20B Rotary

[Kiske]

Originally Posted by themadscientist

Wait, you had an FC. You left out the special stage commandments like
1. The engineer who came up with cold solder joints was an asshole and your fuel pump won't get consistent voltage, dash lights will flick in and out, you wipers might not work or may refuse to stop and roll down the windows if you dare; they may not come back up!
.

When flooded, pop hood, pull fuse, crank car with the gas to the floor, reinstall fuse and restart. Never failed.

Oh god, I completely forgot about the brass power window switch contacts and wiperswitch. Odly enough I never had my wipers fail. But, I also deleted the rear wiper on my GXL... so


Having built a 20b for my FC I want and will do it again but, I wouldn't dare put one any anything that didn't have a 12a or 13b in it to start with. By the time I get back around to it I imagine it will be very hard to find an A or D code 'block' though.

[Canehda]

I'm not going to lie, a brz with a bridgeported 20b in my imagination would sound so badass... but then again a brz with uels and 280 cams

[themadscientist]

13B sounds better, more pronounced lope. With a P-port it gets all rollercoastery. You can see the gas gauge twitching down the scale as it idles.

[M23]

Originally Posted by cdrazic93

I dont think I have ever seen a 1 rotor. A 2 rotor can be built to probably 350-400whp, a 3 rotor would push up against 500, and 4 rotors can break 600whp, all NA.

Thx for the answers guys.

Wow..never knew they could pull off so much NA power (since I've always seen/accustomed to them FI since I was young since the 90s and also because factory rx7's are always FI). I was expecting an answer like "250-300rwhp for an NA 2 or 3 rotor" lol. This def sounds even better than Honda's awesome top 4cyl NA engine (in the s2k).

2 rotor with 350-400rwhp is obviously more than enough for majority of us. I'm sure 3 and 4 rotors would be nice; but it's also impo$$ible to buy for 95% of us and nothing but a pipe dream.

So how much for a decently built NA 2-rotor? ...less than an LS swap perhaps?

[themadscientist]

I would'nt try it without at least $8K on the table to fund it. Stuff gets expensive quick when shit happens and it usually does.

http://atkinsrotary.com/index.php?pag=9
https://www.mazdatrix.com/engnumna.htm
http://www.racingbeat.com/RX7-1986-1...-Services.html

For a budget build I would find a usable FD3S twin turbo engine as a core and have it rebuilt with FC3S NA rotors. The housings are stronger and have better ports stock not to mention being newer. Since you are putting it in a car that never had a 13B in it the engine mounting difference between the FC and FD housings is irrelevant.

[M23]

Yikes..so the engine itself costs basically the same, or more, than a brand new full LS3 and Tremec trans.

Forget that then lol. After getting a 13B, and also getting it nicely rebuilt to new and NA spec, you'll still have to figure out install, tranny, electronics, and all the other subsystems, etc.. Since no one has done it yet, it will take a while to figure out and/or more money for install than an LS3 swap.

I'd just go LS3, Vorshlag kit, easy install ..done deal

[cdrazic93]

If you can find the golden gem, the mazda cosmos engine, its a 20B. I'd definitely make that into a doable swap.

[NOHOME]

If you happen to be a fan of the rotary engine, this swap is as good as any. Fact is that there are many who are not fans, and hence no understanding of why you would do this swap.

As far as I am concerned, if you don't want to go big, stay on the porch. There is your run of the mill 12 rotor wanker engine that needs to be used.

[cdrazic93]

The only concivable engine bay im even thinking that would fit in, is the dodge vipers.

[themadscientist]

It's not the first choice. Even though I am a huge rotary fan I wouldn't recommend it over something else. I wouldn't go V8 either. I would go with some sort of a straight four like an SR20 or 3S.

[Jaden]

Originally Posted by themadscientist

It's not the first choice. Even though I am a huge rotary fan I wouldn't recommend it over something else. I wouldn't go V8 either. I would go with some sort of a straight four like an SR20 or 3S.

ecoboost 3.5....

good for 600hp easy, since it's being used in the new Ford GT...

tens of thousands of them available in F150s...

Jaden

[ZDan]

Originally Posted by cdrazic93

A 2 rotor can be built to probably 350-400whp,

Turbo, sure. NA? No way! 250rwhp n/a is a serious achievement for a 2-rotor. Source for 350-400whp?

a 3 rotor would push up against 500, and 4 rotors can break 600whp, all NA.

Again, source? AFAIK a strong NA 3-rotor is more in the 350rwhp range, 4-rotor NA could hit 500rwhp.

This is done by serious materials and some awesome awesome rev limits (9,500+).

That's only 500rpm higher than the stock RX-8 rev limit!

[TEDDER1]

Defined made 475 in an ITB setup on a 3 rotor.

I have seen 13B based 4 rotors making higher 500s at the wheel.

[cdrazic93]

Originally Posted by ZDan

Turbo, sure. NA? No way! 250rwhp n/a is a serious achievement for a 2-rotor. Source for 350-400whp?

Again, source? AFAIK a strong NA 3-rotor is more in the 350rwhp range, 4-rotor NA could hit 500rwhp.

That's only 500rpm higher than the stock RX-8 rev limit!

My bad, I was talking about the 4 rotor being NA. the 2 & 3 rotors can make those # with a turbo.

The rev limit and other trinkets:

"Uses late style 13b side housings, all side housings are reconditioned and re-nitrated for brand new finish. 9.7:1 rotors, fitted with all new side seals, corner seals, oil retaining rings, oil o-rings, coolant o-rings and springs. Ultra high performance 2mm Ceramic apex seals with brand new ceramic tip springs. Brand new rotor housings, machined and fitted with full peripheral port, "race" port exhaust. Fully dynamically balanced and blueprinted. Extra clearance deep groove race bearings for high rpm safety. Heavy duty extreme use stationary gears. 630+ hp, aggressive idle. 9,800 recommended limit, 10,000 rpm max potential.
That's from defined autoworks' $40,000 build.

While completely custom; the 787 & 787B's were NA 4 rotors that were governed to 700hp