Experts: 20B NA, finally starting my project.
 

So, I am finally starting my project.

I am going to buy a 20B in a JDM shop. But I want to run it NA. I am looking for the higest compression possible. What would my best bet be? I am guessing RX-8 rotors. Right?
Also, I am planning on running it on 3 holley carbs, no injection, what do you guys recommend for a custom intake? Size, shape and lenghts. I would guess same as FCs 13b with carbs.
It will also be street-ported.

I would think that with that set-up, 300hp is easily obtainable, right?

I will be subscribing to this, It seems interesting. As far as 300NA-HP I think Ive seen somewhere north of 400ish with a 20b... Good luck with it though...

-Mike

Iam going to be this threads groupie!:lol:

Go PP! Anyways, s5 N/A are 9.7-1...RX8 rotors are probably the highest...I can't find the ratio, someone else will chime in.

PP is not streetable, so no way in hell I am doing this. I wanna keep the center irons also.
This engine is going in my FC or a second one with a blown engine I will eventually buy. We will see when the engine is assembled in, I would guess, 6 to 7 months.

Oh, and if anyone is interested, I will have everything on the block for sale, wiring harness and ECU also. I found the engine for 3500$ all included....with the auto tranny....

Also, I have a problem with spark. I can buy a 20B distrubutor from i think it's maz-fix in aussie, they are around $1300AUS...but thats like 1/3 of the engine price...Anyother sources I can get that from or how I should go about doing this? My budget is around 10K.

As for exhaust manifold (header) I would be guessing 2" (3 in 1) 3". Think its big enough or it'll chocke the engine?


Spec.

3500$ engine
1500$ custom fab work and tubing
1200$ 3 holley carbs
1200$ 2 rebuild kits
1000$ RX-8 rotors
1500$ improv.

That sounds about right?

Spec.

if you want big power, go semi-pp, then you can keep the streetability

have the semi-pps open later than the regular ports

if you're having the mani made, theres no reason not to make it really special

and if holleys cost 1200, i think you might as well go standalone, it'll cost a lil' more, but you'll get better drive ability, better mileage, and more power

Good luck with that 20B project. There is a guy who did the same thing on his FD, you might want to look around for info.

:icon_no2:

what the hells wrong with that idea?

2" primaries will not choke a streetport. I would skip the Rx-8 rotors, just do s5 n/a. Save the money and put it towards something else. You're going to end up spending more than you think, this is all custom work.

There are a few things brought up that I would like to share my opinions on.

As far as the RX8 rotors, they are designed for a side port motor, exhaust included.
They use narrower, shorter apex seals since they do not have to pass over the big open exhaust ports.

Also, if a 3 rotor dizzy is $1200, why not just go stand alone?

Lastly, its not completely true to consider peripheral ports unstreetable.
People lump all peropheral ports into the same stigma, when there can be a lot of variables. The size and shape or the port determine most of that, but also things like runner length can help make it more driveable (Note, to make big power, it will need to be uncorked, ala LOUD)
Heres a video of Max's car off of the NoPistons forum. Idles under 1000rpm and makes about 230hp to the wheels. It also gets mid 20s on the highway. Around town is a different story though.
http://www.youtube.com/watch?v=GHfyaqH9dt0

+1

The RX-8 rotors will eat up costs quickly due to extra machining, and even after that you still have the issues of different sideseal fitment.


I would just streetport the crap out of it and run S5 N/A rotors. It'll be fun as heck and have some grunt on the bottom.

I would also just run an E8 and probably use 3 FC trailing coil packs for ignition. Probably the cheapest way....

I thought of S5 NA rotors at first, I'm just ignorant when it comes to the renesis engine. Thanks for the info people.
S5 rotors it is.
I already have 2 of those anyhow.
As for porting, street port is what its going to be. Nothing more, I am not looking for 400hp, 300 is well enough for a DD. Once I finish that engine, I plan on runnning it for 120k miles atleast, no fucking around. Thats the main reason I am going 20B NA, reliable power on demand.
I'll be picking up the engine this week-end, I will post pics of it when I get it.

Anyone in need of an auto 20b tranny? :)

Spec.

Are you just using a TII trans?
How do you plan on mounting the motor? Kit?

Using a TII S5 tranny. Keeping my Cusco Flywheel and clutch.

Motor mounts, probably custom ones.

Mate Love the Idea, I always thought Turbos were cheating!!

Check this out Hurley Engineering do a manifold with 3 SU carbs! Myself i think carbs are old school, still give good power but fuel consumption is no the best.

If I were you I'd be looking at ITB's run off a standalone. You could use stock FC trailing coils for the ignition, simple, cheap and would be more reliable and most likely more powerful than a dizzy. You can get some Weber flanged TB's (there's ones with 3, made for Porsches) and make up your own manifold. It'll idle better, make better power across the entire rev range, not be phased by cold temps and generally not suffer from the problems associated with carbs.

All else being equal, fuel injection is much better.

Also, isn't 3 Holley's a lot of overkill? The 20B's only 50% bigger than a 13B and you're talking about 200% more carb. Doesn't seem like such a good idea to me. Maybe 2 are needed, maybe not, but I think it'd be better to run fewer on a manifold with a plenum, will be cheaper that way too.

you know, it wont take very much to make 300rwhp
this guy did 206 with a small streetport on a 13b-re
you do the math
i think if you did a real agressive streetport, some individual throttle bodies, you could get 348rwhp like this guy.
https://www.rx7club.com/20b-forum-95/my-rx-7-done-cup-holders-3-rotor-semi-p-port-n-setup-stock-subframe-454580/
that was on only his streetport setup, if i was you, i'd go the way he is with semi-pp, and see what you get!

good luck with your project!

You need to triple your budget to get it up and running.
You're missing a lot of "small stuff" which is going to push your budget up.

Doing 300hp on a non-turbo 20B is not worth it cause a 13BT will do that without building a sweat.

If you're trying to get cheap on such a project, it's just not going to happen.

There is a 20B section which has a lot more info.


-Ted

ted is right on here guys... 20B = rich blood

people dont do an NA 20b because they want massive power
if they wanted that, they'd turbo a 20b
and i doubt he's far off on that budget. 10,000$$???? theres people that do turbo 20bs for barely more than that..
stop stomping on peoples hopes and dreams

If ones hopes and dreams are going to be dashed by someone posting on the net then those weren't much to being with anyhow.

People are not doing turbo 20b(s) for 10k, if they are please tell me what I've been doing wrong lol...

I have build a 20B FC - have you?
If you haven't, don't even bother trying to add your input to this thread.


I tell you what...
Why don't you build your "carbon fiber wide body" first, and then you can come back and tell me to shut the fuck up?


-Ted

First, its not dashing someone's hope's and dreams, its a reality check. About the cheapest I think I've seen anyone do a 20 swap is patman, and hes still in about 15k, I think. And that was with him doing everything.
Also, how are 2 rebuild kits $1200, and why do you need 2 anyway? Just get a rebuild kit plus the extra stuff for the 3rd chamber, but it will still be more than 1200.
Finally, I'm suprised no one has said this, but Renesis rotors are 10:1 compression. That is not even close to enough to justify the increased cost and work over s5 rotors.

mmmm, its your car =] i say go for it. lol, if it dosnt work out, just sell it. and start over again.

rx8 rotors are lighter and have a higher compression.

interesting.. keep the details of the project coming.. with how much you paid! hope all goes well for you.. ill keep myself posted

Yes RX8 rotors are lighter, but .3 compression ration is pretty negligable.
Also, S5 rotors can be lightened to weigh less than lightened RX8 rotors.
There is the apex seal issue that I adressed earlier and also the different side seals.
All in all, S5 NA rotors are much more available/affordable.

The RX-8 rotors are only fractionally lighter and have only a small increase in static compression. I've read that people have actually experianced reduced compression numbers when the rotors are installed, as shown by a compression tester, so it may not actually be an improvement.

All in all S5 NA rotors are probably a better choice, as they can be installed with no need to re-balance the engine and they'll be cheaper as you can get them used.

Triple my budget?! Explain to me where I am missing 20k please. I gave myself a 10k budget knowing it would probably go up to 13-14k....not 30. Please, give me your input.

I already have that....and so does everyone else. I want around 300whp, very streetable and the sound of the 3 rotor. Been looking at it for the last 5 years or so...I had my 13B for 10 years now, its time to move on.

I never ever cheap out, and I really thought I had it with around 10k...Take note that I am doing everything myself.

What I need:
3500$ Engine and tranny
150$ 1 S5 rotor
1200$ rebuild kit (Yes only 1200$, I have good prices)
1500$ Tubing, metal and fabbing.
1100$ EMS and wiring
1200$ 3 ITBs (Is that figure right? I haven't found them yet, but I would think so)
450$ Motor mounts custom
1500$ improv/unexpected

What already I have:
2 x S5 NA rotors
3 x S4 Trailing coil packs
2 x S4 Leading coil packs
All gauges
S5 TII tranny
Koyo RAD
S4 NA and TII throttle cable....?!?!

I will be running this premix also.

What am I missing for 15k Ted?

Thanks.

Spec.

I'm a bit confused on "EMS and wiring"?
I thought you were going carbs?

I dunno what you're planning on doing with this thing, but cooling might be a problem.
NONE of the aftermarket radiators are big enough for a 20B.
You need to address the oil cooler(s) also.
You might be able to get away with smaller units if it's purely for street, but you can't get anywhere near a track without really good cooling systems.

I dunno what you're planning on doing in terms of engine mounting, but if you're going to keep the transmission in the stock location, no stock location radiator is going to fit.
If you're planning on moving the transmission back, then the "Koyo RAD" will fit, but now it requires a lot more custom work for the shifter.

I dunno you list a mix of leading and trailing coil packs, but you need SIX individual coils.
None of the 20B spark plug fire at the same time on a stock 20B ignition system.
You need either six FC trailings or six aftermarket, single-tower coils.

The stock fuel injectors can support 300hp, but the stock fuel pump cannot.
You got an upgrade fuel pump already?

Do you have a good (aftermarket) LSD?
Original, stock ones are gone by now, so it's a good idea to upgrade to an aftermarket one for the increased torque.

What about wheels and tires?
Although not a necessity, wide rubber is highly recommended.
Having all the torque and unable to put to the ground can be downright dangerous.

I see zero mention of upgraded suspension.
Is this already taken care of?
I would recommend a full suspension upgrade for the higher torque.

Clutch?
An entry-level ACT should be okay, but it's still $300 minimum.
No mention of a flywheel...the 20B doesn't come with one.
Since you're going NA, lightened aftermarket flywheel would be a good choice.

Water pump?
The stock 20B water pump cannot be replaced in the US.
A replacement 20B one from Japan is very hard to get - got hook-up's for this?
They are either swapped with a stock FC or stock FD set-up.
You will also need the mating water pump housing to make this work.

Brakes?
Upgrade pads are highly recommended.

Looking at the prices, it looks like you're trying to do as much of the labor yourself?
Can you tune the EMS yourself?
If not, paying for a professional tuner is added bucks also.

See what I mean by the nickel and dime stuff...



-Ted

Oh, now I understand where your 30k is coming from. I already have 20k on my FC, so most is taken care fo.

No, after much searching, injection seems the way to go. For gas and power optimization. Correct me if I am wrong please.

My Koyo wont do? What do you recommend then?

I have 2 FC oil coolers, would that be enough?

Planning on having the tranny on stock location. The rad problem will be according to your solution.

What would you use? Aftermarket or OEM?

I already have a Walbro 255lph

I am looking for the same amount of power I have now with my 13bt, do I really need to change iyo?

Again, I am only going for 300rwhp. I plan on keeping the same wheels I have now.

All taken car of already. KYB AGX and adjustable E-bach spring with rear and front strut tower bars.

I already have a Cusco 8lbs flywheel and a Cusco Supersingle clutch kit. I am planning on keeping that also.

Why replace? Are they not reliable, or you are just planning ahead? If so, thats no problem, I live in Canada, JDM parts are raining out here.


I already have Hawk ceramic pads. I think that that should do. No?


Thats the only thing I cannont do alone, but a guyI know has a shop and he does it at cost free for me. Flat fee of 300$. He loves my car like if it was his little sister.

Thanks.


Spec.

^and now we have a list of a lot of parts required to pull this off, thank you Ted. out of curiousity, how much did Sky's 20b fc3s cost in total?

Remember that you will need to (or should at least) get the rotating assembly balanced now that you are mixing/matching rotors.

It's definitely doable for cheap if you can rebuild the motor yourself, fab the header, and have a good grasp of where to get obvious parts cheaply and are able to make alot of parts youreslf - ie. custom radiator hoses, fuel/oil lines, etc. I failed on my swap having spent about $25k, but I went all-out on alot of things which aren't necessary in your setup.

Depending on which ECU you go with the ignition coil options can be really cheap (LS1 coils are about $20/ea now). If you REALLY want to save money you could run something like a Megasquirt ECU firing the leadings and trailings at the same time.

Ted's comment above is not entirely accurate regarding the radiator - you CAN fit a stock location radiator using 'off the shelf Cosmo mounts' but the fitment leaves something to be desired and you'll have to bend the mounts slightly:

http://bp2.blogger.com/_xh1AYg4Kj3A/...0/CIMG2388.JPG

If you are only going NA I wouldn't worry about upgraded LSD, wheels/tires, etc.

PP! PP! PP! Do it, who cares if its not streetable its just damn sexy.

Lol, on serious note why not just bridge the hoe...that way you'll still have some streetability and some extra power. Or if your worried about the cons of a bridge then just got big streetport.

Do a semi pport with staged throttle bodies. Run the primary stock ports and plug up the secondaries..

BTW I have 6 ls1 coils sitting in my room in great condition :)

100 shipped

Where is the fan going to go??? Ted is accurate, the radiator mounts need to be moved in order to run off the shelf cosmo mounts. The main crank pully will hit the fan. Not a big deal for someone who plans on making a custom intake manifold. Don't forget about relocating the sway bar as well.

As far as the rear end goes, you might be looking for the same HP as your 13bt has but the additional TQ is what you need to be looking at. Although a stock TII rear end should be fine.

I think you are still missing items for fuel and ignition. add another couple grand.

Fan clears fine:

https://farm2.static.flickr.com/1292...54f0321837.jpg

i will

edit:
i think it was patman that did a full turbo 20b for like 12k or something along those lines
i can imagine that the extra 2k would atribute to all the turbo stuff

We run pullers, and a single electric fan needs to move a LOT of air to keep everything cool.
If I remember correctly, you end up with only like 1" of space on the bottom part, which is not going to clear all of the bigger fans that push over 2000CFM.

I don't think of the stock replacements (i.e. Koyo, Fluidyne, etc.) can keep the 20B cool.
We run AFCO Racing 80125N's and hack the radiator supports just to make them fit.
And even then, it barely keeps a 20B turbo cool on the track.
I would think ducting would help a LOT here.

Sorry, I'll answer the other questions a little later on - I just got done with an 8 hour shift, and I normally go to sleep now. :)


-Ted

Agree on the above and it's alot of the reason that I ended up ditching that setup. For an NA street-cruiser I suspect it would suffice, but only if you were really trying to keep costs down and eyed the watertemp gauge like a hawk.

I couldn't get my radiator setup to work in the stock location... so for those of us that had to relocate the radiator also had to relocate the oil-cooler which required new cooler lines... radiator hoses... blah blah blah... it all adds up and you can expect to spend a few hundred dollars just on little stuff like fittings, heat shrink, tape, terminals, wire, throttle cable, fuel line, hose clamps, filters...

Hey guys dont wanna be negative but TED is spot on the money and until you have built a 20b NA car i dont think you have any idea of the costs involved it is triple the cost and the little things that you choose not to do are the thing that will came back to bite you. Good luck though cause in my opinion we cant have enough NA rotaries on the road!!!


dave

ps my engine and intake system owes me 15000aus dollars alone and i did all the work myself!!!

:lol: :lol: :lol: :lol:

Thats the same guy! both cars/engines were personal cars of the Defined Autoworks Co-Owner Logan. He did the -re as sort of a mini (cheaper) way to experiment with ideas for the 3 rotor. you should call him up or PM him, hes super helpful and could definitely make a lot of the parts you'll end up needing.

haha whoooooops :lol:

There's only one way to do a cheap sub 10k 20b project, that's to do everything yourself including all the fab work.

what about balancing the rotating parts? If you change the rotors you will need custom balancing because you have changed the weights of the rotors. Custom 20B counterweights? Sounds like $$$ to me.

Ramses666

Can help you out with the distributor and the header. I'm currently converting my 20B to turbo and have the following parts for sale:

https://www.rx7club.com/showthread.php?t=736446

http://3rotor.com/index2.htm
This has to be one of the top three best FCs of all time.

I was going to point that out, but you have seen the light. :)

It's all custom.

That should be fine.
This seems to be the minimum to keep the oil temps cool.

(In regards to coils...)
This is purely dictated to your budget.
People have been going with LSx coils for "cheap" and "compact"; they are priced under $100 each (times 6) and include ignitor and coil in one unit.
Personally, I think they have their limitations.

My "ultimate" set-up costs up the ass...
Pair of Autronic 500R's or MoTeC CDI-4's mated to 6 aftermarket coils - MSD HVC or similar.
The CDI boxes are $1,000 EACH, and the coils are easily over $100 EACH.
All together, we're talking about a $3,000 ignition system!
Stepping down on the coils, I think we can get away with a set of Crane Cams LX-92's, which are $62 each from Summit Racing, but it's still almost $400 for just the six coils.
Of course, this system is overkill.

(In regards to the rear diff...)
of course, not necessary, but highly recommended...
You can run with an open diff if you want...it'll run, but it's not fun when you can't put the power down.


That'll work.


I'd question how long Mazda Japan has these in stock.
The Cosmo has been discontinued for about 10 years now, and they (Cosmo 20B production numbers) were not very many made.
It's just a lot easier to source the RX-7 parts, and that double thermostat housing is just a PITA.


Like the diff, it's just highly recommended.
I dunno what "Hawk ceramic pads" are, but most "ceramic" brake pads are entry-level brake pads.
HPS?
HP+?


-Ted

in reguards to the 20b water pump, the parts catalog lists it at 40,000Y and thats the 90's price.... so its like this

effort to get it / cost > bolt on fc water pump assembly....

on the coil issue, having done 3 dual post coils and having it not work all that well, i'd recommend you need to run at least 6 single post coils. cheapest thing are the ls-x GM ones.

if you've got the money, a cdi setup would be better....

fans: you need a BIG radiator, and a lot of fan, remember this is FD heat X 1.5... also it might get by ok with the koyo style setup, but take it up in the hills, or the track and its gonna get hot fast....

walbro fuel pump and stock injectors are fine for 300hp, which is nice

also, next time we do a 3 rotor (or 4 rotor, hint hint) the trans is moving....