of the four suspension hard-points for attaching the upper and lower a-arms. Most of the rest looks pretty straightforward to tackle, although I'm still scratching my head about how the coil-overs are going to get mounted. More to come...

It's been nearly a year since I posted any progress on the car here in this forum. Life and work have caused all kinds of delays with progress, but I've actually been slowly chipping away at the car's to-do list. Here is an update on what's been happening over the summer and fall.

First up are some monster jack stands I finally got around to building. I've had most of the steel to build these for a long time, but only recently got motivated enough to fabricate them. Now that they're built and being used, I can't imagine why I waited so long to fab them. These things are soooo much better than the rag tag collection of ramps, autozone stands, and blocks of wood I've been using. Very strong and easy to use, they're constructed from 4x4x1/4" square steel tubing. I can now safely lift and support the car all the way up to 40 inches off the ground. What a nice feeling to work underneath the car and not worry about it crashing down on my head.



Getting the car safely up in the air then allowed me to get back on the rear end fab work. There's still a bunch of bracing and gussets left to cut out and weld in. There's also brakes to figure out, stiffer springs to select and install, and about a dozen other little things to finish this up. As a reminder, the rear diff is an LSD out of a later model Miata. Hubs and axles are also Miata-sourced.




Finally, I've made some good progress on the intercooler and intake system mounting. Like much of this project, I started down one path, then backed up and went a different route. I think this new, lateral-arrangement of the top-mount intercooler layout is going to work pretty well. It will require some good heat shielding from the turbo and downpipe underneath, but I think it will be an improvement over the previous layout. In addition to hacking up the intercooler, I had to make some further mods to the intake manifold, too.




Life and work don't promise to slow down any in the new year, but I'm going to keep making slow and steady progress on the car...
-Bug

Looking great, Mark! I'm glad to see progress is being made. You've half inspired me to look into rotary power for my own. I've got the 4age- was thinking about turbo-ing it, but thought that perhaps a renesis would give the same kind of power, with simpler installation, but don't know about weight etc. Researching now.

Hey Bug- great build log.. tough with such limited space in that little car!

I'm wondering about your Miata axles.. Obviously you've had to narrow them, and it looks like you simply did a cut and sleeve on each axle.. I will be doing the same to get mine narrowed as needed (VERY small car with Ford 7.5 carrier to Miata uprights).. did you simply weld around the end of each sleeve, or did you also drill and plug weld (rosette weld??) a few places on each sleeve too? I ask because opinions vary on doing this cutting/sleeving- but it seems a smart/cost efficient way to go, especially in my case- (a low-powered BEC build..)

thanks- and again- nice log on this cool car.

amazing work. Show us more please!

2 questions: 1. Did you ever run the 280z upright/hub creations? If so, how did they work. I'm a "use what you have first" guy, and I have some z stuff....
2. I agree that r160 is junk, better jut give it me! (ha! -- oh, the privileges of lower power and less tire!)

I didn't follow clearly the middle era of the build (2009-09) Did you run the first rear setup ever, or go to the (admittedly sweeter and aluminum casting-rich) Miata setup. I too shortened some 510 1/2 shafts for a project (and booted them up and everything, but haven't gotten the project far enough yet to run them and see how they do). How did you handle the ball-bearing circlip issue?

Half a lifetime ago (gulp) I put a 13B in a Bugeye. I got the engine pretty cheap 'cause (if I recall correctly) there's been an SCCA rule change that disallowed something porting-wise the previous owner/racer had done. A guy in my high school had put an SBC in a Bugeye which made it great for smoking the tires and the hood cutaway was a bit too Big Daddy Roth for my tastes, where the rotary didn't change the weight or weight bias at all. I did put Sprite Mk II brakes (disks rather than the original drums, drums manufactured to the same exacting specs as Copenhagen snoos cans) which added 20 pounds (and it only took me one test drive with the drums to determine that even without increased weight, increased braking power was essential)...sorry, I'm digressing; leave it to say that there is nothing wrong with a Bugeye Sprite that disk brakes and quadruple the horsepower don't take care of.

The point (and I do have one) is, I used the stock rear axle. I figured that since Sprite owners could chirp the tires by dropping the clutch (what the 948cc cast iron Austin engine lacked in horsepower, it made up in inertia) the diff and axles could survive if I didn't ask them to handle any higher load than that, so I kept the stock tire sizes and everything was faboo. Your car is going to end up weighing about 60% of what a Miata weighs (I'm estimating from horseback here, but hey, mine weighed 1350 according to the local feed scales) and the light weight will limit the traction available, soooo....I think your axles will be fine.

That is Jeff Kiesel's wife driving his car, It is a family affair, Jeff is a stud, many championships. I met him once, and was super cool. http://www.rogues-racing.com/jeff-kiese ... -champion/

We welded all the way around the end of the sleeves, and then also did two drill/plug/rosette welds on each side. I thought about getting axles made, but the cost was insanely high, so we decided to give this method a go. I've got my fingers crossed.

Yes, I ran the first IRS setup for a couple of years. It worked really great, but with the expected increase in power of the turbo rotary, I decided to put a beefier diff in the car. One thing led to another, and we ended up swapping in the whole new setup. Nothing really wrong with the original setup except the diff strength.



The diff, rear uprights and shortened halfshafts are yours for the taking... provided you are willing to drive to Tucson, AZ and pick them up. Hell, first come, first serve. I'm way too lazy to try and ship 'em, so for now what's left of the rear end is sitting out behind my house, waiting for someone to take 'em.