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.