My Projects

I hope to fill this section with short stories about what I'm working on these days. I hope to update it often.

I've recently been racking my brain about 20B stuff, you know, learning all that I possibly can about them, in order to install one in one of my vehicles. Go ahead and look (scroll down a little too). I'll wait... Ok. The MG can barely hold a 13B and the baja has cracked metal here and there from a VW 1600! Well, as you can see, the two most likely candidates are my truck and Cosmo. They are both heavy by Mazda's rotary standards and can use all the torque I can give them. The Cosmo is supposedly the heaviest, with the REPU a close 2nd weighing about a hundred pounds less, give or take what ever is in the bed (can this really be true about the Cosmo's weight?). Both of these vehicles came stock with oldschool 4 port 13Bs. The only reason why the REPU was so quick, was because of the very low geared rearend to make up for the weak low RPM torque. Can you say wheel spin? Well, smaller ports and higher gearing in the later years had a tendency to help the torque at low revs a little, but weakened the mid to high RPM power quite a bit. Those were the pre FI and turbo days.

When the CD23C Cosmo came out, it was considered 'AP' or 'Anti Polution' because it saved more gas and had a more aerodynamic coeficient of drag than its predecesors. Plus its higher geared rearend and smaller intake ports killed acceleration bigtime and caused the Cosmo to lack in sales. Too bad really, because it is a great car, and Mazda used lots of 'parts bin' parts from this car on the SA22C 1st gen RX-7s a few years later. Needless to say, this car could use some better performance.

For a while now, I've figured that my Cosmo would be the best car to put a 20B into because it has the largest rotary engine bay I've ever seen. The 13B is dwarfed in there. It could pretty easily hold a 20B I think. It also has an automatic which would eliminate the need to move the shifter rearward, and there is no slave cylinder to have to make room for on the firewall/tranny tunnel either. I suppose I could try one of those forkless slave cylinders like what the HITman used on his NOT20B RX-7, but I've already got an automatic, so why not use it? Keep reading.

I've taken almost all the measurements I need in order to see if a 20B is going to fit. The current 13B is old and tired and needs to be rebuilt. What better time to remove it and install a 'test-fit 20B'? If this project is going to be anything like when I installed a 13B in my MG Midget which formerly had an RX-2 twin-dizzy 12A in it, it'll be all anyone can do to keep me from doing it. I will forgo food and sleep for this project! As unhealthy as that sounds, it's what I did when I was 13Bing my MG. Gotta break that habit! How many of you have ever fallen asleep on a creeper under your project car at 5AM after working on it all night? Hehe me! Back to the Cosmo. I was only experiencing minor problems (which I kept on solving pretty easily) while trying to absorb 160mm of extra length with some of it moving forward and the rest moving back, you know, because of the extra length of the 20B, untill it dawned on me that the Cosmo has a unibody. There is no way that it can handle tons of power without tons of mods. The frame would get tweaked. I hadn't planned on 500HP or even 400. I wanted a very basic torque improvement over stock, not to mention the wonderful 20B exhaust note singing in the background. But the stock auto tranny wouldn't like all that extra torque, and I wasn't about to cut up my tranny hump just to fit a powerglide or whatever in there. I wanted to be able to burn out all day long, but I needed to be realistic too.

I know of a Chevy Vega that got a tweaked frame from a 350 V8 that a guy installed in it. You know, the Vega was supposed to get a rotary engine. The Monza has the same platform, as well as the Pontiac Astre, Sunbird, and Buick Skylark. Well no wonder it's so easy to fit a V8 in those cars! Just make sure you upgrade lots of other stuff to handle the torque!

So what do I do? Install a gutless 20B? All that extra weight without much more than stock power didn't sound very apealing. I could get all the torque I needed from a supercharged 13B, and save weight! I also want to continue using an automatic because this is supposed to be Mazda's Thunderbird/Impala/Cadillac luxo-cruiser. A stickshift is cooler yes, but this car is staying an automatic... for now. I didn't want to spend good money on a series 5 TII tranny and also need to install a cluth pedal, clutch cylinder, slave cylinder, not to mention the TII output shaft and relocated shifter hole in my auto-style center console. I didn't want to spend over $10k with most of it going to frame mods either. I also wanted to keep the stock diff because it's already geared pretty high (3.636). Disk brakes too! No LSD though.

The pros: The diff gearing is great, and the engine bay is large enough, disc breaks on all 4 corners. The cons: no limited slip, the automatic tranny can't handle mamoth amounts of torque, the unibody can't either.

So I had a dilema on my hands untill I asked Cal at RX-5 Central how much power the Cosmo could handle and he said the body can handle a lot and the tranny can handle 450HP+ with slight mods but 600 would break it. Hey, that's all I needed to know!

Well, it would seem that the unibody and tranny will be able to handle upwards of 400HP, and I know a 20B will happily produce that much HP all day long.

Before going any further in this project, I still need to figure out if my REPU would still be the better choice. It's got a ladder frame and is probably much stronger by far. Its ride quality isn't too great though because it's a truck. Besides, the low geared diff and gutless engine have been able to handle all the stuff I've thrown at them so far, such as towing a friend's REPU when his clutch blew its lining off (It's a funny story; I'll tell you about it sometime, hehe) and filling the bed with moderate loads. Not too sure if I've ever reached the payload limit of 1400LBS yet though.

What I'd like to do with the truck is get an awesome 13B for it so I can put the truck's old engine back into the MG. It fit really well last time, and while not too powerful in the truck, will feel stronger in a smaller lighter car. That and the fact that the previous owner went through rearends with the street ported twin dizzy 12A.

Well, whatever I decide to do, one thing I've got to remember is that I can't spend heaps of money on projects without some sort of justification. I've got to get them running as cheaply as possible first, and go from there. I'm currently doing exactly this.

Here are the links to what I've been working on recently.




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