Is this possible? Well I guess anything is with enough money, but I can see how this would work.
From what I read, there is 2 ways to do a 20B swap. What 95% of ppl do is just bolt the 20B in place of the 13BT. I have heard of guys though that move that transmission back 6-7 inches so taht the front of the 20B is now where the front of the stock 13BT used to be. Couldn't someone do both? Move transmission back 6-7 inches, and take up the 6-7 inches of room infront of the original 13BT front... essentially making room for a 26B.

But then again, if you have a 4 rotor, you would need a transmission replacement... probably a borg warner t5 (found in some mustangs) or some other very comman and very strong v8 transmission. Installation of a ford 9" rear end would pretty much be the msot logical thing to do, to handle the power and save over lots of custom work money. With the BW tranny and ford 9" rear end it should handle the power and be easy and affordable to find replacement parts.

Engine management would require a stand alone for sure, probably just use 2 systems, such as 2 haltech E6k's. Crank is another issue... very few ppl make them an they are pretty expensive ($2700-4000 range from what I hear/read).

But yeah, I think it would be totally possible to fit in a 4rotor without hacking apart any of the stock frame and panals. What do you guys think>?

 

That reminds me, the hitman (www.hitman.au) has been working on a 4-rotor 1st gen. If he can do that, then for sure a 2nd gen is possible.

 

to fit a bigger radiator for the 20b you have to cut the radiator support http://www.k2rd.com/Projects/20B/Radiator/Radiator2.jpg
while it possible that it will fit, 4 rotor engines arent eactly easy to get.

mike

 

To make a 4 rotor engine the only CUSTOM part one would need would be the eccentric shaft right?

Other than engine accessories of course such as fuel rail, intake manifold, exhaust manifold, etc. I'd be willing to give this a try. Pick up a cheap NA RX-7 in very good condition with high mileage this year and use the winter, spring, and into the summer most likely to get a 4 rotor in there and going. I just think I might give it a try.

Can someone offer some tips on things I might not have looked into yet that will be a concern?

 

you need a custom eccentric shaft, main bearing, and one more custom center plate. mazda will sell you a 26b 4 rotor, but you have to have connections and $$$.
have you ever done a custon engine swap before?? there are enough hassles to get the 3 rotor to fit in an fc that it might not be worth to put the 4 rotor in there.
for the money it will cost to do a 4 rotor it would be cheaper to buy a kudzu from jim downing

mike

 

Word is that Pineapple racing sells "26b" engines for $6500 (with exchange of two old 13 cores). That seems like a decent price. Obviously it would be a rebuilt and not used parts... and I'm willing to bet that it would come with upgraded apex seals, corner seals, streetported too. I should phone them and get some info on this engine.

There is a guy named Jeff Bruce in New Zealand who sells custom 4 rotor shafts for $1320 (not sure what currency).
I've never done a swap with an RX-7 before. I have removed and installed a few engines in cars before, turbocharged engines. I actually helped my dad make a homemade trike (3 wheeled motorcycle) powered by a 2.2L chrysler 4cyl engine.

I doubt I will end up doing this, mainly b/c of the high cost, bit I am thinking seriously about it and trying out line exactly all the work and costs involved.

 

Oh! And to everyone reading this thread.... I just want to get a lot of information about doing this project. I'm not necessarily saying I can do it or will do it or that it is a good idea. Please don't turn this into a big hate thread and being jerks about it like I have seen lots of 4 rotor and 3 rotor threads turn into.

Just lots of information and input (positive or negative!) is appreciated! Thanks!!

 

CODESEVEN21 IS THE SAME MEMBER WHO RIPPED OFF MANY PEOPLE. HE CHANGED FROM COOLIDGE TO CODESEVEN21. RYAN IT WOULD BE A LOT EASIER IF YOU WOULD JUST ANSWER THE PEOPLE YOU RIPPED OFF AND GET IT OVER WITH. IT'S BEEN THREE MONTHS MAN!!!! COME ON, GROW UP!!

 

I sent you a private message explaining what I explained to another member already. Same name - different person. Check your PM for more details.

 

I dunno who you are, but you need to either change your nick or solve the problem with these other folks who keep calling you a fraud...

A 4-rotor just will not fit in an FC or an FD.&nbsp You're talking about cutting the firewall just to get the engine to fit.&nbsp Unless you're going to lengthen the front and extend the wheel base.&nbsp The 20B barely fits with the existing space.&nbsp You're talking about an engine that is almost 12" longer.

You'll need an special (dry) oil sump system that's going to cost at LEAST $2,000.

Are we talking turbo here?&nbsp No stock-type transmission is going to handle the power potential - not even your special T5 trans.&nbsp A dog-geared trans can barely handle a turbo'd 4-rotor.

Use a pair of 13B's?&nbsp you gotta be kidding me.&nbsp The e-shaft is going to flex like a bitch in heat, and you have very serious cooling and oil lubrication issues.&nbsp The R26B had special bearings in the center to support the extra "long" e-shaft.

No "normal" cooling system is going to cool this beast.&nbsp You're talking some really specialized cooling system design to supress all that heat.

Gas mileage is barely going to be 10mpg.

No street tire is going to get you traction, not even "monstrous" 335's sized Viper tires.

You're literally going to twist the chassis in half.&nbsp A 12-point roll-cage will barely keep everything together.

You're looking at a $100k project on a $2,000 chassis.

Your story stinks.&nbsp This pipe dream is exactly that - a pipe dream.&nbsp You have no idea what you're talking about or what's involved.&nbsp You're quoted all kinds of BS that it makes yourself look pretty weak.



-Ted

 

T5 transmission? T5s shatter like glass behind stock 5.0 Mustangs and Camaros, and you think it'll live behind a 4-rotor? It's only rated to 300lb-ft of torque and even that is stretching the limits of the design.

 

You know what I think, all you tossers who keep saying "you can't do it" are all sh*t!
Those who say it can't be done always end up with egg on your faces.
Anything can be done if you have the ***** and $$ to do it. My brother is just building a '78 323 that will have the engine mounted a fair way back. Now, i would say far enough for a 4 rotor to fit. We are fitting a 20B into our 323 and are not moving the firewall anywhere near as far as he has.
There is a guy here in NZ building a 4 rotor PP to go into an FC. it is a Jeff Bruce shaft etc being used (by the way the HitMans S1 RX-7 is a 3 rotor JB shaft engine, not a 4 rotor).
You guys need to come over to NZ or OZ to see what is realy possible. The problem with you guys in the US, as far I can tell, is that you want everything to just bolt in. parts off the shelf, or it can't be done seems to be the attitude. Every one seems to have Trust, HKS, Borla, Racing beat etc exhausts, I never read of a "custom made" exhaust being fitted to a car, where there is an over priced 'brand name' available.
ANYTHING IS POSSIBLE PEOPLE.

 

I found a place called Yashiro Engineering.

http://homepage1.nifty.com/yashiro-eng/profil1.htm

It appears that they make a custom 4 rotor using many of the 13B parts. They have addressed the long e-shaft issue with multiple bearings (5 total, compared to the R26B which used 4). Their engine is also shorter, 820mm (about 32.3"). Still around 8" longer than the 20B, but I think that is doable.

Definitely is going to be expensive.

Custom subframe, dry sump may be required (depending on whether or not you are OK with relocating the steering rack and/or cutting into the firewall).

You could to go to a Jerico (or equal) transmission, which would allow you to choose your gear ratios.

It is a pipe dream, but it could be done and it is fun to talk about.

 

I never said it was IMPOSSIBLE - I implied it was highly improbable.
You might want to add that this custom 3-rotor overheated...



-Ted

 

When the thermos were on, the car ran okay. I think the T2 radiator it had was running maybe 10% past its limit. It was only running a thermo, but with a proper shroud arrangement, I reckon it could have coped up until summer

 

GP Performance here in NZ have a 20B (single turbo, 550HP at 15psi) in their FC, I don't think they are having any overheating problems.

I would go dry sump. I may consider this for our 323.
I met a guy at easter weekend at the Taupo race track here in NZ. He had a 3 rotor like the hit mans (he origionaly had the very first one made) in his S1 RX-7 race car. It was PP using old school housings etc. he claimed the basis for this engine to be over 6 or 8 years old. he was running 4 VW oil pumps joined together to run the dry sump arangement. This is because back when they built it there was nothing available except extremely over priced (by todays standards) parts. He has had no worries with this and saves a lot of hassle with instaltion. maybe this is what the S6 20B conversion guys need to do??
He set the lap record that weekend in this car.

Whats wrong with cutting the firewall?? Is this illegal in the US? To make a 20B fit into an FD I would cut the firewall just for that. Save a lot of dramas with everything else.

 

No wonder they call you Bitchn7 - you can't even keep with the thread properly...



-Ted

 

lmfao, this sure is turning into a shithole thread
Why in gods name would you want a 4 rotor...Only reason I could see is for a super dragster, and they don't have to worry about **** fitting. You can get more HP than you need with a lot more reliability and torque of a 13B from a 20B. Hell you don't even need a 20B. Just learn how to build up the good little 13B right.
And if (really when) that 26B pops, you're gonna have twice the money needed to rebuild unless you just fix the seals/rotor that went.
Possible: yes
Project for the unsponsored, or someone who can't wrench everything themselves: not really

edit
And the only way you're using a domestic tranny is if you keep the redline at about 7k RPM, then you worry about if it can hold up to the power.

 

don't forget also, the frame probably can't handle too too much HP without bending all to shnit.

 

Cutting the firewall up is just a bitch to get sealed back up again, plus it's a bitch to work on the engine since half of it is buried.

 

The guy here in NZ doing this is apparently resonably 'well off' when it comes to coin.
yes it would be a pain in the *** to work on, but then again, aren't most jap cars

I say its being done to be different. I myself would stick to the 20B, but for a race car, could be good.

Chassis not handling it, nothing a good roll cage won't fix, and adds safety that I would say would be needed too.

I don't think reaching to the back seat to change gears would be much fun either

 

I inquired on the price of this...

$44,000 (US Dollars)



They claim 850 horsepower (naturally aspirated). Comes with the carbs and most of the auxilary systems (ignition, water pump, etc.).



You could spend that much (and more) building a V8 to get the same (NA).

They "think" that it will fit in an FD.

 

The same people that make V8 engine cradles for RX-7's made a 4 rotor out of 2 13B's - http://members.tripod.com/~grannys/4rotor.html

 

Here's something I've thought about.
RETed Can you please tell me what is wrong with this idea?

Buy two Jspec 20B's, disassemble them and acquire two more of the 20B style intermediate housings. Take the style of the E-shaft piece that comes apart on the 20B and have 3 of them made to go in between, so that they can couple together, out of billet steel by a custom crank company.
Basically, make a six rotor out of two 20B's and some custom e-shaft parts.
The thing could be run off of three Haltechs, and twin fuel pumps to each fuel rail.
The engine would get horrible gas mileage, yes, but it would make rdiculous power.
Couple this to a ferrari or prosche spce transaxle, and mount it in the rear of a custom chassis'd car, behind the driver.
What is wrong with this setup? It is just the foolish thoughts of a 19 year old mechanical engineer, but I am looking to get into the automotive industry, and hopefully will have money to waste on a completely custom project later on in life.
Sean Cathcart

 

Sure, but it's overkill with three Haltechs.

First, you have to figure out how you want the engine to fire - six unique "offset angles" of the 6 rotors?&nbsp This means rotor offset of 60&#176 with a rotor face firing every 20&#176!&nbsp You can go with a pair of rotors firing every 120&#176, so it'll sound like a normal 20B but with way more power due to the "reinforcing" of the pairs with each other.&nbsp You probably can figure out more combinations, but these would probably be your leading candidates...

Once you got that figured out, you need to get everything balanced.&nbsp Not especially hard if you know what you're doing, but the balance rig itself is going to be huge!

Now, for the custom eccentric shaft - this is not a problem once you understand how a "modular" eccentric shaft is built and assembled with "lobes" and keys to keep everything in place!

Sounds interesting!

I wouldn't even want to touch what transmission and drivetrain is going to handle this kinda potential power!




-Ted