300 Horse goal on a 12A
 

That is my ultimate goal, unless I can squeeze 325Hp

My clutch went out so nows probally the time for me to do all this major work. I want to go with a 12A cause it seems EVERYONE has a 13b Turbo, nothing wrong with that, but who builds up a 12A?

So far I dont have too much of an exact plans, Im just floating around Ideas right now So heres what Im considering

Boraz racing clutch $329 www.rx7.com
P-Port with Weber (more power than Holley it seems) 52 IDA Or perhaps other porting with a supercharger (Thats like $2500)
I was wondering if a Pacesetter 2.5" Header is a good way to go?
Hi flo or no cat / muffler.
MSD Ignition
2 Blaster Coils
Alum. Flywheel
LSD rearend
Larger brass radiator
better pumps, steel hoses
IT said that a 2mm APEX seal was just fine for up to 300 horse, so perhaps a 3MM would be wise?

Also does anyone know if a Miata Tranny will bolt to a 12a???

Let me know any info you have!

Thanks

12AT. not pacesetter, get RB header. Hopefully FBII will chime in with his hp number.

you cant use rb with 12at. talk to rene.

12A is already 3mm apex seals..

I am the crew chief for this car:
http://www.waterfordhills.com/gallery/ehr4y057.jpg

It's a GT2 first gen RX7. It puts out 220 RWHP with a bridgeport and 48 Webers. 300 hp should be no problem.

It is awesome to watch Kurt drive this car around the track, he smokes all of the 500+ horsepower v8's.

Kurt also owns this car:
http://www.waterfordhills.com/gallery/jwr6y0525.jpg
A 550 horsepower v8 Monte Carlo. Thats me holding the flag.


Anywho, GOODLUCK! all it takes is money.

12a... got questions? e-mail me or call me....... 300 hp is just the begining of the potential of a 12a...:)

robert@rotaryshack.com

Japan had some Turbo 1st gens. Not sure if it was 13B or 12A. Can someone confrim which one?

yes japan did have Turbo 1st gens it was their SE model for japan and they were 12A was equiped with a small turbo and low boost so no need for a intercooler, and it was fuel injected. someone correct me if im wrong!

Lol, if you think you can rebuild a 12a for high power, P-Port it AND put an intake on it for $2500 you're seriously misinformed.

You can barely rebuild a stock 12a for that price.

If you want a reliable 300hp 12a, you're gonna need a HELL of a lot more money than that.

Add to that the transmission and rear end replacements you'll need in order to handle that kind of power.

How much money do you want to put forth for this project? I think it's a lot bigger than you realize.

Jon

Welcome to the forum. :) Thats a lofty but noble goal if you plan to try to do it N/A. If thats your direction, tell us. I think everyone is alreay assuming your going forced induction. I dont think a Miata trans will bolt on, but the guts can be used in a FB tranny.

Devil is right, your already at 3mm on the seals.

Ggerg is right. Anything is possible with enough $$$. And Kurt Christies car has always impressed me as a really well built car, even though Ive only seen it on the net. LOL, I smoked a few of those rental GT1 Montes at drivers school in my IT7 car. :rlaugh: :D

Not true, you can get alot for $2500 if you do the work yourself.

TO do it N/A yes, thats a tall order.

I think from my readings that 300hp is about the limit on the stock drivetrain so thats on the edge but not out of the question.

Thats the biggest truth. Its a big money project for sure. And if you wanna talk about how to get there we can do that. But it wont be pretty or cheap. ;)

Thanks for your replies!
Its good to know that 300hp is realistic out of a 12A even if its not cheap. I was not clear earlier about the supercharger for the 12a, what I meant to say was that the supercharger alone is $2500, if thats the route to go.
I want to try to stay away from putting in a turbo, but if thats the best way to make a decently reliable 12A then so be it. The turbo will be my last resort.
Making this kind of motor will definately require an engine rebuild. I read that the 2MM apex seals atvantages over the 3MM are that they last a little longer, little better milage and so on. The disadvantage is that they can only handle up to about 300hp so Id be running them at their limit, which would suggest new 3MM seals would be the right choice.
Also I plan to do all the work my self, and customize any/everything that needs it. If I had the means to forge my own parts I would.
The use for this car will be a daily or semi-daily driver. I know that a PPort for this is insane cause it lasts what about 6000 miles before needing more work? So then it seems going with a bridge might be better. Or what http://www.mazdarotary.net/porting.htm calls an extended port, and working with the extended port to boost power to 300 and beyond...

Off the topic, can you pull off most the rats nest and have the car still run ok on a stock 12A? I havent had time to search for the 'proper emmisions removal forum'

Thanks

One more thing. Ive heard that turbocharging a carburated car is something to avoid because "...The sealing of the intake is imperative to success, the pairing of a turbo a carb guarantees a long painful learning curve, especially if high boost levels are desired" Which would mean that the turbo lag with a carb would be very bad. I want to avoid lag all together, since the rotarys hurt for low end torque to begin with. I dont need tons of boost, just enough to get 300 horses.
But to get 300 at the wheel, Id probally need 360 at the flywheel to factor in a 20% drivetrain loss. The more the merrier, but My goals 300 right now, I can always worry about an additional 60 later.
Does anyone have a wonderfully running carburated, turbo 12A ?

Mazda did not go to the 2mm apex seals until 86. All 1st gens, 12a or 13b are 3mm. If you are not going turbo, the best header out the is the SDJ, pricey, but proven to produce more hp than any other.

If you choose to go turbo, you can easily get 300 with the right turbo and tuning and a large street port. Motor will last longer than a bridge or pp. For streetability and reliabilty, less tuning, concider going FI instead of carb. Not trying to start a fight here, but, depending on how much time one wants to spend retuning, FI is easier in the long run, even though it may take more investment in the begining.

If you are worried about the car running ok, you should not even consider thinking about just maybe going P.Port :D

300hp is possible with a peripheral port, but you need a few essential parts to make it reliable.
You will need race bearings, hardened stationary gears, upgraded oil pump, higher rate oil pressure regulator, a good oilcooler and probably a few more parts that i forgot.

You should be able to pull it off at a fair price if you can do all the machining yourself.
Thanks for reading up on the subject before posting, many a n00b could learn from this :D

Best of luck
-Kim

Thanks again.
UPDATE: I Just found a 12a with Tranny for $500 - 45k on both in great shape - Awesome deal!
While Im considering that, Im definately getting a new hood to cut, And a Holley 650cfm
He said hed sell the Holley with a RB header for $150 \m/ $650 for all of this is a killer deal!! My 12A has 148k on it now, and the 2nd gear syncro is getting harder and harder to shift into. So rather than macining all of the housing and stuff on my motor, Ill get the 45k motor and tranny, rather than run into more expense later. And put all the racing springs, seals, rings, everything into this new(er) motor. Im going to stand by on the RB header for now and research the SDJ header first.
As far as fuel injection, your right, it would be quite the task to set up initially. If I go with F.I. Itll be in the future. It seems like opening up the ports and putting a Holley on with a header is insane performance! Apparantly Weber and Edelbrock have basically turned into the same carburator nowadays. Im told that you can do so much more tuning with a holley carb than anything else, eg, change air/fuel ratio easier, swap out the jets, set a certain rpm to open up the secondaries fully, ect ect. Plus the venturies are much better. So it looks like I was wrong about the Webers. Or perhaps that the Weber 52IDA was the best carb specifically for a P-Port.
Im going to get a chevy Cowl Induction Scoop, and scribe it to the new hood and cut that out, so it cools the whole engine by having so much more room to flow through than only the intake charge. :)
Also the LSD Diffs I just learned are remarkable! Posi for hard acceleration, and then it adjusts for hard cornering or normal cornering, its not in any one mode full time and can handle upwards of 450HP! Impressive! Wooo Go Mazda design team!
I am kind of skeptical but I hear you can run under a 12 sec 1/4 mile with as little as 250 hp!! If thats real, gotta love these RX7s!!

Thanks again.
UPDATE: I Just found a 12a with Tranny for $500 - 45k on both in great shape - Awesome deal!
While Im considering that, Im definately getting a new hood to cut, And a Holley 650cfm
He said hed sell the Holley with a RB header for $150 \m/ $650 for all of this is a killer deal!! My 12A has 148k on it now, and the 2nd gear syncro is getting harder and harder to shift into. So rather than macining all of the housing and stuff on my motor, Ill get the 45k motor and tranny, rather than run into more expense later. And put all the racing springs, seals, rings, everything into this new(er) motor. Im going to stand by on the RB header for now and research the SDJ header first.
As far as fuel injection, your right, it would be quite the task to set up initially. If I go with F.I. Itll be in the future. It seems like opening up the ports and putting a Holley on with a header is insane performance! Apparantly Weber and Edelbrock have basically turned into the same carburator nowadays. Im told that you can do so much more tuning with a holley carb than anything else, eg, change air/fuel ratio easier, swap out the jets, set a certain rpm to open up the secondaries fully, ect ect. Plus the venturies are much better. So it looks like I was wrong about the Webers. Or perhaps that the Weber 52IDA was the best carb specifically for a P-Port.
Im going to get a chevy Cowl Induction Scoop, and scribe it to the new hood and cut that out, so it cools the whole engine by having so much more room to flow through than only the intake charge.
Also the LSD Diffs I just learned are remarkable! Posi for hard acceleration, and then it adjusts for hard cornering or normal cornering, its not in any one mode full time and can handle upwards of 450HP! Impressive! Wooo Go Mazda design team!
I am kind of skeptical but I hear you can run under a 12 sec 1/4 mile with as little as 250 hp!! If thats real, gotta love these RX7s!!

Sound's like you got some good plans. I plan on getting mine to about 200-250, anywhere in there and I'm happy, I just wanna stay N/A. Don't really need much to get moving with these. As for the rats nest there is a link to a write up in the 1st gen faq page but I think I have the link on my bookmarks. one sec................................ http://www.ten15.net/Maz.tutorials/ ......ahh there we go. Thats a great write up from a couple of the guys on this forum. If you look in the right places there is tons of info here. There is a guy on here goes by FB II he built a FB with a turbo/carb setup. I think he is pushing about 250, thats what it says on his cars page. Anyway good luck with the project.

Fred

Just a thought - everyone keeps going on about you need uprated blah-blah, and hardened lah-de-dah to run a PP........


But what about if you limit the rpm's to around 7000-ish? Negating the need for mega-bucks parts to cope with high rpms



And another Q, would a semi-PP (uses the side ports as well a small PP, just so you know Slayerx7) be better than a full PP at those kinda restricted rpms?

Running the motor to only 7000 rpm makes no sense on a P.port motor
They usually make their power between 5-& 10000 and would leave you with a very short powerband.
Streetable yes but thats all about preference, if it runs - i will drive it :D
Peripheral motors likes unrestricted exhaust system, my guess is around 105db and up - not funny at all.

Is there any paticular reason your staying away from a Turbo besides the whole carb. seal thing you read? You REALLY need to talk to 680RWHP12A and FB II. Search FB II under members, and make sure you search for posts started by him.

I guess the decision is up to you, but as far as drivability is concerned, his setup is the way to go.

~Chris

So kim, any idea if a semi-PP would have a more suitable powerband?


might as well ask, since I'm considering doing this at some point in the future anyway :wink:

I have no idea.
All I know is that it either requires for you to make your own manifold or find one for sale $$$$$.

Id give it more boost :D its the solution for most problems ha ha

Dude, go w/ a turbo setup, use the nikki you already have and get a manifold from Rene and a carb hat from rotaryshack. Use a stock second gen turbo. Setup is super easy. I had my downpipe made custom for like 60 bucks at a local muffler shop. Beef up fuel pump and get a wideband air/fuel meter. FBII did my whole setup, drivability is better than the Holley that I had on there, plus the car hauls A$$. Even if you open the ports, put that Holley on there and a header, i doubt you'll ever hit 200 to the wheels on a streetport.

I have a home built 12a BP. (small bridge)
Was running Holleys 456 & 650 DP. best HP was only 140 RW.
Switched to SDS. fuel injection 204 RWHP @ 8000rpm I run to 9000 on the street.
What about a little NOS on a street port??

Looks like this is going to be more tricky than 1st anticipated! Im starting with my Bonez racing clutch though:D

just do what you can to the stock 12a as is. (carb, exhaust, etc...) as this will get you to understand the car more, especially with the hassle of tuning a carb. you need to get down and dirty in there and see what works and what doesn't. this is the best way to learn what will be better down the road when you start getting in to real power.

Kim - these are the joys of owning a welder, and having a few metalworking tools (angle grinder, sabresaw, worktop mounted vice, and a benchtop mounted grinder)

anything's possible if you dont mind spending a bit of time thinking it over!



and I STILL think that an SU carb is the way forwards - you can adjust the mixture with only a screwdriver, and a bit of emery paper (or about $10 for a new needle if you dont want to have to modify the existing one)

If anyone wants to convert - there's plenty of info online on how to tune SU carbs. Some are complete rubbish though, and they try to tell you to swap the dashpot spring for another one (REALLY not needed!)



plus - there's a turbo verison available, which is sealed, and can cope with over 20psi of boost (like my friends one does!) :wink:

sheesh! this is alot of info.

in essence - not really


1) bigger/better carb
2) bigger/better inlet (including some form of porting)
3) bigger/better exhaust (including headers + some porting)


and that's pretty much all there is to N/A tuning!

Ok heres another update -
FBII has given me a new mission in life, heres what Im going to do. Im going to rebuild my 12A with racing components and an extemded port with a 60-1 turbo. At about 15 or more PSI this could hopefully hit 400HP and have NO LAG after 2000rpm.
Today I bought a Holley 650 with vacuum secondaries, a new hood to cut for a chevy cowl induction scoop, and 4 lowering springs for just $150!! For now that is. I may have to get some higher rate springs at the stock length to fit 16 to 18 " rims, Im thinking 215/35zr16 - 18 would be a great way to go for wheels.
My new goal is to be able to hit high speeds, like 160+ mph Vroooooooooooooooooooommmmm
Ill need some great body kit for that though!!
If I can find an intake manifold for my Holley (hopefully with an extended port) then bolting a 60-1 turbo up to the Holley.. :-D

sounds nice.

I think for my second rex I'm just going to start with TII swap

Look what I found:)


1979 198?+
Ratios: 1st 3.674 3.622
2nd 2.217 2.186
3rd 1.432 1.419
4th 1.000 1.000
5th 0.825 0.758 SE: 0.807
Reverse 3.542 3.493

AND

RX7 Stock Rear Axle Ratios
Year/Model Ratio Year/Model Ratio
79-85 3.909 86-88 Automatic 3.909
83-84 12a 3.933 89-92 Turbo 4.10
84-85 13b GSLSE 4.076 89-92 Non-Turbo/Non LSD 4.10
85 12a 3.909 89-92 Non-Turbo Viscous LSD 4.30
86-88 5-speed
Turbo & Non Turbo 4.10 93-95 Manual Trans 4.10
93-95 Automatic 3.909

dood take a look at the 12a turbo on www.rotaryshack.com that thing is pure SEX

If anyone has a spare Holley to 12A manifold, please let me know:)

Is 300hp from a 12A realistic?

The works 12A with PP in 1980 could only put out 280-300 hp. So it can be done with a lot of money and short engine life if you keep to NA.

Adding a turbo and efi will get you 300hp. However remember a 13BT in stock trim only gives you 180-250hp. It is possible to upgrade everything to give you a twice that but the cost does up geometrically as does fuel consumption and maintenance costs.

As far as the 12A is concerned, the best route is get a Jsec12AT, rebuild, add a large turbo and two extra injectors. Fit a TII tranny, 13B rear end, heavy duty clutgh, large FMIC. Add the usual bolt-on upgrades to the exhaust and fuel systems, plus suspension, wheels, tires and brakes. For a street car with noise and emmission limitations you can get a reliable car with 300 hp at 12 lbs boost. This is what I have, anything more creates handling problems, the front gets too light above 150mph, and the backend develops a life of its own. You can end up drifting in normal traffic.Fuel consumption would be around 10mpg at 300hp falling to 5mpg at 400hp- assuming you use the power available!. An indication of cost would be $12-15,000. for a well prepared 300hp car.

A good reflection of the way costs go up with power is to look at the different versions of the Mitsubisih Lancer. The top 'off the floor; version produces 400hp which for a 2 litre 4door sedan is real performance. Some rice products are great cars, but I still happy with my 20 year old rotary inspite of its old technology.

Instead of a Turbo, I was wondering if anyone has tried bolting up a Paxton Procharger to their rotaries? I havent heard anything about that...
I can think that it would be better for a couple of reasons. 1)No Lag what so ever and 2)a little more power than a turbo@the same psi because there would be nothing restricting the exhaust gas flow (such as a turbine wheel)
Ill bet you could also hook up an intercooler to the procharger as well...
Why hasnt anyone tried this yet?
Only thing I can think of is that it might not boost as much as a turbo? But if itll boost 15-20PSI that would be perfect!

The answer is in the question.

Boost isn't everything. Ever heard of compressor efficiency?

prochargers don't have the amazing "boost off idle" response that eaton style's do. in fact, an ATI procharger is basically a belt driven turbo. it DOES LAG! see it all the time on the mustangs here. they're great tho, for them, because you can run an intercooler and can get some massive sized compressors and crank the boost. still not as efficient as a turbo lol. they build boost based on rpm pretty much. if you want 15psi from one, you may not see it till you're about to let out. for the weight and how complex it is to set up... it's just not worth it. Plus, they're expensive as nawlz

http://www.procharger.com/images/blue_camaro_uhbig.jpg

Ok, Maybe the procharger isnt the miracle device afterall heheh

Im aware that boost is only caused by resistance.... such as if you had say 10 psi because you have a small port, the port is causing most of that boost because of its restrictions... now if the port was say twice as large, youd only be flowing 5lbs of boost, but have 2x the volume of air! - much better. now if you had the same 10psi with 2x the air... oooooh yeahhhhh! So I was thinking having 15 or more lbs of boost with an extended port should really haul some ass!

It didnt seem like the prochargers were all that difficut, and I didnt think they would be that heavy, maybe the same weight as a turbo at worst. But if theyre not as efficient, and more expensive, those are 2 major points in favor of a turbo. But if say an Eaton Procharger has LESS lag than any turbo, and can flow the same amount of air with the same boost for the intake, then it might be worth looking into further correct?
Ill also admit though, I havent learned to read a turbo chart yet, looks like that may take about a half or full hour to understand?

Well Im off to Pull my tranny, put in the racing clutch, pop out the sleeves in the exhaust ports (I was told you can pop them right out) and install a new cd player w/ awesome speakers

Thanks again for all the info!! keep it coming!

Ok, so those sleeves dont just pop out.. I left them in. Got the new clutch in :) much quicker! So after I replace my tranny, Ill start the job for horsepower. So far heres my to do list:
650 Holley
RB Header (till I can find an SDJ)
Lowering springs (RB I think)

The quest for HP:
Extendport or Streetport, what do you think?
a 60-1 Turbo
Large intercooler
3mm racing Apex seals
New side housing seals!!
2nd gen water & oil pumps
A fuel pump to handle the massive holley


Does anyone know if theres a turbo header for rotary? Or will it bolt to the header itself? Ive heard its best if the turbo is as close as possible to the exhaust port

Rene at RX3mist.com can fab you up a equal length turbo manifold. I highly reccomend it, I got mine off of FB II.....

2nd gen oil pump isn't really necessay, and I don't think it will work anyway. If you want to upgrade, you can go with a GSL-SE unit, but a better idea would be to get a 2nd gen oil cooler and front mount it.

If your seriously considering going turbo, give Robert at Rotaryshack.com a call, he can give you all the details you need about turbo'ng your 12A, and whatever power goals you intend to reach. Also, teh archives has a write-up on turbo 12A stuff, serach for FB II's threads, and there are also a BUNCH of others guys here who can give you info. about turbo 12A stuff.

wow man, this reminds me of me when i was new to rotaries, you just read every little thing you can find on the internet and pick out all the best or whatever you know?
turbo setups are awesome and can be reliable. I am craving a built N/A like you but for
some other reasons, and lots of thought.

When you say 300hp 12a goal is realistic, no it's doable, not realistic. take lots of money and the right people building and tuning your motor. You might be able to skimp but it'll bite you in the butt, which is why when my turbo motor blew I'm spending more than $5k revamping the motor, cooling, intercooler and lots of nice stuff to support. I've been doing the same thing you're doing and just asking what works best and why cause I wanted to know. I learned more and more and its taken a while to realize how stupid I was before. Don't just rush into this with just barely enough money, you'll end up selling your 1/2 finished project car.
think it through. i like to get all the supporting parts that you can run w/ both cars. cooling, gauges, clutchs.
im done blabbing
-Ben Martin

Give robert at rotary shack a call, did wonders for my 12A.

Ive decided to save up a little more before attempting anything too major, probally something I wouldnt have done before coming to this forum!
I put my lowering springs in the front, and just installed my stereo :) That was tough, cause someone had done something to it before, so none of the wires were what the wiring diagram specified... e.g. red wire wasnt doing a thing, but the blue/green stripe was coming from the acc switch. Just glad I had a multimeter!

My car backfired REALLY loudly on the way to work the other day, and when I got the the Idle dropped from its usual 850 rpm to fluctuating between 3 & 400 rpms.. I was starting to think what could have happened, and fearing the worst, thought it may have put a hole in one of thr rotors.... but it acceleraties just fine over 1000 rpm, and when its at at 100% operating temperature, itll idle normal. However itll do the 3-400 rpm thing like up till 99% warmend up (operating temperature) so maybe its a colling issue? Also I realized, this is the 1st time I used regular gas, when Ive been using premium since I got the car in December.
Im basically just waiting til it or some seals blow so I can tear it down and port it then rebuilt it :)

Ok seems like Im the only one posting anymore, but hey why not. I just got my manifold and Holley, Im excited for my next day off to install it. I found an SDJ header, for $450 on ebay, brand new, killer deal eh? I also am getting a Streetported engine with carbon seals thats pretty new. By the way does anyone know someone who builds race 12A's in Boston? Apparantly thats who this motor came from.

Its probally been covered many times, and I will get my car dyno'd but does anyone know howmuch horsepower to expect from:

mild / large streetport
SDJ header
465cfm Holley intake
and a K&N filter

Im hoping for 200hp, and that should be good enough for a 13.5 1/4 mi. Im sure like 165hp is more realistic, but does anyone think 200 is out of reason?
Thanks

I have to admit, I've got zero idea on how much BHP it should make - but it should be satisfying enough for ya :wink:

But am I the only person on here, who thinks that $450 for a pair of bent tubes is close to extortionate?

My estimate is on a dyno you will get around 140-155hp depending on the porting, exhast system, and tune.

I should have specified between, BHP and RWHP
200BHP should be about 155 give or take RWHP, which seems ok to expect:)

I may be putting in the streetport motor as soon as tomorrow, If anyone at all knows, What are some precaautions to take when installing a Holley intake? Ive been swamped for time, so any help is appriciated!!!
Such as, if this motors timing is all out of whack, is it hard to time a rotary? I have the service manual, but thats all in reference to stock ports. Are there any tricks to timing a streetported motor?
It may be already perfectly set up, but I need to plan for the worse, as Ill have only 3days to get it running after I swap engines. Plus the more you know about engines the better!
Thanks!