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Branson

Branson

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my goal has been 100hp and to achieve that with the 1275 is going to take quite abit of $$ or for me to learn to fabricate metal to accomodate a turbo...soooooooo

Im thinking about a 13b rotary swap.

Now, just to clarify my car is NOT stock...if anything it is more of a parts car (or a car with alot of boxes of parts?) that is being salvaged so I am not taking a survivor and mutilating it or anything like that.

I would likely sell the 1275 and ribcase tranny that I have now to fund the swap.

I have done some research on what it takes to make the swap work and this is what I have gathered:

[]Remove or notch heater shelf - mine is already removed and I have a brand new one that I would sellRemove or notch the heater shelf
[]custom motor mounts - the ones I have seem done are very simple and are based on the original RX-7 motor mounts. I have some friends and a stepfather that are capable of simple metal fabrication so this shouldnt be too difficult for them
[]Exhaust headder - this may be a bit of a challenge, or there may be an aftermarket one available that would work
[]Custom driveshaft- this I would have done by a driveline shop
[]Clutch hydraulics- im going to assume that I will need a custom clutch hydraulic line from the sprite MC to the mazda slave
[]Hardened rear axles- im not planning on nitrous or any kind of forced induction on this one so hopefully the stronger axels will suffice, otherwise I am going to have to change out the rear end.
[]Electrical / Ignition- I will use a carbed set up most likely (although I keep looking at a FI Twin sequential turbo 13b on ebay /bcforum/images/%%GRAEMLIN_URL%%/smile.gif )so the interface between the sprite harness and the mazda harness shouldnt bee too difficult. i think I will go ahead and add a fuse panel while I am at it just to be on the safe side.

anything I am missing? Thoughts / comments?
 
Just to be the "voice of reason"...

1) Unless your 1275 is already pretty tricked out, it is not going to fund much of your project. There are 2 for sale down the road from me for $100 a pop.

2) There is WAAAAAY more metal fab involved in lumping the rotary than fabbing up a turbo manifold. Furthermore, if you keep your eye on eBay UK, you may find an MG Metro Turbo manifold.

3) If your time has any value at all, the rotary swap is going to cost you quite a bit more than a mild 1275.

4) 100hp is just a number. You can just as easily violate national, state and local traffic laws with 85, 75, or 65 hp.


All that being said... Go for it! Rotary lumps are cool!
 
Biggest problem with the rotary is the exhaust system.

Exits drivers right and a nice HOT pipe from the manifold really has very little room and no place to go. You need a BIG muffler........just room for a very small one...wil give a new meaning to Vrooom---Vrooom.
 
I would add... if you're going to do that much fab work and custom install work, it'd be worth putting it into a top-notch shell. (Shush, purists!)

- If your end goal is a nice-driving spridget, keep & tune the 1275.

- If your goal is a car with a huge power to weight ratio... sell the Midget and buy an Omni GLH. Or a 1.8/2L VW turbo. Or a Corvette. /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

- If your goal is a cheap, nice Spriget with lots of power, on a budget, and with limited time, welding, or fabrication skills... you need to modify your goal.
 
dag....you guys really knwo what your talkin' 'bout! Wish I knew what the heck this all meant!
 
Morris is right. Don't focus on a number. I'm racing on about 70 HP, and *no one* has more fun than I do.
Build a nice 1275 and spend your time driving one of nicest sports cars ever built.

If I wanted to have a small sports car with a Mazda rotary engine, I'd find an appropriate fiberglass body, buy a pile of steel tube and build a suitable chassis from scratch.

It would be easier.
 
Something else that was bugging me....just remembered!

Keep in mind that the rotary was originally considered for the Miata, but it was considered too powerful for the platform without costly modifications. The Miata is a much more modern design, and handles, what, 128hp in stock form? Miata guys help me here.....

My point is this. The Sprite/Midget bodyshell was designed to cope with much less power than is available these days. A modern bodyshell is subjected to stresses and forces that a fifty year old design will not take kindly to.

My take is to tune the 1275, spend less, and have one heck of a nice little car in the process. If you must get silly, why not a 1.6 or even a 1.8 Miata engine? Be an easier project for one, and it would certainly give you all the added power you could handle with a less limited safety factor.
 
All good, solid voices of reason!!! I could add no more than has already been said!! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif /bcforum/images/%%GRAEMLIN_URL%%/thumbsup.gif
 
Back in the late 60`s I saw a Bugeye with a 289 H.O. in it, Actualy my brother in laws brother owned it. It would run VERY fast in a straight line, as long as you didnt try to nail it off of the start. Otherwise you`d go around in circles producing a lot of smoke. Wasn`t much in the corners either, However the look on Mustang and Camaro owners face as you left them in the dust was priceless.
 
LOL, sounds like great fun.
 
....still on the fence..... fortunately I have nothing but time....I have a buddy that has sourced a 13b and a 5spd for me for less than $500 here locally. The nice thing about the rotary is its size (and weight)...other than having to notch the heater shelf and opening up the hole for the shifter there isnt much more of the car that has to be cut. so ideally, none of the changes that I am making (other than the shifter hole) are irreversible. As for the motor I am looking at a stock 13b with a carb..it gets me to my performance goals and can be a reliable lump too.

my car has disc brakes....should I still look at upgrading them if I go with the rotary?

id like to go around in circles producing alot of smoke...just not from the engine. /bcforum/images/%%GRAEMLIN_URL%%/smile.gif

Im crazy enough to do it...and tinkering with the car is my therapy from work...maybe I just need to go down to the local vo-tech and learn a skill that no one can take from me. lol

The only catch is that I want to have the car done in time for the gathering in the Ozarks.....guess I'd better get to work!

Goals:
A lighting quick spridget, fun little roadster to run about town in and drop the occaisional highschool kid in his pimped out honda accord that is a hand me down from his folks.
Budget conscious...absolutely...but arent we all.
I want > or = 100hp...yes its just a number but by golly I want it and I want it all.
I want to have 5spds for highway cruising
I want to be able to blast down a 1/4 mile on occasion
Im not going to install a radio...why? because I want to hear the car. I want to spin the tires for 100ft or so....just because I can.
I dont care if its loud and obnoxious...its my version of a harley. /bcforum/images/%%GRAEMLIN_URL%%/smile.gif
 
Branson,
get to it. /bcforum/images/%%GRAEMLIN_URL%%/smile.gif
Sounds to me as if you've made up your mind.

Just make sure it stops as well as it starts.
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]because I want to hear the car[/QUOTE]

Rotaries make noise? hehehehe
 
/bcforum/images/%%GRAEMLIN_URL%%/iagree.gif hmmmmmmmmm!
 
Believe me ....... the only smoke coming out of Johns 289 H.O. bugeye wasn`t coming from the engine ..... and ..... in first gear it would smoke the tires until you either let off of it or crashed into something cause you were out of control. Even racing it in a straight line shifting from first to second was risky buisness with too much accelerator pedal. Same for third. BTW I asked the same thing a lot of you might be thinking {how did he keep the rear axel from breaking} He didn`t, the original one broke almost immediately upon the first hard run with the 289 engine. He ended up having a 9 In. ford Posi axel cut down and modified to fit, that pretty much cured the broken axel, ring & pinion and driveshaft problem. That car was a hoot to drive but never the less risky buissness to really get after it. I only drove it once but i`ll never forget.
 
eschneider said:
Branson said:
The nice thing about the rotary is its size (and weight)...
Click to expand...

Isn't a 13B heavier than a 1275?
Click to expand...

I doubt it, pretty much all aluminum.

I would recommend you look up Bryan Krause, since he has done a rotory Midget, he could shed some light on your project.
 
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