I want a fast na rotary. Im considering a 20b swap. If i do buy a jdm 20b what would i have to do to get it ready for na application.

 

I'd begin by searching this forum and learning all I could.

https://www.rx7club.com/20b-forum-95/

 

whoa, Double post.

Here's a pic for content. :p

 

he did ask for n/a, but that is going to require custom intake and exhaust as well as IDAs and suitable ECU in conjunction with a semi PP or PP.

 

minumum you need a header, and an ecu. it would be nice to open the engine up and put in the 9.7 rotors. higher oil pressure is good too. the stock intake isn't that great NA, but anything else needs to be custom.

 

Well i been researching for about a month i know the basics.

1. ECU - Micro Tech LT-16
2. Exhaust: Mazdatrix exhaust flange custome down pipe and a nice quite exhaust with resonator.
3. ITB's for intake (need help in this area found one at tweekits site not sure how good it is though)
4. If compression is good keep engine internals stock. If not rebuild with 9.7 rotors and street ports)
5. T2 flywheel, exedy stage 2 clutch, t2 tranny, GXL rear end (may be a 1.5 or 2.0 kaaz lsd)

I need help one the tt to na conversion. Like i know t2 13b's have a hole in the rear rotor that channels engine oil to the turbo which needs to be sealed. Is there other stuff i need to know about the conversion process.

Thanks

 

this thread will give you a better idea what it will take and where the weakpoints will be in the setup while trying to shoot for a goal like 500 with a non turbo.

https://www.rx7club.com/build-threads-292/non-turbo-428rwhp-fd-build-up-history-937570/

it will wind up taking you years of development time and tens of thousands of dollars invested so be prepared. natey is correct in that it is much more simple and less of a headache with forced induction, but nothing beats the sound of a healthy n/a 20b in my opinion. hearing a car with an F1 tone to it on the street any car enthusiast would have to look.

 

You can run N/A by scraping the turbos off, capping off the various fluid feeds/returns, and mounting a header.

IIRC, that configuration is worth about 250 crank horsepower.

 

My goal is 300 whp for now

 

then you need to replace/modify the stock intake manifold

 

That debatable per application though.

 

first question.

why do you want it to be na?

300whp is possible with the stock twins.

keeping the engine on the stock twins will save you buckets of money

any turbo application will probably be cheaper than the n/a setup

i sure do love the sound of na 20b though

 

simple, i love n/a and i really love n/a rotaries

 

Replacing the stock intake isn't necessary. Logan has already proved that a stock intake with shortened LIM, 9.7 rotors, nice designed header, and good port will make 350rwhp. You can make some really good power with a 20b keeping it simple.

Keeping the LIM at stock height will lower the torque curve and create more power down low.

 

yes but whats the point if later on you want to increase those figures?

go PP or forget it.

 

i kind of agree, the only penalty to the PP is noise, and the 3 rotor won't be as bad, because it sounds GOOD.

the only real problem is that the PP is 450hp, which might be too much.

 

can always detune it but it does defeat the purpose of having that upper powerband of a motor.

i guess i just have a hard time envisioning it being side ported to meet the 350 demand to only be later on torn down and go in a completely different direction in order to gain the extra power that he will eventually want.

if shooting for a lower power level i never recommend building an engine based off a simplistic design that has to be completely reworked later.

 

if o-p. is planning something think about this ,, on the semi-p-port set -up ,, the semi-p port connect them to the secondary runners, instead of running itbs for the p-ports,, and regular large street port and exhaust port, port the intake manifold for velocity.

its just my opinion,ijs

 

I look at it this way. The OP doesn't have much knowledge on the subject. So why give him advice that takes him to the top so fast? To me that's ike being in elementury school and all of a sudden your in college. At some point it's good to learn the in between stuff.

If he's got the money and can deal with all the noise a PP will make then be my quess. I've experimented my self with PP's and as nice as they are, I couldn't live with the noise on a daily bases.

 

I totally agree with you

 

then go PP! the only downside is noise... and make sure you get the 1990+ port spec, or smaller. there is an SAE paper, 900032? where mazda optimized the port timing and intake lengths, the OLD spec was 450hp on a 3 rotor, new spec is +15%. the ports got smaller too, with less overlap, so it should street better

 

^The ports actually got BIGGER, but the timing was reduced. Placing the port higher puts the port in the curvature of the rotor housing. Less timing still nets a larger diameter, strangely.