mr.12a

how much power can i get just with a 12a n/a and what parts should i get for it. or should i just go boost.

BridgePorted12A

iTrader: (6)

what mods are on the car now? Stock? W/ a bridgeported 12a, you could get 180 rwhp+ depending on the carb, port job, ignition, etc. It all depends on what the car is going to be used for. I am sure you could get 200-250 hp @ the flywheel if properly setup w/ a NA 12a. Anyone else want to chime in?

Rogue_Wulff

The wilder you go with porting, the more the power will increase. Driveability decreases at the same rate as the power increases. Durability also decreases, since the larger the port job, the higher the RPM range the engine will need, in order to take advantage of those ports.
The driveability goes down due to the higher idle RPM required, and the fact that the engine will lose low RPM power, making it less street-freindly.

t_g_farrell

iTrader: (1)

Without cracking the engine open you can ~150 bhp. That would require at minimum headers with a non-restrictive tuned exhaust setup, a carb that flows more than the stock nikki (webber, sterling) and an otherwise well tuned engine ( good wires, plugs, cap, and rotor) and removal of the rats nest along with any belt driven acc. you don't need ( air pump, air conditioning).

mr.12a

thanks people you been really helpful i really appreciate it......wats a rats nest?......pleaz keep coming wit as much info as u think i need

trochoid

iTrader: (6)

Peruse the FAQ sticky at the beginning of the 1st gen forum. That will give you a basic tro to the 7, mods and troubleshooting. Then maybe you will be ready for the 11's.

No_Rotor_RX7

if you want a street driven high power 12a it's not going to come in the form of N/A. either boost it or do an engine swap. you will spend so much money on doing a bridgeport and the junk that goes with making that work reliably and you'll still run 13's in the 1/4. not saying that's slow by any means, but ... well yes i am. just boost the sucker and run 12's for half the price.

years ago when i tried my best to get power out of a stock port 12a i reached an almighty 113 rwhp. that was with my own setup holley 600, rb intake, msd ignition, rb streetport header, full 2.5" exhaust with straight thru muffler (if you could call it a muffler), etc.... get my drift? that's alot of money for nothing.

just seriously pick a goal for this car and do research and go from there. pretty much the best way to get street friendly power from a rotary is boost. mazda realized this and so will you hahaha

FCKing1995

iTrader: (3)

If your going for a quick, not fast, daily driver thats fun to drive and still gets good gas milage and is easy to drive. stock porting on a 12a is terrible, so a good street porting would do wonders for power. i never really realised how small the stock port on a 12a is (exhaust anyway)

No_Rotor_RX7

yea, the stock exhaust port size is insanely retarded. its stupid how small they are and they are the main reason the 12a doesn't make as much power as it could when you just slap a turbo on there. even if you didn't touch the intake ports and just hogged out the exhaust ports a ton you would make a massive increase in power under the same boosted situation coming from stock ports.

blwfly

iTrader: (4)

building a really good n/a 12a with porting of choice can allways be boosted later

Nicholas P.

iTrader: (1)

First , get the engine into good shape. tuneup. second, realize that without thousends of dollars, its not going to go to the 13's. Third, Just get the basic setup, Streetport,(option)
Racingbeat exhaust(manditory), and A really good carb. Jose said Holly carbs are good, and hes a rotary mechanic, so Ill go with what he sias.

Nicholas P.

iTrader: (1)

Take a wheel , and spin it.

Take a smaller wheel and spin it.

Which one is easier to spin, and which one Is easier to push.

FCKing1995

iTrader: (3)

not to hog the thread, but i have a 12a n/a port issue. the guy who installed my mikuni carb before i bought the car jetted it way too large for stock port, it runs rich under all situations, though most of it might just be the lack of fpr. do you think the large street port i plan on doing soon will help compinsate for such huge jets on the carb? seems like a commen sense thing, but im just seeing what others think, incase im not thinking clearly

Nicholas P.

iTrader: (1)

yes it will, but beware of the driving range.

trochoid

iTrader: (6)

First, get an fpr and gauge, set the the psi at 4.5. The jets may not be too big, there is no way of knowing without the correct fuel pressure and what size jets you have.

Common sense? Sure, I would tear down, rebuild and port a motor just because I thought the jets were too big. I mean, jets are what, 7 bucks a piece and a full rebuild and port is 12-1500+. Not trying to be a smart ***, but I find your statement rather ironic. lol

You need a solid foundation on which to build a house, same with modding the engine. Take care of the basics, get the carb tuned/jetted correctly first, then when you rebuild and port, you will have a base/experience to work from to re-tune the carb for the larger porting.

FCKing1995

iTrader: (3)

well i was planning on streetporting and rebuilding anyway, just asking if once i get done with this will it be better off. not like im gonna rebuild and port an engine for the reason of fixing a jetting problem lol... and i know the jets are too big because the jets that are in it now are a good bit larger than the stock mikuni jets, he has the carb built to run streetport, so im guessing itll run better once it really is streetported.

and woukldnt it be smarter to streetport it FIRST, THEN tune the carb? but yea, im not completely retarded, i can do a little lol

trochoid

iTrader: (6)

I know, I found the 'common sense' term usage a little odd so I had to poke at it a little bit. As far as the jets being right when the porting is done, there are too many variables. Slight differences in port size/configuration, exhaust set up, which brand of headers and mufflers, long or short primaries, altitude, temperature, barometric pressure for the day, humidity, etc., all affect the afrs to some degree. Those factors can make tuning a carb frustrating, time consuming and jet cost can add up. I have a wideband to tune with, now I need a jet kit for the Mikunis. Lack of jets is why mine is not tuned optimally.

I do try to add some humor to my posts, since you're not cursing at me, I guess it came across as intended.

Ishi Kashigawa

Funny thing I have a full bridge port 12a N/A, but i'm still running the stock carb and stock fuel pump. With a 2 inch Exhaust and a cat on it. To a flowmaster muffler. To top that off I also have a Tokico Suspension system on my car. All this I got when I bought the Car for only $1,500. I don't think that was a bad deal. Does anyone know how much more power the engine can probly make if the Fuel pump, Carb, and Exhaust system were up graded. Right now it stops making power at around 7250 rpm. My friend has a smaller street port than I do and the rest of his systems are upgraded and pulls to about 11000 rpm. At that point who much more should the fuel system be upgraded? I was thinking about making the exaust a 3 inch off the headers and all the way back to a three inch bullet muffler from dynomax. Any one have any ideas.

trochoid

iTrader: (6)

I have a 1/2 bp, just recently ran a full 3" exhaust. Fighting a fuel pump leak atm and haven't had a chance to do any tuning with the new exhaust. On your set up, I'd be suprised if it even ran much faster than a stock engine. Carb is way to small and the stock exhaust is choking it to death. With the overlap a bp has, your fuel charge is hot and very dirty with exhaust.

Headers, with at least a 2-1/2. preferably 3" exhaust and a 48/51 mm Weber will bring it to life. I don't know if Carl and Sterling are modding the Nikkis for a full bridge yet, but that may be another option.

Are you sure it's a full bridge? I cannot see someone building a full bridge, then re-installing the stock intake and exhaust. Those are the 1st mods on a stock engine.

FCKing1995

iTrader: (3)

well im not really looking for world class, racecar tuning, just a good enough street tuned 12a. the jets will probably be close enough for me, and if not can laways buy an entire set of jets in all different sizes for probably less than 20 bucks and try em all out till i get the right ones.

Ishi Kashigawa

well I bought the car from the guy after he bent the front right lower control arm. He said he just did some work to the engine not too long ago, but ran out of money to finish the rest of the car. He said he got bored and wanted to get rid of it. So I bought it.