Progress.....ah yes progress! Should I let some things slip or wait until its done? I have been totally busy for a while, but have made alot of changes already. Okay, I just completed my custom front strut brace, and alot of new internal engine parts are sitting waiting for me to assemble a meaner version of MR. 20B. The p-ports are going to open the same time the car runs, I wont allow it to run until the p-ports are fully working. I am still doing some testing on a new intake system, and working out the details. Looking at many different clutch combos as well, as my old one failed at life. A full new cooling system is now intact, and might be able to cool my house along with the car! So check back once in a while, I am still alive!

 

I could arrange that, and yes it works with the stock twins.

 

hahaha, thats awesome!!! good to see that this thing is gonna run the pports open. this is my most favoritest 20b conversion!!!

 

hey, with the video, i can host it on my website if you want for everyone to download it. i see the video is not on streetfire anymore :-(

 

Yeah, that would be great, PM forum member Nopr, he has the videos. Ask him to make a re-mix with some unseen footage, and take out the stupid parts (aka me talking) haha.

 

wow....im stunned. Partly to the fact i just sat down and read 407 posts over 28 pages, But mostly cause of your car. If i had the money i would so do this to my s5 vert. Maybe i could sell my s-10.......

 

If you like it now, you'll most likely REALLY like the version 2 of the car coming soon!

 

If I may ask one question.. what mods were done to your FD with the 13B-rew... (any HP numbers?) and how does the N/A 20B stack up compared to that? As you know Ive PMd you a few times and have been doing alot of my own research on the subject, and Im just afraid that I wont get the performance out of the N/A 20B that I could for a reasonable price from my REW. I understand the reliability issues of a 400WHP boosted 13B, but Im not to willing to trade off power.

 

Ah, you made me think back in the past...I am going to give a brief Logan Rx-7 history, this is a overview-

1983 rx-7 first car, never modded
1984 GSL-SE few mods, springs shocks, carbon clutch
1985 GSL Dellorto intake, header exhaust, springs, carbon clutch 116 rwhp WOW!
1984 GS ,bought, drove sold
1988 turbo II racing beat exhaust
1983 GS daily driver, RB exhaust
1993 FD Touring, RB sway bars, bov, usual stuff
1985 GS started out an auto, turned into the Widebody rx, with my first TII engine 340rwhp 60-1 turbo and haltech
1990 GXL, built 6-port, sucked *****, turned daily driver and sold
1988 turbo II, converted to N/a dyno'd 180 rwhp w/ stock exhaust mani, 2,530lbs, fun *** daily driver, inspired the 3-rotor
1991 GTU daily driver
1988 SE daily driver
1988 SE converted to TII drivetrain (current daily driver)
1994 touring (this is the 3-rotor now)

SO on with the story of the 1994 since that is what you asked about
I bought it two years ago, and it had a reman engine in it. I quickly installed my Haltech E6X, and precision turbo GT-40, And front mount intercooler, upgraded pump ect. It drove it like this for a short time, and it was making about est. of 340-350rwhp at about 16 psi. I liked it alot, but it was just like my First gen widebody, but with a FD engine instead of a FC engine. Around this time my daily driver was a blast (see n/a Turbo II in the timeline) and I got the idea of a n/a 3-rotor, as I never really wanted much more than 350rwhp. So that night I pulled the motor, and started selling everything off. I had little support, and much doubt from alot of people, but I went on anyway. My wife was another person responsible for the idea saying "cant you make a fast car, and be non-turbo?" It was a honest question, I wanted to find out. It was well worth it, and thanks to being lighter than ever, it was faster than the single turbo 13b before it. Comparison, I like them both, the n/a 3-rotor is so much more a pure race engine driving it around and on the track. And the sound will win you over for life! Hope that answers your question! Hahah

 

I really can't imagine being disappointed with a 350whp 20B FD. You'd have to work a bit to get 350whp out of the stock engine anyway.

A turbo car is always great fun to drive. But this car has a rock-steady torque band that just keeps going and going, and I'm really excited about making my own N/A 20b.

EDIT: One more thing. A lot of times, people will comment that X horsepower isn't all that impressive or whatever. But 350whp in a chassis this light is a FAST CAR. You really have to experience it to realize it. For most people, 350whp is more than they need for a daily driver. Now I can accept that some people want a little more in the case that they need to race someone (at the track of course), so why not throw a little nitrous on top? My point is, this car is fast, and if you think it isn't, you probably haven't driven a car of this calibur.

 

yes, those people are called bench racers, and they suck.

'oh you spent that much and only have 310rwhp? you could agot an LS1 and da-durka-derka-poop-poop-jargon! stock twins with a powerFC blah blah **** *****! or how about a nice turbo ford 2.3L with a 3482psi of junkyard turbo boost blah blah da durka durka! yeah that'd be better!'

thats what the bench racers say, but I've ridden in this car (and drove it 20 feet at 1% throttle once!!) and it's seriously fast. fast enough to be entertaining for sure, especially through exit ramps (horrifying). not to mention it can embarass nearly anything on the street. also, it can be romped on all day worry free, especially with the new raiator set up. the power is instant, and the sound is amazing (wish you guys could hear it in person, really), and when its done again its going to rev until the cows come home (which I've been told is quite a long period of time). its just a fun car which people seem to overlook when comparing cost/parts lists and dyno numbers. is it the absolute most cost effective dollar per hp swap? no, of course not, but who ******* cares!? its not a budget race car.

anyway, this car is sweet and bench racers suck.

 

Not sure if this post was in response to my comments or not, but Ill chime in with my opinion. IS 350RWHP in an FD fast, yes of course. BUT, I personally want just a tad more. Id like to be able to trap ~120mph in the 1/4. Im not asking for much more, just 25-50HP. Im not a bench racer, and I have very good reasons for wanting to do the N/A 20B thing, but I want to be pretty certain of the power I can expect from it before I sink thousands of dollars into something I personally wont be happy with. Ive owned alot of rx-7s over the past ~7 years, ranging from FBs, N/A and turbo FCs, and now my FD. I think the most fun car Ive owned was my S5 N/A, i really liked the fact I could just beat the **** out of it all day long and I woundnt have to worry about a thing, but that being said I still wouldnt trade back from the power of my FD. Thats why Im looking into this, to get a nice blend of both. When I PMd GToRx7 a while back , I asked him for trap speeds from his car, and he told me it was ~112mph. Now is that impressive for a N/A rotary, yes. But it is still what I was doing with just a bolt on FD, and barely enough to hang with a stock C5 vette. Im just looking for a bit more out of it.

 

No dont worry, those responses werent directed to you at all! They were speaking of others. Now I understand fully of how much power you want, but out of curiosity, how heavy do you want your car to be? Its a strange question, but the n/a 3-rotor frees up a good amount of weight. If you are ALOT like me, you will be willing to sacrifice some luxury to have a faster car, with LESS power than before. For example, are you going to keep the A/C? Do you really need the ABS brakes? Is cruise control a must? You said that your car has 400rwhp, what does it weigh? Its power to weight as you already know, but it seems to be something your not taking into account. Trap speed is a horsepower race, but its quickest time that will cross the line first. Its a matter of asking yourself what you want to do with the car, and if a 3-rotor N/a will fit your needs. Last year my car was getting into 350rwhp and weighed 2600 lbs with a 120lb cage in it, which is 7.4 to 1. As a example a 400rwhp FD weighing 2890lbs is 7.2 to 1. That is damn close, and why I have raced three single turbo Rx-7's and hung with them all. Add to the fact you zero lag, I have caught many cars so far off-guard it almost not a fair race. But then again, drag racing is a fun thing to do with my car, not what it was made for.

Oh on a side note- Not trying to brag at all, I raced a Z06 last year, a guy that I knew, and did work to at the shop I worked for. I beat that Z06 from a 45 mph roll to 120. I also raced a C6 non-Z06 from a light, and had him by 2 car lengths by the second light (1/8th mile run)

 

The only accessory I would really like to keep is A/C, and I will be keeping ABS. Mine is an R2 so I dont have cruise anyway. I would rather have a lighter lower HP car than a heavier, higher HP car. This is the reason I dont really want to go with a turbo 3-rotor, all that weight on the front end just doesnt appeal to me, even if I can make 600WHP on 12psi or whatever. I would rather go LS1 1st. My car is/will not be built specifically for drag either, but it is something fun I like to do , and would like to be fairly competitive at it. Im not trying to knock your efforts or your car at all... I have great respect for what you've accomplished, Im just trying to make the decision if this is for me or not. I want to go N/A, so I was this close to buying an LS1 swap, but this has caught my attention since, and Im trying to see exactly what I will end up with as an end result before commiting to anything.

 

I understand fully, and I knew from the start you were not knocking my efforts.
It sounds like you are on the fence, and like to have a very streetable, very comfortable, and quite fast car at the same time. With that said, honestly a n/a 3-rotor is going to have a hard time meeting your needs AND have the power you mentioned. Mostly due to the fact that a n/a 3-rotor pushing 350+ is a loud bad *** sounding mother. However drivablity, and reliablity, are its strengths. The 20B n/a is more expensive than the LS-1, period. Its a fault that I am trying hard to help others with, aka I want to develop a very cost effective intake manifold, and headers, so a person can order a whole "340 package". You buy it, install it, and have 340rwhp. Then make it expandable to support more power as the user has income, or desire to go farther. It still wont be as cheap as american aluminum, but it will narrow the gap, and give true rotor heads a chance to stay faithful for life. I think, your car will end up loosing 40lbs in the front, and make 330-350rwhp, and you'll love it for a while. Once that is complete, I should have answers for making much more, while still tame to drive everyday/weekend. And we can all learn from each other, and take n/a 3-rotors to levels not yet reached. Go 3-rotor, and I will help you as much as possible is the point to this story!

Oh yeah, and if you dont mind nitrous, its a hands down decision to go rotor. A 3-rotor n/a can handle ALOT of nitrous.

 

I've liked this project since I first saw this thread...can you give the thumbs up on a couple details.

FD Tranny, which requires FD rear iron, which allows for the rear iron motor mounts and FD subframe...is that correct?

Did you use FD housings? (I see the FD front cover) What other parts did you use from an FD?

S5 N/A rotors

Do have just two motor mounts?? (couldn't tell from the pics)

 

The FD tranny bolts up directly to a cosmo rear iron, no problems. You could use a FD rear plate, and use FD motor mounts, but unless you do a hack job "stock subframe" and still lower the steering rack down 3-5" it wont bolt down. Moving the rack that far down is going to kill the handling, esp. if the car is then lowered 2-3"

No, I have a C series 20b, which is beefy already, so all the housings, except two rotor housings, and front cover, are 20B.

Yep

Yes, two motor mounts. I make and offer these for sale, and will place the engine as low as it can go, without moving the steering rack. My kit is still the only one "I" know of that uses a FULL stock subframe.

 

I know there are differences between the earlier and latter series 20B engines, but are any of these things to be concerned about when looking for a 20B to go N/A with? Say I can find a good condition A series engine, should I hold out for a D series to come along, or will I be fine with the weaker E-shaft and such on the A series.

 

^^^ I was curious about this too.

 

The whole e-shaft deal was rumored to be only on the number series. Even still it was to do with fatigue at low rpm/ boost, which we dont have any of. The A series is suppose to have good shafts, but the castings are still S5 turbo II baised, and the B and up have the FD baised with very thick dowel castings. For N/a use it wont really matter as much, so A series, and most likely even number series will work. This should make cheaper 20B's availible to guys wanting to go n/a. However, if you are planning on tossing in a good shot of nitrous, might want to hold out for a B series, or make you own using a front and rear plate from a FD.

 

I like the sound of stock subframe...not moving the steering rack...and no turbo. How much modification is require? (I'm guessing clearances for an oil pan)

did you use the stock cosmo oil pan? (sorry if this has been discussed...I should probably reread this entire thread)

I have to think an extra iron and housing will weigh less than a turbo, manifold, IC, piping, BOV, WG, WI kit, IC sprayer, etc, etc...

What I'd like is an FD with 340rwhp, PS, AC, and last for 200k miles. I'm tired of wrenching...next time I pull the motor I want it to be the last. And when I fill up, it's nothing but gasoline...well and premix. No water or meth...

I would guess, lightened rotors, and the lightest flywheel possible are things to consider???

How lean do you go with the tuning?? How do you think a zero split ignition set-up would preform in street driving?

Is there a need for "something" similar to AUX ports to enhance low end torque? (hard to have too much with a rotary, haha!!)

that's all I can think to ask at this point.


oh, and is it possible to keep the radiator in the stock location?

 

There is a slight clearance issue on the back of the pan. You can "notch" the back of the subframe, or slightly re-weld the pan at the back.

Its too damn long to read, lol! But I did use the stock pan entirely, notched the rear subframe, and welded a small plate back in.

Considering the 20B "engine" itself is about 70lbs heavier, and the custom intake and exhaust are lighter than a 13B, leaving it 50lbs heavier. Now subtract turbo -30lbs, turbo mani -8lbs, intercooler piping -18lbs, wastegate -12lbs, intercooler -25lbs, intercooler sprayer -36lbs, BOV -4 lbs, turbo electronics -1lbs. THat is a total of 84lbs less than a single turbo 13B. And we all know how much the stock air pump, twin turbo, everything cast iron 13B-rew weighs, about 40lbs more than a single turbo FD! So yes, its a good bit lighter!


I can guide you to this point pretty easy, the ps and ac is a slight challenge, but not really, the alt. can go off to where the air pump used to be. Now if you want a air pump, hmmm, we will go electric, I cant do it all! J/k of course, haha. Oh dont forget the savings at the pump, 89 octane is all you need.


Well, you have to keep the 20b rear counterweight, so a lightweight flywheel is a token gain. lightened rotors....not unless you want more than 360rwhp n/a

The center rotor runs a little different from the rest, so unless you have three EGT's, in each exhaust runner, and a haltech or motec to adjust each injector trim, I can only go to about 13.0 afr before it runs rough on full power. All I run is zero split in most rpms ranges. It performs perfectly, better than perfect.

Not at all, even with three 55mm running primary and secondary together, I had more than enough down low torque, and you will be more than happy with it at ANY rpm. I shifted at 2,200 daily driving, and it felt like shifting at 5,500 on a n/a 2-rotor.
Now, my next manifold I am making is a multi-throttle body setup, and will have something similar to "aux" ports (wait and see!) Mainly I am doing it to prove a point on how much bottom end torque can be made, while making great amounts of top end torque too.

I didnt think so originally, but with a aftermarket rad, that has the pickup on the far right side, and BARLEY longer lower mounts, yes, it is possible.

So lets do this, I have a set of motor mounts with your name on them!

 

^HAHA!!! Slow it down tiger, but I like your enthusiasm! Thanks for answering my questions...

I do run a single turbo now, with electric air pump...and a haltech. When I'm ready for this I'll most likely go with a Haltech E8, and use 3 EGT's. I just moved to a state that doesn't require emissions testing so...you know what I'm thinking.

why is the 20B rear counter weight a must?? Is it because no one makes an aftermarket combo?

I need to talk with Carlos at CLR (in Miami), and see how he feels about port phased rotors in an N/A (sideport) application. Are P-Ports necessary to achieve 340rwhp?

Radiator...I'll probably have Ron Davis make a radiator for me...to use an eletric water pump. But I'd like to keep it in the stock location.

I've been thinking about the PS...seems a lot of the racers (Damian, howard coleman, axr6, etc) feel PS is not necessary with a car this light. I don't drift, so I'm looking for a track/autoX/weekend toy. I wonder if having an extra rotor hanging over the front axle will effect NO PS?? Or is it just the weight the corners see??


I read earlier in the thread...you had an issue with varying vacuum at high rpms. You said you throttle pumps were too sensitive. With a haltech, throttle pumps are TPS actuated...is the mircotech different?? Does microtech have a WOT map you could utilize to correct this as well?

here is a picture of something similar to what I'd like to do...mainly to avoid cutting a whole in the hood.


then route an intake filter somewhere where space allows.

 

The 20b rear counter weight is much larger, and has a bigger span. Due to two rotors being only 120 degree's apart, they both kinda act together as a large weight themselves, making the rear weight so big, and needed.

No not at all, I was at that level on the side street ports. Carlos at CLR is one of the best there is, so listen to all he says.

It will be better than before, a front mount intercooler, and turbo together will have the same amount of inertia on turn in. Static weight will be the same or better as well. So if you dont want to use p.s you dont have to, I just hate it when you are going slow around town. Makes driving more of a chore.


Yes microtech uses map based throttle pumps, and if you change it to TPS, it changes the fuel map to TPS also. It was able to be fixed, just had to turn down how sensitive it was set at. Haltech will have no problem. A hole in the hood isnt needed, that was a quick fix, to get the car fresh air. This year I wont have that, and making your style of intake is quite easy.

 

This thread just keeps getting better and better.

I really want to do something similar in an FC shell.