ok I Got a 87 mazda RX7 SE . it has PS and A/C . I want to make it a Street car That I can drive around all the time . I dont want crazy power but I want to be able to move when I want it to . I never did an N/A setup before so Need some help this is a Fuel Injected 6port motor. I know Im going to do a Bridgeport and a Full Racing Beat headers and exaust. and I work with Microtechs so Im going to use one of them. but what should I do with ..

Injectors.
intake.
rotors.
Flywheel.
just tell me what you guys think need some N/A help Thanks ...... Tony

 

I would junk the 6 port irons and get a set of good Cosmo or fd irons either steetport or bridgeport them.

 

the 4 port bridge route is time proven. a holley, or staged 4 barrel EFI would work really well.

exhaust is tricky, the BP wants something very freeflow, which is usually also very loud.

injectors; the stock NA injectors might be just about enough for a BP, worst case you could do 4x550...

rotors, ideally you want the 9.7's from the 89-91 na's. although the 9.4's are fine. you loose a little tq down low.

flywheel; IMO as light as you can stand on the street. i think the RB steel flywheel is what the car should have had from the factory, the aluminum is more race car, but still streetable

 

First off let's hear what your honest real world budget is. Then it would be easier to advise. My personal opinion is that if you want a smooth driving street car that you should stay with a street port. Too many people think that by jumping to a larger more aggressive porting style that they'll be faster but if you haven't changed everything about the intake, exhaust, and ecu, the exact opposite may be true.

 

Ayup. My half bridge makes less horsepower than an IT 6-port, which is by definition a stock port. My intake manifold is the typical peejay 5 pounds of JB Weld abomination - it's a Series 4 N/A intake modified to mate up properly to the Turbo II block. I really wanted those long intake runners.

On the other hand, it makes more low- and mid-range torque than any stock or street port 13B that I've ever seen. Which is all that I care about. Horsepower at 8000rpm means nothing if you're coming out of the corner at 3000-4000rpm. (And the N/A intake manifold makes more power everywhere than the TII manifold did - food for thought for people who adapt TII manifold to N/A engines!)

On the other other hand, it's not as street drivable. There are some things you just can't do. Even with EFI, you can't cruise below 35mph. Accelerate and neutral, accelerate and neutral. Not enough load on the engine to keep it from bucking. I accept this, other people find it maddening. "You mean I can't drive at light throttle and shift at 4000?" No, you have to drive at heavy throttle and shift at 2200, or it will buck and destroy the drivetrain. High overlap engines need to be loaded down to be happy.

Plus, a stock car is much faster on the street, because you can use full power on the street without attracting every police officer within 5 miles. My car is fairly quiet on the street for what it is, but I also drive it really conservatively. I probably never see over 5000rpm on the street, it's too socially irresponsible. I went for a drive in mazdaverx7's factory-stock GSL-SE and was amazed at how FAST it was compared to mine. Because it was smooth everywhere, and was quiet, and he could use full power and the loudest sounds the car made were the fan and some transmission and differential whine. His car at full throttle is about like mine at 40mph cruise. (A bone stock, 100% original-and-good-shape RX-7 is a very quiet car!) That's true street power.

Maybe it's just a sign of me getting old. When I was 18, my daily driver was a 429-engined Ford whose exhaust system consisted of foot-long pipe stubs on the exhaust manifolds. It was fun then, not so much anymore.

 

yea nice advice thanks. but im looking for a street setup I can use as my DD to and from school and work but I want it to sound good but want it quite lol hard to say. And I want it a little faster then stock . This was my plan Doing the Rebuild And Porting the 6port 13B . Putting some 550cc injectors RacingBeat Headers & Full exaust,a lightwight Flywheel , act cluch, .That was the setup I was thinking of before I want to spend Like maybe 2500 to 3000 maybe on parts . and like I said Im not used to N/As and dont know if that setup would be good for me or if Im just going to have Problums wit it

 

i agree, with the getting old part! i just drove the PP to the gas station, and its not loud IN the car (in fact you can now hear a bad axle bearing, something that you couldn't with the stock engine...) but you can hear the reverberation off, um everything concrete.... its still too loud OUTSIDE the car.

the PP generally is like your BP, but tamer, surprisingly so.

i think my other experiment worked too, i covered the car in ridiculous stickers, and nobody notices it....

 

SEP field works again!

 

look at this thread couple months ago he did a cosmo enigine stock internals just large street port and 2in cut off the lower intake manifold ,,,,,thought but it can be uptain with a turbo2 block with 91 n/a rotating mass and a rew intake manifolds and with a powerfc instead of haltech


read the whole thread to understand what he did
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/gtus-resurection-project-844957/

 

what kind of power levels would I be looking at with a setup like this

 

I don't really get caught up in the numbers game and I think too many put too much emphasis on knowing an actual number on paper and then deciding that it is or isn't going to be good enough. Your car made 146 hp at the crank bone stock when new. It should have been around 115 hp at the wheels. Give or take a few. Let's say you do a street port to it, get it tuned, add a light flywheel (which I personally love!) to change the driving characteristics and feel of the car. What if this gets you 185 hp at the wheels? Would you be happy with 70 more usable horsepower and still have the ability to keep it quiet and quite easy to drive? That's about a 50% gain in power. That's how you should look at it.

I wouldn't alter intake manifold lengths or go too crazy on porting. Stick to a mild street port. Please resist the urge to do a bridgeport on those housings with that intake manifold. It'll be a disaster. Don't even be tempted to try the ill-fated bridgeport on the auxiliary ports only either. Everyone fails at it because they don't work well.

You'll be surprised at how fast you'll blow through that $2500-$3000 budget. I would personally do porting as the very LAST mod. Do everything else first. Get that flywheel. Upgrade the ignition. Do the full exhaust. Get the ecu control and get it tuned. You'll be surprised at just how much more you'll get out of doing all of those things first. If you don't have all of these things in place up front, there isn't much point in getting it ported. You won't be utilizing it to it's full potential and never build an engine with "room to grow". In other words, never port an engine around what mods are on your wish list. Port the engine around what mods you've already done. This way you'll do it once and be happy rather than being unhappy and doing it over and over again. See what happens to a budget if you do it this way!

 

Rotarygod : great advice thanks lot sounds great thanks

 

it does!

 

+ 1

 

Would a CDI add any benefits for an N/A? I know it's good for turbo applications but it should be helpful on an N/A?