vipernicus42

iTrader: (4)

hmm... that's a good point... I've got an 84GS, if my oil pump is just as big as an -SE's, it makes it easier for me. Add to that the fact that those with 79-82 oil pumps would have an easier time finding a bigger one

Jon

GtoRx7

iTrader: (5)

Racing beat says the oil pump is bigger in their catalogue (it may be an older catalogue). I bought the hardened aftermarket pump from Mazdatrix, who says that it is definately larger than the 12a pump.

GtoRx7

iTrader: (5)

If you only want 200 horsepower, you should be fine on the stock engine. 8-10 psi should yield around that much power. It is always a good idea to upgrade your oiling system, however. Remember, rotaries are 1/3 oil cooled, so the oil does much more than just lubricate.

1stgen_tn

Kewl

CarlRx7

i dont wana start anything. but it sounds like me to that you got sold. not that any of those mods aren't good.

i would like to see better intercooling. and oil cooling. and tuning. why are you detonating? find out why you are detonating first before you throw money at it.

my 12at will be done next month. and im hoping for 200 hp at 8-10 psi, and another 75hp with some no2.

carl.

how much did you spend?

shm21284

The detonation happened a long time ago on my very first engine, when i used the stock fuel pump on a drawthrough carbureted turbocharged engine. It was a stock rebuild. The fuel pump supported the power made by 12 psi of boost up to 140 mph just fine. One day I cranked the boost up to 18 psi (by accident, only wanted 15), and removed the baffled muffler, and ran a quarter mile. It detonated for the 2nd half. Since then, I have rebuilt the engine.

By the way, the oil cooling is a front mount, 79 style oil cooler. It's plenty for the power I plan on having.

The tuning was top notch. My friend is an experienced tuner, and owns a wideband O2 sensor. I have never detonated since the one time. The low compression only affected start up and low speed operation. The low compression was due to the lack of oil fed to the rotors, according to the experts at Racing Beat.

Coldy13 has gone through a few engines himself. I know that I am not the only person with this problem. He happened to have about 275 horsepower (felt like it by the seat of the pants) on his 12at, and now it suffers from low compression, but had fine compression before. Sounds like to me that there is a pattern with the higher output, turbocharged 12a's, not lack of tuning.

MarkPerez

thats right, 12a's, even 12aT are not designed for that much output, and live.
i'm sure with tons of money, time , and the know-how one can get a 12a to produce 300 HP and last for awhile. the more ponies produced the shorter the life span.

if a person had all the resources at hand one could build a ' frankin-rotor '
the engine has been around for awhile and people have tried to devolope the 12a, and some have to a point or as far as the design allows. thats when supercharging
starts but the 12a is still limited by it's tolerances for any forced induction(s)

CarlRx7

while your doing all of that stuff to your motor, send your oil cooler to these guys:

http://www.oil-cooler.com/

i heard its around 150 bucks and turnaround is a week. they flush it in hot solution for 24 hrs. straighten all the fins and give it a protective coating. heard nothing but good things from them.

a clean oil cooler will flow more oil and provide better cooling. =)

carl.

shm21284

cool thanks for the tip

mikey D

i disagree with alot of what is said.
a PROPERLY tuned Stock 12a should be able to turn out 250hp with no issues. 9.4:1 is only 1/2 a point higher than an s5 TII motor.
there are alot of 9.7:1 boosted 13bs out there making big power.

a properly sized intercooler and turbo will keep the temps down.
blow thru or TB injection also further reduces the intake temps.
a good air/air oil cooler wouldnt hurt. when your oil gets to hot it gets thinner which can harm lubrication. when to hot it the oil barrier protecting things breaks down.

the correct or slightly richer fuel mixture ration and properly set timing also affects the engine greatly. Setting your timing incorrectly adds a HUGE amount of heat to everything.

an NA stock port can make a max of about 150hp...200 hp isnt that much at all.
the stock 84-85 radiator is fine. Mine was tested in central cali on 110 degree days.

theres no reason to spend that kind of money on internal mods for anything under a 200WHP car.

GtoRx7

iTrader: (5)

Me and SHM21284 Have been messing with rotaries for a little while now. I'm a big 13B guy, and he is a big 12a guy. One mistake we keep doing was comparing the 12a to the 13B. I have made 400 horsepower out of my S5 13b and was perfectly dependable, only mods I had done was higher oil pressure and S6 staitionary gears and race rotor bearings. Its not the compression that is the problem.
As far as when talking about termal stress, its not that the temps are incorrect, its the same temps the 13b will see, more or less depending on setup. The point is that Mazda made HUGE changes beside the compression of the rotors, when going to 13B. I had all the luxury of a bigger oil pump, better staionary gears ect. The 12a needs to be UPDATED to handle even close to the same levels of power. Increased oil is a #1 issue, as it will transfer the heat away from the rotor faster, which is too much for a stock system after 200 flywheel horsepower. YOu show me a stock 12a boosting reliable power at 200 WHEEL horsepower for any length of time, you wont see it. If you look at each motor made from mazda, as power went up the things they did changed. Like the S6 motor, what is included STOCK
1) hardened stationary gears, 3 window bearings, 110psi Oil regulator, even BIGGER oil pump than S5, Race clearanced rotors, and dynamically balanced, and LARGER needle bearing. All just to handle a small 255 horsepower and 8500rpm Dependable at that. And they last about 70,000-100,000 miles. SO think about what mazda did, and simply update the poor underdeveloped 12a, to acheive similar dependable power. Its one of those things if you want to Half *** it, dont worry about it, and make throw away motors. If you want to do it right, it will cost you, period.

GtoRx7

iTrader: (5)

Oh yeah, 150-200 N/A power will have WAAAAY less heat than a turbo of similar output. Due to the increased torque the motor will have, and backpressure of the turbo in the way of the exhaust. Turbo engine will need more if you are racing on a track. The stock radiator is fine for quarter mile bursts, and then let cool for a little bit. Anything more than that, Aluminum is a must.

shm21284

I have noticed people like to build throw away engines, or say, "ah, you dont need that. It can do it without it." The simple fact is, the 12a is an old engine, with old technology, and needs upgrades to get it up to par with the the newer rotaries.

I dont understand why people keep referencing tuning issues. THere were no tuning issues, except that the tuning was perfect (actually a little on the rich side with an AFR of 10.8 at WOT). Obviously, someone is not reading slowly enough. I mentioned that I broke my rear cast plate on a previous engine due to stupidity. I beefed up that cast plate NOT because I wanted to make sure it would break under detonation (detonation will NEVER happen again). I bought the beefed up one to UPDATE the engine to the s5 strength, so it could handle close to 500 hp.

You say you have tested your stock radiator in so cal. OK, but what did your car have done to it? I recommend that you upgrade the radiator as a safety precaution. I never had issues with my stock radiator, but felt it would be professional and smart to upgrade it with more power.

I did say that the increases OIL COOLING was a necessity. The fact is, 12a's have a shitty oil system (the pump does not flow enough and the pressure is not high enough) for anything much above 200 horsepower. The oil coolers (the big ones, not the water to oil ones) were kick ***, but the pumps suck.

When I mentioned thermal load, I am not talking about the fact that the 12a would be OK with 8.5:1 or 9:1 rotors. I am saying that the 9.4:1 makes it worse for us; but more importantly, the more horsepower you make, the more heat you're putting out, period. The stock oiling system was designed for 100hp and not much more. I understand there are plenty of 9.7:1 turboed engines out there. These engines have much better oiling systems than our old 12a's.

It sucks that the 12a is a cheap engine to get ahold of, but when you are striving for big power, you HAVE to throw money at it, because there comes a line when the stock parts and systems are no longer sufficient. I haven't spent that much on my engine, and the really expensive stuff like the haltech and throttle body, not the oil pump and water pump and radiator. Those parts are easy to come by, and can be mounted with little pain.

REVHED

Have you ever considered water injection?

nimrodTT

With all the emphasis on the oil system, I'm surprised that oil jets weren't mentioned. BTW, your oil system should not be of a huge concern unless you plan to spend lots of time above 7k. Upgrade the pump, regulators, put jets in the eccentric, maybe throw a three-window or a grooved bearing out back, and you're good to go. Now if you were a road racer and spent all your time in the 8-11k region then you'll want to start seriously addressing oil system modifications, otherwise you are wasting your time and money. Just my opinion though.

bonus info: stock third gen oil regulators only cost about $20 at the dealer, no need for RB stuff - don't forget to shim the front regulator. And oil jets are cheaper from mazdaspeed than buying weber jets.

Directfreak

iTrader: (2)

I personally know 4 12A Turbo engines, 2 Blow through, 2 EFI, all producing well over 300hp on a daily basis.

2 of them have about 300 rwhp. (One Holley, and One Microtech)
One has about 350 (blow through), and the 4th produced 498rwhp at 32 PSI.(Haltech F9)

The 4th one normaly runs about 19PSI = 390 rwhp on
the street.

All of them have been running for over 3 years now in South Florida heat and humidity. 2 of those run 22 PSI every day.

Somebody doesn't know what they are doing with a Turbo Rotary, or is running into some other problem.

The 12A's appear to be more reliable than any 13B for boost, with the exception the S5 and S6 Turbo models.

CarlRx7

DF, are those stock 12a engines?

carl.

Gregs

^ i HIGHTLY doubt it.

12at

If you used the genuine 12a turbo engine from japan as a base it is just as good as a 13b. They have the high volume oil pump standard and the 8.5:1 rotors standard. The chrome on the housings is also of a much better quality than the N/A counterparts. My last 12a turbo engine produced 300 horsepower at the wheels and it lasted 30,000 miles before i broke my boost controller and it cracked the rear plate. If I hadn't got unlimited boost im sure the engine would still be running. My current engine produces 480 horsepower at the wheels and is going strong.

Putting boost into an old N/A 12a is asking for trouble without pulling it down anyway. Do it once properly and it will save you money in the long run.

shm21284

I agree with 12a turbo. I started out improperly and now have wasted money on rebuild kits when i could be enjoying my car. I am trying to help people build a 12at properly

Pele

iTrader: (28)

Where can one source the 74 12A rear plate?

Sudox_E

This thread is getting me worried.... I believe my setup could produce a decent amount of power. I'm using an s4 turbocharger that has been rebuilt and modified with turbonetics goodies, a large spearco intercooler, and a ported 12a. If I remember correctly, my engine builder used the 3rd gen corner seal springs, and I know something was done with the oil pump to increase pressure. Now it's looking like I need to focus more on oil cooling and possibly an upgraded radiator. Also, seems to be a lot of 12at guys posting in this thread, how much power should I expect out of my setup (it is carbed, weber 45 dcoe), assuming I'll be running around 14lbs of boost?

MarkPerez

i don't think anyone is saying it can't be done, of coarse it can. and maybe a few exceptions like in DF's case. or robert from rotory shack. this thread is some very good info on what to beef up for a 12a - HO (hi-output) turbo. the 3 window gears, 3rd gen corner springs, the rear iron (13b) and water pump/oil pumps. to me 30.000 miles is way to short but maybe more with care could last longer. something to think about and consider for those hot on turboing the 12a. we all agree upgrading the oiling system is a must, never heard about jets in the e-shaft. me, i would buy a moroso oil pan and plate to go with the upgraded pump/reg. more oil is good and it makes sense to match the turbo/innercooler combo to the output desired. IMO the 13bt IS the engine to use to play the game of,,,boost and live.

shm21284

You should expect around 275 engine horsepower with that setup. You need to upgrade your oil pump to the GSL-SE pump, as well as the pressure regulator to the 3rd gen style. The oil cooler needs to be the 79 style or GSL-SE style, preferably mounted up front. Your engine probably wont last that long if you dont pay close attention to the oil cooling, as it is almost identical to what Coldy 13 had and what i had when it was carbureted. Find out what oil system mods you had done to it and give me a PM, I can help if you want.

For that sort of power, you dont need to do any jetting on the eccentric shaft. When consulting Racing Beat, I found that you can get away without modding the E-shaft jets to about the 400 hp mark, on a STREET DRIVEN vehicle, not a race car. Of course, it never hurts to do this mod....

74 rear cast plates are hard as hell to find. I had to search for almost 6 months before i found some on ebay. Keep your eyes out! Try searching on the Rotary Pickup forums, I found that a useful source.

MarkPerez

i would say around 170- 200 horse power, maybe i'm way off. i do know my s4 t2 is 182 horse power stock engine. and for 182 it pulls pretty hard. 100 mph comes up fast for a big *** 2ed gen. it's also important to port the 12a so the turbo does something, for the engine to breath.